main.cpp

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin developers
// Copyright (c) 2014-2015 The Dash developers
// Copyright (c) 2015-2018 The KORE developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "main.h"
#include "addrman.h"
#include "alert.h"
#include "arith_uint256.h" // Legacy
#include "base58.h"
#include "blocksignature.h"
#include "chainparams.h"
#include "checkpoints.h"
#include "checkqueue.h"
#include "init.h"
#include "invalid.h"
#include "kernel.h"
#include "legacy/consensus/merkle.h"
#include "merkleblock.h"
#include "miner.h"
#include "net.h"
#include "pos.h" // Old from Kore, will be deprecated
#include "pow.h"
#include "txdb.h"
#include "txmempool.h"
#include "ui_interface.h"
#include "util.h"
#include "utilmoneystr.h"
#include "validationinterface.h"
#include "wallet.h"

#include <condition_variable>
#include <mutex>
#include <sstream>

#include <boost/algorithm/string/replace.hpp>
#include <boost/filesystem.hpp>
#include <boost/filesystem/fstream.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/thread.hpp>

using namespace boost;
using namespace std;

#if defined(NDEBUG)
#error "KORE cannot be compiled without assertions."
#endif

// 6 comes from OPCODE (1) + vch.size() (1) + BIGNUM size (4)
#define SCRIPT_OFFSET 6
// For Script size (BIGNUM/Uint256 size)
#define BIGNUM_SIZE 4
/**
 * Global state
 */

CCriticalSection cs_main;

BlockMap mapBlockIndex;
map<uint256, uint256> mapProofOfStake;
set<pair<COutPoint, unsigned int> > setStakeSeen;
map<unsigned int, unsigned int> mapHashedBlocks;
CChain chainActive;
CBlockIndex* pindexBestHeader = NULL;
int64_t nTimeBestReceived = 0;
std::mutex csBestBlock;
std::condition_variable cvBlockChange;
int nScriptCheckThreads = 0;
bool fImporting = false;
bool fReindex = false;
bool fTxIndex = true;
bool fHavePruned = false;            // Legacy
bool fPruneMode = false;             // Legacy
uint64_t nPruneTarget = 0;           // Legacy
bool fAddrIndex = false;             // Legacy
size_t nCoinCacheUsage = 5000 * 300; // Legacy
// TODO: Remove?
//bool fCheckpointsEnabled = DEFAULT_CHECKPOINTS_ENABLED; // Legacy
bool fRequireStandard = true;                                 // Legacy
unsigned int nBytesPerSigOp = DEFAULT_BYTES_PER_SIGOP_LEGACY; // Legacy
bool fIsBareMultisigStd = true;
bool fCheckBlockIndex = false;
bool fVerifyingBlocks = false;
unsigned int nCoinCacheSize = 5000;
bool fAlerts = DEFAULT_ALERTS;
bool fEnableReplacement = DEFAULT_ENABLE_REPLACEMENT; // Legacy

int nChainHeight = -1;
CMedianFilter<int> cPeerBlockCounts(5, 0);

int64_t nReserveBalance = 0;

/** Fees smaller than this (in uKORE) are considered zero fee (for relaying and mining)
 * We are ~100 times smaller then bitcoin now (2015-06-23), set minRelayTxFee only 10 times higher
 * so it's still 10 times lower comparing to bitcoin.
 */
CFeeRate minRelayTxFee = CFeeRate(10000);

CTxMemPool mempool(::minRelayTxFee);

struct COrphanTx {
    CTransaction tx;
    NodeId fromPeer;
};
map<uint256, COrphanTx> mapOrphanTransactions;
map<uint256, set<uint256> > mapOrphanTransactionsByPrev;
map<uint256, int64_t> mapRejectedBlocks;


void EraseOrphansFor(NodeId peer);

static void CheckBlockIndex();

/** Constant stuff for coinbase transactions we create: */
CScript COINBASE_FLAGS;

const string strMessageMagic = "Kore Signed Message:\n";

// Internal stuff
namespace
{
struct CBlockIndexWorkComparator {
    bool operator()(CBlockIndex* pa, CBlockIndex* pb) const
    {
        // First sort by most total work, ...
        if (pa->nChainWork > pb->nChainWork) return false;
        if (pa->nChainWork < pb->nChainWork) return true;

        // ... then by earliest time received, ...
        if (pa->nSequenceId < pb->nSequenceId) return false;
        if (pa->nSequenceId > pb->nSequenceId) return true;

        // Use pointer address as tie breaker (should only happen with blocks
        // loaded from disk, as those all have id 0).
        if (pa < pb) return false;
        if (pa > pb) return true;

        // Identical blocks.
        return false;
    }
};

CBlockIndex* pindexBestInvalid;

/**
     * The set of all CBlockIndex entries with BLOCK_VALID_TRANSACTIONS (for itself and all ancestors) and
     * as good as our current tip or better. Entries may be failed, though.
     */
set<CBlockIndex*, CBlockIndexWorkComparator> setBlockIndexCandidates;
/** Number of nodes with fSyncStarted. */
int nSyncStarted = 0;
/** All pairs A->B, where A (or one if its ancestors) misses transactions, but B has transactions. */
multimap<CBlockIndex*, CBlockIndex*> mapBlocksUnlinked;

CCriticalSection cs_LastBlockFile;
std::vector<CBlockFileInfo> vinfoBlockFile;
int nLastBlockFile = 0;
/** Global flag to indicate we should check to see if there are
     *  block/undo files that should be deleted.  Set on startup
     *  or if we allocate more file space when we're in prune mode
     */
bool fCheckForPruning = false; // Legacy

/**
     * Every received block is assigned a unique and increasing identifier, so we
     * know which one to give priority in case of a fork.
     */
CCriticalSection cs_nBlockSequenceId;
/** Blocks loaded from disk are assigned id 0, so start the counter at 1. */
uint32_t nBlockSequenceId = 1;

/**
     * Sources of received blocks, to be able to send them reject messages or ban
     * them, if processing happens afterwards. Protected by cs_main.
     */
map<uint256, NodeId> mapBlockSource;

/**
     * Filter for transactions that were recently rejected by
     * AcceptToMemoryPool. These are not rerequested until the chain tip
     * changes, at which point the entire filter is reset. Protected by
     * cs_main.
     *
     * Without this filter we'd be re-requesting txs from each of our peers,
     * increasing bandwidth consumption considerably. For instance, with 100
     * peers, half of which relay a tx we don't accept, that might be a 50x
     * bandwidth increase. A flooding attacker attempting to roll-over the
     * filter using minimum-sized, 60byte, transactions might manage to send
     * 1000/sec if we have fast peers, so we pick 120,000 to give our peers a
     * two minute window to send invs to us.
     *
     * Decreasing the false positive rate is fairly cheap, so we pick one in a
     * million to make it highly unlikely for users to have issues with this
     * filter.
     *
     * Memory used: 1.7MB
     */
boost::scoped_ptr<CRollingBloomFilter> recentRejects;
uint256 hashRecentRejectsChainTip;

/** Blocks that are in flight, and that are in the queue to be downloaded. Protected by cs_main. */
struct QueuedBlock {
    uint256 hash;
    CBlockIndex* pindex;        //! Optional.
    int64_t nTime;              //! Time of "getdata" request in microseconds.
    int nValidatedQueuedBefore; //! Number of blocks queued with validated headers (globally) at the time this one is requested.
    bool fValidatedHeaders;     //! Whether this block has validated headers at the time of request.
};
map<uint256, pair<NodeId, list<QueuedBlock>::iterator> > mapBlocksInFlight;

/** Number of blocks in flight with validated headers. */
int nQueuedValidatedHeaders = 0;

/** Number of preferable block download peers. */
int nPreferredDownload = 0;

/** Dirty block index entries. */
set<CBlockIndex*> setDirtyBlockIndex;

/** Dirty block file entries. */
set<int> setDirtyFileInfo;

/** Number of peers from which we're downloading blocks. */
int nPeersWithValidatedDownloads = 0;

} // namespace

//////////////////////////////////////////////////////////////////////////////
//
// Registration of network node signals.
//

namespace
{
struct CBlockReject {
    unsigned char chRejectCode;
    string strRejectReason;
    uint256 hashBlock;
};

/**
 * Maintain validation-specific state about nodes, protected by cs_main, instead
 * by CNode's own locks. This simplifies asynchronous operation, where
 * processing of incoming data is done after the ProcessMessage call returns,
 * and we're no longer holding the node's locks.
 */
struct CNodeState {
    //! The peer's address
    CService address;
    //! Whether we have a fully established connection.
    bool fCurrentlyConnected;
    //! Accumulated misbehaviour score for this peer.
    int nMisbehavior;
    //! Whether this peer should be disconnected and banned (unless whitelisted).
    bool fShouldBan;
    //! String name of this peer (debugging/logging purposes).
    std::string name;
    //! List of asynchronously-determined block rejections to notify this peer about.
    std::vector<CBlockReject> rejects;
    //! The best known block we know this peer has announced.
    CBlockIndex* pindexBestKnownBlock;
    //! The hash of the last unknown block this peer has announced.
    uint256 hashLastUnknownBlock;
    //! The last full block we both have.
    CBlockIndex* pindexLastCommonBlock;
    //! The best header we have sent our peer.
    CBlockIndex* pindexBestHeaderSent_Legacy;
    //! Whether we've started headers synchronization with this peer.
    bool fSyncStarted;
    //! Since when we're stalling block download progress (in microseconds), or 0.
    int64_t nStallingSince;
    list<QueuedBlock> vBlocksInFlight;
    int nBlocksInFlight;
    int nBlocksInFlightValidHeaders; // Legacy
    int64_t nDownloadingSince;       // Legacy
    //! Whether we consider this a preferred download peer.
    bool fPreferredDownload;
    bool fPreferHeaders; // Legacy

    CNodeState()
    {
        fCurrentlyConnected = false;
        nMisbehavior = 0;
        fShouldBan = false;
        pindexBestKnownBlock = NULL;
        hashLastUnknownBlock = uint256(0);
        pindexLastCommonBlock = NULL;
        pindexBestHeaderSent_Legacy = NULL;
        fSyncStarted = false;
        nStallingSince = 0;
        nBlocksInFlight = 0;
        fPreferredDownload = false;
        //Legacy
        nDownloadingSince = 0;
        nBlocksInFlightValidHeaders = 0;
        fPreferHeaders = false;
    }
};

/** Map maintaining per-node state. Requires cs_main. */
map<NodeId, CNodeState> mapNodeState;

// Requires cs_main.
CNodeState* State(NodeId pnode)
{
    map<NodeId, CNodeState>::iterator it = mapNodeState.find(pnode);
    if (it == mapNodeState.end())
        return NULL;
    return &it->second;
}

int GetHeight()
{
    while (!ShutdownRequested()) {
        TRY_LOCK(cs_main, lockMain);
        if (!lockMain) {
            MilliSleep(50);
            continue;
        }
        return chainActive.Height();
    }
}

void UpdatePreferredDownload(CNode* node, CNodeState* state)
{
    nPreferredDownload -= state->fPreferredDownload;

    // Whether this node should be marked as a preferred download node.
    state->fPreferredDownload = (!node->fInbound || node->fWhitelisted) && !node->fOneShot && !node->fClient;

    nPreferredDownload += state->fPreferredDownload;
}

void InitializeNode(NodeId nodeid, const CNode* pnode)
{
    LOCK(cs_main);
    CNodeState& state = mapNodeState.insert(std::make_pair(nodeid, CNodeState())).first->second;
    state.name = pnode->addrName;
    state.address = pnode->addr;
}

void FinalizeNode(NodeId nodeid)
{
    LOCK(cs_main);
    CNodeState* state = State(nodeid);

    if (state->fSyncStarted)
        nSyncStarted--;

    if (state->nMisbehavior == 0 && state->fCurrentlyConnected) {
        AddressCurrentlyConnected(state->address);
    }

    BOOST_FOREACH (const QueuedBlock& entry, state->vBlocksInFlight)
        mapBlocksInFlight.erase(entry.hash);
    EraseOrphansFor(nodeid);
    nPreferredDownload -= state->fPreferredDownload;

    mapNodeState.erase(nodeid);
}

void FinalizeNode_Legacy(NodeId nodeid)
{
    LOCK(cs_main);
    CNodeState* state = State(nodeid);

    if (state->fSyncStarted)
        nSyncStarted--;

    if (state->nMisbehavior == 0 && state->fCurrentlyConnected) {
        AddressCurrentlyConnected(state->address);
    }

    BOOST_FOREACH (const QueuedBlock& entry, state->vBlocksInFlight) {
        mapBlocksInFlight.erase(entry.hash);
    }
    EraseOrphansFor(nodeid);
    nPreferredDownload -= state->fPreferredDownload;
    nPeersWithValidatedDownloads -= (state->nBlocksInFlightValidHeaders != 0);
    assert(nPeersWithValidatedDownloads >= 0);

    mapNodeState.erase(nodeid);

    if (mapNodeState.empty()) {
        // Do a consistency check after the last peer is removed.
        assert(mapBlocksInFlight.empty());
        assert(nPreferredDownload == 0);
        assert(nPeersWithValidatedDownloads == 0);
    }
}

bool FinalizeNode_Fork(NodeId nodeid)
{
    if (UseLegacyCode(chainActive.Height())) {
        FinalizeNode_Legacy(nodeid);
    } else {
        FinalizeNode(nodeid);
    }
}

// Requires cs_main.
void MarkBlockAsReceived(const uint256& hash)
{
    map<uint256, pair<NodeId, list<QueuedBlock>::iterator> >::iterator itInFlight = mapBlocksInFlight.find(hash);
    if (itInFlight != mapBlocksInFlight.end()) {
        CNodeState* state = State(itInFlight->second.first);
        nQueuedValidatedHeaders -= itInFlight->second.second->fValidatedHeaders;
        state->vBlocksInFlight.erase(itInFlight->second.second);
        state->nBlocksInFlight--;
        state->nStallingSince = 0;
        mapBlocksInFlight.erase(itInFlight);
    }
}

// Requires cs_main.
// Returns a bool indicating whether we requested this block.
bool MarkBlockAsReceived_Legacy(const uint256& hash)
{
    map<uint256, pair<NodeId, list<QueuedBlock>::iterator> >::iterator itInFlight = mapBlocksInFlight.find(hash);
    if (itInFlight != mapBlocksInFlight.end()) {
        CNodeState* state = State(itInFlight->second.first);
        state->nBlocksInFlightValidHeaders -= itInFlight->second.second->fValidatedHeaders;
        if (state->nBlocksInFlightValidHeaders == 0 && itInFlight->second.second->fValidatedHeaders) {
            // Last validated block on the queue was received.
            nPeersWithValidatedDownloads--;
        }
        if (state->vBlocksInFlight.begin() == itInFlight->second.second) {
            // First block on the queue was received, update the start download time for the next one
            state->nDownloadingSince = std::max(state->nDownloadingSince, GetTimeMicros());
        }
        state->vBlocksInFlight.erase(itInFlight->second.second);
        state->nBlocksInFlight--;
        state->nStallingSince = 0;
        mapBlocksInFlight.erase(itInFlight);
        return true;
    }
    return false;
}


// Requires cs_main.
void MarkBlockAsInFlight(NodeId nodeid, const uint256& hash, CBlockIndex* pindex = NULL)
{
    CNodeState* state = State(nodeid);
    assert(state != NULL);

    // Make sure it's not listed somewhere already.
    MarkBlockAsReceived(hash);

    QueuedBlock newentry = {hash, pindex, GetTimeMicros(), nQueuedValidatedHeaders, pindex != NULL};
    nQueuedValidatedHeaders += newentry.fValidatedHeaders;
    list<QueuedBlock>::iterator it = state->vBlocksInFlight.insert(state->vBlocksInFlight.end(), newentry);
    state->nBlocksInFlight++;
    mapBlocksInFlight[hash] = std::make_pair(nodeid, it);
}

// Requires cs_main.
void MarkBlockAsInFlight_Legacy(NodeId nodeid, const uint256& hash, CBlockIndex* pindex = NULL)
{
    CNodeState* state = State(nodeid);
    assert(state != NULL);

    // Make sure it's not listed somewhere already.
    MarkBlockAsReceived_Legacy(hash);

    QueuedBlock newentry = {hash, pindex, pindex != NULL};
    list<QueuedBlock>::iterator it = state->vBlocksInFlight.insert(state->vBlocksInFlight.end(), newentry);
    state->nBlocksInFlight++;
    state->nBlocksInFlightValidHeaders += newentry.fValidatedHeaders;
    if (state->nBlocksInFlight == 1) {
        // We're starting a block download (batch) from this peer.
        state->nDownloadingSince = GetTimeMicros();
    }
    if (state->nBlocksInFlightValidHeaders == 1 && pindex != NULL) {
        nPeersWithValidatedDownloads++;
    }
    mapBlocksInFlight[hash] = std::make_pair(nodeid, it);
}

/** Check whether the last unknown block a peer advertized is not yet known. */
void ProcessBlockAvailability(NodeId nodeid)
{
    CNodeState* state = State(nodeid);
    assert(state != NULL);

    if (state->hashLastUnknownBlock != 0) {
        BlockMap::iterator itOld = mapBlockIndex.find(state->hashLastUnknownBlock);
        if (itOld != mapBlockIndex.end() && itOld->second->nChainWork > 0) {
            if (state->pindexBestKnownBlock == NULL || itOld->second->nChainWork >= state->pindexBestKnownBlock->nChainWork)
                state->pindexBestKnownBlock = itOld->second;
            state->hashLastUnknownBlock = uint256(0);
        }
    }
}

/** Update tracking information about which blocks a peer is assumed to have. */
void UpdateBlockAvailability(NodeId nodeid, const uint256& hash)
{
    CNodeState* state = State(nodeid);
    assert(state != NULL);

    ProcessBlockAvailability(nodeid);

    BlockMap::iterator it = mapBlockIndex.find(hash);
    if (it != mapBlockIndex.end() && it->second->nChainWork > 0) {
        // An actually better block was announced.
        if (state->pindexBestKnownBlock == NULL || it->second->nChainWork >= state->pindexBestKnownBlock->nChainWork)
            state->pindexBestKnownBlock = it->second;
    } else {
        // An unknown block was announced; just assume that the latest one is the best one.
        state->hashLastUnknownBlock = hash;
    }
}

/** Find the last common ancestor two blocks have.
 *  Both pa and pb must be non-NULL. */
CBlockIndex* LastCommonAncestor(CBlockIndex* pa, CBlockIndex* pb)
{
    if (pa->nHeight > pb->nHeight) {
        pa = pa->GetAncestor(pb->nHeight);
    } else if (pb->nHeight > pa->nHeight) {
        pb = pb->GetAncestor(pa->nHeight);
    }

    while (pa != pb && pa && pb) {
        pa = pa->pprev;
        pb = pb->pprev;
    }

    // Eventually all chain branches meet at the genesis block.
    assert(pa == pb);
    return pa;
}

/** Update pindexLastCommonBlock and add not-in-flight missing successors to vBlocks, until it has
 *  at most count entries. */
void FindNextBlocksToDownload(NodeId nodeid, unsigned int count, std::vector<CBlockIndex*>& vBlocks, NodeId& nodeStaller)
{
    if (count == 0)
        return;

    vBlocks.reserve(vBlocks.size() + count);
    CNodeState* state = State(nodeid);
    assert(state != NULL);

    // Make sure pindexBestKnownBlock is up to date, we'll need it.
    ProcessBlockAvailability(nodeid);

    if (state->pindexBestKnownBlock == NULL || state->pindexBestKnownBlock->nChainWork < chainActive.Tip()->nChainWork) {
        // This peer has nothing interesting.
        return;
    }

    if (state->pindexLastCommonBlock == NULL) {
        // Bootstrap quickly by guessing a parent of our best tip is the forking point.
        // Guessing wrong in either direction is not a problem.
        state->pindexLastCommonBlock = chainActive[std::min(state->pindexBestKnownBlock->nHeight, chainActive.Height())];
    }

    // If the peer reorganized, our previous pindexLastCommonBlock may not be an ancestor
    // of their current tip anymore. Go back enough to fix that.
    state->pindexLastCommonBlock = LastCommonAncestor(state->pindexLastCommonBlock, state->pindexBestKnownBlock);
    if (state->pindexLastCommonBlock == state->pindexBestKnownBlock)
        return;

    std::vector<CBlockIndex*> vToFetch;
    CBlockIndex* pindexWalk = state->pindexLastCommonBlock;
    // Never fetch further than the best block we know the peer has, or more than BLOCK_DOWNLOAD_WINDOW + 1 beyond the last
    // linked block we have in common with this peer. The +1 is so we can detect stalling, namely if we would be able to
    // download that next block if the window were 1 larger.
    int nWindowEnd = state->pindexLastCommonBlock->nHeight + BLOCK_DOWNLOAD_WINDOW;
    int nMaxHeight = std::min<int>(state->pindexBestKnownBlock->nHeight, nWindowEnd + 1);
    NodeId waitingfor = -1;
    while (pindexWalk->nHeight < nMaxHeight) {
        // Read up to 128 (or more, if more blocks than that are needed) successors of pindexWalk (towards
        // pindexBestKnownBlock) into vToFetch. We fetch 128, because CBlockIndex::GetAncestor may be as expensive
        // as iterating over ~100 CBlockIndex* entries anyway.
        int nToFetch = std::min(nMaxHeight - pindexWalk->nHeight, std::max<int>(count - vBlocks.size(), 128));
        vToFetch.resize(nToFetch);
        pindexWalk = state->pindexBestKnownBlock->GetAncestor(pindexWalk->nHeight + nToFetch);
        vToFetch[nToFetch - 1] = pindexWalk;
        for (unsigned int i = nToFetch - 1; i > 0; i--) {
            vToFetch[i - 1] = vToFetch[i]->pprev;
        }

        // Iterate over those blocks in vToFetch (in forward direction), adding the ones that
        // are not yet downloaded and not in flight to vBlocks. In the mean time, update
        // pindexLastCommonBlock as long as all ancestors are already downloaded.
        BOOST_FOREACH (CBlockIndex* pindex, vToFetch) {
            if (!pindex->IsValid(BLOCK_VALID_TREE)) {
                // We consider the chain that this peer is on invalid.
                return;
            }
            if (pindex->nStatus & BLOCK_HAVE_DATA) {
                if (pindex->nChainTx)
                    state->pindexLastCommonBlock = pindex;
            } else if (mapBlocksInFlight.count(pindex->GetBlockHash()) == 0) {
                // The block is not already downloaded, and not yet in flight.
                if (pindex->nHeight > nWindowEnd) {
                    // We reached the end of the window.
                    if (vBlocks.size() == 0 && waitingfor != nodeid) {
                        // We aren't able to fetch anything, but we would be if the download window was one larger.
                        nodeStaller = waitingfor;
                    }
                    return;
                }
                vBlocks.push_back(pindex);
                if (vBlocks.size() == count) {
                    return;
                }
            } else if (waitingfor == -1) {
                // This is the first already-in-flight block.
                waitingfor = mapBlocksInFlight[pindex->GetBlockHash()].first;
            }
        }
    }
}

} // namespace

bool GetNodeStateStats(NodeId nodeid, CNodeStateStats& stats)
{
    LOCK(cs_main);
    CNodeState* state = State(nodeid);
    if (state == NULL)
        return false;
    stats.nMisbehavior = state->nMisbehavior;
    stats.nSyncHeight = state->pindexBestKnownBlock ? state->pindexBestKnownBlock->nHeight : -1;
    stats.nCommonHeight = state->pindexLastCommonBlock ? state->pindexLastCommonBlock->nHeight : -1;
    BOOST_FOREACH (const QueuedBlock& queue, state->vBlocksInFlight) {
        if (queue.pindex)
            stats.vHeightInFlight.push_back(queue.pindex->nHeight);
    }
    return true;
}

void RegisterNodeSignals(CNodeSignals& nodeSignals)
{
    nodeSignals.GetHeight.connect(&GetHeight);
    nodeSignals.ProcessMessages.connect(&ProcessMessages);
    nodeSignals.SendMessages.connect(&SendMessages);
    nodeSignals.InitializeNode.connect(&InitializeNode);
    nodeSignals.FinalizeNode.connect(&FinalizeNode_Fork);
}

void UnregisterNodeSignals(CNodeSignals& nodeSignals)
{
    nodeSignals.GetHeight.disconnect(&GetHeight);
    nodeSignals.ProcessMessages.disconnect(&ProcessMessages);
    nodeSignals.SendMessages.disconnect(&SendMessages);
    nodeSignals.InitializeNode.disconnect(&InitializeNode);
    nodeSignals.FinalizeNode.disconnect(&FinalizeNode_Fork);
}

CBlockIndex* FindForkInGlobalIndex(const CChain& chain, const CBlockLocator& locator)
{
    // Find the first block the caller has in the main chain
    BOOST_FOREACH (const uint256& hash, locator.vHave) {
        BlockMap::iterator mi = mapBlockIndex.find(hash);
        if (mi != mapBlockIndex.end()) {
            CBlockIndex* pindex = (*mi).second;
            if (chain.Contains(pindex))
                return pindex;
        }
    }
    return chain.Genesis();
}

CCoinsViewCache* pcoinsTip = NULL;
CBlockTreeDB* pblocktree = NULL;


static const int32_t GetCurrentTransactionVersion()
{
    return UseLegacyCode() ? 1 : 2;
}

//////////////////////////////////////////////////////////////////////////////
//
// mapOrphanTransactions
//

bool AddOrphanTx(const CTransaction& tx, NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
{
    uint256 hash = tx.GetHash();
    if (mapOrphanTransactions.count(hash))
        return false;

    // Ignore big transactions, to avoid a
    // send-big-orphans memory exhaustion attack. If a peer has a legitimate
    // large transaction with a missing parent then we assume
    // it will rebroadcast it later, after the parent transaction(s)
    // have been mined or received.
    // 10,000 orphans, each of which is at most 5,000 bytes big is
    // at most 500 megabytes of orphans:
    unsigned int sz = tx.GetSerializeSize(SER_NETWORK, GetCurrentTransactionVersion());
    if (sz > 5000) {
        LogPrint("mempool", "ignoring large orphan tx (size: %u, hash: %s)\n", sz, hash.ToString());
        return false;
    }

    mapOrphanTransactions[hash].tx = tx;
    mapOrphanTransactions[hash].fromPeer = peer;
    BOOST_FOREACH (const CTxIn& txin, tx.vin)
        mapOrphanTransactionsByPrev[txin.prevout.hash].insert(hash);

    LogPrint("mempool", "stored orphan tx %s (mapsz %u prevsz %u)\n", hash.ToString(),
        mapOrphanTransactions.size(), mapOrphanTransactionsByPrev.size());
    return true;
}

void static EraseOrphanTx(uint256 hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
{
    map<uint256, COrphanTx>::iterator it = mapOrphanTransactions.find(hash);
    if (it == mapOrphanTransactions.end())
        return;
    BOOST_FOREACH (const CTxIn& txin, it->second.tx.vin) {
        map<uint256, set<uint256> >::iterator itPrev = mapOrphanTransactionsByPrev.find(txin.prevout.hash);
        if (itPrev == mapOrphanTransactionsByPrev.end())
            continue;
        itPrev->second.erase(hash);
        if (itPrev->second.empty())
            mapOrphanTransactionsByPrev.erase(itPrev);
    }
    mapOrphanTransactions.erase(it);
}

void EraseOrphansFor(NodeId peer)
{
    int nErased = 0;
    map<uint256, COrphanTx>::iterator iter = mapOrphanTransactions.begin();
    while (iter != mapOrphanTransactions.end()) {
        map<uint256, COrphanTx>::iterator maybeErase = iter++; // increment to avoid iterator becoming invalid
        if (maybeErase->second.fromPeer == peer) {
            EraseOrphanTx(maybeErase->second.tx.GetHash());
            ++nErased;
        }
    }
    if (nErased > 0) LogPrint("mempool", "Erased %d orphan tx from peer %d\n", nErased, peer);
}


unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
{
    unsigned int nEvicted = 0;
    while (mapOrphanTransactions.size() > nMaxOrphans) {
        // Evict a random orphan:
        uint256 randomhash = GetRandHash();
        map<uint256, COrphanTx>::iterator it = mapOrphanTransactions.lower_bound(randomhash);
        if (it == mapOrphanTransactions.end())
            it = mapOrphanTransactions.begin();
        EraseOrphanTx(it->first);
        ++nEvicted;
    }
    return nEvicted;
}

bool IsStandardTx(const CTransaction& tx, string& reason, bool isLoadingTx)
{
    if (isLoadingTx)
        return true;

    AssertLockHeld(cs_main);
    if (tx.GetVersion() > GetCurrentTransactionVersion() || tx.GetVersion() < 1) {
        reason = "version";
        return false;
    }

    // Treat non-final transactions as non-standard to prevent a specific type
    // of double-spend attack, as well as DoS attacks. (if the transaction
    // can't be mined, the attacker isn't expending resources broadcasting it)
    // Basically we don't want to propagate transactions that can't be included in
    // the next block.
    //
    // However, IsFinalTx() is confusing... Without arguments, it uses
    // chainActive.Height() to evaluate nLockTime; when a block is accepted, chainActive.Height()
    // is set to the value of nHeight in the block. However, when IsFinalTx()
    // is called within CBlock::AcceptBlock(), the height of the block *being*
    // evaluated is what is used. Thus if we want to know if a transaction can
    // be part of the *next* block, we need to call IsFinalTx() with one more
    // than chainActive.Height().
    //
    // Timestamps on the other hand don't get any special treatment, because we
    // can't know what timestamp the next block will have, and there aren't
    // timestamp applications where it matters.
    if (!IsFinalTx(tx, chainActive.Height() + 1)) {
        reason = "non-final";
        return false;
    }

    // Extremely large transactions with lots of inputs can cost the network
    // almost as much to process as they cost the sender in fees, because
    // computing signature hashes is O(ninputs*txsize). Limiting transactions
    // to MAX_STANDARD_TX_SIZE mitigates CPU exhaustion attacks.
    unsigned int sz = tx.GetSerializeSize(SER_NETWORK, GetCurrentTransactionVersion());
    unsigned int nMaxSize = MAX_STANDARD_TX_SIZE;
    if (sz >= nMaxSize) {
        reason = "tx-size";
        return false;
    }

    for (const CTxIn& txin : tx.vin) {
        // Biggest 'standard' txin is a 15-of-15 P2SH multisig with compressed
        // keys. (remember the 520 byte limit on redeemScript size) That works
        // out to a (15*(33+1))+3=513 byte redeemScript, 513+1+15*(73+1)+3=1627
        // bytes of scriptSig, which we round off to 1650 bytes for some minor
        // future-proofing. That's also enough to spend a 20-of-20
        // CHECKMULTISIG scriptPubKey, though such a scriptPubKey is not
        // considered standard)
        if (txin.scriptSig.size() > 1650) {
            reason = "scriptsig-size";
            return false;
        }
        if (!txin.scriptSig.IsPushOnly()) {
            reason = "scriptsig-not-pushonly";
            return false;
        }
    }

    unsigned int nDataOut = 0;
    txnouttype whichType;
    BOOST_FOREACH (const CTxOut& txout, tx.vout) {
        if (!::IsStandard(txout.scriptPubKey, whichType)) {
            reason = "scriptpubkey";
            return false;
        }

        if (whichType == TX_NULL_DATA)
            nDataOut++;
        else if (whichType == TX_MULTISIG && !fIsBareMultisigStd) {
            reason = "bare-multisig";
            return false;
        } else if (txout.IsDust(::minRelayTxFee)) {
            reason = "dust";
            return false;
        }
    }

    // only one OP_RETURN txout is permitted
    if (nDataOut > 1) {
        reason = "multi-op-return";
        return false;
    }

    return true;
}

bool IsFinalTx(const CTransaction& tx, int nBlockHeight, int64_t nBlockTime)
{
    AssertLockHeld(cs_main);
    // Time based nLockTime implemented in 0.1.6
    if (tx.nLockTime == 0)
        return true;
    if (nBlockHeight == 0)
        nBlockHeight = chainActive.Height();
    if (nBlockTime == 0)
        nBlockTime = GetAdjustedTime();
    if ((int64_t)tx.nLockTime < ((int64_t)tx.nLockTime < LOCKTIME_THRESHOLD ? (int64_t)nBlockHeight : nBlockTime))
        return true;
    BOOST_FOREACH (const CTxIn& txin, tx.vin)
        if (!txin.IsFinal())
            return false;
    return true;
}

/**
 * Check transaction inputs to mitigate two
 * potential denial-of-service attacks:
 *
 * 1. scriptSigs with extra data stuffed into them,
 *    not consumed by scriptPubKey (or P2SH script)
 * 2. P2SH scripts with a crazy number of expensive
 *    CHECKSIG/CHECKMULTISIG operations
 */
bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
{
    if (tx.IsCoinBase())
        return true;

    for (unsigned int i = 0; i < tx.vin.size(); i++) {
        const CTxOut& prev = mapInputs.GetOutputFor(tx.vin[i]);

        vector<vector<unsigned char> > vSolutions;
        txnouttype whichType;
        // get the scriptPubKey corresponding to this input:
        const CScript& prevScript = prev.scriptPubKey;
        if (!Solver(prevScript, whichType, vSolutions))
            return false;
        int nArgsExpected = ScriptSigArgsExpected(whichType, vSolutions);
        if (nArgsExpected < 0)
            return false;

        // Transactions with extra stuff in their scriptSigs are
        // non-standard. Note that this EvalScript() call will
        // be quick, because if there are any operations
        // beside "push data" in the scriptSig
        // IsStandard() will have already returned false
        // and this method isn't called.
        vector<vector<unsigned char> > stack;
        if (!EvalScript(stack, tx.vin[i].scriptSig, false, BaseSignatureChecker()))
            return false;

        if (whichType == TX_SCRIPTHASH) {
            if (stack.empty())
                return false;
            CScript subscript(stack.back().begin(), stack.back().end());
            vector<vector<unsigned char> > vSolutions2;
            txnouttype whichType2;
            if (Solver(subscript, whichType2, vSolutions2)) {
                int tmpExpected = ScriptSigArgsExpected(whichType2, vSolutions2);
                if (tmpExpected < 0)
                    return false;
                nArgsExpected += tmpExpected;
            } else {
                // Any other Script with less than 15 sigops OK:
                unsigned int sigops = subscript.GetSigOpCount(true);
                // ... extra data left on the stack after execution is OK, too:
                return (sigops <= MAX_P2SH_SIGOPS);
            }
        }

        if (stack.size() != (unsigned int)nArgsExpected)
            return false;
    }

    return true;
}

bool AreInputsStandard_Legacy(const CTransaction& tx, const CCoinsViewCache& mapInputs)
{
    if (tx.IsCoinBase())
        return true; // Coinbases don't use vin normally

    for (unsigned int i = 0; i < tx.vin.size(); i++) {
        const CTxOut& prev = mapInputs.GetOutputFor(tx.vin[i]);

        std::vector<std::vector<unsigned char> > vSolutions;
        txnouttype whichType;
        // get the scriptPubKey corresponding to this input:
        const CScript& prevScript = prev.scriptPubKey;
        if (!Solver(prevScript, whichType, vSolutions))
            return false;

        if (whichType == TX_SCRIPTHASH) {
            std::vector<std::vector<unsigned char> > stack;
            // convert the scriptSig into a stack, so we can inspect the redeemScript
            if (!EvalScript(stack, tx.vin[i].scriptSig, SCRIPT_VERIFY_NONE, BaseSignatureChecker(), 0))
                return false;
            if (stack.empty())
                return false;
            CScript subscript(stack.back().begin(), stack.back().end());
            if (subscript.GetSigOpCount(true) > MAX_P2SH_SIGOPS) {
                return false;
            }
        }
    }

    return true;
}


unsigned int GetLegacySigOpCount(const CTransaction& tx)
{
    unsigned int nSigOps = 0;
    BOOST_FOREACH (const CTxIn& txin, tx.vin) {
        nSigOps += txin.scriptSig.GetSigOpCount(false);
    }
    BOOST_FOREACH (const CTxOut& txout, tx.vout) {
        nSigOps += txout.scriptPubKey.GetSigOpCount(false);
    }
    return nSigOps;
}

unsigned int GetP2SHSigOpCount(const CTransaction& tx, const CCoinsViewCache& inputs)
{
    if (tx.IsCoinBase())
        return 0;

    unsigned int nSigOps = 0;
    for (unsigned int i = 0; i < tx.vin.size(); i++) {
        const CTxOut& prevout = inputs.GetOutputFor(tx.vin[i]);
        if (prevout.scriptPubKey.IsPayToScriptHash())
            nSigOps += prevout.scriptPubKey.GetSigOpCount(tx.vin[i].scriptSig);
    }
    return nSigOps;
}

int GetInputAge(CTxIn& vin)
{
    CCoinsView viewDummy;
    CCoinsViewCache view(&viewDummy);
    {
        LOCK(mempool.cs);
        CCoinsViewMemPool viewMempool(pcoinsTip, mempool);
        view.SetBackend(viewMempool); // temporarily switch cache backend to db+mempool view

        const CCoins* coins = view.AccessCoins(vin.prevout.hash);

        if (coins) {
            if (coins->nHeight < 0) return 0;
            return (chainActive.Tip()->nHeight + 1) - coins->nHeight;
        } else
            return -1;
    }
}

bool MoneyRange(CAmount nValueOut)
{
    return nValueOut >= 0 && nValueOut <= Params().GetMaxMoneyOut();
}

bool CheckTransaction(const CTransaction& tx, CValidationState& state)
{
    // Basic checks that don't depend on any context
    if (tx.vin.empty())
        return state.DoS(10, false, REJECT_INVALID, "bad-txns-vin-empty");
    if (tx.vout.empty())
        return state.DoS(10, false, REJECT_INVALID, "bad-txns-vout-empty");

    // Size limits
    if (::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION) > MAX_BLOCK_SIZE_LEGACY)
        return state.DoS(100, false, REJECT_INVALID, "bad-txns-oversize");

    // Check for negative or overflow output values
    CAmount nValueOut = 0;
    BOOST_FOREACH (const CTxOut& txout, tx.vout) {
        if (txout.IsEmpty() && !tx.IsCoinBase() && !tx.IsLegacyCoinStake())
            return state.DoS(100, error("CheckTransaction(): txout empty for user transaction"));

        if (txout.nValue < 0)
            return state.DoS(100, false, REJECT_INVALID, "bad-txns-vout-negative");
        if (txout.nValue > Params().GetMaxMoneyOut())
            return state.DoS(100, false, REJECT_INVALID, "bad-txns-vout-toolarge");
        nValueOut += txout.nValue;
        if (!MoneyRange(nValueOut))
            return state.DoS(100, false, REJECT_INVALID, "bad-txns-txouttotal-toolarge");
    }

    // Check for duplicate inputs
    set<COutPoint> vInOutPoints;
    BOOST_FOREACH (const CTxIn& txin, tx.vin) {
        if (vInOutPoints.count(txin.prevout))
            return state.DoS(100, false, REJECT_INVALID, "bad-txns-inputs-duplicate");
        vInOutPoints.insert(txin.prevout);
    }

    if (tx.IsCoinBase()) {
        if (tx.vin[0].scriptSig.size() < 2 || tx.vin[0].scriptSig.size() > 100)
            return state.DoS(100, false, REJECT_INVALID, "bad-cb-length");
    } else {
        BOOST_FOREACH (const CTxIn& txin, tx.vin)
            if (txin.prevout.IsNull())
                return state.DoS(10, false, REJECT_INVALID, "bad-txns-prevout-null");
    }
    return true;
}

bool CheckFinalTx(const CTransaction& tx, int flags)
{
    AssertLockHeld(cs_main);

    // By convention a negative value for flags indicates that the
    // current network-enforced consensus rules should be used. In
    // a future soft-fork scenario that would mean checking which
    // rules would be enforced for the next block and setting the
    // appropriate flags. At the present time no soft-forks are
    // scheduled, so no flags are set.
    flags = std::max(flags, 0);

    // CheckFinalTx() uses chainActive.Height()+1 to evaluate
    // nLockTime because when IsFinalTx() is called within
    // CBlock::AcceptBlock(), the height of the block *being*
    // evaluated is what is used. Thus if we want to know if a
    // transaction can be part of the *next* block, we need to call
    // IsFinalTx() with one more than chainActive.Height().
    const int nBlockHeight = chainActive.Height() + 1;

    // BIP113 will require that time-locked transactions have nLockTime set to
    // less than the median time of the previous block they're contained in.
    // When the next block is created its previous block will be the current
    // chain tip, so we use that to calculate the median time passed to
    // IsFinalTx() if LOCKTIME_MEDIAN_TIME_PAST is set.
    const int64_t nBlockTime = (flags & LOCKTIME_MEDIAN_TIME_PAST) ? chainActive.Tip()->GetMedianTimePast() : GetAdjustedTime();

    return IsFinalTx(tx, nBlockHeight, nBlockTime);
}

CAmount GetMinRelayFee(const CTransaction& tx, unsigned int nBytes, bool fAllowFree)
{
    {
        LOCK(mempool.cs);
        uint256 hash = tx.GetHash();
        double dPriorityDelta = 0;
        CAmount nFeeDelta = 0;
        mempool.ApplyDeltas(hash, dPriorityDelta, nFeeDelta);
        if (dPriorityDelta > 0 || nFeeDelta > 0)
            return 0;
    }

    CAmount nMinFee = ::minRelayTxFee.GetFee(nBytes);

    if (fAllowFree) {
        // There is a free transaction area in blocks created by most miners,
        // * If we are relaying we allow transactions up to DEFAULT_BLOCK_PRIORITY_SIZE - 1000
        //   to be considered to fall into this category. We don't want to encourage sending
        //   multiple transactions instead of one big transaction to avoid fees.
        if (nBytes < (DEFAULT_BLOCK_PRIORITY_SIZE - 1000))
            nMinFee = 0;
    }

    if (!MoneyRange(nMinFee))
        nMinFee = Params().GetMaxMoneyOut();
    return nMinFee;
}

ThresholdState VersionBitsTipState_Legacy(CChainParams::DeploymentPos pos)
{
    LOCK(cs_main);
    return VersionBitsState(chainActive.Tip(), pos, versionbitscache);
}

bool TestLockPointValidity(const LockPoints* lp)
{
    AssertLockHeld(cs_main);
    assert(lp);
    // If there are relative lock times then the maxInputBlock will be set
    // If there are no relative lock times, the LockPoints don't depend on the chain
    if (lp->maxInputBlock) {
        // Check whether chainActive is an extension of the block at which the LockPoints
        // calculation was valid.  If not LockPoints are no longer valid
        if (!chainActive.Contains(lp->maxInputBlock)) {
            return false;
        }
    }

    // LockPoints still valid
    return true;
}

/**
 * Calculates the block height and previous block's median time past at
 * which the transaction will be considered final in the context of BIP 68.
 * Also removes from the vector of input heights any entries which did not
 * correspond to sequence locked inputs as they do not affect the calculation.
 */
static std::pair<int, int64_t> CalculateSequenceLocks(const CTransaction& tx, int flags, std::vector<int>* prevHeights, const CBlockIndex& block)
{
    assert(prevHeights->size() == tx.vin.size());

    // Will be set to the equivalent height- and time-based nLockTime
    // values that would be necessary to satisfy all relative lock-
    // time constraints given our view of block chain history.
    // The semantics of nLockTime are the last invalid height/time, so
    // use -1 to have the effect of any height or time being valid.
    int nMinHeight = -1;
    int64_t nMinTime = -1;

    // tx.nVersion is signed integer so requires cast to unsigned otherwise
    // we would be doing a signed comparison and half the range of nVersion
    // wouldn't support BIP 68.
    bool fEnforceBIP68 = static_cast<uint32_t>(tx.GetVersion()) >= 2 && flags & LOCKTIME_VERIFY_SEQUENCE;

    // Do not enforce sequence numbers as a relative lock time
    // unless we have been instructed to
    if (!fEnforceBIP68) {
        return std::make_pair(nMinHeight, nMinTime);
    }

    for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) {
        const CTxIn& txin = tx.vin[txinIndex];

        // Sequence numbers with the most significant bit set are not
        // treated as relative lock-times, nor are they given any
        // consensus-enforced meaning at this point.
        if (txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG) {
            // The height of this input is not relevant for sequence locks
            (*prevHeights)[txinIndex] = 0;
            continue;
        }

        int nCoinHeight = (*prevHeights)[txinIndex];

        if (txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) {
            int64_t nCoinTime = block.GetAncestor(std::max(nCoinHeight - 1, 0))->GetMedianTimePast();
            // NOTE: Subtract 1 to maintain nLockTime semantics
            // BIP 68 relative lock times have the semantics of calculating
            // the first block or time at which the transaction would be
            // valid. When calculating the effective block time or height
            // for the entire transaction, we switch to using the
            // semantics of nLockTime which is the last invalid block
            // time or height.  Thus we subtract 1 from the calculated
            // time or height.

            // Time-based relative lock-times are measured from the
            // smallest allowed timestamp of the block containing the
            // txout being spent, which is the median time past of the
            // block prior.
            nMinTime = std::max(nMinTime, nCoinTime + (int64_t)((txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_MASK) << CTxIn::SEQUENCE_LOCKTIME_GRANULARITY) - 1);
        } else {
            nMinHeight = std::max(nMinHeight, nCoinHeight + (int)(txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_MASK) - 1);
        }
    }

    return std::make_pair(nMinHeight, nMinTime);
}

static bool EvaluateSequenceLocks(const CBlockIndex& block, std::pair<int, int64_t> lockPair)
{
    assert(block.pprev);
    int64_t nBlockTime = block.pprev->GetMedianTimePast();
    if (lockPair.first >= block.nHeight || lockPair.second >= nBlockTime)
        return false;

    return true;
}

bool SequenceLocks(const CTransaction& tx, int flags, std::vector<int>* prevHeights, const CBlockIndex& block)
{
    return EvaluateSequenceLocks(block, CalculateSequenceLocks(tx, flags, prevHeights, block));
}

bool CheckSequenceLocks(const CTransaction& tx, int flags, LockPoints* lp, bool useExistingLockPoints)
{
    AssertLockHeld(cs_main);
    AssertLockHeld(mempool.cs);

    CBlockIndex* tip = chainActive.Tip();
    CBlockIndex index;
    index.pprev = tip;
    // CheckSequenceLocks() uses chainActive.Height()+1 to evaluate
    // height based locks because when SequenceLocks() is called within
    // ConnectBlock(), the height of the block *being*
    // evaluated is what is used.
    // Thus if we want to know if a transaction can be part of the
    // *next* block, we need to use one more than chainActive.Height()
    index.nHeight = tip->nHeight + 1;

    std::pair<int, int64_t> lockPair;
    if (useExistingLockPoints) {
        assert(lp);
        lockPair.first = lp->height;
        lockPair.second = lp->time;
    } else {
        // pcoinsTip contains the UTXO set for chainActive.Tip()
        CCoinsViewMemPool viewMemPool(pcoinsTip, mempool);
        std::vector<int> prevheights;
        prevheights.resize(tx.vin.size());
        for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) {
            const CTxIn& txin = tx.vin[txinIndex];
            CCoins coins;
            if (!viewMemPool.GetCoins(txin.prevout.hash, coins)) {
                return error("%s: Missing input", __func__);
            }
            if (coins.nHeight == MEMPOOL_HEIGHT) {
                // Assume all mempool transaction confirm in the next block
                prevheights[txinIndex] = tip->nHeight + 1;
            } else {
                prevheights[txinIndex] = coins.nHeight;
            }
        }
        lockPair = CalculateSequenceLocks(tx, flags, &prevheights, index);
        if (lp) {
            lp->height = lockPair.first;
            lp->time = lockPair.second;
            // Also store the hash of the block with the highest height of
            // all the blocks which have sequence locked prevouts.
            // This hash needs to still be on the chain
            // for these LockPoint calculations to be valid
            // Note: It is impossible to correctly calculate a maxInputBlock
            // if any of the sequence locked inputs depend on unconfirmed txs,
            // except in the special case where the relative lock time/height
            // is 0, which is equivalent to no sequence lock. Since we assume
            // input height of tip+1 for mempool txs and test the resulting
            // lockPair from CalculateSequenceLocks against tip+1.  We know
            // EvaluateSequenceLocks will fail if there was a non-zero sequence
            // lock on a mempool input, so we can use the return value of
            // CheckSequenceLocks to indicate the LockPoints validity
            int maxInputHeight = 0;
            BOOST_FOREACH (int height, prevheights) {
                // Can ignore mempool inputs since we'll fail if they had non-zero locks
                if (height != tip->nHeight + 1) {
                    maxInputHeight = std::max(maxInputHeight, height);
                }
            }
            lp->maxInputBlock = tip->GetAncestor(maxInputHeight);
        }
    }
    return EvaluateSequenceLocks(index, lockPair);
}


void LimitMempoolSize(CTxMemPool& pool, size_t limit, unsigned long age)
{
    int expired = pool.Expire(GetTime() - age);
    if (expired != 0)
        LogPrint("mempool", "Expired %i transactions from the memory pool\n", expired);

    std::vector<uint256> vNoSpendsRemaining;
    pool.TrimToSize(limit, &vNoSpendsRemaining);
    BOOST_FOREACH (const uint256& removed, vNoSpendsRemaining)
        pcoinsTip->Uncache(removed);
}

/** Convert CValidationState to a human-readable message for logging */
std::string FormatStateMessage_Legacy(const CValidationState& state)
{
    return strprintf("%s%s (code %i)",
        state.GetRejectReason(),
        state.GetDebugMessage_Legacy().empty() ? "" : ", " + state.GetDebugMessage_Legacy(),
        state.GetRejectCode());
}

bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const CTransaction& tx, bool fLimitFree, bool* pfMissingInputs, bool fOverrideMempoolLimit, bool fRejectAbsurdFee, std::vector<uint256>& vHashTxnToUncache, bool ignoreFees, bool isLoadingTx)
{
    AssertLockHeld(cs_main);
    if (pfMissingInputs)
        *pfMissingInputs = false;

    if (!CheckTransaction(tx, state))
        return state.DoS(100, error("AcceptToMemoryPool: : CheckTransaction failed"), REJECT_INVALID, "bad-tx");

    // Coinbase is only valid in a block, not as a loose transaction
    if (tx.IsCoinBase())
        return state.DoS(100, error("AcceptToMemoryPool: : coinbase as individual tx"),
            REJECT_INVALID, "coinbase");

    // Coinstake is only valid in a block, not as a loose transaction
    if (tx.IsCoinStake())
        return state.DoS(100, error("AcceptToMemoryPool: coinstake as individual tx. txid=%s", tx.GetHash().GetHex()),
            REJECT_INVALID, "coinstake");

    // Rather not work on nonstandard transactions (unless -testnet/-regtest)
    string reason;
    if (Params().RequireStandard() && !IsStandardTx(tx, reason, isLoadingTx))
        return state.DoS(0,
            error("AcceptToMemoryPool : nonstandard transaction: %s", reason),
            REJECT_NONSTANDARD, reason);

    // Only accept nLockTime-using transactions that can be mined in the next
    // block; we don't want our mempool filled up with transactions that can't
    // be mined yet.
    if (!isLoadingTx && !CheckFinalTx(tx, STANDARD_LOCKTIME_VERIFY_FLAGS))
        return state.DoS(0, false, REJECT_NONSTANDARD, "non-final");

    // is it already in the memory pool?
    uint256 hash = tx.GetHash();
    if (pool.exists(hash))
        return state.Invalid(false, REJECT_ALREADY_KNOWN, "txn-already-in-mempool");


    // Check for conflicts with in-memory transactions
    set<uint256> setConflicts;
    {
        LOCK(pool.cs); // protect pool.mapNextTx
        BOOST_FOREACH (const CTxIn& txin, tx.vin) {
            if (pool.mapNextTx.count(txin.prevout)) {
                const CTransaction* ptxConflicting = pool.mapNextTx[txin.prevout].ptx;
                if (!setConflicts.count(ptxConflicting->GetHash())) {
                    // Allow opt-out of transaction replacement by setting
                    // nSequence >= maxint-1 on all inputs.
                    //
                    // maxint-1 is picked to still allow use of nLockTime by
                    // non-replacable transactions. All inputs rather than just one
                    // is for the sake of multi-party protocols, where we don't
                    // want a single party to be able to disable replacement.
                    //
                    // The opt-out ignores descendants as anyone relying on
                    // first-seen mempool behavior should be checking all
                    // unconfirmed ancestors anyway; doing otherwise is hopelessly
                    // insecure.
                    bool fReplacementOptOut = true;
                    if (fEnableReplacement) {
                        BOOST_FOREACH (const CTxIn& txin, ptxConflicting->vin) {
                            if (txin.nSequence < std::numeric_limits<unsigned int>::max() - 1) {
                                fReplacementOptOut = false;
                                break;
                            }
                        }
                    }
                    if (fReplacementOptOut)
                        return state.Invalid(false, REJECT_CONFLICT, "txn-mempool-conflict");

                    setConflicts.insert(ptxConflicting->GetHash());
                }
            }
        }
    }

    {
        CCoinsView dummy;
        CCoinsViewCache view(&dummy);

        CAmount nValueIn = 0;
        LockPoints lp;
        {
            LOCK(pool.cs);
            CCoinsViewMemPool viewMemPool(pcoinsTip, pool);
            view.SetBackend(viewMemPool);

            // do we already have it?
            bool fHadTxInCache = pcoinsTip->HaveCoinsInCache_Legacy(hash);
            if (view.HaveCoins(hash)) {
                if (!fHadTxInCache)
                    vHashTxnToUncache.push_back(hash);
                return state.Invalid(false, REJECT_ALREADY_KNOWN, "txn-already-known");
            }

            // do all inputs exist?
            // Note that this does not check for the presence of actual outputs (see the next check for that),
            // and only helps with filling in pfMissingInputs (to determine missing vs spent).
            BOOST_FOREACH (const CTxIn txin, tx.vin) {
                if (!pcoinsTip->HaveCoinsInCache_Legacy(txin.prevout.hash))
                    vHashTxnToUncache.push_back(txin.prevout.hash);
                if (!view.HaveCoins(txin.prevout.hash)) {
                    if (pfMissingInputs)
                        *pfMissingInputs = true;
                    return false; // fMissingInputs and !state.IsInvalid() is used to detect this condition, don't set state.Invalid()
                }

                //Check for invalid/fraudulent inputs
                if (!ValidOutPoint(txin.prevout, chainActive.Height())) {
                    return state.Invalid(error("%s : tried to spend invalid input %s in tx %s", __func__, txin.prevout.ToString(),
                                             tx.GetHash().GetHex()),
                        REJECT_INVALID, "bad-txns-invalid-inputs");
                }
            }

            // are the actual inputs available?
            if (!view.HaveInputs(tx))
                return state.Invalid(error("AcceptToMemoryPool : inputs already spent"),
                    REJECT_DUPLICATE, "bad-txns-inputs-spent");

            // Bring the best block into scope
            view.GetBestBlock();

            nValueIn = view.GetValueIn(tx);

            // we have all inputs cached now, so switch back to dummy, so we don't need to keep lock on mempool
            view.SetBackend(dummy);

            // Only accept BIP68 sequence locked transactions that can be mined in the next
            // block; we don't want our mempool filled up with transactions that can't
            // be mined yet.
            // Must keep pool.cs for this unless we change CheckSequenceLocks to take a
            // CoinsViewCache instead of create its own
            if (!CheckSequenceLocks(tx, STANDARD_LOCKTIME_VERIFY_FLAGS, &lp))
                return state.DoS(0, false, REJECT_NONSTANDARD, "non-BIP68-final");
        }

        // Check for non-standard pay-to-script-hash in inputs
        if (Params().RequireStandard() && !AreInputsStandard(tx, view))
            return state.Invalid(error("AcceptToMemoryPool: : nonstandard transaction input"), REJECT_NONSTANDARD, "bad-txns-nonstandard-inputs");

        CAmount nValueOut = tx.GetValueOut();
        CAmount nFees = nValueIn - nValueOut;
        // nModifiedFees includes any fee deltas from PrioritiseTransaction
        CAmount nModifiedFees = nFees;
        double nPriorityDummy = 0;
        pool.ApplyDeltas(hash, nPriorityDummy, nModifiedFees);

        CAmount inChainInputValue;
        double dPriority = view.GetPriority(tx, chainActive.Height(), inChainInputValue);

        // Keep track of transactions that spend a coinbase, which we re-scan
        // during reorgs to ensure COINBASE_MATURITY is still met.
        bool fSpendsCoinbase = false;
        BOOST_FOREACH (const CTxIn& txin, tx.vin) {
            const CCoins* coins = view.AccessCoins(txin.prevout.hash);
            if (coins->IsCoinBase()) {
                fSpendsCoinbase = true;
                break;
            }
        }

        unsigned int nSigOps = GetLegacySigOpCount(tx);
        nSigOps += GetP2SHSigOpCount(tx, view);
        CTxMemPoolEntry entry(tx, nFees, GetTime(), dPriority, chainActive.Height(), pool.HasNoInputsOf(tx), inChainInputValue, fSpendsCoinbase, nSigOps, lp);
        unsigned int nSize = entry.GetTxSize();

        unsigned int nMaxSigOps = MAX_TX_SIGOPS_CURRENT;
        if (nSigOps > nMaxSigOps || (nBytesPerSigOp && nSigOps > nSize / nBytesPerSigOp))
            return state.DoS(0,
                error("AcceptToMemoryPool : too many sigops %s, %d > %d",
                    hash.ToString(), nSigOps, nMaxSigOps),
                REJECT_NONSTANDARD, "bad-txns-too-many-sigops");

        // Don't accept it if it can't get into a block
        // but prioritise dstx and don't check fees for it
        if (!ignoreFees) {
            CAmount mempoolRejectFee = pool.GetMinFee(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE_LEGACY) * 1000000).GetFee(nSize);
            if (mempoolRejectFee > 0 && nModifiedFees < mempoolRejectFee) {
                return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool min fee not met", false, strprintf("%d < %d", nFees, mempoolRejectFee));
            } else if (GetBoolArg("-relaypriority", DEFAULT_RELAYPRIORITY_LEGACY) && nModifiedFees < ::minRelayTxFee.GetFee(nSize) && !AllowFree(entry.GetPriority(chainActive.Height() + 1))) {
                // Require that free transactions have sufficient priority to be mined in the next block.

                return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "insufficient priority");
            }

            // Continuously rate-limit free (really, very-low-fee) transactions
            // This mitigates 'penny-flooding' -- sending thousands of free transactions just to
            // be annoying or make others' transactions take longer to confirm.
            if (fLimitFree && nModifiedFees < ::minRelayTxFee.GetFee(nSize)) {
                static CCriticalSection csFreeLimiter;
                static double dFreeCount;
                static int64_t nLastTime;
                int64_t nNow = GetTime();

                LOCK(csFreeLimiter);

                // Use an exponentially decaying ~10-minute window:
                dFreeCount *= pow(1.0 - 1.0 / 600.0, (double)(nNow - nLastTime));
                nLastTime = nNow;
                // -limitfreerelay unit is thousand-bytes-per-minute
                // At default rate it would take over a month to fill 1GB
                if (dFreeCount >= GetArg("-limitfreerelay", DEFAULT_LIMITFREERELAY_LEGACY) * 10 * 1000)

                    return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "rate limited free transaction");
                LogPrint("mempool", "Rate limit dFreeCount: %g => %g\n", dFreeCount, dFreeCount + nSize);
                dFreeCount += nSize;
            }

            if (fRejectAbsurdFee && nFees > ::minRelayTxFee.GetFee(nSize) * 10000)
                return state.Invalid(false,
                    REJECT_HIGHFEE_LEGACY, "absurdly-high-fee",
                    strprintf("%d > %d", nFees, ::minRelayTxFee.GetFee(nSize) * 10000));

            // Check if it's economically rational to mine this transaction rather
            // than the ones it replaces.
            CAmount nConflictingFees = 0;
            size_t nConflictingSize = 0;
            uint64_t nConflictingCount = 0;
            CTxMemPool::setEntries allConflicting;

            // If we don't hold the lock allConflicting might be incomplete; the
            // subsequent RemoveStaged() and addUnchecked() calls don't guarantee
            // mempool consistency for us.
            LOCK(pool.cs);
            if (setConflicts.size()) {
                CFeeRate newFeeRate(nModifiedFees, nSize);
                set<uint256> setConflictsParents;
                const int maxDescendantsToVisit = 100;
                CTxMemPool::setEntries setIterConflicting;
                BOOST_FOREACH (const uint256& hashConflicting, setConflicts) {
                    CTxMemPool::txiter mi = pool.mapTx.find(hashConflicting);
                    if (mi == pool.mapTx.end())
                        continue;

                    // Save these to avoid repeated lookups
                    setIterConflicting.insert(mi);

                    // If this entry is "dirty", then we don't have descendant
                    // state for this transaction, which means we probably have
                    // lots of in-mempool descendants.
                    // Don't allow replacements of dirty transactions, to ensure
                    // that we don't spend too much time walking descendants.
                    // This should be rare.
                    if (mi->IsDirty()) {
                        return state.DoS(0, error("AcceptToMemoryPool: rejecting replacement %s; cannot replace tx %s with untracked descendants", hash.ToString(), mi->GetTx().GetHash().ToString()), REJECT_NONSTANDARD, "too many potential replacements");
                    }

                    // Don't allow the replacement to reduce the feerate of the
                    // mempool.
                    //
                    // We usually don't want to accept replacements with lower
                    // feerates than what they replaced as that would lower the
                    // feerate of the next block. Requiring that the feerate always
                    // be increased is also an easy-to-reason about way to prevent
                    // DoS attacks via replacements.
                    //
                    // The mining code doesn't (currently) take children into
                    // account (CPFP) so we only consider the feerates of
                    // transactions being directly replaced, not their indirect
                    // descendants. While that does mean high feerate children are
                    // ignored when deciding whether or not to replace, we do
                    // require the replacement to pay more overall fees too,
                    // mitigating most cases.
                    CFeeRate oldFeeRate(mi->GetModifiedFee(), mi->GetTxSize());
                    if (newFeeRate <= oldFeeRate) {
                        return state.DoS(0, error("AcceptToMemoryPool: rejecting replacement %s; new feerate %s <= old feerate %s", hash.ToString(), newFeeRate.ToString(), oldFeeRate.ToString()), REJECT_INSUFFICIENTFEE, "insufficient fee");
                    }

                    BOOST_FOREACH (const CTxIn& txin, mi->GetTx().vin) {
                        setConflictsParents.insert(txin.prevout.hash);
                    }

                    nConflictingCount += mi->GetCountWithDescendants();
                }
                // This potentially overestimates the number of actual descendants
                // but we just want to be conservative to avoid doing too much
                // work.
                if (nConflictingCount <= maxDescendantsToVisit) {
                    // If not too many to replace, then calculate the set of
                    // transactions that would have to be evicted
                    BOOST_FOREACH (CTxMemPool::txiter it, setIterConflicting) {
                        pool.CalculateDescendants(it, allConflicting);
                    }
                    BOOST_FOREACH (CTxMemPool::txiter it, allConflicting) {
                        nConflictingFees += it->GetModifiedFee();
                        nConflictingSize += it->GetTxSize();
                    }
                } else {
                    return state.DoS(0, error("AcceptToMemoryPool: rejecting replacement %s; too many potential replacements (%d > %d)\n", hash.ToString(), nConflictingCount, maxDescendantsToVisit), REJECT_NONSTANDARD, "too many potential replacements");
                }

                for (unsigned int j = 0; j < tx.vin.size(); j++) {
                    // We don't want to accept replacements that require low
                    // feerate junk to be mined first. Ideally we'd keep track of
                    // the ancestor feerates and make the decision based on that,
                    // but for now requiring all new inputs to be confirmed works.
                    if (!setConflictsParents.count(tx.vin[j].prevout.hash)) {
                        // Rather than check the UTXO set - potentially expensive -
                        // it's cheaper to just check if the new input refers to a
                        // tx that's in the mempool.
                        if (pool.mapTx.find(tx.vin[j].prevout.hash) != pool.mapTx.end())
                            return state.DoS(0, error("AcceptToMemoryPool: replacement %s adds unconfirmed input, idx %d", hash.ToString(), j), REJECT_NONSTANDARD, "replacement-adds-unconfirmed");
                    }
                }

                // The replacement must pay greater fees than the transactions it
                // replaces - if we did the bandwidth used by those conflicting
                // transactions would not be paid for.
                if (nModifiedFees < nConflictingFees) {
                    return state.DoS(0, error("AcceptToMemoryPool: rejecting replacement %s, less fees than conflicting txs; %s < %s", hash.ToString(), FormatMoney(nModifiedFees), FormatMoney(nConflictingFees)),
                        REJECT_INSUFFICIENTFEE, "insufficient fee");
                }

                // Finally in addition to paying more fees than the conflicts the
                // new transaction must pay for its own bandwidth.
                CAmount nDeltaFees = nModifiedFees - nConflictingFees;
                if (nDeltaFees < ::minRelayTxFee.GetFee(nSize)) {
                    return state.DoS(0,
                        error("AcceptToMemoryPool: rejecting replacement %s, not enough additional fees to relay; %s < %s",
                            hash.ToString(), FormatMoney(nDeltaFees), FormatMoney(::minRelayTxFee.GetFee(nSize))),
                        REJECT_INSUFFICIENTFEE, "insufficient fee");
                }
            }

            // Remove conflicting transactions from the mempool
            BOOST_FOREACH (const CTxMemPool::txiter it, allConflicting) {
                LogPrint("mempool", "replacing tx %s with %s for %s KORE additional fees, %d delta bytes\n",
                    it->GetTx().GetHash().ToString(),
                    hash.ToString(),
                    FormatMoney(nModifiedFees - nConflictingFees),
                    (int)nSize - (int)nConflictingSize);
            }
            pool.RemoveStaged(allConflicting);
        }

        // Check against previous transactions
        // This is done last to help prevent CPU exhaustion denial-of-service attacks.
        if (!CheckInputs(tx, state, view, true, STANDARD_SCRIPT_VERIFY_FLAGS, true))
            return false;


        // Check again against just the consensus-critical mandatory script
        // verification flags, in case of bugs in the standard flags that cause
        // transactions to pass as valid when they're actually invalid. For
        // instance the STRICTENC flag was incorrectly allowing certain
        // CHECKSIG NOT scripts to pass, even though they were invalid.
        //
        // There is a similar check in CreateNewBlock() to prevent creating
        // invalid blocks, however allowing such transactions into the mempool
        // can be exploited as a DoS attack.
        if (!CheckInputs(tx, state, view, true, MANDATORY_SCRIPT_VERIFY_FLAGS, true)) {
            return error("%s: BUG! PLEASE REPORT THIS! ConnectInputs failed against MANDATORY but not STANDARD flags %s, %s",
                __func__, hash.ToString(), FormatStateMessage_Legacy(state));
        }

        // Calculate in-mempool ancestors, up to a limit.
        CTxMemPool::setEntries setAncestors;

        size_t nLimitAncestors = GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT_LEGACY);
        size_t nLimitAncestorSize = GetArg("-limitancestorsize", DEFAULT_ANCESTOR_SIZE_LIMIT_LEGACY) * 1000;
        size_t nLimitDescendants = GetArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT_LEGACY);
        size_t nLimitDescendantSize = GetArg("-limitdescendantsize", DEFAULT_DESCENDANT_SIZE_LIMIT_LEGACY) * 1000;
        std::string errString;
        if (!pool.CalculateMemPoolAncestors(entry, setAncestors, nLimitAncestors, nLimitAncestorSize, nLimitDescendants, nLimitDescendantSize, errString)) {
            return state.DoS(0, false, REJECT_NONSTANDARD, "too-long-mempool-chain", false, errString);
        }

        // A transaction that spends outputs that would be replaced by it is invalid. Now
        // that we have the set of all ancestors we can detect this
        // pathological case by making sure setConflicts and setAncestors don't
        // intersect.
        BOOST_FOREACH (CTxMemPool::txiter ancestorIt, setAncestors) {
            const uint256& hashAncestor = ancestorIt->GetTx().GetHash();
            if (setConflicts.count(hashAncestor)) {
                return state.DoS(10, error("AcceptToMemoryPool: %s spends conflicting transaction %s", hash.ToString(), hashAncestor.ToString()), REJECT_INVALID, "bad-txns-spends-conflicting-tx");
            }
        }

        // Store transaction in memory
        pool.addUnchecked(hash, entry, setAncestors, !IsInitialBlockDownload());
        // trim mempool and check if tx was trimmed
        if (!fOverrideMempoolLimit) {
            LimitMempoolSize(pool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE_LEGACY) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY_LEGACY) * 60 * 60);
            if (!pool.exists(hash))
                return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool full");
        }
    }

    SyncWithWallets(tx, NULL);

    return true;
}

bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState& state, const CTransaction& tx, bool fLimitFree, bool* pfMissingInputs, bool fOverrideMempoolLimit, bool fRejectAbsurdFee, bool ignoreFees, bool isLoadingTx)
{
    std::vector<uint256> vHashTxToUncache;
    bool res = AcceptToMemoryPoolWorker(pool, state, tx, fLimitFree, pfMissingInputs, fOverrideMempoolLimit, fRejectAbsurdFee, vHashTxToUncache, ignoreFees, isLoadingTx);
    if (!res) {
        BOOST_FOREACH (const uint256& hashTx, vHashTxToUncache)
            pcoinsTip->Uncache(hashTx);
    }
    return res;
}

bool AcceptableInputs(CTxMemPool& pool, CValidationState& state, const CTransaction& tx, bool fLimitFree, bool* pfMissingInputs, bool fRejectInsaneFee, bool isDSTX)
{
    AssertLockHeld(cs_main);
    if (pfMissingInputs)
        *pfMissingInputs = false;

    if (!CheckTransaction(tx, state))
        return error("AcceptableInputs: CheckTransaction failed");

    // Coinbase is only valid in a block, not as a loose transaction
    if (tx.IsCoinBase())
        return state.DoS(100, error("AcceptableInputs: coinbase as individual tx"),
            REJECT_INVALID, "coinbase");

    // is it already in the memory pool?
    uint256 hash = tx.GetHash();
    if (pool.exists(hash))
        return false;

    // Check for conflicts with in-memory transactions
    {
        LOCK(pool.cs); // protect pool.mapNextTx
        for (unsigned int i = 0; i < tx.vin.size(); i++) {
            COutPoint outpoint = tx.vin[i].prevout;
            if (pool.mapNextTx.count(outpoint)) {
                // Disable replacement feature for now
                return false;
            }
        }
    }


    {
        CCoinsView dummy;
        CCoinsViewCache view(&dummy);

        CAmount nValueIn = 0;
        {
            LOCK(pool.cs);
            CCoinsViewMemPool viewMemPool(pcoinsTip, pool);
            view.SetBackend(viewMemPool);

            // do we already have it?
            if (view.HaveCoins(hash))
                return false;

            // do all inputs exist?
            // Note that this does not check for the presence of actual outputs (see the next check for that),
            // only helps filling in pfMissingInputs (to determine missing vs spent).
            for (const CTxIn txin : tx.vin) {
                if (!view.HaveCoins(txin.prevout.hash)) {
                    if (pfMissingInputs)
                        *pfMissingInputs = true;
                    return false;
                }

                // check for invalid/fraudulent inputs
                if (!ValidOutPoint(txin.prevout, chainActive.Height())) {
                    return state.Invalid(error("%s: tried to spend invalid input %s in tx %s", __func__, txin.prevout.ToString(),
                                             tx.GetHash().GetHex()),
                        REJECT_INVALID, "bad-txns-invalid-inputs");
                }
            }

            // are the actual inputs available?
            if (!view.HaveInputs(tx))
                return state.Invalid(error("AcceptableInputs: inputs already spent"),
                    REJECT_DUPLICATE, "bad-txns-inputs-spent");

            // Bring the best block into scope
            view.GetBestBlock();

            nValueIn = view.GetValueIn(tx);

            // we have all inputs cached now, so switch back to dummy, so we don't need to keep lock on mempool
            view.SetBackend(dummy);
        }

        // Check for non-standard pay-to-script-hash in inputs
        // for any real tx this will be checked on AcceptToMemoryPool anyway
        //        if (Params().RequireStandard() && !AreInputsStandard(tx, view))
        //            return error("AcceptableInputs: nonstandard transaction input");

        // Check that the transaction doesn't have an excessive number of
        // sigops, making it impossible to mine. Since the coinbase transaction
        // itself can contain sigops MAX_TX_SIGOPS is less than
        // MAX_BLOCK_SIGOPS; we still consider this an invalid rather than
        // merely non-standard transaction.
        unsigned int nSigOps = GetLegacySigOpCount(tx);
        unsigned int nMaxSigOps = MAX_TX_SIGOPS_CURRENT;
        nSigOps += GetP2SHSigOpCount(tx, view);
        if (nSigOps > nMaxSigOps)
            return state.DoS(0,
                error("AcceptableInputs: too many sigops %s, %d > %d",
                    hash.ToString(), nSigOps, nMaxSigOps),
                REJECT_NONSTANDARD, "bad-txns-too-many-sigops");

        CAmount nValueOut = tx.GetValueOut();
        CAmount nFees = nValueIn - nValueOut;
        CAmount inChainInputValue;
        double dPriority = view.GetPriority(tx, chainActive.Height(), inChainInputValue);

        CTxMemPoolEntry entry(tx, nFees, GetTime(), dPriority, chainActive.Height());
        unsigned int nSize = entry.GetTxSize();

        // Don't accept it if it can't get into a block
        // but prioritise dstx and don't check fees for it
        if (isDSTX) {
            mempool.PrioritiseTransaction(hash, hash.ToString(), 1000, 0.1 * COIN);
        } else { // same as !ignoreFees for AcceptToMemoryPool
            CAmount txMinFee = GetMinRelayFee(tx, nSize, true);
            if (fLimitFree && nFees < txMinFee)
                return state.DoS(0, error("AcceptableInputs: not enough fees %s, %d < %d", hash.ToString(), nFees, txMinFee),
                    REJECT_INSUFFICIENTFEE, "insufficient fee");

            // Require that free transactions have sufficient priority to be mined in the next block.
            CAmount inChainInputValue;
            if (GetBoolArg("-relaypriority", true) && nFees < ::minRelayTxFee.GetFee(nSize) && !AllowFree(view.GetPriority(tx, chainActive.Height() + 1, inChainInputValue))) {
                return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "insufficient priority");
            }

            // Continuously rate-limit free (really, very-low-fee) transactions
            // This mitigates 'penny-flooding' -- sending thousands of free transactions just to
            // be annoying or make others' transactions take longer to confirm.
            if (fLimitFree && nFees < ::minRelayTxFee.GetFee(nSize)) {
                static CCriticalSection csFreeLimiter;
                static double dFreeCount;
                static int64_t nLastTime;
                int64_t nNow = GetTime();

                LOCK(csFreeLimiter);

                // Use an exponentially decaying ~10-minute window:
                dFreeCount *= pow(1.0 - 1.0 / 600.0, (double)(nNow - nLastTime));
                nLastTime = nNow;
                // -limitfreerelay unit is thousand-bytes-per-minute
                // At default rate it would take over a month to fill 1GB
                if (dFreeCount >= GetArg("-limitfreerelay", 30) * 10 * 1000)
                    return state.DoS(0, error("AcceptableInputs: free transaction rejected by rate limiter"),
                        REJECT_INSUFFICIENTFEE, "rate limited free transaction");
                LogPrint("mempool", "Rate limit dFreeCount: %g => %g\n", dFreeCount, dFreeCount + nSize);
                dFreeCount += nSize;
            }
        }

        if (fRejectInsaneFee && nFees > ::minRelayTxFee.GetFee(nSize) * 10000)
            return error("AcceptableInputs: insane fees %s, %d > %d",
                hash.ToString(),
                nFees, ::minRelayTxFee.GetFee(nSize) * 10000);

        // Check against previous transactions
        // This is done last to help prevent CPU exhaustion denial-of-service attacks.
        if (!CheckInputs(tx, state, view, false, STANDARD_SCRIPT_VERIFY_FLAGS, true)) {
            return error("AcceptableInputs: ConnectInputs failed %s", hash.ToString());
        }
    }
    return true;
}

bool FindTransactionsByDestination(const CTxDestination& dest, std::set<CExtDiskTxPos>& setpos)
{
    uint160 addrid;
    const CKeyID* pkeyid = boost::get<CKeyID>(&dest);
    if (pkeyid)
        addrid = static_cast<uint160>(*pkeyid);
    if (addrid.IsNull()) {
        const CScriptID* pscriptid = boost::get<CScriptID>(&dest);
        if (pscriptid)
            addrid = static_cast<uint160>(*pscriptid);
    }
    if (addrid.IsNull())
        return false;

    LOCK(cs_main);
    if (!fAddrIndex)
        return false;
    std::vector<CExtDiskTxPos> vPos;
    if (!pblocktree->ReadAddrIndex(addrid, vPos))
        return false;
    setpos.insert(vPos.begin(), vPos.end());
    return true;
}

/** Return transaction in tx, and if it was found inside a block, its hash is placed in hashBlock */
bool GetTransaction(const uint256& hash, CTransaction& txOut, uint256& hashBlock, bool fAllowSlow)
{
    CBlockIndex* pindexSlow = NULL;
    {
        LOCK(cs_main);
        {
            if (mempool.lookup(hash, txOut)) {
                return true;
            }
        }

        if (fTxIndex) {
            CDiskTxPos postx;
            if (pblocktree->ReadTxIndex(hash, postx)) {
                CAutoFile file(OpenBlockFile(postx, true), SER_DISK, CLIENT_VERSION);
                if (file.IsNull())
                    return error("%s: OpenBlockFile failed", __func__);
                CBlockHeader header;
                try {
                    file >> header;
                    fseek(file.Get(), postx.nTxOffset, SEEK_CUR);
                    file >> txOut;
                } catch (std::exception& e) {
                    return error("%s : Deserialize or I/O error - %s", __func__, e.what());
                }
                hashBlock = header.GetHash();
                if (txOut.GetHash() != hash)
                    return error("%s : txid mismatch", __func__);
                return true;
            }

            // transaction not found in the index, nothing more can be done
            return false;
        }

        if (fAllowSlow) { // use coin database to locate block that contains transaction, and scan it
            int nHeight = -1;
            {
                CCoinsViewCache& view = *pcoinsTip;
                const CCoins* coins = view.AccessCoins(hash);
                if (coins)
                    nHeight = coins->nHeight;
            }
            if (nHeight > 0)
                pindexSlow = chainActive[nHeight];
        }
    }

    if (pindexSlow) {
        CBlock block;
        if (ReadBlockFromDisk(block, pindexSlow)) {
            BOOST_FOREACH (const CTransaction& tx, block.vtx) {
                if (tx.GetHash() == hash) {
                    txOut = tx;
                    hashBlock = pindexSlow->GetBlockHash();
                    return true;
                }
            }
        }
    }

    return false;
}


//////////////////////////////////////////////////////////////////////////////
//
// CBlock and CBlockIndex
//

bool WriteBlockToDisk(const CBlock& block, CDiskBlockPos& pos)
{
    // Open history file to append
    CAutoFile fileout(OpenBlockFile(pos), SER_DISK, CLIENT_VERSION);
    if (fileout.IsNull())
        return error("WriteBlockToDisk : OpenBlockFile failed");

    // Write index header
    unsigned int nSize = fileout.GetSerializeSize(block);
    fileout << FLATDATA(Params().MessageStart()) << nSize;

    // Write block
    long fileOutPos = ftell(fileout.Get());
    if (fileOutPos < 0)
        return error("WriteBlockToDisk : ftell failed");
    pos.nPos = (unsigned int)fileOutPos;
    fileout << block;

    return true;
}

bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos)
{
    block.SetNull();

    // Open history file to read
    CAutoFile filein(OpenBlockFile(pos, true), SER_DISK, CLIENT_VERSION);
    if (filein.IsNull())
        return error("ReadBlockFromDisk : OpenBlockFile failed");

    // Read block
    try {
        filein >> block;
    } catch (std::exception& e) {
        return error("%s : Deserialize or I/O error - %s", __func__, e.what());
    }

    // Check the header
    if (block.IsProofOfWork()) {
        if (UseLegacyCode(block)) {
            if (!CheckProofOfWork_Legacy(block.GetHash(), block.nBits))
                return error("ReadBlockFromDisk : Errors in block header");
        } else {
            if (!CheckProofOfWork(block.GetHash(), block.nBits))
                return error("ReadBlockFromDisk : Errors in block header");
        }
    }

    return true;
}

bool ReadBlockFromDisk(CBlock& block, const CBlockIndex* pindex)
{
    if (!ReadBlockFromDisk(block, pindex->GetBlockPos()))
        return false;
    if (block.GetHash() != pindex->GetBlockHash()) {
        if (fDebug) {
            LogPrintf("%s : block=%s index=%s\n", __func__, block.GetHash().ToString().c_str(), pindex->GetBlockHash().ToString().c_str());
            LogPrintf("    %s \n", block.ToString());
        }
        return error("ReadBlockFromDisk(CBlock&, CBlockIndex*) : GetHash() doesn't match index");
    }
    return true;
}

double ConvertBitsToDouble(unsigned int nBits)
{
    int nShift = (nBits >> 24) & 0xff;

    double dDiff =
        (double)0x0000ffff / (double)(nBits & 0x00ffffff);

    while (nShift < 29) {
        dDiff *= 256.0;
        nShift++;
    }
    while (nShift > 29) {
        dDiff /= 256.0;
        nShift--;
    }

    return dDiff;
}

CAmount GetProofOfStakeSubsidy_Legacy(int nHeight, CAmount input)
{
    CAmount subsidy = input + input * 0.00024;

    return subsidy;
}


int64_t GetBlockValue(int nHeight)
{
    if (Params().EnableBigRewards()) {
        if (nHeight >= 0 && nHeight <= 50)
            return 40000 * COIN;
    }
    return 5 * COIN;
}

CAmount GetMasternodeFundPayment(CAmount blockReward, CAmount stakedBalance, CBlockIndex* pindexPrev)
{
    double moneySupplyDouble = pindexPrev->nMoneySupply;
    double blockRewardDouble = (double)blockReward;
    double stakedBalanceDouble = (double)min(stakedBalance, MAXIMUM_STAKE_VALUE);

    return (1 - ((4e-13 * stakedBalanceDouble) + (1e-58 * pow(stakedBalanceDouble, 2) * moneySupplyDouble) + 0.43)) * blockReward;
}

int GetBestPeerHeight()
{
    return std::max(cPeerBlockCounts.median(), Checkpoints::GetTotalBlocksEstimate());
}

bool IsInitialBlockDownload()
{
    const CChainParams& chainParams = Params();
    LOCK(cs_main);
    if (fImporting || fReindex || fVerifyingBlocks || chainActive.Height() < Checkpoints::GetTotalBlocksEstimate())
        return true;
    static bool lockIBDState = false;
    if (lockIBDState)
        return false;
    bool state = (chainActive.Height() < pindexBestHeader->nHeight - 2 * 60 || // 60 Blocks per hour
                  pindexBestHeader->GetBlockTime() < GetTime() - chainParams.GetMaxTipAge()); // ~1440 blocks behind -> 2 x fork detection time
    if (!state)
        lockIBDState = true;
    return state;
}

bool fLargeWorkForkFound = false;
bool fLargeWorkInvalidChainFound = false;
CBlockIndex *pindexBestForkTip = NULL, *pindexBestForkBase = NULL;

void CheckForkWarningConditions()
{
    AssertLockHeld(cs_main);
    // Before we get past initial download, we cannot reliably alert about forks
    // (we assume we don't get stuck on a fork before the last checkpoint)
    if (IsInitialBlockDownload())
        return;

    // If our best fork is no longer within 72 blocks (+/- 12 hours if no one mines it)
    // of our head, drop it
    if (pindexBestForkTip && chainActive.Height() - pindexBestForkTip->nHeight >= 72)
        pindexBestForkTip = NULL;

    if (pindexBestForkTip || (pindexBestInvalid && pindexBestInvalid->nChainWork > chainActive.Tip()->nChainWork + (GetBlockProof(*chainActive.Tip()) * Params().GetCoinMaturity()))) {
        if (!fLargeWorkForkFound && pindexBestForkBase) {
            std::string warning = std::string("'Warning: Large-work fork detected, forking after block ") +
                                  pindexBestForkBase->phashBlock->ToString() + std::string("'");
            CAlert::Notify(warning, true);
        }
        if (pindexBestForkTip && pindexBestForkBase) {
            LogPrintf("%s: Warning: Large valid fork found\n  forking the chain at height %d (%s)\n  lasting to height %d (%s).\nChain state database corruption likely.\n", __func__,
                pindexBestForkBase->nHeight, pindexBestForkBase->phashBlock->ToString(),
                pindexBestForkTip->nHeight, pindexBestForkTip->phashBlock->ToString());
            fLargeWorkForkFound = true;
        } else {
            LogPrintf("%s: Warning: Found invalid chain at least ~%d blocks longer than our best chain.\nChain state database corruption likely.\n", __func__, Params().GetCoinMaturity());
            fLargeWorkInvalidChainFound = true;
        }
    } else {
        fLargeWorkForkFound = false;
        fLargeWorkInvalidChainFound = false;
    }
}


void CheckForkWarningConditionsOnNewFork(CBlockIndex* pindexNewForkTip)
{
    AssertLockHeld(cs_main);
    // If we are on a fork that is sufficiently large, set a warning flag
    CBlockIndex* pfork = pindexNewForkTip;
    CBlockIndex* plonger = chainActive.Tip();
    while (pfork && pfork != plonger) {
        while (plonger && plonger->nHeight > pfork->nHeight)
            plonger = plonger->pprev;
        if (pfork == plonger)
            break;
        pfork = pfork->pprev;
    }

    // We define a condition which we should warn the user about as a fork of at least 7 blocks
    // who's tip is within 72 blocks (+/- 3 hours if no one mines it) of ours
    // or a chain that is entirely longer than ours and invalid (note that this should be detected by both)
    // We use 7 blocks rather arbitrarily as it represents just under 10% of sustained network
    // hash rate operating on the fork.
    // We define it this way because it allows us to only store the highest fork tip (+ base) which meets
    // the 7-block condition and from this always have the most-likely-to-cause-warning fork
    if (pfork && (!pindexBestForkTip || (pindexBestForkTip && pindexNewForkTip->nHeight > pindexBestForkTip->nHeight)) &&
        pindexNewForkTip->nChainWork - pfork->nChainWork > (GetBlockProof(*pfork) * 7) &&
        chainActive.Height() - pindexNewForkTip->nHeight < 72) {
        pindexBestForkTip = pindexNewForkTip;
        pindexBestForkBase = pfork;
    }

    CheckForkWarningConditions();
}

// Requires cs_main.
void Misbehaving(NodeId pnode, int howmuch, std::string reason)
{
    if (howmuch == 0)
        return;

    CNodeState* state = State(pnode);
    if (state == NULL)
        return;

    state->nMisbehavior += howmuch;
    int banscore = GetArg("-banscore", 100);
    LogPrintf("Misbehaving: %s (%d -> %d)\n", state->name, state->nMisbehavior - howmuch, state->nMisbehavior);
    LogPrintf("Reason: %s", reason);

    if (state->nMisbehavior >= banscore && state->nMisbehavior - howmuch < banscore) {
        LogPrintf("Misbehaving: %s (%d -> %d) BAN THRESHOLD EXCEEDED\n", state->name, state->nMisbehavior - howmuch, state->nMisbehavior);

        state->fShouldBan = true;
    }
}

void static InvalidChainFound(CBlockIndex* pindexNew)
{
    if (!pindexBestInvalid || pindexNew->nChainWork > pindexBestInvalid->nChainWork)
        pindexBestInvalid = pindexNew;

    if (fDebug)
        LogPrintf("%s: invalid block=%s  height=%d  log2_work=%.8g  date=%s\n", __func__,
            pindexNew->GetBlockHash().ToString(), pindexNew->nHeight,
            log(pindexNew->nChainWork.getdouble()) / log(2.0), DateTimeStrFormat("%Y-%m-%d %H:%M:%S", pindexNew->GetBlockTime()));
    CBlockIndex* tip = chainActive.Tip();
    assert(tip);
    if (fDebug) 
        LogPrintf("%s:  current best=%s  height=%d  log2_work=%.8g  date=%s\n", __func__,
            tip->GetBlockHash().ToString(), chainActive.Height(), log(tip->nChainWork.getdouble()) / log(2.0),
            DateTimeStrFormat("%Y-%m-%d %H:%M:%S", tip->GetBlockTime()));
    CheckForkWarningConditions();
}

void static InvalidBlockFound(CBlockIndex* pindex, const CValidationState& state)
{
    int nDoS = 0;
    if (state.IsInvalid(nDoS)) {
        std::map<uint256, NodeId>::iterator it = mapBlockSource.find(pindex->GetBlockHash());
        if (it != mapBlockSource.end() && State(it->second)) {
            CBlockReject reject = {state.GetRejectCode(), state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), pindex->GetBlockHash()};
            State(it->second)->rejects.push_back(reject);
            if (nDoS > 0)
                Misbehaving(it->second, nDoS, "Invalid block found");
        }
    }
    if (!state.CorruptionPossible()) {
        pindex->nStatus |= BLOCK_FAILED_VALID;
        setDirtyBlockIndex.insert(pindex);
        setBlockIndexCandidates.erase(pindex);
        InvalidChainFound(pindex);
    }
}

void UpdateCoins(const CTransaction& tx, CValidationState& state, CCoinsViewCache& inputs, CTxUndo& txundo, int nHeight)
{
    // mark inputs spent
    if (!tx.IsCoinBase()) {
        txundo.vprevout.reserve(tx.vin.size());
        BOOST_FOREACH (const CTxIn& txin, tx.vin) {
            CCoinsModifier coins = inputs.ModifyCoins(txin.prevout.hash);
            unsigned nPos = txin.prevout.n;

            if (nPos >= coins->vout.size() || coins->vout[nPos].IsNull())
                assert(false);
            // mark an outpoint spent, and construct undo information
            txundo.vprevout.push_back(CTxInUndo(coins->vout[nPos]));
            bool ret = coins->Spend(txin.prevout, txundo.vprevout.back());
        }
        // add outputs
        inputs.ModifyNewCoins(tx.GetHash())->FromTx(tx, nHeight);
    } else {
        // add outputs for coinbase tx
        // In this case call the full ModifyCoins which will do a database
        // lookup to be sure the coins do not already exist otherwise we do not
        // know whether to mark them fresh or not.  We want the duplicate coinbases
        // before BIP30 to still be properly overwritten.
        inputs.ModifyCoins(tx.GetHash())->FromTx(tx, nHeight);
    }
}

bool CScriptCheck::operator()()
{
    const CScript& scriptSig = ptxTo->vin[nIn].scriptSig;
    if (!VerifyScript(scriptSig, scriptPubKey, nFlags, CachingTransactionSignatureChecker(ptxTo, nIn, cacheStore), &error)) {
        return ::error("CScriptCheck(): %s:%d VerifySignature failed: %s", ptxTo->GetHash().ToString(), nIn, ScriptErrorString(error));
    }
    return true;
}

CBitcoinAddress addressExp1("DQZzqnSR6PXxagep1byLiRg9ZurCZ5KieQ");
CBitcoinAddress addressExp2("DTQYdnNqKuEHXyNeeYhPQGGGdqHbXYwjpj");

bool ValidOutPoint(const COutPoint out, int nHeight)
{
    bool isInvalid = nHeight >= Params().HeightToFork() && invalid_out::ContainsOutPoint(out);
    return !isInvalid;
}

CAmount GetInvalidUTXOValue()
{
    CAmount nValue = 0;
    for (auto out : invalid_out::setInvalidOutPoints) {
        bool fSpent = false;
        CCoinsViewCache cache(pcoinsTip);
        const CCoins* coins = cache.AccessCoins(out.hash);
        if (!coins || !coins->IsAvailable(out.n))
            fSpent = true;

        if (!fSpent)
            nValue += coins->vout[out.n].nValue;
    }

    return nValue;
}

int GetSpendHeight(const CCoinsViewCache& inputs)
{
    LOCK(cs_main);
    CBlockIndex* pindexPrev = mapBlockIndex.find(inputs.GetBestBlock())->second;
    return pindexPrev->nHeight + 1;
}


bool CheckInputs(const CTransaction& tx, CValidationState& state, const CCoinsViewCache& inputs, bool fScriptChecks, unsigned int flags, bool cacheStore, std::vector<CScriptCheck>* pvChecks)
{
    if (!tx.IsCoinBase()) {
        if (pvChecks)
            pvChecks->reserve(tx.vin.size());

        // This doesn't trigger the DoS code on purpose; if it did, it would make it easier
        // for an attacker to attempt to split the network.
        if (!inputs.HaveInputs(tx))
            return state.Invalid(error("CheckInputs() : %s inputs unavailable", tx.GetHash().ToString()));

        // While checking, GetBestBlock() refers to the parent block.
        // This is also true for mempool checks.
        int nSpendHeight = GetSpendHeight(inputs);
        CAmount nValueIn = 0;
        CAmount nFees = 0;
        for (unsigned int i = 0; i < tx.vin.size(); i++) {
            const COutPoint& prevout = tx.vin[i].prevout;
            const CCoins* coins = inputs.AccessCoins(prevout.hash);
            assert(coins);

            // If prev is coinbase, check that it's matured
            if (coins->IsCoinBase()) {
                if (coins->IsCoinStake()) {
                    CTransaction txStake;
                    uint256 blockHash;

                    if (!GetTransaction(prevout.hash, txStake, blockHash, true))
                        return state.Invalid(
                            error("CheckInputs(): could not find tx %s", prevout.hash.ToString()),
                            REJECT_INVALID, "bad-txns-premature-spend-of-coinbase");
                    
                    if (txStake.IsLegacyCoinStake() && nSpendHeight - coins->nHeight < Params().GetCoinMaturity())
                        return state.Invalid(
                            error("CheckInputs(): tried to spend coinbase at depth %d", nSpendHeight - coins->nHeight),
                            REJECT_INVALID, "bad-txns-premature-spend-of-coinbase");
                }

                if (nSpendHeight - coins->nHeight < Params().GetCoinMaturity())
                    return state.Invalid(
                        error("CheckInputs(): tried to spend coinbase at depth %d", nSpendHeight - coins->nHeight),
                        REJECT_INVALID, "bad-txns-premature-spend-of-coinbase");
            }

            // Check transaction timestamp
            if (coins->nTime > tx.nTime)
                return state.DoS(100, false, REJECT_INVALID, "bad-txns-time-earlier-than-input");

            // Check for negative or overflow input values
            nValueIn += coins->vout[prevout.n].nValue;
            if (!MoneyRange(coins->vout[prevout.n].nValue) || !MoneyRange(nValueIn))
                return state.DoS(100, error("CheckInputs() : txin values out of range"),
                    REJECT_INVALID, "bad-txns-inputvalues-outofrange");
        }

        if (!tx.IsCoinStake()) {
            if (nValueIn < tx.GetValueOut())
                return state.DoS(100, error("CheckInputs() : %s value in (%s) < value out (%s)", tx.GetHash().ToString(), FormatMoney(nValueIn), FormatMoney(tx.GetValueOut())),
                    REJECT_INVALID, "bad-txns-in-belowout");

            // Tally transaction fees
            CAmount nTxFee = nValueIn - tx.GetValueOut();
            if (nTxFee < 0)
                return state.DoS(100, error("CheckInputs() : %s nTxFee < 0", tx.GetHash().ToString()),
                    REJECT_INVALID, "bad-txns-fee-negative");
            nFees += nTxFee;
            if (!MoneyRange(nFees))
                return state.DoS(100, error("CheckInputs() : nFees out of range"),
                    REJECT_INVALID, "bad-txns-fee-outofrange");
        }
        // The first loop above does all the inexpensive checks.
        // Only if ALL inputs pass do we perform expensive ECDSA signature checks.
        // Helps prevent CPU exhaustion attacks.

        // Skip ECDSA signature verification when connecting blocks
        // before the last block chain checkpoint. This is safe because block merkle hashes are
        // still computed and checked, and any change will be caught at the next checkpoint.
        if (fScriptChecks) {
            for (unsigned int i = 0; i < tx.vin.size(); i++) {
                const COutPoint& prevout = tx.vin[i].prevout;
                const CCoins* coins = inputs.AccessCoins(prevout.hash);
                assert(coins);

                // Verify signature
                CScriptCheck check(*coins, tx, i, flags, cacheStore);
                if (pvChecks) {
                    pvChecks->push_back(CScriptCheck());
                    check.swap(pvChecks->back());
                } else if (!check()) {
                    if (flags & STANDARD_NOT_MANDATORY_VERIFY_FLAGS) {
                        // Check whether the failure was caused by a
                        // non-mandatory script verification check, such as
                        // non-standard DER encodings or non-null dummy
                        // arguments; if so, don't trigger DoS protection to
                        // avoid splitting the network between upgraded and
                        // non-upgraded nodes.
                        CScriptCheck check2(*coins, tx, i,
                            flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheStore);
                        if (check2())
                            return state.Invalid(false, REJECT_NONSTANDARD, strprintf("non-mandatory-script-verify-flag (%s)", ScriptErrorString(check2.GetScriptError())));
                    }
                    // Failures of other flags indicate a transaction that is
                    // invalid in new blocks, e.g. a invalid P2SH. We DoS ban
                    // such nodes as they are not following the protocol. That
                    // said during an upgrade careful thought should be taken
                    // as to the correct behavior - we may want to continue
                    // peering with non-upgraded nodes even after a soft-fork
                    // super-majority vote has passed.
                    return state.DoS(100, false, REJECT_INVALID, strprintf("mandatory-script-verify-flag-failed (%s)", ScriptErrorString(check.GetScriptError())));
                }
            }
        }
    }

    return true;
}

bool DisconnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, CCoinsViewCache& view, bool* pfClean)
{
    if (UseLegacyCode(block))
        return DisconnectBlock_Legacy(block, state, pindex, view, pfClean);

    if (pindex->GetBlockHash() != view.GetBestBlock() && fDebug)
        LogPrintf("%s : pindex=%s view=%s\n", __func__, pindex->GetBlockHash().GetHex(), view.GetBestBlock().GetHex());

    assert(pindex->GetBlockHash() == view.GetBestBlock());

    if (pfClean)
        *pfClean = false;

    bool fClean = true;

    CBlockUndo blockUndo;
    CDiskBlockPos pos = pindex->GetUndoPos();
    if (pos.IsNull())
        return error("DisconnectBlock() : no undo data available");
    if (!blockUndo.ReadFromDisk(pos, pindex->pprev->GetBlockHash()))
        return error("DisconnectBlock() : failure reading undo data");

    if (blockUndo.vtxundo.size() + 1 != block.vtx.size())
        return error("DisconnectBlock() : block and undo data inconsistent");

    // undo transactions in reverse order
    for (int i = block.vtx.size() - 1; i >= 0; i--) {
        const CTransaction& tx = block.vtx[i];

        uint256 hash = tx.GetHash();

        // Check that all outputs are available and match the outputs in the block itself
        // exactly. Note that transactions with only provably unspendable outputs won't
        // have outputs available even in the block itself, so we handle that case
        // specially with outsEmpty.
        {
            CCoins outsEmpty;
            CCoinsModifier outs = view.ModifyCoins(hash);
            outs->ClearUnspendable();

            CCoins outsBlock(tx, pindex->nHeight);
            // The CCoins serialization does not serialize negative numbers.
            // No network rules currently depend on the version here, so an inconsistency is harmless
            // but it must be corrected before txout nversion ever influences a network rule.
            if (outsBlock.nVersion < 0)
                outs->nVersion = outsBlock.nVersion;
            if (*outs != outsBlock)
                fClean = fClean && error("DisconnectBlock(): added transaction mismatch? database corrupted");

            // remove outputs
            outs->Clear();
        }

        // restore inputs
        if (!tx.IsCoinBase()) {
            const CTxUndo& txundo = blockUndo.vtxundo[i - 1];
            if (txundo.vprevout.size() != tx.vin.size())
                return error("DisconnectBlock() : transaction and undo data inconsistent - txundo.vprevout.siz=%d tx.vin.siz=%d", txundo.vprevout.size(), tx.vin.size());
            for (unsigned int j = tx.vin.size(); j-- > 0;) {
                const COutPoint& out = tx.vin[j].prevout;
                const CTxInUndo& undo = txundo.vprevout[j];
                CCoinsModifier coins = view.ModifyCoins(out.hash);
                if (undo.nHeight != 0) {
                    // undo data contains height: this is the last output of the prevout tx being spent
                    if (!coins->IsPruned())
                        fClean = fClean && error("DisconnectBlock() : undo data overwriting existing transaction");
                    coins->FromUndo(undo);
                } else {
                    if (coins->IsPruned())
                        fClean = fClean && error("DisconnectBlock() : undo data adding output to missing transaction");
                }
                if (coins->IsAvailable(out.n))
                    fClean = fClean && error("DisconnectBlock() : undo data overwriting existing output");
                if (coins->vout.size() < out.n + 1)
                    coins->vout.resize(out.n + 1);
                coins->vout[out.n] = undo.txout;
            }
        }
    }

    // move best block pointer to prevout block
    view.SetBestBlock(pindex->pprev->GetBlockHash());

    if (pfClean) {
        *pfClean = fClean;
        return true;
    } else {
        return fClean;
    }
}

/**
 * Apply the undo operation of a CTxInUndo to the given chain state.
 * @param undo The undo object.
 * @param view The coins view to which to apply the changes.
 * @param out The out point that corresponds to the tx input.
 * @return True on success.
 */
static bool ApplyTxInUndo_Legacy(const CTxInUndo& undo, CCoinsViewCache& view, const COutPoint& out)
{
    bool fClean = true;

    CCoinsModifier coins = view.ModifyCoins(out.hash);
    if (undo.nHeight != 0) {
        // undo data contains height: this is the last output of the prevout tx being spent
        if (!coins->IsPruned())
            fClean = fClean && error("%s: undo data overwriting existing transaction", __func__);
        coins->FromUndo(undo);
    } else {
        if (coins->IsPruned())
            fClean = fClean && error("%s: undo data adding output to missing transaction", __func__);
    }
    if (coins->IsAvailable(out.n))
        fClean = fClean && error("%s: undo data overwriting existing output", __func__);
    if (coins->vout.size() < out.n + 1)
        coins->vout.resize(out.n + 1);
    coins->vout[out.n] = undo.txout;

    return fClean;
}

bool UndoReadFromDisk_Legacy(CBlockUndo& blockundo, const CDiskBlockPos& pos, const uint256& hashBlock)
{
    // Open history file to read
    CAutoFile filein(OpenUndoFile(pos, true), SER_DISK, CLIENT_VERSION);
    if (filein.IsNull())
        return error("%s: OpenBlockFile failed", __func__);

    // Read block
    uint256 hashChecksum;
    try {
        filein >> blockundo;
        filein >> hashChecksum;
    } catch (const std::exception& e) {
        return error("%s: Deserialize or I/O error - %s", __func__, e.what());
    }

    // Verify checksum
    CHashWriter hasher(SER_GETHASH, PROTOCOL_VERSION);
    hasher << hashBlock;
    hasher << blockundo;
    if (hashChecksum != hasher.GetHash())
        return error("%s: Checksum mismatch", __func__);

    return true;
}


bool DisconnectBlock_Legacy(const CBlock& block, CValidationState& state, const CBlockIndex* pindex, CCoinsViewCache& view, bool* pfClean)
{
    assert(pindex->GetBlockHash() == view.GetBestBlock());

    if (pfClean)
        *pfClean = false;

    bool fClean = true;

    CBlockUndo blockUndo;
    CDiskBlockPos pos = pindex->GetUndoPos();
    if (pos.IsNull())
        return error("DisconnectBlock(): no undo data available");
    if (!UndoReadFromDisk_Legacy(blockUndo, pos, pindex->pprev->GetBlockHash()))
        return error("DisconnectBlock(): failure reading undo data");

    if (blockUndo.vtxundo.size() + 1 != block.vtx.size())
        return error("DisconnectBlock(): block and undo data inconsistent");

    // undo transactions in reverse order
    for (int i = block.vtx.size() - 1; i >= 0; i--) {
        const CTransaction& tx = block.vtx[i];
        uint256 hash = tx.GetHash();
        if (hash.ToString() == "b5f5580e459252fd1bf6547b62daf70af8100fc0b835b524b30b95aa2f48f6d3")
            cout << "here here";
        if (fDebug)
            LogPrintf("tx Hash %s pos=%d\n", hash.ToString().c_str(), i);
        // Check that all outputs are available and match the outputs in the block itself
        // exactly.
        {
            CCoinsModifier outs = view.ModifyCoins(hash);
            outs->ClearUnspendable();

            CCoins outsBlock(tx, pindex->nHeight);
            // The CCoins serialization does not serialize negative numbers.
            // No network rules currently depend on the version here, so an inconsistency is harmless
            // but it must be corrected before txout nversion ever influences a network rule.
            if (outsBlock.nVersion < 0)
                outs->nVersion = outsBlock.nVersion;
            if (*outs != outsBlock)
                fClean = fClean && error("DisconnectBlock(): added transaction mismatch? database corrupted");

            // remove outputs
            outs->Clear();
        }

        // restore inputs
        if (i > 0) { // not coinbases
            const CTxUndo& txundo = blockUndo.vtxundo[i - 1];
            if (txundo.vprevout.size() != tx.vin.size())
                return error("DisconnectBlock(): transaction and undo data inconsistent");
            for (unsigned int j = tx.vin.size(); j-- > 0;) {
                const COutPoint& out = tx.vin[j].prevout;
                const CTxInUndo& undo = txundo.vprevout[j];
                if (!ApplyTxInUndo_Legacy(undo, view, out))
                    fClean = false;
            }
        }
    }

    // move best block pointer to prevout block
    view.SetBestBlock(pindex->pprev->GetBlockHash());

    if (pfClean) {
        *pfClean = fClean;
        return true;
    }

    return fClean;
}

void static FlushBlockFile(bool fFinalize = false)
{
    LOCK(cs_LastBlockFile);

    CDiskBlockPos posOld(nLastBlockFile, 0);

    FILE* fileOld = OpenBlockFile(posOld);
    if (fileOld) {
        if (fFinalize)
            TruncateFile(fileOld, vinfoBlockFile[nLastBlockFile].nSize);
        FileCommit(fileOld);
        fclose(fileOld);
    }

    fileOld = OpenUndoFile(posOld);
    if (fileOld) {
        if (fFinalize)
            TruncateFile(fileOld, vinfoBlockFile[nLastBlockFile].nUndoSize);
        FileCommit(fileOld);
        fclose(fileOld);
    }
}

bool FindUndoPos(CValidationState& state, int nFile, CDiskBlockPos& pos, unsigned int nAddSize);
bool FindUndoPos_Legacy(CValidationState& state, int nFile, CDiskBlockPos& pos, unsigned int nAddSize);

static CCheckQueue<CScriptCheck> scriptcheckqueue(128);

void ThreadScriptCheck()
{
    RenameThread("kore-scriptch");
    scriptcheckqueue.Thread();
}

bool RecalculateKORESupply(int nHeightStart)
{
    if (nHeightStart > chainActive.Height())
        return false;

    CBlockIndex* pindex = chainActive[nHeightStart];
    CAmount nSupplyPrev = pindex->pprev->nMoneySupply;

    while (true) {
        if (pindex->nHeight % 1000 == 0 && fDebug) LogPrintf("%s : block %d...\n", __func__, pindex->nHeight);

        CBlock block;
        assert(ReadBlockFromDisk(block, pindex));

        CAmount nValueIn = 0;
        CAmount nValueOut = 0;
        for (const CTransaction tx : block.vtx) {
            for (unsigned int i = 0; i < tx.vin.size(); i++) {
                if (tx.IsCoinBase())
                    break;

                COutPoint prevout = tx.vin[i].prevout;
                CTransaction txPrev;
                uint256 hashBlock;
                assert(GetTransaction(prevout.hash, txPrev, hashBlock, true));
                nValueIn += txPrev.vout[prevout.n].nValue;
            }

            for (unsigned int i = 0; i < tx.vout.size(); i++) {
                if (i == 0 && tx.IsCoinStake())
                    continue;

                nValueOut += tx.vout[i].nValue;
            }
        }

        // Rewrite money supply
        pindex->nMoneySupply = nSupplyPrev + nValueOut - nValueIn;
        nSupplyPrev = pindex->nMoneySupply;

        assert(pblocktree->WriteBlockIndex(CDiskBlockIndex(pindex)));

        if (pindex->nHeight < chainActive.Height())
            pindex = chainActive.Next(pindex);
        else
            break;
    }
    return true;
}

int32_t ComputeBlockVersion_Legacy(const CBlockIndex* pindexPrev)
{
    LOCK(cs_main);
    int32_t nVersion = VERSIONBITS_TOP_BITS;

    for (int i = 0; i < (int)CChainParams::MAX_VERSION_BITS_DEPLOYMENTS; i++) {
        ThresholdState state = VersionBitsState(pindexPrev, (CChainParams::DeploymentPos)i, versionbitscache);
        if (state == THRESHOLD_LOCKED_IN || state == THRESHOLD_STARTED) {
            nVersion |= VersionBitsMask((CChainParams::DeploymentPos)i);
        }
    }

    return nVersion;
}

// This is a Legacy Class
/**
 * Threshold condition checker that triggers when unknown versionbits are seen on the network.
 */
class WarningBitsConditionChecker : public AbstractThresholdConditionChecker
{
private:
    int bit;

public:
    WarningBitsConditionChecker(int bitIn) : bit(bitIn) {}

    int64_t BeginTime() const { return 0; }
    int64_t EndTime() const { return std::numeric_limits<int64_t>::max(); }
    int Period() const { return Params().GetMinerConfirmationWindow(); }
    int Threshold() const { return Params().GetRuleChangeActivationThreshold(); }

    bool Condition(const CBlockIndex* pindex) const
    {
        return ((pindex->nVersion & VERSIONBITS_TOP_MASK) == VERSIONBITS_TOP_BITS) &&
               ((pindex->nVersion >> bit) & 1) != 0 &&
               ((ComputeBlockVersion_Legacy(pindex->pprev) >> bit) & 1) == 0;
    }
};

static ThresholdConditionCache warningcache[VERSIONBITS_NUM_BITS]; // Legacy
static int64_t nTimeCheck = 0;                                     // Legacy
static int64_t nTimeForks = 0;                                     // Legacy
static int64_t nTimeVerify = 0;
static int64_t nTimeConnect = 0;
static int64_t nTimeIndex = 0;
static int64_t nTimeCallbacks = 0;
static int64_t nTimeTotal = 0;

bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pindex, CCoinsViewCache& view, bool fJustCheck, bool fAlreadyChecked)
{
    if (UseLegacyCode(block))
        return ConnectBlock_Legacy(block, state, pindex, view, fJustCheck);
    AssertLockHeld(cs_main);
    // Check it again in case a previous version let a bad block in
    if (!fAlreadyChecked && !CheckBlock(block, state, !fJustCheck, !fJustCheck))
        return false;

    // verify that the view's current state corresponds to the previous block
    uint256 hashPrevBlock = pindex->pprev == NULL ? uint256(0) : pindex->pprev->GetBlockHash();
    if (hashPrevBlock != view.GetBestBlock() && fDebug)
        LogPrintf("%s: hashPrev=%s view=%s\n", __func__, hashPrevBlock.ToString().c_str(), view.GetBestBlock().ToString().c_str());

    assert(hashPrevBlock == view.GetBestBlock());

    // Special case for the genesis block, skipping connection of its transactions
    // (its coinbase is unspendable)
    if (block.GetHash() == Params().HashGenesisBlock()) {
        view.SetBestBlock(pindex->GetBlockHash());
        return true;
    }

    if (pindex->nHeight > Params().GetLastPoWBlock() && block.IsProofOfWork())
        return state.DoS(100, error("ConnectBlock() : PoW period ended"),
            REJECT_INVALID, "PoW-ended");

    bool fScriptChecks = pindex->nHeight >= Checkpoints::GetTotalBlocksEstimate();

    // Do not allow blocks that contain transactions which 'overwrite' older transactions,
    // unless those are already completely spent.
    // If such overwrites are allowed, coinbases and transactions depending upon those
    // can be duplicated to remove the ability to spend the first instance -- even after
    // being sent to another address.
    // See BIP30 and http://r6.ca/blog/20120206T005236Z.html for more information.
    // This logic is not necessary for memory pool transactions, as AcceptToMemoryPool
    // already refuses previously-known transaction ids entirely.
    // This rule was originally applied all blocks whose timestamp was after March 15, 2012, 0:00 UTC.
    // Now that the whole chain is irreversibly beyond that time it is applied to all blocks except the
    // two in the chain that violate it. This prevents exploiting the issue against nodes in their
    // initial block download.
    bool fEnforceBIP30 = (!pindex->phashBlock) || // Enforce on CreateNewBlock invocations which don't have a hash.
                         !((pindex->nHeight == 91842 && pindex->GetBlockHash() == uint256("0x00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec")) ||
                             (pindex->nHeight == 91880 && pindex->GetBlockHash() == uint256("0x00000000000743f190a18c5577a3c2d2a1f610ae9601ac046a38084ccb7cd721")));
    if (fEnforceBIP30) {
        BOOST_FOREACH (const CTransaction& tx, block.vtx) {
            const CCoins* coins = view.AccessCoins(tx.GetHash());
            if (coins && !coins->IsPruned())
                return state.DoS(100, error("ConnectBlock() : tried to overwrite transaction"),
                    REJECT_INVALID, "bad-txns-BIP30");
        }
    }

    CCheckQueueControl<CScriptCheck> control(fScriptChecks && nScriptCheckThreads ? &scriptcheckqueue : NULL);

    int64_t nTimeStart = GetTimeMicros();
    CAmount nFees = 0;
    int nInputs = 0;
    unsigned int nSigOps = 0;
    CDiskTxPos pos(pindex->GetBlockPos(), GetSizeOfCompactSize(block.vtx.size()));
    std::vector<std::pair<uint256, CDiskTxPos> > vPos;
    vPos.reserve(block.vtx.size());
    CBlockUndo blockundo;
    blockundo.vtxundo.reserve(block.vtx.size() - 1);
    CAmount nValueOut = 0;
    CAmount nValueIn = 0;
    unsigned int nMaxBlockSigOps = MAX_BLOCK_SIGOPS_CURRENT;
    vector<uint256> vSpendsInBlock;
    uint256 hashBlock = block.GetHash();
    for (unsigned int i = 0; i < block.vtx.size(); i++) {
        const CTransaction& tx = block.vtx[i];

        nInputs += tx.vin.size();
        nSigOps += GetLegacySigOpCount(tx);
        if (nSigOps > nMaxBlockSigOps)
            return state.DoS(100, error("ConnectBlock(): too many sigops"), REJECT_INVALID, "bad-blk-sigops");

        if (!tx.IsCoinBase()) {
            if (!view.HaveInputs(tx))
                return state.DoS(100, error("ConnectBlock(): inputs missing/spent"),
                    REJECT_INVALID, "bad-txns-inputs-missingorspent");

            // Check that the inputs are not marked as invalid/fraudulent
            for (CTxIn in : tx.vin) {
                if (!ValidOutPoint(in.prevout, pindex->nHeight)) {
                    return state.DoS(100, error("ConnectBlock(): tried to spend invalid input %s in tx %s", in.prevout.ToString(), tx.GetHash().GetHex()),
                        REJECT_INVALID, "bad-txns-invalid-inputs");
                }
            }

            // Add in sigops done by pay-to-script-hash inputs;
            // this is to prevent a "rogue miner" from creating
            // an incredibly-expensive-to-validate block.
            nSigOps += GetP2SHSigOpCount(tx, view);
            if (nSigOps > nMaxBlockSigOps)
                return state.DoS(100, error("ConnectBlock(): too many sigops"), REJECT_INVALID, "bad-blk-sigops");

            if (!tx.IsCoinStake())
                nFees += view.GetValueIn(tx) - tx.GetValueOut();
            nValueIn += view.GetValueIn(tx);

            std::vector<CScriptCheck> vChecks;
            unsigned int flags = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_DERSIG;
            if (!CheckInputs(tx, state, view, fScriptChecks, flags, false, nScriptCheckThreads ? &vChecks : NULL))
                return false;
            control.Add(vChecks);
        }
        nValueOut += tx.GetValueOut();

        CTxUndo undoDummy;
        if (i > 0) {
            blockundo.vtxundo.push_back(CTxUndo());
        }
        UpdateCoins(tx, state, view, i == 0 ? undoDummy : blockundo.vtxundo.back(), pindex->nHeight);

        vPos.push_back(std::make_pair(tx.GetHash(), pos));
        pos.nTxOffset += ::GetSerializeSize(tx, SER_DISK, CLIENT_VERSION);
    }

    // track money supply and mint amount info
    CAmount nMoneySupplyPrev = pindex->pprev ? pindex->pprev->nMoneySupply : 0;
    pindex->nMoneySupply = nMoneySupplyPrev + nValueOut - nValueIn;
    pindex->nMint = pindex->nMoneySupply - nMoneySupplyPrev + nFees;

    int64_t nTime1 = GetTimeMicros();
    nTimeConnect += nTime1 - nTimeStart;
    LogPrint("bench", "  - Connect %u transactions: %.2fms (%.3fms/tx, %.3fms/txin) [%.2fs]\n",
        (unsigned)block.vtx.size(), 0.001 * (nTime1 - nTimeStart), 0.001 * (nTime1 - nTimeStart) / block.vtx.size(),
        nInputs <= 1 ? 0 : 0.001 * (nTime1 - nTimeStart) / (nInputs - 1), nTimeConnect * 0.000001);

    //PoW phase redistributed fees to miner. PoS stage destroys fees.
    CAmount nExpectedMint = GetBlockReward(pindex->pprev) + nFees;

    //Check that the block does not overmint
    if (nExpectedMint != pindex->nMint) {
        return state.DoS(100, error("ConnectBlock(): reward pays too much (actual=%s vs limit=%s)", FormatMoney(pindex->nMint), FormatMoney(nExpectedMint)),
            REJECT_INVALID, "bad-cb-amount");
    }

    if (!control.Wait())
        return state.DoS(100, false);

    int64_t nTime2 = GetTimeMicros();
    nTimeVerify += nTime2 - nTimeStart;
    LogPrint("bench", "  - Verify %u txins: %.2fms (%.3fms/txin) [%.2fs]\n", nInputs - 1, 0.001 * (nTime2 - nTimeStart),
        nInputs <= 1 ? 0 : 0.001 * (nTime2 - nTimeStart) / (nInputs - 1), nTimeVerify * 0.000001);

    //IMPORTANT NOTE: Nothing before this point should actually store to disk (or even memory)
    if (fJustCheck)
        return true;

    // Write undo information to disk
    if (pindex->GetUndoPos().IsNull() || !pindex->IsValid(BLOCK_VALID_SCRIPTS)) {
        if (pindex->GetUndoPos().IsNull()) {
            CDiskBlockPos pos;
            if (!FindUndoPos(state, pindex->nFile, pos, ::GetSerializeSize(blockundo, SER_DISK, CLIENT_VERSION) + 40))
                return error("ConnectBlock(): FindUndoPos failed");
            if (!blockundo.WriteToDisk(pos, pindex->pprev->GetBlockHash()))
                return state.Abort("Failed to write undo data");

            // update nUndoPos in block index
            pindex->nUndoPos = pos.nPos;
            pindex->nStatus |= BLOCK_HAVE_UNDO;
        }

        pindex->RaiseValidity(BLOCK_VALID_SCRIPTS);
        setDirtyBlockIndex.insert(pindex);
    }

    if (fTxIndex && !pblocktree->WriteTxIndex(vPos))
        return state.Abort("Failed to write transaction index");

    // add this block to the view's block chain
    view.SetBestBlock(pindex->GetBlockHash());

    int64_t nTime3 = GetTimeMicros();
    nTimeIndex += nTime3 - nTime2;
    LogPrint("bench", "  - Index writing: %.2fms [%.2fs]\n", 0.001 * (nTime3 - nTime2), nTimeIndex * 0.000001);

    // Watch for changes to the previous coinbase transaction.
    static uint256 hashPrevBestCoinBase;
    GetMainSignals().UpdatedTransaction(hashPrevBestCoinBase);
    hashPrevBestCoinBase = block.vtx[0].GetHash();

    int64_t nTime4 = GetTimeMicros();
    nTimeCallbacks += nTime4 - nTime3;
    LogPrint("bench", "  - Callbacks: %.2fms [%.2fs]\n", 0.001 * (nTime4 - nTime3), nTimeCallbacks * 0.000001);

    return true;
}

// Index either: a) every data push >=8 bytes,  b) if no such pushes, the entire script
void static BuildAddrIndex_Legacy(const CScript& script, const CExtDiskTxPos& pos, std::vector<std::pair<uint160, CExtDiskTxPos> >& out)
{
    CScript::const_iterator pc = script.begin();
    CScript::const_iterator pend = script.end();
    std::vector<unsigned char> data;
    opcodetype opcode;
    bool fHaveData = false;
    while (pc < pend) {
        script.GetOp(pc, opcode, data);
        if (0 <= opcode && opcode <= OP_PUSHDATA4 && data.size() >= 8) { // data element
            uint160 addrid;
            if (data.size() <= 20) {
                memcpy(&addrid, &data[0], data.size());
            } else {
                addrid = Hash160(data);
            }
            out.push_back(std::make_pair(addrid, pos));
            fHaveData = true;
        }
    }
    if (!fHaveData) {
        uint160 addrid = Hash160(script);
        out.push_back(std::make_pair(addrid, pos));
    }
}


bool UndoWriteToDisk_Legacy(const CBlockUndo& blockundo, CDiskBlockPos& pos, const uint256& hashBlock, const CMessageHeader::MessageStartChars& messageStart)
{
    // Open history file to append
    CAutoFile fileout(OpenUndoFile(pos), SER_DISK, CLIENT_VERSION);
    if (fileout.IsNull())
        return error("%s: OpenUndoFile failed", __func__);

    // Write index header
    unsigned int nSize = fileout.GetSerializeSize(blockundo);
    fileout << FLATDATA(messageStart) << nSize;

    // Write undo data
    long fileOutPos = ftell(fileout.Get());
    if (fileOutPos < 0)
        return error("%s: ftell failed", __func__);
    pos.nPos = (unsigned int)fileOutPos;
    fileout << blockundo;

    // calculate & write checksum
    CHashWriter hasher(SER_GETHASH, PROTOCOL_VERSION);
    hasher << hashBlock;
    hasher << blockundo;
    fileout << hasher.GetHash();

    return true;
}

bool ConnectBlock_Legacy(const CBlock& block, CValidationState& state, CBlockIndex* pindex, CCoinsViewCache& view, bool fJustCheck)
{
    const CChainParams& chainparams = Params();
    AssertLockHeld(cs_main);

    int64_t nTimeStart = GetTimeMicros();

    CTxUndo undoDummy;
    CBlockUndo blockundo;

    if (pindex->nHeight > Params().GetLastPoWBlock() && block.IsProofOfWork())
        return state.DoS(100, error("ConnectBlock() : PoW period ended"),
            REJECT_INVALID, "PoW-ended");

    // Check it again in case a previous version let a bad block in
    if (!CheckBlock_Legacy(block, state, !fJustCheck, !fJustCheck))
        return false;

    // Special case for the genesis block, skipping connection of its transactions
    // (its coinbase is unspendable)
    if (block.GetHash() == Params().HashGenesisBlock()) {
        if (!fJustCheck)
            view.SetBestBlock(pindex->GetBlockHash());
        return true;
    }
    // verify that the view's current state corresponds to the previous block
    uint256 hashPrevBlock = pindex->pprev == NULL ? uint256() : pindex->pprev->GetBlockHash();
    if (fDebug)
        LogPrintf("ConnectBlock_Legacy block height: %d hashPrevBlock: %s", pindex->nHeight, hashPrevBlock.ToString());
    assert(hashPrevBlock == view.GetBestBlock());

    // Check proof-of-stake
    if (block.IsProofOfStake()) {
        const COutPoint& prevout = block.vtx[1].vin[0].prevout;
        const CCoins* coins = view.AccessCoins(prevout.hash);
        if (!coins)
            return state.DoS(100, error("%s: kernel input unavailable", __func__), REJECT_INVALID, "bad-cs-kernel");

        if (fDebug) {
            LogPrintf("ConnectBlock_Legacy - Coin found hash: %s \n", prevout.hash.ToString());
            LogPrintf("   %s \n", coins->ToString());
        }


        // Check proof-of-stake min confirmations
        if (pindex->nHeight - coins->nHeight < Params().GetCoinMaturity())
            return state.DoS(100, error("%s: tried to stake at depth %d", __func__, pindex->nHeight - coins->nHeight), REJECT_INVALID, "bad-cs-premature");

        if (coins->nTime + 4 * 60 * 60 > block.vtx[1].nTime) // Min age requirement
            return error("CheckProofOfStake_Legacy() : min age violation - nTimeBlockFrom=%d nStakeMinAge=%d nTimeTx=%d \n", coins->nTime,  4 * 60 * 60, block.vtx[1].nTime);
        if (!CheckStakeKernelHash_Legacy(pindex->pprev, block.nBits, coins, prevout, block.vtx[1].nTime))
            return state.DoS(100, error("%s: proof-of-stake hash doesn't match nBits", __func__), REJECT_INVALID, "bad-cs-proofhash");
    }


    bool fScriptChecks = true;
    if (Checkpoints::fEnabled) {
        CBlockIndex* pindexLastCheckpoint = Checkpoints::GetLastCheckpoint();
        if (pindexLastCheckpoint && pindexLastCheckpoint->GetAncestor(pindex->nHeight) == pindex) {
            // This block is an ancestor of a checkpoint: disable script checks
            fScriptChecks = false;
        }
    }

    int64_t nTime1 = GetTimeMicros();
    nTimeCheck += nTime1 - nTimeStart;
    LogPrint("bench", "    - Sanity checks: %.2fms [%.2fs]\n", 0.001 * (nTime1 - nTimeStart), nTimeCheck * 0.000001);

    BOOST_FOREACH (const CTransaction& tx, block.vtx) {
        const CCoins* coins = view.AccessCoins(tx.GetHash());
        if (coins && !coins->IsPruned())
            return state.DoS(100, error("ConnectBlock(): tried to overwrite transaction"), REJECT_INVALID, "bad-txns-BIP30");
    }

    bool fStrictPayToScriptHash = true;
    unsigned int flags = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY | SCRIPT_VERIFY_NULLDUMMY | SCRIPT_VERIFY_CHECKSEQUENCEVERIFY;
    int nLockTimeFlags = LOCKTIME_VERIFY_SEQUENCE;

    int64_t nTime2 = GetTimeMicros();
    nTimeForks += nTime2 - nTime1;
    LogPrint("bench", "    - Fork checks: %.2fms [%.2fs]\n", 0.001 * (nTime2 - nTime1), nTimeForks * 0.000001);

    CCheckQueueControl<CScriptCheck> control(fScriptChecks && nScriptCheckThreads ? &scriptcheckqueue : NULL);

    std::vector<int> prevheights;
    CAmount nFees = 0;
    CAmount nActualStakeReward = 0;
    int nInputs = 0;
    unsigned int nSigOps = 0;
    CExtDiskTxPos pos(CDiskTxPos(pindex->GetBlockPos(), GetSizeOfCompactSize(block.vtx.size())), pindex->nHeight);
    std::vector<std::pair<uint256, CDiskTxPos> > vPosTxid;
    std::vector<std::pair<uint160, CExtDiskTxPos> > vPosAddrid;
    if (fTxIndex)
        vPosTxid.reserve(block.vtx.size());
    if (fAddrIndex)
        vPosAddrid.reserve(4 * block.vtx.size());
    blockundo.vtxundo.reserve(block.vtx.size() - 1);

    for (unsigned int i = 0; i < block.vtx.size(); i++) {
        const CTransaction& tx = block.vtx[i];

        nInputs += tx.vin.size();
        nSigOps += GetLegacySigOpCount(tx);
        if (nSigOps > MAX_BLOCK_SIGOPS_LEGACY)
            return state.DoS(100, error("ConnectBlock(): too many sigops"), REJECT_INVALID, "bad-blk-sigops");

        if (!tx.IsCoinBase()) {
            if (!view.HaveInputs(tx))
                return state.DoS(100, error("ConnectBlock(): inputs missing/spent"), REJECT_INVALID, "bad-txns-inputs-missingorspent");

            // Check that transaction is BIP68 final
            // BIP68 lock checks (as opposed to nLockTime checks) must
            // be in ConnectBlock because they require the UTXO set
            prevheights.resize(tx.vin.size());
            for (size_t j = 0; j < tx.vin.size(); j++) {
                prevheights[j] = view.AccessCoins(tx.vin[j].prevout.hash)->nHeight;
            }

            if (!SequenceLocks(tx, nLockTimeFlags, &prevheights, *pindex)) {
                return state.DoS(100, error("%s: contains a non-BIP68-final transaction", __func__), REJECT_INVALID, "bad-txns-nonfinal");
            }

            if (fStrictPayToScriptHash) {
                // Add in sigops done by pay-to-script-hash inputs;
                // this is to prevent a "rogue miner" from creating
                // an incredibly-expensive-to-validate block.
                nSigOps += GetP2SHSigOpCount(tx, view);
                if (nSigOps > MAX_BLOCK_SIGOPS_LEGACY)
                    return state.DoS(100, error("ConnectBlock(): too many sigops"), REJECT_INVALID, "bad-blk-sigops");
            }

            if (tx.IsCoinStake())
                nActualStakeReward = tx.GetValueOut() - view.GetValueIn(tx);
            else {
                nFees += view.GetValueIn(tx) - tx.GetValueOut();
            }

            std::vector<CScriptCheck> vChecks;
            bool fCacheResults = fJustCheck; // Don't cache results if we're actually connecting blocks (still consult the cache, though)
            if (!CheckInputs(tx, state, view, fScriptChecks, flags, fCacheResults, nScriptCheckThreads ? &vChecks : NULL))
                return error("ConnectBlock(): CheckInputs on %s failed with %s", tx.GetHash().ToString(), FormatStateMessage_Legacy(state));
            control.Add(vChecks);
        }

        if (fTxIndex)
            vPosTxid.push_back(std::make_pair(tx.GetHash(), pos));
        if (fAddrIndex) {
            if (!tx.IsCoinBase()) {
                BOOST_FOREACH (const CTxIn& txin, tx.vin) {
                    CCoins coins;
                    view.GetCoins(txin.prevout.hash, coins);
                    BuildAddrIndex_Legacy(coins.vout[txin.prevout.n].scriptPubKey, pos, vPosAddrid);
                }
            }
            BOOST_FOREACH (const CTxOut& txout, tx.vout)
                BuildAddrIndex_Legacy(txout.scriptPubKey, pos, vPosAddrid);
        }

        if (i > 0) {
            blockundo.vtxundo.push_back(CTxUndo());
        }
        UpdateCoins(tx, state, view, i == 0 ? undoDummy : blockundo.vtxundo.back(), pindex->nHeight);
        pos.nTxOffset += ::GetSerializeSize(tx, SER_DISK, CLIENT_VERSION);
    }

    int64_t nTime3 = GetTimeMicros();
    nTimeConnect += nTime3 - nTime2;
    LogPrint("bench", "      - Connect %u transactions: %.2fms (%.3fms/tx, %.3fms/txin) [%.2fs]\n", (unsigned)block.vtx.size(), 0.001 * (nTime3 - nTime2), 0.001 * (nTime3 - nTime2) / block.vtx.size(), nInputs <= 1 ? 0 : 0.001 * (nTime3 - nTime2) / (nInputs - 1), nTimeConnect * 0.000001);

    CAmount blockReward = nFees + GetBlockValue(pindex->nHeight);

    if (block.vtx[0].GetValueOut() > blockReward && pindex->nHeight > 1)
        return state.DoS(100, error("ConnectBlock(): coinbase pays too much (actual=%d vs limit=%d)", block.vtx[0].GetValueOut(), blockReward), REJECT_INVALID, "bad-cb-amount");

    if (block.IsProofOfStake()) {
        CAmount nValueIns = 0;
        CTransaction tx2;
        uint256 hash;
        BOOST_FOREACH (const CTxIn& txin, block.vtx[1].vin) {
            if (GetTransaction(txin.prevout.hash, tx2, hash, true))
                if (tx2.vout.size() > txin.prevout.n)
                    nValueIns += tx2.vout[txin.prevout.n].nValue;
        }

        CAmount blockReward = nFees + GetProofOfStakeSubsidy_Legacy(pindex->nHeight, nValueIns);

        if (nActualStakeReward > blockReward)
            return state.DoS(100, error("ConnectBlock(): coinstake pays too much (actual=%d vs limit=%d)", nActualStakeReward, blockReward), REJECT_INVALID, "bad-cs-amount");
    }

    CAmount reward = block.IsProofOfStake() ? nActualStakeReward : block.vtx[0].GetValueOut();

    if (block.IsProofOfStake()) {
        pindex->SetProofOfStake();
        pindex->SetProofOfStake_Legacy();
    }

    pindex->nMoneySupply = (pindex->pprev ? pindex->pprev->nMoneySupply : 0) + reward;


    if (!fJustCheck)
        pindex->nStakeModifierOld = ComputeStakeModifier_Legacy(pindex->pprev, block.IsProofOfStake() ? block.vtx[1].vin[0].prevout.hash : pindex->GetBlockHash());

    if (fJustCheck)
        return true;

    if (!control.Wait())
        return state.DoS(100, false);

    int64_t nTime4 = GetTimeMicros();
    nTimeVerify += nTime4 - nTime2;
    LogPrint("bench", "    - Verify %u txins: %.2fms (%.3fms/txin) [%.2fs]\n", nInputs - 1, 0.001 * (nTime4 - nTime2), nInputs <= 1 ? 0 : 0.001 * (nTime4 - nTime2) / (nInputs - 1), nTimeVerify * 0.000001);

    // Write undo information to disk
    if (pindex->GetUndoPos().IsNull() || !pindex->IsValid(BLOCK_VALID_SCRIPTS)) {
        if (pindex->GetUndoPos().IsNull()) {
            CDiskBlockPos pos;
            if (!FindUndoPos_Legacy(state, pindex->nFile, pos, ::GetSerializeSize(blockundo, SER_DISK, CLIENT_VERSION) + 40))
                return error("ConnectBlock(): FindUndoPos failed");
            if (!UndoWriteToDisk_Legacy(blockundo, pos, pindex->pprev->GetBlockHash(), chainparams.MessageStart()))
                return AbortNode(state, "Failed to write undo data");

            // update nUndoPos in block index
            pindex->nUndoPos = pos.nPos;
            pindex->nStatus |= BLOCK_HAVE_UNDO;
        }

        pindex->RaiseValidity(BLOCK_VALID_SCRIPTS);
        setDirtyBlockIndex.insert(pindex);
    }
    if (fTxIndex)
        if (!pblocktree->WriteTxIndex(vPosTxid))
            return AbortNode(state, "Failed to write transaction index");

    if (fAddrIndex)
        if (!pblocktree->AddAddrIndex(vPosAddrid))
            return AbortNode(state, "Failed to write address index");

    // add this block to the view's block chain
    view.SetBestBlock(pindex->GetBlockHash());
    int64_t nTime5 = GetTimeMicros();
    nTimeIndex += nTime5 - nTime4;
    LogPrint("bench", "    - Index writing: %.2fms [%.2fs]\n", 0.001 * (nTime5 - nTime4), nTimeIndex * 0.000001);

    // Watch for changes to the previous coinbase transaction.
    static uint256 hashPrevBestCoinBase;
    GetMainSignals().UpdatedTransaction(hashPrevBestCoinBase);
    hashPrevBestCoinBase = block.vtx[0].GetHash();

    int64_t nTime6 = GetTimeMicros();
    nTimeCallbacks += nTime6 - nTime5;
    LogPrint("bench", "    - Callbacks: %.2fms [%.2fs]\n", 0.001 * (nTime6 - nTime5), nTimeCallbacks * 0.000001);


    return true;
}

enum FlushStateMode {
    FLUSH_STATE_NONE, // legacy
    FLUSH_STATE_IF_NEEDED,
    FLUSH_STATE_PERIODIC,
    FLUSH_STATE_ALWAYS
};

/**
 * Update the on-disk chain state.
 * The caches and indexes are flushed depending on the mode we're called with
 * if they're too large, if it's been a while since the last write,
 * or always and in all cases if we're in prune mode and are deleting files.
 */
bool static FlushStateToDisk(CValidationState& state, FlushStateMode mode)
{
    const CChainParams& chainparams = Params();
    LOCK2(cs_main, cs_LastBlockFile);
    static int64_t nLastWrite = 0;
    static int64_t nLastFlush = 0;
    static int64_t nLastSetChain = 0;
    std::set<int> setFilesToPrune;
    bool fFlushForPrune = false;
    try {
        if (fPruneMode && fCheckForPruning && !fReindex) {
            FindFilesToPrune(setFilesToPrune, chainparams.PruneAfterHeight());
            fCheckForPruning = false;
            if (!setFilesToPrune.empty()) {
                fFlushForPrune = true;
                if (!fHavePruned) {
                    pblocktree->WriteFlag("prunedblockfiles", true);
                    fHavePruned = true;
                }
            }
        }
        int64_t nNow = GetTimeMicros();
        // Avoid writing/flushing immediately after startup.
        if (nLastWrite == 0) {
            nLastWrite = nNow;
        }
        if (nLastFlush == 0) {
            nLastFlush = nNow;
        }
        if (nLastSetChain == 0) {
            nLastSetChain = nNow;
        }
        size_t cacheSize = pcoinsTip->DynamicMemoryUsage();
        // The cache is large and close to the limit, but we have time now (not in the middle of a block processing).
        bool fCacheLarge = mode == FLUSH_STATE_PERIODIC && cacheSize * (10.0 / 9) > nCoinCacheUsage;
        // The cache is over the limit, we have to write now.
        bool fCacheCritical = mode == FLUSH_STATE_IF_NEEDED && cacheSize > nCoinCacheUsage;
        // It's been a while since we wrote the block index to disk. Do this frequently, so we don't need to redownload after a crash.
        bool fPeriodicWrite = mode == FLUSH_STATE_PERIODIC && nNow > nLastWrite + (int64_t)DATABASE_WRITE_INTERVAL * 1000000;
        // It's been very long since we flushed the cache. Do this infrequently, to optimize cache usage.
        bool fPeriodicFlush = mode == FLUSH_STATE_PERIODIC && nNow > nLastFlush + (int64_t)DATABASE_FLUSH_INTERVAL * 1000000;
        // Combine all conditions that result in a full cache flush.
        bool fDoFullFlush = (mode == FLUSH_STATE_ALWAYS) || fCacheLarge || fCacheCritical || fPeriodicFlush || fFlushForPrune;
        // Write blocks and block index to disk.
        if (fDoFullFlush || fPeriodicWrite) {
            // Depend on nMinDiskSpace to ensure we can write block index
            if (!CheckDiskSpace(0))
                return state.Error("out of disk space");
            // First make sure all block and undo data is flushed to disk.
            FlushBlockFile();
            // Then update all block file information (which may refer to block and undo files).
            {
                std::vector<std::pair<int, const CBlockFileInfo*> > vFiles;
                vFiles.reserve(setDirtyFileInfo.size());
                for (set<int>::iterator it = setDirtyFileInfo.begin(); it != setDirtyFileInfo.end();) {
                    vFiles.push_back(make_pair(*it, &vinfoBlockFile[*it]));
                    setDirtyFileInfo.erase(it++);
                }
                std::vector<const CBlockIndex*> vBlocks;
                vBlocks.reserve(setDirtyBlockIndex.size());
                for (set<CBlockIndex*>::iterator it = setDirtyBlockIndex.begin(); it != setDirtyBlockIndex.end();) {
                    vBlocks.push_back(*it);
                    setDirtyBlockIndex.erase(it++);
                }
                if (!pblocktree->WriteBatchSync(vFiles, nLastBlockFile, vBlocks)) {
                    return AbortNode(state, "Files to write to block index database");
                }
            }
            // Finally remove any pruned files
            if (fFlushForPrune)
                UnlinkPrunedFiles(setFilesToPrune);
            nLastWrite = nNow;
        }
        // Flush best chain related state. This can only be done if the blocks / block index write was also done.
        if (fDoFullFlush) {
            // Typical CCoins structures on disk are around 128 bytes in size.
            // Pushing a new one to the database can cause it to be written
            // twice (once in the log, and once in the tables). This is already
            // an overestimation, as most will delete an existing entry or
            // overwrite one. Still, use a conservative safety factor of 2.
            if (!CheckDiskSpace(128 * 2 * 2 * pcoinsTip->GetCacheSize()))
                return state.Error("out of disk space");
            // Flush the chainstate (which may refer to block index entries).
            if (!pcoinsTip->Flush())
                return AbortNode(state, "Failed to write to coin database");
            nLastFlush = nNow;
        }
        if (fDoFullFlush || ((mode == FLUSH_STATE_ALWAYS || mode == FLUSH_STATE_PERIODIC) && nNow > nLastSetChain + (int64_t)DATABASE_WRITE_INTERVAL * 1000000)) {
            // Update best block in wallet (so we can detect restored wallets).
            GetMainSignals().SetBestChain(chainActive.GetLocator());
            nLastSetChain = nNow;
        }
    } catch (const std::runtime_error& e) {
        return AbortNode(state, std::string("System error while flushing: ") + e.what());
    }
    return true;
}

void FlushStateToDisk()
{
    CValidationState state;
    FlushStateToDisk(state, FLUSH_STATE_ALWAYS);
}


/**
 * BLOCK PRUNING CODE
 */

/* Calculate the amount of disk space the block & undo files currently use */
uint64_t CalculateCurrentUsage_Legacy()
{
    uint64_t retval = 0;
    BOOST_FOREACH (const CBlockFileInfo& file, vinfoBlockFile) {
        retval += file.nSize + file.nUndoSize;
    }
    return retval;
}

/* Prune a block file (modify associated database entries)*/
void PruneOneBlockFile_Legacy(const int fileNumber)
{
    for (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); ++it) {
        CBlockIndex* pindex = it->second;
        if (pindex->nFile == fileNumber) {
            pindex->nStatus &= ~BLOCK_HAVE_DATA;
            pindex->nStatus &= ~BLOCK_HAVE_UNDO;
            pindex->nFile = 0;
            pindex->nDataPos = 0;
            pindex->nUndoPos = 0;
            setDirtyBlockIndex.insert(pindex);

            // Prune from mapBlocksUnlinked -- any block we prune would have
            // to be downloaded again in order to consider its chain, at which
            // point it would be considered as a candidate for
            // mapBlocksUnlinked or setBlockIndexCandidates.
            std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> range = mapBlocksUnlinked.equal_range(pindex->pprev);
            while (range.first != range.second) {
                std::multimap<CBlockIndex*, CBlockIndex*>::iterator it = range.first;
                range.first++;
                if (it->second == pindex) {
                    mapBlocksUnlinked.erase(it);
                }
            }
        }
    }

    vinfoBlockFile[fileNumber].SetNull();
    setDirtyFileInfo.insert(fileNumber);
}


void UnlinkPrunedFiles(std::set<int>& setFilesToPrune)
{
    for (set<int>::iterator it = setFilesToPrune.begin(); it != setFilesToPrune.end(); ++it) {
        CDiskBlockPos pos(*it, 0);
        boost::filesystem::remove(GetBlockPosFilename(pos, "blk"));
        boost::filesystem::remove(GetBlockPosFilename(pos, "rev"));
        if (fDebug)
            LogPrintf("Prune: %s deleted blk/rev (%05u)\n", __func__, *it);
    }
}

/* Calculate the block/rev files that should be deleted to remain under target*/
void FindFilesToPrune(std::set<int>& setFilesToPrune, uint64_t nPruneAfterHeight)
{
    LOCK2(cs_main, cs_LastBlockFile);
    if (chainActive.Tip() == NULL || nPruneTarget == 0) {
        return;
    }
    if ((uint64_t)chainActive.Tip()->nHeight <= nPruneAfterHeight) {
        return;
    }

    unsigned int nLastBlockWeCanPrune = chainActive.Tip()->nHeight - MIN_BLOCKS_TO_KEEP;
    uint64_t nCurrentUsage = CalculateCurrentUsage_Legacy();
    // We don't check to prune until after we've allocated new space for files
    // So we should leave a buffer under our target to account for another allocation
    // before the next pruning.
    uint64_t nBuffer = BLOCKFILE_CHUNK_SIZE + UNDOFILE_CHUNK_SIZE;
    uint64_t nBytesToPrune;
    int count = 0;

    if (nCurrentUsage + nBuffer >= nPruneTarget) {
        for (int fileNumber = 0; fileNumber < nLastBlockFile; fileNumber++) {
            nBytesToPrune = vinfoBlockFile[fileNumber].nSize + vinfoBlockFile[fileNumber].nUndoSize;

            if (vinfoBlockFile[fileNumber].nSize == 0)
                continue;

            if (nCurrentUsage + nBuffer < nPruneTarget) // are we below our target?
                break;

            // don't prune files that could have a block within MIN_BLOCKS_TO_KEEP of the main chain's tip but keep scanning
            if (vinfoBlockFile[fileNumber].nHeightLast > nLastBlockWeCanPrune)
                continue;

            PruneOneBlockFile_Legacy(fileNumber);
            // Queue up the files for removal
            setFilesToPrune.insert(fileNumber);
            nCurrentUsage -= nBytesToPrune;
            count++;
        }
    }

    LogPrint("prune", "Prune: target=%dMiB actual=%dMiB diff=%dMiB max_prune_height=%d removed %d blk/rev pairs\n",
        nPruneTarget / 1024 / 1024, nCurrentUsage / 1024 / 1024,
        ((int64_t)nPruneTarget - (int64_t)nCurrentUsage) / 1024 / 1024,
        nLastBlockWeCanPrune, count);
}


void PruneAndFlush()
{
    CValidationState state;
    fCheckForPruning = true;
    FlushStateToDisk(state, FLUSH_STATE_NONE);
}


bool UseLegacyCode(const CBlockHeader& block)
{
    return (block.nVersion & ~CBlockHeader::SIGNALING_NEW_VERSION_MASK) <= (CBlockHeader::CURRENT_VERSION & ~CBlockHeader::SIGNALING_NEW_VERSION_MASK);
}

bool UseLegacyCode(int nHeight)
{
    return nHeight < Params().HeightToFork();
}
bool UseLegacyCode()
{
    return chainActive.Tip()->nHeight < Params().HeightToFork();
}

/** Update chainActive and related internal data structures. */
void static UpdateTip(CBlockIndex* pindexNew)
{
    const CChainParams& chainParams = Params();
    chainActive.SetTip(pindexNew);

    // New best block
    nChainHeight = pindexNew->nHeight;
    nTimeBestReceived = GetTime();
    mempool.AddTransactionsUpdated(1);

    if (fDebug) 
        LogPrintf("%s:\n",                  __func__);
        LogPrintf("New Best Block: %s\n",   chainActive.Tip()->GetBlockHash().ToString());
        LogPrintf("Height: %d\n",           chainActive.Height());
        LogPrintf("log2_work: %.8g\n",      log(chainActive.Tip()->nChainWork.getdouble()) / log(2.0));
        LogPrintf("tx: %lu\n",              (unsigned long)chainActive.Tip()->nChainTx);
        LogPrintf("date: %s\n",             DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()));
        LogPrintf("progress: %f\n",         Checkpoints::GuessVerificationProgress(Params().GetTxData(), chainActive.Tip()));
        LogPrintf("cache: %.1fMiB(%utx)\n", pcoinsTip->DynamicMemoryUsage() * (1.0 / (1 << 20)), pcoinsTip->GetCacheSize());
    cvBlockChange.notify_all();

    // Check the version of the last 100 blocks to see if we need to upgrade:
    static bool fWarned = false;
    if (!IsInitialBlockDownload()) {
        int nUpgraded = 0;
        const CBlockIndex* pindex = chainActive.Tip();
        for (int bit = 0; bit < VERSIONBITS_NUM_BITS; bit++) {
            WarningBitsConditionChecker checker(bit);
            ThresholdState state = checker.GetStateFor(pindex, warningcache[bit]);
            if (state == THRESHOLD_ACTIVE || state == THRESHOLD_LOCKED_IN) {
                if (state == THRESHOLD_ACTIVE) {
                    strMiscWarning = strprintf(_("Warning: unknown new rules activated (versionbit %i)"), bit);
                    if (!fWarned) {
                        CAlert::Notify(strMiscWarning, true);
                        fWarned = true;
                    }
                } 
                else
                    LogPrintf("%s: unknown new rules are about to activate (versionbit %i)\n", __func__, bit);
            }
        }
    }
}

/** Disconnect chainActive's tip. You probably want to call mempool.removeForReorg and manually re-limit mempool size after this, with cs_main held. */
bool static DisconnectTip(CValidationState& state, bool isLoadingTx = false)
{
    CBlockIndex* pindexDelete = chainActive.Tip();
    assert(pindexDelete);
    // Read block from disk.
    CBlock block;
    if (!ReadBlockFromDisk(block, pindexDelete))
        return AbortNode(state, "Failed to read block");
    // Apply the block atomically to the chain state.
    int64_t nStart = GetTimeMicros();
    {
        CCoinsViewCache view(pcoinsTip);
        if (!DisconnectBlock(block, state, pindexDelete, view))
            return error("DisconnectTip(): DisconnectBlock %s failed", pindexDelete->GetBlockHash().ToString());
        assert(view.Flush());
    }
    LogPrint("bench", "- Disconnect block: %.2fms\n", (GetTimeMicros() - nStart) * 0.001);
    // Write the chain state to disk, if necessary.
    if (!FlushStateToDisk(state, FLUSH_STATE_IF_NEEDED))
        return false;
    // Resurrect mempool transactions from the disconnected block.
    std::vector<uint256> vHashUpdate;
    BOOST_FOREACH (const CTransaction& tx, block.vtx) {
        // ignore validation errors in resurrected transactions
        list<CTransaction> removed;
        CValidationState stateDummy;
        if (tx.IsCoinBase() || tx.IsCoinStake() || !AcceptToMemoryPool(mempool, stateDummy, tx, false, NULL, true, true, false, isLoadingTx)) {
            mempool.remove(tx, removed, true);
        } else if (mempool.exists(tx.GetHash())) {
            vHashUpdate.push_back(tx.GetHash());
        }
    }
    // AcceptToMemoryPool/addUnchecked all assume that new mempool entries have
    // no in-mempool children, which is generally not true when adding
    // previously-confirmed transactions back to the mempool.
    // UpdateTransactionsFromBlock finds descendants of any transactions in this
    // block that were added back and cleans up the mempool state.
    mempool.UpdateTransactionsFromBlock(vHashUpdate);
    // Update chainActive and related variables.
    UpdateTip(pindexDelete->pprev);
    // Let wallets know transactions went from 1-confirmed to
    // 0-confirmed or conflicted:
    BOOST_FOREACH (const CTransaction& tx, block.vtx) {
        SyncWithWallets(tx, NULL);
    }
    return true;
}

static int64_t nTimeReadFromDisk = 0;
static int64_t nTimeConnectTotal = 0;
static int64_t nTimeFlush = 0;
static int64_t nTimeChainState = 0;
static int64_t nTimePostConnect = 0;

/**
 * Connect a new block to chainActive. pblock is either NULL or a pointer to a CBlock
 * corresponding to pindexNew, to bypass loading it again from disk.
 */
bool static ConnectTip(CValidationState& state, CBlockIndex* pindexNew, const CBlock* pblock)
{
    const CChainParams& chainParams = Params();
    assert(pindexNew->pprev == chainActive.Tip());
    // Read block from disk.
    int64_t nTime1 = GetTimeMicros();
    CBlock block;
    if (!pblock) {
        if (!ReadBlockFromDisk(block, pindexNew))
            return AbortNode(state, "Failed to read block");
        pblock = &block;
    }
    // Apply the block atomically to the chain state.
    int64_t nTime2 = GetTimeMicros();
    nTimeReadFromDisk += nTime2 - nTime1;
    int64_t nTime3;
    LogPrint("bench", "  - Load block from disk: %.2fms [%.2fs]\n", (nTime2 - nTime1) * 0.001, nTimeReadFromDisk * 0.000001);
    {
        CCoinsViewCache view(pcoinsTip);
        bool rv = ConnectBlock(*pblock, state, pindexNew, view, false);
        GetMainSignals().BlockChecked(*pblock, state);
        if (!rv) {
            if (state.IsInvalid())
                InvalidBlockFound(pindexNew, state);
            return error("ConnectTip(): ConnectBlock %s failed", pindexNew->GetBlockHash().ToString());
        }
        mapBlockSource.erase(pindexNew->GetBlockHash());
        nTime3 = GetTimeMicros();
        nTimeConnectTotal += nTime3 - nTime2;
        LogPrint("bench", "  - Connect total: %.2fms [%.2fs]\n", (nTime3 - nTime2) * 0.001, nTimeConnectTotal * 0.000001);
        assert(view.Flush());
    }
    int64_t nTime4 = GetTimeMicros();
    nTimeFlush += nTime4 - nTime3;
    LogPrint("bench", "  - Flush: %.2fms [%.2fs]\n", (nTime4 - nTime3) * 0.001, nTimeFlush * 0.000001);
    // Write the chain state to disk, if necessary.
    if (!FlushStateToDisk(state, FLUSH_STATE_IF_NEEDED))
        return false;
    int64_t nTime5 = GetTimeMicros();
    nTimeChainState += nTime5 - nTime4;
    LogPrint("bench", "  - Writing chainstate: %.2fms [%.2fs]\n", (nTime5 - nTime4) * 0.001, nTimeChainState * 0.000001);
    // Remove conflicting transactions from the mempool.
    list<CTransaction> txConflicted;
    mempool.removeForBlock(pblock->vtx, pindexNew->nHeight, txConflicted, !IsInitialBlockDownload());
    // Update chainActive & related variables.
    UpdateTip(pindexNew);
    // Tell wallet about transactions that went from mempool
    // to conflicted:
    BOOST_FOREACH (const CTransaction& tx, txConflicted) {
        SyncWithWallets(tx, NULL);
    }
    // ... and about transactions that got confirmed:
    BOOST_FOREACH (const CTransaction& tx, pblock->vtx) {
        SyncWithWallets(tx, pblock);
    }
    int64_t nTime6 = GetTimeMicros();
    nTimePostConnect += nTime6 - nTime5;
    nTimeTotal += nTime6 - nTime1;
    LogPrint("bench", "- Connect postprocess: %.2fms [%.2fs]\n", (nTime6 - nTime5) * 0.001, nTimePostConnect * 0.000001);
    LogPrint("bench", "- Connect block: %.2fms [%.2fs]\n", (nTime6 - nTime1) * 0.001, nTimeTotal * 0.000001);

    return true;
}

bool DisconnectBlocksAndReprocess(int blocks)
{
    LOCK(cs_main);

    CValidationState state;

    if (fDebug)
        LogPrintf("DisconnectBlocksAndReprocess: Got command to replay %d blocks\n", blocks);

    for (int i = 0; i <= blocks; i++)
        DisconnectTip(state);

    return true;
}

/*
    DisconnectBlockAndInputs

    Remove conflicting blocks for successful SwiftX transaction locks
    This should be very rare (Probably will never happen)
*/
// ***TODO*** clean up here
bool DisconnectBlockAndInputs(CValidationState& state, CTransaction txLock)
{
    // All modifications to the coin state will be done in this cache.
    // Only when all have succeeded, we push it to pcoinsTip.
    //    CCoinsViewCache view(*pcoinsTip, true);

    CBlockIndex* BlockReading = chainActive.Tip();
    CBlockIndex* pindexNew = NULL;

    bool foundConflictingTx = false;

    //remove anything conflicting in the memory pool
    list<CTransaction> txConflicted;
    mempool.removeConflicts(txLock, txConflicted);


    // List of what to disconnect (typically nothing)
    vector<CBlockIndex*> vDisconnect;

    for (unsigned int i = 1; BlockReading && BlockReading->nHeight > 0 && !foundConflictingTx && i < Params().GetCoinMaturity(); i++) {
        vDisconnect.push_back(BlockReading);
        pindexNew = BlockReading->pprev; //new best block

        CBlock block;
        if (!ReadBlockFromDisk(block, BlockReading))
            return state.Abort(_("Failed to read block"));

        // Queue memory transactions to resurrect.
        // We only do this for blocks after the last checkpoint (reorganisation before that
        // point should only happen with -reindex/-loadblock, or a misbehaving peer.
        BOOST_FOREACH (const CTransaction& tx, block.vtx) {
            if (!tx.IsCoinBase()) {
                BOOST_FOREACH (const CTxIn& in1, txLock.vin) {
                    BOOST_FOREACH (const CTxIn& in2, tx.vin) {
                        if (in1.prevout == in2.prevout) foundConflictingTx = true;
                    }
                }
            }
        }

        if (BlockReading->pprev == NULL) {
            assert(BlockReading);
            break;
        }
        BlockReading = BlockReading->pprev;
    }

    if (!foundConflictingTx) {
        if (fDebug)
            LogPrintf("DisconnectBlockAndInputs: Can't find a conflicting transaction to inputs\n");

        return false;
    }

    if (vDisconnect.size() > 0) {
        if (fDebug)
            LogPrintf("REORGANIZE: Disconnect Conflicting Blocks %lli blocks; %s..\n", vDisconnect.size(), pindexNew->GetBlockHash().ToString());

        BOOST_FOREACH (CBlockIndex* pindex, vDisconnect) {
            if (fDebug)
                LogPrintf(" -- disconnect %s\n", pindex->GetBlockHash().ToString());

            DisconnectTip(state);
        }
    }

    return true;
}


/**
 * Return the tip of the chain with the most work in it, that isn't
 * known to be invalid (it's however far from certain to be valid).
 */
static CBlockIndex* FindMostWorkChain()
{
    do {
        CBlockIndex* pindexNew = NULL;

        // Find the best candidate header.
        {
            std::set<CBlockIndex*, CBlockIndexWorkComparator>::reverse_iterator it = setBlockIndexCandidates.rbegin();
            if (it == setBlockIndexCandidates.rend())
                return NULL;
            pindexNew = *it;
        }

        // Check whether all blocks on the path between the currently active chain and the candidate are valid.
        // Just going until the active chain is an optimization, as we know all blocks in it are valid already.
        CBlockIndex* pindexTest = pindexNew;
        bool fInvalidAncestor = false;
        while (pindexTest && !chainActive.Contains(pindexTest)) {
            assert(pindexTest->nChainTx || pindexTest->nHeight == 0);

            // Pruned nodes may have entries in setBlockIndexCandidates for
            // which block files have been deleted.  Remove those as candidates
            // for the most work chain if we come across them; we can't switch
            // to a chain unless we have all the non-active-chain parent blocks.
            bool fFailedChain = pindexTest->nStatus & BLOCK_FAILED_MASK;
            bool fMissingData = !(pindexTest->nStatus & BLOCK_HAVE_DATA);
            if (fFailedChain || fMissingData) {
                // Candidate chain is not usable (either invalid or missing data)
                if (fFailedChain && (pindexBestInvalid == NULL || pindexNew->nChainWork > pindexBestInvalid->nChainWork))
                    pindexBestInvalid = pindexNew;
                CBlockIndex* pindexFailed = pindexNew;
                // Remove the entire chain from the set.
                while (pindexTest != pindexFailed) {
                    if (fFailedChain) {
                        pindexFailed->nStatus |= BLOCK_FAILED_CHILD;
                    } else if (fMissingData) {
                        // If we're missing data, then add back to mapBlocksUnlinked,
                        // so that if the block arrives in the future we can try adding
                        // to setBlockIndexCandidates again.
                        mapBlocksUnlinked.insert(std::make_pair(pindexFailed->pprev, pindexFailed));
                    }
                    setBlockIndexCandidates.erase(pindexFailed);
                    pindexFailed = pindexFailed->pprev;
                }
                setBlockIndexCandidates.erase(pindexTest);
                fInvalidAncestor = true;
                break;
            }
            pindexTest = pindexTest->pprev;
        }
        if (!fInvalidAncestor)
            return pindexNew;
    } while (true);
}

/** Delete all entries in setBlockIndexCandidates that are worse than the current tip. */
static void PruneBlockIndexCandidates()
{
    // Note that we can't delete the current block itself, as we may need to return to it later in case a
    // reorganization to a better block fails.
    std::set<CBlockIndex*, CBlockIndexWorkComparator>::iterator it = setBlockIndexCandidates.begin();
    while (it != setBlockIndexCandidates.end() && setBlockIndexCandidates.value_comp()(*it, chainActive.Tip())) {
        setBlockIndexCandidates.erase(it++);
    }
    // Either the current tip or a successor of it we're working towards is left in setBlockIndexCandidates.
    assert(!setBlockIndexCandidates.empty());
}

/**
 * Try to make some progress towards making pindexMostWork the active block.
 * pblock is either NULL or a pointer to a CBlock corresponding to pindexMostWork.
 */
static bool ActivateBestChainStep(CValidationState& state, CBlockIndex* pindexMostWork, const CBlock* pblock, bool isLoadingTx = false)
{
    AssertLockHeld(cs_main);
    bool fInvalidFound = false;
    const CBlockIndex* pindexOldTip = chainActive.Tip();
    const CBlockIndex* pindexFork = chainActive.FindFork(pindexMostWork);

    // Disconnect active blocks which are no longer in the best chain.
    bool fBlocksDisconnected = false;
    while (chainActive.Tip() && chainActive.Tip() != pindexFork) {
        if (!DisconnectTip(state, isLoadingTx))
            return false;
        fBlocksDisconnected = true;
    }
    // Build list of new blocks to connect.
    std::vector<CBlockIndex*> vpindexToConnect;
    bool fContinue = true;
    int nHeight = pindexFork ? pindexFork->nHeight : -1;
    while (fContinue && nHeight != pindexMostWork->nHeight) {
        // Don't iterate the entire list of potential improvements toward the best tip, as we likely only need
        // a few blocks along the way.
        int nTargetHeight = std::min(nHeight + 32, pindexMostWork->nHeight);
        vpindexToConnect.clear();
        vpindexToConnect.reserve(nTargetHeight - nHeight);
        CBlockIndex* pindexIter = pindexMostWork->GetAncestor(nTargetHeight);
        while (pindexIter && pindexIter->nHeight != nHeight) {
            vpindexToConnect.push_back(pindexIter);
            pindexIter = pindexIter->pprev;
        }
        nHeight = nTargetHeight;
        // Connect new blocks.
        BOOST_REVERSE_FOREACH (CBlockIndex* pindexConnect, vpindexToConnect) {
            if (!ConnectTip(state, pindexConnect, pindexConnect == pindexMostWork ? pblock : NULL)) {
                if (state.IsInvalid()) {
                    // The block violates a consensus rule.
                    if (!state.CorruptionPossible())
                        InvalidChainFound(vpindexToConnect.back());
                    state = CValidationState();
                    fInvalidFound = true;
                    fContinue = false;
                    break;
                } else {
                    // A system error occurred (disk space, database error, ...).
                    return false;
                }
            } else {
                PruneBlockIndexCandidates();
                if (!pindexOldTip || chainActive.Tip()->nChainWork > pindexOldTip->nChainWork) {
                    // We're in a better position than we were. Return temporarily to release the lock.
                    if(fDebug)
                        LogPrintf("%s(): We have a new best chain.\n", __func__);
                    fContinue = false;
                    break;
                }
            }
        }
    }

    if (fBlocksDisconnected) {
        mempool.removeForReorg(pcoinsTip, chainActive.Tip()->nHeight + 1, STANDARD_LOCKTIME_VERIFY_FLAGS);
        LimitMempoolSize(mempool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE_LEGACY) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY_LEGACY) * 60 * 60);
    }
    mempool.check_Legacy(pcoinsTip);

    // Callbacks/notifications for a new best chain.
    if (fInvalidFound)
        CheckForkWarningConditionsOnNewFork(vpindexToConnect.back());
    else
        CheckForkWarningConditions();

    return true;
}

/**
 * Make the best chain active, in multiple steps. The result is either failure
 * or an activated best chain. pblock is either NULL or a pointer to a block
 * that is already loaded (to avoid loading it again from disk).
 */
bool ActivateBestChain(CValidationState& state, const CBlock* pblock, bool isLoadingTx)
{
    CBlockIndex* pindexMostWork = NULL;
    do {
        boost::this_thread::interruption_point();

        if (ShutdownRequested())
            break;

        CBlockIndex* pindexNewTip = NULL;
        const CBlockIndex* pindexFork;
        bool fInitialDownload;
        {
            LOCK(cs_main);
            CBlockIndex* pindexOldTip = chainActive.Tip();
            pindexMostWork = FindMostWorkChain();

            // Whether we have anything to do at all.
            if (pindexMostWork == NULL || pindexMostWork == chainActive.Tip())
                return true;
            if (!ActivateBestChainStep(state, pindexMostWork, pblock && pblock->GetHash() == pindexMostWork->GetBlockHash() ? pblock : NULL, isLoadingTx))
                return false;
            pindexNewTip = chainActive.Tip();
            pindexFork = chainActive.FindFork(pindexOldTip);
            fInitialDownload = IsInitialBlockDownload();
        }
        // When we reach this point, we switched to a new tip (stored in pindexNewTip).

        // Notifications/callbacks that can run without cs_main
        // Always notify the UI if a new block tip was connected
        if (pindexFork != pindexNewTip) {
            uiInterface.NotifyBlockTip_Legacy(fInitialDownload, pindexNewTip);
            if (!fInitialDownload) {
                // Find the hashes of all blocks that weren't previously in the best chain.
                std::vector<uint256> vHashes;
                CBlockIndex* pindexToAnnounce = pindexNewTip;
                while (pindexToAnnounce != pindexFork) {
                    vHashes.push_back(pindexToAnnounce->GetBlockHash());
                    pindexToAnnounce = pindexToAnnounce->pprev;
                    if (vHashes.size() == MAX_BLOCKS_TO_ANNOUNCE_LEGACY) {
                        // Limit announcements in case of a huge reorganization.
                        // Rely on the peer's synchronization mechanism in that case.
                        break;
                    }
                }
                // Relay inventory, but don't relay old inventory during initial block download.
                int nBlockEstimate = 0;
                if (Checkpoints::fEnabled)
                    nBlockEstimate = Checkpoints::GetTotalBlocksEstimate();
                {
                    LOCK(cs_vNodes);
                    BOOST_FOREACH (CNode* pnode, vNodes) {
                        if (chainActive.Height() > (pnode->nStartingHeight != -1 ? pnode->nStartingHeight - 2000 : nBlockEstimate)) {
                            BOOST_REVERSE_FOREACH (const uint256& hash, vHashes) {
                                pnode->PushBlockHash(hash);
                            }
                        }
                    }
                }
                // Notify external listeners about the new tip.
                if (!vHashes.empty()) {
                    GetMainSignals().UpdatedBlockTip(pindexNewTip);
                }
            }
        }
    } while (pindexMostWork != chainActive.Tip());
    CheckBlockIndex();

    // Write changes periodically to disk, after relay.
    if (!FlushStateToDisk(state, FLUSH_STATE_PERIODIC)) {
        return false;
    }
    return true;
}

bool InvalidateBlock(CValidationState& state, CBlockIndex* pindex)
{
    AssertLockHeld(cs_main);

    // Mark the block itself as invalid.
    pindex->nStatus |= BLOCK_FAILED_VALID;
    setDirtyBlockIndex.insert(pindex);
    setBlockIndexCandidates.erase(pindex);

    while (chainActive.Contains(pindex)) {
        CBlockIndex* pindexWalk = chainActive.Tip();
        pindexWalk->nStatus |= BLOCK_FAILED_CHILD;
        setDirtyBlockIndex.insert(pindexWalk);
        setBlockIndexCandidates.erase(pindexWalk);
        // ActivateBestChain considers blocks already in chainActive
        // unconditionally valid already, so force disconnect away from it.
        if (!DisconnectTip(state)) {
            return false;
        }
    }

    // The resulting new best tip may not be in setBlockIndexCandidates anymore, so
    // add them again.
    BlockMap::iterator it = mapBlockIndex.begin();
    while (it != mapBlockIndex.end()) {
        if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) && it->second->nChainTx && !setBlockIndexCandidates.value_comp()(it->second, chainActive.Tip())) {
            setBlockIndexCandidates.insert(it->second);
        }
        it++;
    }

    InvalidChainFound(pindex);
    return true;
}

bool ReconsiderBlock(CValidationState& state, CBlockIndex* pindex)
{
    AssertLockHeld(cs_main);

    int nHeight = pindex->nHeight;

    // Remove the invalidity flag from this block and all its descendants.
    BlockMap::iterator it = mapBlockIndex.begin();
    while (it != mapBlockIndex.end()) {
        if (!it->second->IsValid() && it->second->GetAncestor(nHeight) == pindex) {
            it->second->nStatus &= ~BLOCK_FAILED_MASK;
            setDirtyBlockIndex.insert(it->second);
            if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) && it->second->nChainTx && setBlockIndexCandidates.value_comp()(chainActive.Tip(), it->second)) {
                setBlockIndexCandidates.insert(it->second);
            }
            if (it->second == pindexBestInvalid) {
                // Reset invalid block marker if it was pointing to one of those.
                pindexBestInvalid = NULL;
            }
        }
        it++;
    }

    // Remove the invalidity flag from all ancestors too.
    while (pindex != NULL) {
        if (pindex->nStatus & BLOCK_FAILED_MASK) {
            pindex->nStatus &= ~BLOCK_FAILED_MASK;
            setDirtyBlockIndex.insert(pindex);
        }
        pindex = pindex->pprev;
    }
    return true;
}

CBlockIndex* AddToBlockIndex(const CBlock& block)
{
    // Check for duplicate
    uint256 hash = block.GetHash();
    BlockMap::iterator it = mapBlockIndex.find(hash);
    if (it != mapBlockIndex.end())
        return it->second;

    // Construct new block index object
    CBlockIndex* pindexNew = new CBlockIndex(block);
    assert(pindexNew);
    // We assign the sequence id to blocks only when the full data is available,
    // to avoid miners withholding blocks but broadcasting headers, to get a
    // competitive advantage.
    pindexNew->nSequenceId = 0;
    BlockMap::iterator mi = mapBlockIndex.insert(make_pair(hash, pindexNew)).first;
    pindexNew->phashBlock = &((*mi).first);
    BlockMap::iterator miPrev = mapBlockIndex.find(block.hashPrevBlock);
    if (miPrev != mapBlockIndex.end()) {
        pindexNew->pprev = (*miPrev).second;
        pindexNew->nHeight = pindexNew->pprev->nHeight + 1;
        pindexNew->BuildSkip();
        if (!UseLegacyCode(block)) {
            //update previous block pointer
            pindexNew->pprev->pnext = pindexNew;

            // ppcoin: compute chain trust score
            pindexNew->bnChainTrust = (pindexNew->pprev ? pindexNew->pprev->bnChainTrust : 0) + pindexNew->GetBlockTrust();

            // ppcoin: compute stake entropy bit for stake modifier
            if (!pindexNew->SetStakeEntropyBit(pindexNew->GetStakeEntropyBit()) && fDebug)
                LogPrintf("AddToBlockIndex() : SetStakeEntropyBit() failed \n");

            // ppcoin: record proof-of-stake hash value
            if (pindexNew->IsProofOfStake()) {
                if (!mapProofOfStake.count(hash) && fDebug)
                    LogPrintf("AddToBlockIndex() : hashProofOfStake not found in map \n");

                pindexNew->hashProofOfStake = mapProofOfStake[hash];
            }

            // ppcoin: compute stake modifier
            uint64_t nStakeModifier = 0;
            bool fGeneratedStakeModifier = false;
            if (!ComputeNextStakeModifier(pindexNew->pprev, nStakeModifier, fGeneratedStakeModifier) && fDebug)
                LogPrintf("AddToBlockIndex() : ComputeNextStakeModifier() failed \n");

            if (fDebug)
                LogPrintf("ComputeNextStakeModifier() => Block : %d Modifier Generated ? %s Modifier: %u \n", pindexNew->nHeight, fGeneratedStakeModifier ? "true" : "false", nStakeModifier);
            
            pindexNew->SetStakeModifier(nStakeModifier, fGeneratedStakeModifier);
            pindexNew->nStakeModifierOld = ComputeStakeModifier_Legacy(pindexNew->pprev, block.IsProofOfStake() ? block.vtx[1].vin[0].prevout.hash : pindexNew->GetBlockHash());
            pindexNew->nStakeModifierChecksum = GetStakeModifierChecksum(pindexNew);
            if (!CheckStakeModifierCheckpoints(pindexNew->nHeight, pindexNew->nStakeModifierChecksum) && fDebug)
                LogPrintf("AddToBlockIndex() : Rejected by stake modifier checkpoint height=%d, modifier=%s \n", pindexNew->nHeight, boost::lexical_cast<std::string>(nStakeModifier));
        }
    }
    pindexNew->nChainWork = (pindexNew->pprev ? pindexNew->pprev->nChainWork : 0) + GetBlockProof(*pindexNew);
    pindexNew->RaiseValidity(BLOCK_VALID_TREE);
    if (pindexBestHeader == NULL || pindexBestHeader->nChainWork < pindexNew->nChainWork)
        pindexBestHeader = pindexNew;
    if (!UseLegacyCode(block)) {
        //update previous block pointer
        if (pindexNew->nHeight)
            pindexNew->pprev->pnext = pindexNew;
    }
    setDirtyBlockIndex.insert(pindexNew);

    return pindexNew;
}

/** Mark a block as having its data received and checked (up to BLOCK_VALID_TRANSACTIONS). */
bool ReceivedBlockTransactions(const CBlock& block, CValidationState& state, CBlockIndex* pindexNew, const CDiskBlockPos& pos)
{
    if (block.IsProofOfStake()) {
        pindexNew->SetProofOfStake();
        pindexNew->SetProofOfStake_Legacy();
    }
    pindexNew->nTx = block.vtx.size();
    pindexNew->nChainTx = 0;
    pindexNew->nFile = pos.nFile;
    pindexNew->nDataPos = pos.nPos;
    pindexNew->nUndoPos = 0;
    pindexNew->nStatus |= BLOCK_HAVE_DATA;
    pindexNew->RaiseValidity(BLOCK_VALID_TRANSACTIONS);
    setDirtyBlockIndex.insert(pindexNew);

    if (pindexNew->pprev == NULL || pindexNew->pprev->nChainTx) {
        // If pindexNew is the genesis block or all parents are BLOCK_VALID_TRANSACTIONS.
        deque<CBlockIndex*> queue;
        queue.push_back(pindexNew);

        // Recursively process any descendant blocks that now may be eligible to be connected.
        while (!queue.empty()) {
            CBlockIndex* pindex = queue.front();
            queue.pop_front();
            pindex->nChainTx = (pindex->pprev ? pindex->pprev->nChainTx : 0) + pindex->nTx;
            {
                LOCK(cs_nBlockSequenceId);
                pindex->nSequenceId = nBlockSequenceId++;
            }
            if (chainActive.Tip() == NULL || !setBlockIndexCandidates.value_comp()(pindex, chainActive.Tip())) {
                setBlockIndexCandidates.insert(pindex);
            }
            std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> range = mapBlocksUnlinked.equal_range(pindex);
            while (range.first != range.second) {
                std::multimap<CBlockIndex*, CBlockIndex*>::iterator it = range.first;
                queue.push_back(it->second);
                range.first++;
                mapBlocksUnlinked.erase(it);
            }
        }
    } else {
        if (pindexNew->pprev && pindexNew->pprev->IsValid(BLOCK_VALID_TREE)) {
            mapBlocksUnlinked.insert(std::make_pair(pindexNew->pprev, pindexNew));
        }
    }

    return true;
}

bool FindBlockPos(CValidationState& state, CDiskBlockPos& pos, unsigned int nAddSize, unsigned int nHeight, uint64_t nTime, bool fKnown = false)
{
    LOCK(cs_LastBlockFile);

    unsigned int nFile = fKnown ? pos.nFile : nLastBlockFile;
    if (vinfoBlockFile.size() <= nFile) {
        vinfoBlockFile.resize(nFile + 1);
    }

    if (!fKnown) {
        while (vinfoBlockFile[nFile].nSize + nAddSize >= MAX_BLOCKFILE_SIZE) {
            nFile++;
            if (vinfoBlockFile.size() <= nFile) {
                vinfoBlockFile.resize(nFile + 1);
            }
        }
        pos.nFile = nFile;
        pos.nPos = vinfoBlockFile[nFile].nSize;
    }

    if ((int)nFile != nLastBlockFile) {
        if (!fKnown && fDebug)
            LogPrintf("Leaving block file %i: %s\n", nLastBlockFile, vinfoBlockFile[nLastBlockFile].ToString());

        FlushBlockFile(!fKnown);
        nLastBlockFile = nFile;
    }

    vinfoBlockFile[nFile].AddBlock(nHeight, nTime);
    if (fKnown)
        vinfoBlockFile[nFile].nSize = std::max(pos.nPos + nAddSize, vinfoBlockFile[nFile].nSize);
    else
        vinfoBlockFile[nFile].nSize += nAddSize;

    if (!fKnown) {
        unsigned int nOldChunks = (pos.nPos + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
        unsigned int nNewChunks = (vinfoBlockFile[nFile].nSize + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
        if (nNewChunks > nOldChunks) {
            if (fPruneMode)
                fCheckForPruning = true;
            if (CheckDiskSpace(nNewChunks * BLOCKFILE_CHUNK_SIZE - pos.nPos)) {
                FILE* file = OpenBlockFile(pos);
                if (file) {
                    if (fDebug)
                        LogPrintf("Pre-allocating up to position 0x%x in blk%05u.dat\n", nNewChunks * BLOCKFILE_CHUNK_SIZE, pos.nFile);
                    
                    AllocateFileRange(file, pos.nPos, nNewChunks * BLOCKFILE_CHUNK_SIZE - pos.nPos);
                    fclose(file);
                }
            } else
                return state.Error("out of disk space");
        }
    }

    setDirtyFileInfo.insert(nFile);
    return true;
}


bool FindUndoPos(CValidationState& state, int nFile, CDiskBlockPos& pos, unsigned int nAddSize)
{
    pos.nFile = nFile;

    LOCK(cs_LastBlockFile);

    unsigned int nNewSize;
    pos.nPos = vinfoBlockFile[nFile].nUndoSize;
    nNewSize = vinfoBlockFile[nFile].nUndoSize += nAddSize;
    setDirtyFileInfo.insert(nFile);

    unsigned int nOldChunks = (pos.nPos + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
    unsigned int nNewChunks = (nNewSize + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
    if (nNewChunks > nOldChunks) {
        if (CheckDiskSpace(nNewChunks * UNDOFILE_CHUNK_SIZE - pos.nPos)) {
            FILE* file = OpenUndoFile(pos);
            if (file) {
                if (fDebug)
                    LogPrintf("Pre-allocating up to position 0x%x in rev%05u.dat\n", nNewChunks * UNDOFILE_CHUNK_SIZE, pos.nFile);
                
                AllocateFileRange(file, pos.nPos, nNewChunks * UNDOFILE_CHUNK_SIZE - pos.nPos);
                fclose(file);
            }
        } else
            return state.Error("out of disk space");
    }

    return true;
}

bool FindUndoPos_Legacy(CValidationState& state, int nFile, CDiskBlockPos& pos, unsigned int nAddSize)
{
    pos.nFile = nFile;

    LOCK(cs_LastBlockFile);

    unsigned int nNewSize;
    pos.nPos = vinfoBlockFile[nFile].nUndoSize;
    nNewSize = vinfoBlockFile[nFile].nUndoSize += nAddSize;
    setDirtyFileInfo.insert(nFile);

    unsigned int nOldChunks = (pos.nPos + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
    unsigned int nNewChunks = (nNewSize + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
    if (nNewChunks > nOldChunks) {
        if (fPruneMode)
            fCheckForPruning = true;
        if (CheckDiskSpace(nNewChunks * UNDOFILE_CHUNK_SIZE - pos.nPos)) {
            FILE* file = OpenUndoFile(pos);
            if (file) {
                if (fDebug)
                    LogPrintf("Pre-allocating up to position 0x%x in rev%05u.dat\n", nNewChunks * UNDOFILE_CHUNK_SIZE, pos.nFile);
                
                AllocateFileRange(file, pos.nPos, nNewChunks * UNDOFILE_CHUNK_SIZE - pos.nPos);
                fclose(file);
            }
        } else
            return state.Error("out of disk space");
    }

    return true;
}

int GetnHeight(const CBlockIndex* pIndex)
{
    return pIndex ? pIndex->nHeight : chainActive.Height();
}

bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, bool fCheckPOW)
{
    if (fDebug && fCheckPOW)
        LogPrintf("CheckBlockHeader fCheckPOW: true");
    if(block.nVersion < CBlockHeader::POS_FORK_VERSION)
        return state.DoS(100, error("CheckBlockHeader(): CURRENT_VERSION is not valid"),
            REJECT_INVALID, "Invalid Version");
    // Check proof of work matches claimed amount
    if (fCheckPOW && !CheckProofOfWork(block.GetHash(), block.nBits))
        return state.DoS(50, error("CheckBlockHeader(): proof of work failed"),
            REJECT_INVALID, "high-hash");

    return true;
}

bool CheckBlockHeader_Legacy(const CBlockHeader& block, CValidationState& state, bool fCheckPOW)
{
    // Check proof of work matches claimed amount
    if (fCheckPOW && !CheckProofOfWork_Legacy(block.GetHash(), block.nBits))
        return state.DoS(50, error("CheckBlockHeader(): proof of work failed"), REJECT_INVALID, "high-hash");

    // Check timestamp
    if (block.GetBlockTime() > GetAdjustedTime() + 2 * 60 * 60)
        return state.Invalid(error("CheckBlockHeader(): block timestamp too far in the future"), REJECT_INVALID, "time-too-new");

    return true;
}

bool CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW, bool fCheckMerkleRoot, bool fCheckSig)
{
    if (UseLegacyCode(block))
        return CheckBlock_Legacy(block, state, fCheckPOW, fCheckMerkleRoot);
    else if (block.nVersion < CBlockHeader::POS_FORK_VERSION)
        return state.Invalid(error("CheckBlock(): block version smaller than 2"), REJECT_INVALID, "bad-block-version");

    // These are checks that are independent of context.
    bool fBlockIsProofOfStake = block.IsProofOfStake();
    bool fBlockIsProofOfWork = !fBlockIsProofOfStake;
    // Check that the header is valid (particularly PoW).  This is mostly
    // redundant with the call in AcceptBlockHeader.

    if (!CheckBlockHeader(block, state, fBlockIsProofOfWork && fCheckPOW))
        return state.DoS(100, error("CheckBlock() : CheckBlockHeader failed"),
            REJECT_INVALID, "bad-header", true);

    // Check timestamp
    if (fDebug)
        LogPrint("debug", "%s: block=%s  is proof of stake=%s \n", __func__, block.GetHash().ToString().c_str(), block.IsProofOfStake() ? "true" : "false");
    
    if (block.GetBlockTime() > GetAdjustedTime() + (fBlockIsProofOfStake ? 180 : 7200)) // 3 minute future drift for PoS
        return state.DoS(25, error("CheckBlock(): block timestamp too far in the future"),
            REJECT_INVALID, "time-too-new");

    // Check the merkle root.
    if (fCheckMerkleRoot) {
        bool mutated;
        uint256 hashMerkleRoot2 = block.BuildMerkleTree(&mutated);
        if (block.hashMerkleRoot != hashMerkleRoot2)
            return state.DoS(100, error("CheckBlock(): hashMerkleRoot mismatch"),
                REJECT_INVALID, "bad-txnmrklroot", true);

        // Check for merkle tree malleability (CVE-2012-2459): repeating sequences
        // of transactions in a block without affecting the merkle root of a block,
        // while still invalidating it.
        if (mutated)
            return state.DoS(100, error("CheckBlock(): duplicate transaction"),
                REJECT_INVALID, "bad-txns-duplicate", true);
    }

    // All potential-corruption validation must be done before we do any
    // transaction validation, as otherwise we may mark the header as invalid
    // because we receive the wrong transactions for it.

    // Size limits
    unsigned int nMaxBlockSize = MAX_BLOCK_SIZE;
    if (block.vtx.empty() || block.vtx.size() > nMaxBlockSize || ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION) > nMaxBlockSize)
        return state.DoS(100, error("CheckBlock(): size limits failed"),
            REJECT_INVALID, "bad-blk-length");

    // First transaction must be coinbase, the rest must not be
    if (block.vtx.empty() || !block.vtx[0].IsCoinBase())
        return state.DoS(100, error("CheckBlock(): first tx is not coinbase"),
            REJECT_INVALID, "bad-cb-missing");
    for (unsigned int i = 1; i < block.vtx.size(); i++)
        if (block.vtx[i].IsCoinBase())
            return state.DoS(100, error("CheckBlock(): more than one coinbase"),
                REJECT_INVALID, "bad-cb-multiple");

    // Coinbase first transaction must have only 1 vin
    if (block.vtx[0].vin.size() != 1)
        return state.DoS(100, error("CheckBlock(): coinbase first transaction must have only 1 vin"));

    // First transaction first input must have exactly 2 vout
    if (block.vtx[0].vout.size() != 2)
        return state.DoS(100, error("CheckBlock(): coinbase first transaction must have exactly 3 vout"));

    // First Transaction must pay to dev fund
    if (block.vtx.empty() || !block.vtx[0].PaidToDev())
        return state.DoS(100, error("CheckBlock(): first tx, first vout did not pay to dev"));

    if (fBlockIsProofOfStake) {
        // Must have at least 2 transactions
        if (block.vtx.empty() || block.vtx.size() < 2)
            return state.DoS(100, error("CheckBlock(): coinstake must have at least 2 transactions"));

        // Second transaction must be coinstake, the rest must not be
        if (block.vtx.empty() || !block.vtx[1].IsCoinStake())
            return state.DoS(100, error("CheckBlock(): second tx is not coinstake"));
        for (unsigned int i = 2; i < block.vtx.size(); i++)
            if (block.vtx[i].IsCoinStake())
                return state.DoS(100, error("CheckBlock(): more than one coinstake"));

        // Second transaction must have at least 1 vin
        if (block.vtx[1].vin.size() < 1)
            return state.DoS(100, error("CheckBlock(): coinstake second transaction must have at least 1 vin"));
        // Second transaction must have at most 25 vin
        if (block.vtx[1].vin.size() > MAXIMUM_STAKE_INPUT_SIZE)
            return state.DoS(100, error("CheckBlock(): coinstake second transaction must have at most 25 vin"));

        // First vout must be a locking transaction
        if (!block.vtx[1].vout[0].IsCoinStake())
            return state.DoS(100, error("CheckBlock(): second tx, first vout is not locking"));
        // Second vout must be a locking transaction if total value bigger than 2200 KORE
        int startCheckingNotStake = 1;
        if (block.vtx[1].vout.size() > 1 && block.vtx[1].vout[0].nValue + block.vtx[1].vout[1].nValue >= STAKE_SPLIT_TRESHOLD) {
            if (!block.vtx[1].vout[1].IsCoinStake())
                return state.DoS(100, error("CheckBlock(): second tx, second vout is not locking"));
            
            startCheckingNotStake = 2;
        }
        // Other transaction can't be locking
        for (unsigned int i = startCheckingNotStake; i < block.vtx[1].vout.size(); i++)
            if (block.vtx[1].vout[i].IsCoinStake())
                return state.DoS(100, error("CheckBlock(): too many locking vout"));
    }

    // Check transactions
    for (const CTransaction& tx : block.vtx) {
        if (!CheckTransaction(tx, state))
            return error("CheckBlock() : CheckTransaction failed");
    }

    unsigned int nSigOps = 0;
    BOOST_FOREACH (const CTransaction& tx, block.vtx) {
        nSigOps += GetLegacySigOpCount(tx);
    }
    unsigned int nMaxBlockSigOps = MAX_BLOCK_SIGOPS_LEGACY;
    if (nSigOps > nMaxBlockSigOps)
        return state.DoS(100, error("CheckBlock() : out-of-bounds SigOpCount"),
            REJECT_INVALID, "bad-blk-sigops", true);

    return true;
}

bool CheckBlock_Legacy(const CBlock& block, CValidationState& state, bool fCheckPOW, bool fCheckMerkleRoot)
{
    // These are checks that are independent of context.

    if (block.fChecked)
        return true;

    // Check that the header is valid (particularly PoW).  This is mostly
    // redundant with the call in AcceptBlockHeader.
    if (!CheckBlockHeader_Legacy(block, state, block.IsProofOfWork() && fCheckPOW))
        return false;

    CBlockIndex* pindexPrev = chainActive.Tip();

    // Check the merkle root.
    if (fCheckMerkleRoot) {
        bool mutated;
        uint256 hashMerkleRoot2 = BlockMerkleRoot(block, &mutated);
        if (block.hashMerkleRoot != hashMerkleRoot2)
            return state.DoS(100, error("CheckBlock(): hashMerkleRoot mismatch"), REJECT_INVALID, "bad-txnmrklroot", true);

        // Check for merkle tree malleability (CVE-2012-2459): repeating sequences
        // of transactions in a block without affecting the merkle root of a block,
        // while still invalidating it.
        if (mutated)
            return state.DoS(100, error("CheckBlock(): duplicate transaction"), REJECT_INVALID, "bad-txns-duplicate", true);
    }


    // All potential-corruption validation must be done before we do any
    // transaction validation, as otherwise we may mark the header as invalid
    // because we receive the wrong transactions for it.

    // Size limits
    if (block.vtx.empty() || block.vtx.size() > MAX_BLOCK_SIZE_LEGACY || ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION) > MAX_BLOCK_SIZE_LEGACY)
        return state.DoS(100, error("CheckBlock(): size limits failed"), REJECT_INVALID, "bad-blk-length");


    // First transaction must be coinbase, the rest must not be
    if (block.vtx.empty() || !block.vtx[0].IsCoinBase())
        return state.DoS(100, error("CheckBlock(): first tx is not coinbase"), REJECT_INVALID, "bad-cb-missing");
    for (unsigned int i = 1; i < block.vtx.size(); i++)
        if (block.vtx[i].IsCoinBase())
            return state.DoS(100, error("CheckBlock(): more than one coinbase"), REJECT_INVALID, "bad-cb-multiple");

    // Check coinbase timestamp
    if (block.GetBlockTime() > GetAdjustedTime() + 2 * 60 * 60)
        return state.DoS(25, error("CheckBlock(): coinbase timestamp is too early blocktime=%d nTimeTx=%u", block.GetBlockTime(), block.vtx[0].nTime),
            REJECT_INVALID, "bad-cb-time");


    // Check coinstake timestamp
    if (block.IsProofOfStake() && !CheckCoinStakeTimestamp(block.GetBlockTime(), block.vtx[1].nTime))
        return state.DoS(50, error("CheckBlock(): coinstake timestamp violation nTimeBlock=%d nTimeTx=%u", block.GetBlockTime(), block.vtx[1].nTime),
            REJECT_INVALID, "bad-cs-time");

    if (block.IsProofOfStake()) {
        // Coinbase output must be empty if proof-of-stake block
        if (block.vtx[0].vout.size() != 1 || !block.vtx[0].vout[0].IsEmpty())
            return state.DoS(100, error("CheckBlock(): coinbase output not empty for proof-of-stake block"), REJECT_INVALID, "bad-cb-not-empty");

        // Second transaction must be coinstake, the rest must not be
        if (block.vtx.size() < 2 || !block.vtx[1].IsLegacyCoinStake())
            return state.DoS(100, error("CheckBlock(): second tx is not coinstake"), REJECT_INVALID, "bad-cs-missing");

        for (unsigned int i = 2; i < block.vtx.size(); i++)
            if (block.vtx[i].IsLegacyCoinStake())
                return state.DoS(100, error("CheckBlock(): more than one coinstake"), REJECT_INVALID, "bad-cs-multiple");
    }

    // Check proof-of-stake block signature
    if (!CheckBlockSignature_Legacy(block, block.GetHash()))
        return state.DoS(100, error("CheckBlock(): bad proof-of-stake block signature"), REJECT_INVALID, "bad-block-signature");

    // ----------- masternode payments / budgets -----------


    if (pindexPrev != NULL) {
        int nHeight = 0;
        if (pindexPrev->GetBlockHash() == block.hashPrevBlock) {
            nHeight = pindexPrev->nHeight + 1;
        } else { //out of order
            BlockMap::iterator mi = mapBlockIndex.find(block.hashPrevBlock);
            if (mi != mapBlockIndex.end() && (*mi).second)
                nHeight = (*mi).second->nHeight + 1;
        }
    }
    // Check transactions
    BOOST_FOREACH (const CTransaction& tx, block.vtx) {
        if (!CheckTransaction(tx, state))
            return error("CheckBlock(): CheckTransaction of %s failed with %s", tx.GetHash().ToString(), FormatStateMessage_Legacy(state));

        // check transaction timestamp
        if (block.GetBlockTime() < (int64_t)tx.nTime)
            return state.DoS(100, error("CheckBlock() : block timestamp earlier than transaction timestamp"), REJECT_INVALID, "bad-tx-time");
    }
    unsigned int nSigOps = 0;
    BOOST_FOREACH (const CTransaction& tx, block.vtx) {
        nSigOps += GetLegacySigOpCount(tx);
    }
    if (nSigOps > MAX_BLOCK_SIGOPS_LEGACY)
        return state.DoS(100, error("CheckBlock(): out-of-bounds SigOpCount"),
            REJECT_INVALID, "bad-blk-sigops");

    if (fCheckPOW && fCheckMerkleRoot)
        block.fChecked = true;
    return true;
}

bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& state, CBlockIndex* const pindexPrev)
{
    uint256 hash = block.GetHash();

    if (hash == Params().HashGenesisBlock())
        return true;

    assert(pindexPrev);

    int nHeight = pindexPrev->nHeight + 1;

    //If this is a reorg, check that it is not too deep
    int nMaxReorgDepth = GetArg("-maxreorg", Params().GetMaxReorganizationDepth());
    if (chainActive.Height() - nHeight >= nMaxReorgDepth)
        return state.DoS(1, error("%s: forked chain older than max reorganization depth (height %d)", __func__, nHeight));

    // Check timestamp against prev
    if (block.GetBlockTime() <= pindexPrev->GetMedianTimePast()) {
        if (fDebug)
            LogPrintf("Block time = %d , GetMedianTimePast = %d \n", block.GetBlockTime(), pindexPrev->GetMedianTimePast());
        
        return state.Invalid(error("%s : block's timestamp is too early", __func__),
            REJECT_INVALID, "time-too-old");
    }

    // Check that the block chain matches the known block chain up to a checkpoint
    if (!Checkpoints::CheckBlock(nHeight, hash))
        return state.DoS(100, error("%s : rejected by checkpoint lock-in at %d", __func__, nHeight),
            REJECT_CHECKPOINT, "checkpoint mismatch");

    // Don't accept any forks from the main chain prior to last checkpoint
    CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint();
    if (pcheckpoint && nHeight < pcheckpoint->nHeight)
        return state.DoS(0, error("%s : forked chain older than last checkpoint (height %d)", __func__, nHeight));

    return true;
}

bool ContextualCheckBlockHeader_Legacy(const CBlockHeader& block, CValidationState& state, CBlockIndex* const pindexPrev)
{
    // Check timestamp against prev
    if (block.GetBlockTime() <= pindexPrev->GetMedianTimePast())
        return state.Invalid(error("%s: block's timestamp is too early nVersion= %d ", __func__, block.nVersion), REJECT_INVALID, "time-too-old");

    return true;
}


bool IsBlockHashInChain(const uint256& hashBlock)
{
    if (hashBlock == 0 || !mapBlockIndex.count(hashBlock))
        return false;

    return chainActive.Contains(mapBlockIndex[hashBlock]);
}

bool IsTransactionInChain(const uint256& txId, int& nHeightTx, CTransaction& tx)
{
    uint256 hashBlock;
    if (!GetTransaction(txId, tx, hashBlock, true))
        return false;
    if (!IsBlockHashInChain(hashBlock))
        return false;

    nHeightTx = mapBlockIndex.at(hashBlock)->nHeight;
    return true;
}

bool IsTransactionInChain(const uint256& txId, int& nHeightTx)
{
    CTransaction tx;
    return IsTransactionInChain(txId, nHeightTx, tx);
}

bool ContextualCheckBlock(const CBlock& block, CValidationState& state, CBlockIndex* const pindexPrev)
{
    const int nHeight = pindexPrev == NULL ? 0 : pindexPrev->nHeight + 1;

    // Check that all transactions are finalized
    BOOST_FOREACH (const CTransaction& tx, block.vtx)
        if (!IsFinalTx(tx, nHeight, block.GetBlockTime())) {
            return state.DoS(10, error("%s : contains a non-final transaction", __func__), REJECT_INVALID, "bad-txns-nonfinal");
        }

    // Enforce rule that the coinbase starts with serialized block height
    CScript expect = CScript() << nHeight;
    if (block.vtx[0].vin[0].scriptSig.size() < expect.size() ||
        !std::equal(expect.begin(), expect.end(), block.vtx[0].vin[0].scriptSig.begin())) {
        return state.DoS(100, error("%s : block height mismatch in coinbase", __func__), REJECT_INVALID, "bad-cb-height");
    }

    return true;
}

// Protected by cs_main
VersionBitsCache versionbitscache;

bool ContextualCheckBlock_Legacy(const CBlock& block, CValidationState& state, CBlockIndex* const pindexPrev)
{
    const int nHeight = pindexPrev == NULL ? 0 : pindexPrev->nHeight + 1;

    if (block.IsProofOfWork() && nHeight > Params().GetLastPoWBlock())
        return state.DoS(100, error("%s : reject proof-of-work at height %d", __func__, nHeight), REJECT_INVALID, "bad-pow-height");

    // Start enforcing BIP113 (Median Time Past) using versionbits logic.
    int nLockTimeFlags = 0;
    if (VersionBitsState(pindexPrev, CChainParams::DEPLOYMENT_CSV, versionbitscache) == THRESHOLD_ACTIVE) {
        nLockTimeFlags |= LOCKTIME_MEDIAN_TIME_PAST;
    }

    int64_t nLockTimeCutoff = (nLockTimeFlags & LOCKTIME_MEDIAN_TIME_PAST) ? pindexPrev->GetMedianTimePast() : block.GetBlockTime();

    // Check that all transactions are finalized
    BOOST_FOREACH (const CTransaction& tx, block.vtx) {
        if (!IsFinalTx(tx, nHeight, nLockTimeCutoff)) {
            return state.DoS(10, error("%s: contains a non-final transaction", __func__), REJECT_INVALID, "bad-txns-nonfinal");
        }
    }

    // Enforce rule that the coinbase starts with serialized block height

    CScript expect = CScript() << nHeight;
    if (block.vtx[0].vin[0].scriptSig.size() < expect.size() ||
        !std::equal(expect.begin(), expect.end(), block.vtx[0].vin[0].scriptSig.begin())) {
        return state.DoS(100, error("%s: block height mismatch in coinbase", __func__), REJECT_INVALID, "bad-cb-height");
    }

    return true;
}

static bool CheckIndexAgainstCheckpoint_Legacy(const CBlockIndex* pindexPrev, CValidationState& state, const uint256& hash)
{
    if (*pindexPrev->phashBlock == Params().HashGenesisBlock())
        return true;

    int nHeight = pindexPrev->nHeight + 1;
    // Don't accept any forks from the main chain prior to last checkpoint
    CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint();
    if (pcheckpoint && nHeight < pcheckpoint->nHeight)
        return state.DoS(100, error("%s: forked chain older than last checkpoint (height %d)", __func__, nHeight));

    if (chainActive.Height() - nHeight >= Params().GetMaxReorganizationDepth())
        return state.DoS(1, error("%s: forked chain older than max reorganization depth (height %d)", __func__, nHeight));

    return true;
}

bool AcceptBlockHeader(const CBlockHeader& block, CValidationState& state, CBlockIndex** ppindex)
{
    if (UseLegacyCode(block)) {
        CBlockIndex*& pindex = *ppindex;
        return AcceptBlockHeader_Legacy(block, state, &pindex);
    }
    AssertLockHeld(cs_main);
    // Check for duplicate
    uint256 hash = block.GetHash();
    BlockMap::iterator miSelf = mapBlockIndex.find(hash);
    CBlockIndex* pindex = NULL;

    // TODO : ENABLE BLOCK CACHE IN SPECIFIC CASES
    if (miSelf != mapBlockIndex.end()) {
        // Block header is already known.
        pindex = miSelf->second;
        if (ppindex)
            *ppindex = pindex;
        if (pindex->nStatus & BLOCK_FAILED_MASK)
            return state.Invalid(error("%s : block is marked invalid", __func__), 0, "duplicate");
        return true;
    }

    if (!CheckBlockHeader(block, state, false)) {
        if (fDebug)
            LogPrintf("AcceptBlockHeader(): CheckBlockHeader failed \n");
        
        return false;
    }

    // Get prev block index
    CBlockIndex* pindexPrev = NULL;
    if (hash != Params().HashGenesisBlock()) {
        BlockMap::iterator mi = mapBlockIndex.find(block.hashPrevBlock);
        if (mi == mapBlockIndex.end())
            return state.DoS(0, error("%s : prev block %s not found", __func__, block.hashPrevBlock.ToString().c_str()), 0, "bad-prevblk");
        pindexPrev = (*mi).second;
        if (pindexPrev->nStatus & BLOCK_FAILED_MASK) {
            //If this "invalid" block is an exact match from the checkpoints, then reconsider it
            if (pindex && Checkpoints::CheckBlock(pindex->nHeight - 1, block.hashPrevBlock, true)) {
                if (fDebug)
                    LogPrintf("%s : Reconsidering block %s height %d\n", __func__, pindexPrev->GetBlockHash().GetHex(), pindexPrev->nHeight);
                
                CValidationState statePrev;
                ReconsiderBlock(statePrev, pindexPrev);
                if (statePrev.IsValid()) {
                    ActivateBestChain(statePrev);
                    return true;
                }
            }

            return state.DoS(100, error("%s : prev block height=%d hash=%s is invalid, unable to add block %s", __func__, pindexPrev->nHeight, block.hashPrevBlock.GetHex(), block.GetHash().GetHex()),
                REJECT_INVALID, "bad-prevblk");
        }
    }

    if (!ContextualCheckBlockHeader(block, state, pindexPrev))
        return false;

    if (pindex == NULL)
        pindex = AddToBlockIndex(block);

    if (ppindex)
        *ppindex = pindex;

    return true;
}

bool AcceptBlockHeader_Legacy(const CBlockHeader& block, CValidationState& state, CBlockIndex** ppindex)
{
    AssertLockHeld(cs_main);
    // Check for duplicate
    uint256 hash = block.GetHash();
    BlockMap::iterator miSelf = mapBlockIndex.find(hash);
    CBlockIndex* pindex = NULL;
    if (hash != Params().HashGenesisBlock()) {
        if (miSelf != mapBlockIndex.end()) {
            // Block header is already known.
            pindex = miSelf->second;
            if (ppindex)
                *ppindex = pindex;
            if (pindex->nStatus & BLOCK_FAILED_MASK)
                return state.Invalid(error("%s: block is marked invalid", __func__), 0, "duplicate");
            return true;
        }

        if (!CheckBlockHeader_Legacy(block, state, false))
            return false;

        // Get prev block index
        CBlockIndex* pindexPrev = NULL;
        BlockMap::iterator mi = mapBlockIndex.find(block.hashPrevBlock);
        if (mi == mapBlockIndex.end())
            return state.DoS(10, error("%s: prev block not found", __func__), 0, "bad-prevblk");
        pindexPrev = (*mi).second;
        if (pindexPrev->nStatus & BLOCK_FAILED_MASK) {
            if (Checkpoints::fEnabled && CheckIndexAgainstCheckpoint_Legacy(pindexPrev, state, hash)) {
                if (fDebug)
                    LogPrintf("%s : Reconsidering block %s height %d\n", __func__, pindexPrev->GetBlockHash().GetHex(), pindexPrev->nHeight);
                
                CValidationState statePrev;
                ReconsiderBlock(statePrev, pindexPrev);
                if (statePrev.IsValid()) {
                    ActivateBestChain(statePrev);
                    return true;
                }
            }
            return state.DoS(100, error("%s : prev block height=%d hash=%s is invalid, unable to add block %s", __func__, pindexPrev->nHeight, block.hashPrevBlock.GetHex(), block.GetHash().GetHex()),
                REJECT_INVALID, "bad-prevblk");
        }

        if (!ContextualCheckBlockHeader_Legacy(block, state, pindexPrev))
            return false;
    }
    if (pindex == NULL)
        pindex = AddToBlockIndex(block);

    if (ppindex)
        *ppindex = pindex;

    return true;
}

/** Store block on disk. If dbp is non-NULL, the file is known to already reside on disk */
static bool AcceptBlock_Legacy(const CBlock& block, CValidationState& state, CBlockIndex** ppindex, bool fRequested, CDiskBlockPos* dbp)
{
    AssertLockHeld(cs_main);

    CBlockIndex*& pindex = *ppindex;

    if (!AcceptBlockHeader_Legacy(block, state, &pindex))
        return false;

    // Try to process all requested blocks that we don't have, but only
    // process an unrequested block if it's new and has enough work to
    // advance our tip, and isn't too many blocks ahead.
    bool fAlreadyHave = pindex->nStatus & BLOCK_HAVE_DATA;
    bool fHasMoreWork = (chainActive.Tip() ? pindex->nChainWork > chainActive.Tip()->nChainWork : true);
    // Blocks that are too out-of-order needlessly limit the effectiveness of
    // pruning, because pruning will not delete block files that contain any
    // blocks which are too close in height to the tip.  Apply this test
    // regardless of whether pruning is enabled; it should generally be safe to
    // not process unrequested blocks.
    bool fTooFarAhead = (pindex->nHeight > int(chainActive.Height() + MIN_BLOCKS_TO_KEEP));

    // TODO: deal better with return value and error conditions for duplicate
    // and unrequested blocks.
    if (fAlreadyHave) return true;
    if (!fRequested) {                     // If we didn't ask for it:
        if (pindex->nTx != 0) return true; // This is a previously-processed block that was pruned
        if (!fHasMoreWork) return true;    // Don't process less-work chains
        if (fTooFarAhead) return true;     // Block height is too high
    }


    if ((!CheckBlock_Legacy(block, state)) || !ContextualCheckBlock_Legacy(block, state, pindex->pprev)) {
        if (state.IsInvalid() && !state.CorruptionPossible()) {
            pindex->nStatus |= BLOCK_FAILED_VALID;
            setDirtyBlockIndex.insert(pindex);
        }
        return false;
    }


    int nHeight = pindex->nHeight;
    if (block.IsProofOfStake()) {
        pindex->SetProofOfStake();
        pindex->SetProofOfStake_Legacy();
    }
    // Write block to history file
    try {
        unsigned int nBlockSize = ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
        CDiskBlockPos blockPos;
        if (dbp != NULL)
            blockPos = *dbp;
        if (!FindBlockPos(state, blockPos, nBlockSize + 8, nHeight, block.GetBlockTime(), dbp != NULL))
            return error("AcceptBlock(): FindBlockPos failed");
        if (dbp == NULL)
            if (!WriteBlockToDisk(block, blockPos))
                AbortNode(state, "Failed to write block");
        if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
            return error("AcceptBlock(): ReceivedBlockTransactions failed");
    } catch (const std::runtime_error& e) {
        return AbortNode(state, std::string("System error: ") + e.what());
    }

    if (fCheckForPruning)
        FlushStateToDisk(state, FLUSH_STATE_NONE); // we just allocated more disk space for block files

    if (fDebug)
        LogPrintf("AcceptBlock_Legacy block: %d<-- \n", nHeight);

    return true;
}

bool AcceptBlock(CBlock& block, CValidationState& state, CBlockIndex** ppindex, CDiskBlockPos* dbp, bool fAlreadyCheckedBlock)
{
    if (fDebug)
        LogPrintf("AcceptBlock --> \n");
    AssertLockHeld(cs_main);

    CBlockIndex*& pindex = *ppindex;

    if (!AcceptBlockHeader(block, state, &pindex))
        return false;

    int nHeight = pindex->nHeight;

    // Get prev block index
    CBlockIndex* pindexPrev = NULL;
    if (block.GetHash() != Params().HashGenesisBlock()) {
        BlockMap::iterator mi = mapBlockIndex.find(block.hashPrevBlock);
        if (mi == mapBlockIndex.end())
            return state.DoS(0, error("%s : prev block %s not found", __func__, block.hashPrevBlock.ToString().c_str()), 0, "bad-prevblk");
        pindexPrev = (*mi).second;
        if (pindexPrev->nStatus & BLOCK_FAILED_MASK) {
            //If this "invalid" block is an exact match from the checkpoints, then reconsider it
            if (Checkpoints::CheckBlock(pindexPrev->nHeight, block.hashPrevBlock, true)) {
                if (fDebug)
                    LogPrintf("%s : Reconsidering block %s height %d\n", __func__, pindexPrev->GetBlockHash().GetHex(), pindexPrev->nHeight);
                
                CValidationState statePrev;
                ReconsiderBlock(statePrev, pindexPrev);
                if (statePrev.IsValid()) {
                    ActivateBestChain(statePrev);
                    return true;
                }
            }
            return state.DoS(100, error("%s : prev block %s is invalid, unable to add block %s", __func__, block.hashPrevBlock.GetHex(), block.GetHash().GetHex()),
                REJECT_INVALID, "bad-prevblk");
        }
    }

    if (block.IsProofOfStake()) {
        uint256 hashProofOfStake = 0;
        std::list<CKoreStake> listStake;
        CAmount stakedBalance;

        if (!CheckProofOfStake(block, hashProofOfStake, listStake, stakedBalance)){
            if (IsInitialBlockDownload())
                return state.DoS(0, error("%s: proof of stake check failed", __func__));
            return state.DoS(100, error("%s: proof of stake check failed", __func__));
        }

        //Check minimum stake value
        if (stakedBalance < MINIMUM_STAKE_VALUE)
            return state.DoS(100, error("CheckBlock(): staked balance too low"));

        //Check maximum stake value
        CAmount stakedValue = block.vtx[1].vout[0].nValue;
        if (stakedBalance >= STAKE_SPLIT_TRESHOLD)
            stakedValue += block.vtx[1].vout[1].nValue;

        if (stakedValue > MAXIMUM_STAKE_VALUE)
            return state.DoS(100, error("CheckBlock(): staked balance too low"));
        
        if (listStake.empty())
            return error("%s: empty list stake ptr", __func__);

        for (std::list<CKoreStake>::iterator it = listStake.begin(); it != listStake.end(); ++it) {
            if ((*it).IsNull())
                return error("%s: null stake ptr", __func__);
        }

        uint256 hash = block.GetHash();
        if (!mapProofOfStake.count(hash)) // add to mapProofOfStake
            mapProofOfStake.insert(make_pair(hash, hashProofOfStake));
    }

    if (pindex->nStatus & BLOCK_HAVE_DATA) {
        // TODO: deal better with duplicate blocks.
        // return state.DoS(20, error("AcceptBlock() : already have block %d %s", pindex->nHeight, pindex->GetBlockHash().ToString()), REJECT_DUPLICATE, "duplicate");
        return true;
    }

    if ((!fAlreadyCheckedBlock && !CheckBlock(block, state)) || !ContextualCheckBlock(block, state, pindex->pprev)) {
        if (state.IsInvalid() && !state.CorruptionPossible()) {
            pindex->nStatus |= BLOCK_FAILED_VALID;
            setDirtyBlockIndex.insert(pindex);
        }
        return false;
    }

    // Write block to history file
    try {
        unsigned int nBlockSize = ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
        CDiskBlockPos blockPos;
        if (dbp != NULL)
            blockPos = *dbp;
        if (!FindBlockPos(state, blockPos, nBlockSize + 8, nHeight, block.GetBlockTime(), dbp != NULL))
            return error("AcceptBlock() : FindBlockPos failed");
        if (dbp == NULL)
            if (!WriteBlockToDisk(block, blockPos))
                return state.Abort("Failed to write block");
        if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
            return error("AcceptBlock() : ReceivedBlockTransactions failed");
    } catch (std::runtime_error& e) {
        return state.Abort(std::string("System error: ") + e.what());
    }

    if (fDebug) { 
        LogPrintf("AcceptBlock block: %d \n",nHeight);
    }
    return true;
}

/** Turn the lowest '1' bit in the binary representation of a number into a '0'. */
int static inline InvertLowestOne(int n) { return n & (n - 1); }

/** Compute what height to jump back to with the CBlockIndex::pskip pointer. */
int static inline GetSkipHeight(int height)
{
    if (height < 2)
        return 0;

    // Determine which height to jump back to. Any number strictly lower than height is acceptable,
    // but the following expression seems to perform well in simulations (max 110 steps to go back
    // up to 2**18 blocks).
    return (height & 1) ? InvertLowestOne(InvertLowestOne(height - 1)) + 1 : InvertLowestOne(height);
}

CBlockIndex* CBlockIndex::GetAncestor(int height)
{
    if (height > nHeight || height < 0)
        return NULL;

    CBlockIndex* pindexWalk = this;
    int heightWalk = nHeight;
    while (heightWalk > height) {
        int heightSkip = GetSkipHeight(heightWalk);
        int heightSkipPrev = GetSkipHeight(heightWalk - 1);
        if (pindexWalk->pskip != NULL &&
            (heightSkip == height ||
                (heightSkip > height && !(heightSkipPrev < heightSkip - 2 &&
                                            heightSkipPrev >= height)))) {
            // Only follow pskip if pprev->pskip isn't better than pskip->pprev.
            pindexWalk = pindexWalk->pskip;
            heightWalk = heightSkip;
        } else {
            assert(pindexWalk->pprev);
            pindexWalk = pindexWalk->pprev;
            heightWalk--;
        }
    }
    return pindexWalk;
}

const CBlockIndex* CBlockIndex::GetAncestor(int height) const
{
    return const_cast<CBlockIndex*>(this)->GetAncestor(height);
}

void CBlockIndex::BuildSkip()
{
    if (pprev)
        pskip = pprev->GetAncestor(GetSkipHeight(nHeight));
}

bool ProcessNewBlock(CValidationState& state, CNode* pfrom, CBlock* pblock, CDiskBlockPos* dbp)
{
    // Preliminary checks
    int64_t nStartTime = GetTimeMillis();
    // we will be processing the next tip block
    bool checked = CheckBlock(*pblock, state);

    if (!CheckBlockSignature(*pblock))
        return error("ProcessNewBlock() : bad proof-of-stake block signature");

    if (pblock->GetHash() != Params().HashGenesisBlock() && pfrom != NULL) {
        //if we get this far, check if the prev block is our prev block, if not then request sync and return false
        BlockMap::iterator mi = mapBlockIndex.find(pblock->hashPrevBlock);
        if (mi == mapBlockIndex.end()) {
            pfrom->PushMessage("getblocks", chainActive.GetLocator(), uint256(0));
            return false;
        }
    }

    {
        LOCK(cs_main); // Replaces the former TRY_LOCK loop because busy waiting wastes too much resources

        MarkBlockAsReceived(pblock->GetHash());
        if (!checked) {
            return error("%s : CheckBlock FAILED for block %s", __func__, pblock->GetHash().GetHex());
        }

        // Store to disk
        CBlockIndex* pindex = NULL;
        bool ret = AcceptBlock(*pblock, state, &pindex, dbp, checked);
        if (pindex && pfrom) {
            mapBlockSource[pindex->GetBlockHash()] = pfrom->GetId();
        }
        CheckBlockIndex();

        if (!ret)
            return error("%s : AcceptBlock FAILED block", __func__);
    }

    if (!ActivateBestChain(state, pblock))
        return error("%s : ActivateBestChain failed", __func__);


    if (pwalletMain) {
        // If turned on MultiSend will send a transaction (or more) on the after maturity of a stake
        if (pwalletMain->isMultiSendEnabled())
            pwalletMain->MultiSend();

        // If turned on Auto Combine will scan wallet for dust to combine
        if (pwalletMain->fCombineDust)
            pwalletMain->AutoCombineDust();
    }

    if (fDebug)
        LogPrintf("%s : ACCEPTED Block %ld in %ld milliseconds with size=%d\n", __func__, GetHeight(), GetTimeMillis() - nStartTime,
            pblock->GetSerializeSize(SER_DISK, CLIENT_VERSION));

    return true;
}

bool static IsCanonicalBlockSignature_Legacy(const CBlock* pblock)
{
    if (pblock->IsProofOfWork()) {
        return pblock->vchBlockSig.empty();
    }

    return IsValidSignatureEncoding(pblock->vchBlockSig, false);
}


bool ProcessNewBlock_Legacy(CValidationState& state, const CChainParams& chainparams, const CNode* pfrom, const CBlock* pblock, bool fForceProcessing, CDiskBlockPos* dbp)
{
    if (fDebug)
        LogPrintf("ProcessNewBlock_Legacy starts\n");

    // Preliminary checks
    if (!CheckBlock_Legacy(*pblock, state))
        return error("%s : CheckBlock FAILED for block %s", __func__, pblock->GetHash().GetHex());

    if (!IsCanonicalBlockSignature_Legacy(pblock)) {
        if (pfrom && pfrom->nVersion >= CANONICAL_BLOCK_SIG_VERSION)
            return state.DoS(100, error("ProcessNewBlock_Legacy(): bad block signature encoding"), REJECT_INVALID, "bad-block-signature-encoding");

        return false;
    }

    {
        LOCK(cs_main);
        bool fRequested = MarkBlockAsReceived_Legacy(pblock->GetHash());
        fRequested |= fForceProcessing;

        // Store to disk
        CBlockIndex* pindex = NULL;
        bool ret = AcceptBlock_Legacy(*pblock, state, &pindex, fRequested, dbp);
        if (pindex && pfrom) {
            mapBlockSource[pindex->GetBlockHash()] = pfrom->GetId();
        }
        CheckBlockIndex();
        if (!ret)
            return error("%s: AcceptBlock FAILED", __func__);
    }

    if (!ActivateBestChain(state, pblock))
        return error("%s: ActivateBestChain failed", __func__);

    if (pwalletMain) {
        // If turned on MultiSend will send a transaction (or more) on the after maturity of a stake
        if (pwalletMain->isMultiSendEnabled())
            pwalletMain->MultiSend();

        //If turned on Auto Combine will scan wallet for dust to combine
        if (pwalletMain->fCombineDust)
            pwalletMain->AutoCombineDust();
    }

    if (fDebug)
        LogPrintf("%s : ACCEPTED\n", __func__);

    return true;
}

bool TestBlockValidity(CValidationState& state, const CBlock& block, CBlockIndex* const pindexPrev, bool fCheckPOW, bool fCheckMerkleRoot)
{
    AssertLockHeld(cs_main);
    assert(pindexPrev == chainActive.Tip());

    CCoinsViewCache viewNew(pcoinsTip);
    CBlockIndex indexDummy(block);
    indexDummy.pprev = pindexPrev;
    indexDummy.nHeight = pindexPrev->nHeight + 1;

    // NOTE: CheckBlockHeader is called by CheckBlock
    if (!ContextualCheckBlockHeader(block, state, pindexPrev))
        return false;
    if (!CheckBlock(block, state, fCheckPOW, fCheckMerkleRoot))
        return false;
    if (!ContextualCheckBlock(block, state, pindexPrev))
        return false;
    if (!ConnectBlock(block, state, &indexDummy, viewNew, true))
        return false;
    assert(state.IsValid());

    return true;
}


bool TestBlockValidity_Legacy(CValidationState& state, const CChainParams& chainparams, const CBlock& block, CBlockIndex* pindexPrev, bool fCheckPOW, bool fCheckMerkleRoot)
{
    AssertLockHeld(cs_main);
    assert(pindexPrev && pindexPrev == chainActive.Tip());
    if (Checkpoints::fEnabled && !CheckIndexAgainstCheckpoint_Legacy(pindexPrev, state, block.GetHash()))
        return error("%s: CheckIndexAgainstCheckpoint(): %s", __func__, state.GetRejectReason().c_str());

    CCoinsViewCache viewNew(pcoinsTip);
    CBlockIndex indexDummy(block);
    indexDummy.pprev = pindexPrev;
    indexDummy.nHeight = pindexPrev->nHeight + 1;

    // NOTE: CheckBlockHeader is called by CheckBlock
    if (!ContextualCheckBlockHeader_Legacy(block, state, pindexPrev))
        return false;
    if (!CheckBlock_Legacy(block, state, fCheckPOW, fCheckMerkleRoot))
        return false;
    if (!ContextualCheckBlock_Legacy(block, state, pindexPrev))
        return false;
    if (!ConnectBlock_Legacy(block, state, &indexDummy, viewNew, true))
        return false;
    assert(state.IsValid());

    return true;
}

bool AbortNode(const std::string& strMessage, const std::string& userMessage)
{
    strMiscWarning = strMessage;
    if (fDebug)
        LogPrintf("*** %s\n", strMessage);
    uiInterface.ThreadSafeMessageBox(
        userMessage.empty() ? _("Error: A fatal internal error occured, see debug.log for details") : userMessage,
        "", CClientUIInterface::MSG_ERROR);
    StartShutdown();
    return false;
}

bool AbortNode(CValidationState& state, const std::string& strMessage, const std::string& userMessage)
{
    AbortNode(strMessage, userMessage);
    return state.Error(strMessage);
}

bool CheckDiskSpace(uint64_t nAdditionalBytes)
{
    uint64_t nFreeBytesAvailable = filesystem::space(GetDataDir()).available;

    // Check for nMinDiskSpace bytes (currently 50MB)
    if (nFreeBytesAvailable < nMinDiskSpace + nAdditionalBytes)
        return AbortNode("Disk space is low!", _("Error: Disk space is low!"));

    return true;
}

FILE* OpenDiskFile(const CDiskBlockPos& pos, const char* prefix, bool fReadOnly)
{
    if (pos.IsNull())
        return NULL;
    boost::filesystem::path path = GetBlockPosFilename(pos, prefix);
    boost::filesystem::create_directories(path.parent_path());
    FILE* file = fopen(path.string().c_str(), "rb+");
    if (!file && !fReadOnly)
        file = fopen(path.string().c_str(), "wb+");
    if (!file) {
        if (fDebug)
            LogPrintf("Unable to open file %s\n", path.string());
        return NULL;
    }
    if (pos.nPos) {
        if (fseek(file, pos.nPos, SEEK_SET)) {
            if (fDebug)
                LogPrintf("Unable to seek to position %u of %s\n", pos.nPos, path.string());
            fclose(file);
            return NULL;
        }
    }
    return file;
}

FILE* OpenBlockFile(const CDiskBlockPos& pos, bool fReadOnly)
{
    return OpenDiskFile(pos, "blk", fReadOnly);
}

FILE* OpenUndoFile(const CDiskBlockPos& pos, bool fReadOnly)
{
    return OpenDiskFile(pos, "rev", fReadOnly);
}

boost::filesystem::path GetBlockPosFilename(const CDiskBlockPos& pos, const char* prefix)
{
    return GetDataDir() / "blocks" / strprintf("%s%05u.dat", prefix, pos.nFile);
}

CBlockIndex* InsertBlockIndex(uint256 hash)
{
    if (hash == 0)
        return NULL;

    // Return existing
    BlockMap::iterator mi = mapBlockIndex.find(hash);
    if (mi != mapBlockIndex.end())
        return (*mi).second;

    // Create new
    CBlockIndex* pindexNew = new CBlockIndex();
    if (!pindexNew)
        throw runtime_error("LoadBlockIndex() : new CBlockIndex failed");
    mi = mapBlockIndex.insert(make_pair(hash, pindexNew)).first;

    pindexNew->phashBlock = &((*mi).first);

    return pindexNew;
}

bool static LoadBlockIndexDB()
{
    if (!pblocktree->LoadBlockIndexGuts())
        return false;

    boost::this_thread::interruption_point();

    // Calculate nChainWork
    vector<pair<int, CBlockIndex*> > vSortedByHeight;
    vSortedByHeight.reserve(mapBlockIndex.size());
    BOOST_FOREACH (const PAIRTYPE(uint256, CBlockIndex*) & item, mapBlockIndex) {
        CBlockIndex* pindex = item.second;
        vSortedByHeight.push_back(make_pair(pindex->nHeight, pindex));
    }
    sort(vSortedByHeight.begin(), vSortedByHeight.end());
    BOOST_FOREACH (const PAIRTYPE(int, CBlockIndex*) & item, vSortedByHeight) {
        CBlockIndex* pindex = item.second;
        pindex->nChainWork = (pindex->pprev ? pindex->pprev->nChainWork : 0) + GetBlockProof(*pindex);
        bool check = UseLegacyCode(pindex->nHeight) ? pindex->nTx > 0 : pindex->nStatus & BLOCK_HAVE_DATA;
        if (check) {
            if (pindex->pprev) {
                if (pindex->pprev->nChainTx) {
                    pindex->nChainTx = pindex->pprev->nChainTx + pindex->nTx;
                } else {
                    pindex->nChainTx = 0;
                    mapBlocksUnlinked.insert(std::make_pair(pindex->pprev, pindex));
                }
            } else {
                pindex->nChainTx = pindex->nTx;
            }
        }
        if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && (pindex->nChainTx || pindex->pprev == NULL))
            setBlockIndexCandidates.insert(pindex);
        if (pindex->nStatus & BLOCK_FAILED_MASK && (!pindexBestInvalid || pindex->nChainWork > pindexBestInvalid->nChainWork))
            pindexBestInvalid = pindex;
        if (pindex->pprev)
            pindex->BuildSkip();
        if (pindex->IsValid(BLOCK_VALID_TREE) && (pindexBestHeader == NULL || CBlockIndexWorkComparator()(pindexBestHeader, pindex)))
            pindexBestHeader = pindex;
    }

    // Load block file info
    pblocktree->ReadLastBlockFile(nLastBlockFile);
    vinfoBlockFile.resize(nLastBlockFile + 1);
    if (fDebug)
        ("%s: last block file = %i\n", __func__, nLastBlockFile);
    
    for (int nFile = 0; nFile <= nLastBlockFile; nFile++) {
        pblocktree->ReadBlockFileInfo(nFile, vinfoBlockFile[nFile]);
    }

    if (fDebug)
        LogPrintf("%s: last block file info: %s\n", __func__, vinfoBlockFile[nLastBlockFile].ToString());
    
    for (int nFile = nLastBlockFile + 1; true; nFile++) {
        CBlockFileInfo info;
        if (pblocktree->ReadBlockFileInfo(nFile, info)) {
            vinfoBlockFile.push_back(info);
        } else {
            break;
        }
    }

    // Check presence of blk files
    if (fDebug)
        LogPrintf("Checking all blk files are present...\n");
    
    set<int> setBlkDataFiles;
    BOOST_FOREACH (const PAIRTYPE(uint256, CBlockIndex*) & item, mapBlockIndex) {
        CBlockIndex* pindex = item.second;
        if (pindex->nStatus & BLOCK_HAVE_DATA) {
            setBlkDataFiles.insert(pindex->nFile);
        }
    }
    for (std::set<int>::iterator it = setBlkDataFiles.begin(); it != setBlkDataFiles.end(); it++) {
        CDiskBlockPos pos(*it, 0);
        if (CAutoFile(OpenBlockFile(pos, true), SER_DISK, CLIENT_VERSION).IsNull()) {
            return false;
        }
    }

    // Check whether we have ever pruned block & undo files
    pblocktree->ReadFlag("prunedblockfiles", fHavePruned);
    if (fHavePruned && fDebug)
        LogPrintf("LoadBlockIndexDB(): Block files have previously been pruned\n");

    //Check if the shutdown procedure was followed on last client exit
    bool fLastShutdownWasPrepared = true;
    pblocktree->ReadFlag("shutdown", fLastShutdownWasPrepared);
    LogPrintf("%s: Last shutdown was prepared: %s\n", __func__, fLastShutdownWasPrepared);

    // Check whether we need to continue reindexing
    bool fReindexing = false;
    pblocktree->ReadReindexing(fReindexing);
    fReindex |= fReindexing;

    // Check whether we have a transaction index
    pblocktree->ReadFlag("txindex", fTxIndex);

    pblocktree->ReadFlag("addrindex", fAddrIndex);

    // If this is written true before the next client init, then we know the shutdown process failed
    pblocktree->WriteFlag("shutdown", false);

    // Load pointer to end of best chain
    BlockMap::iterator it = mapBlockIndex.find(pcoinsTip->GetBestBlock());
    if (it == mapBlockIndex.end())
        return true;
    chainActive.SetTip(it->second);

    PruneBlockIndexCandidates();

    if (fDebug) 
        LogPrintf("%s: hashBestChain=%s height=%d date=%s progress=%f\n", __func__,
            chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(),
            DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()),
            Checkpoints::GuessVerificationProgress(Params().GetTxData(), chainActive.Tip()));

    return true;
}

CVerifyDB::CVerifyDB()
{
    uiInterface.ShowProgress(_("Verifying blocks..."), 0);
}

CVerifyDB::~CVerifyDB()
{
    uiInterface.ShowProgress("", 100);
}

bool CVerifyDB::VerifyDB(CCoinsView* coinsview, int nCheckLevel, int nCheckDepth)
{
    LOCK(cs_main);
    if (chainActive.Tip() == NULL || chainActive.Tip()->pprev == NULL)
        return true;

    // Verify blocks in the best chain
    if (nCheckDepth <= 0)
        nCheckDepth = 1000000000; // suffices until the year 19000
    if (nCheckDepth > chainActive.Height())
        nCheckDepth = chainActive.Height();
    nCheckLevel = std::max(0, std::min(4, nCheckLevel));
    if (fDebug)
        LogPrintf("Verifying last %i blocks at level %i\n", nCheckDepth, nCheckLevel);
    
    CCoinsViewCache coins(coinsview);
    CBlockIndex* pindexState = chainActive.Tip();
    CBlockIndex* pindexFailure = NULL;
    int nGoodTransactions = 0;
    CValidationState state;
    for (CBlockIndex* pindex = chainActive.Tip(); pindex && pindex->pprev; pindex = pindex->pprev) {
        boost::this_thread::interruption_point();
        uiInterface.ShowProgress(_("Verifying blocks..."), std::max(1, std::min(99, (int)(((double)(chainActive.Height() - pindex->nHeight)) / (double)nCheckDepth * (nCheckLevel >= 4 ? 50 : 100)))));
        if (fDebug)
            LogPrintf("Verifying Block: %d \n", pindex->nHeight);
        
        if (pindex->nHeight < chainActive.Height() - nCheckDepth)
            break;
        CBlock block;
        // check level 0: read from disk
        if (!ReadBlockFromDisk(block, pindex))
            return error("VerifyDB() : *** ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
        // check level 1: verify block validity
        if (nCheckLevel >= 1 && !CheckBlock(block, state))
            return error("VerifyDB() : *** found bad block at %d, hash=%s\n", pindex->nHeight, pindex->GetBlockHash().ToString());
        // check level 2: verify undo validity
        if (nCheckLevel >= 2 && pindex) {
            CBlockUndo undo;
            CDiskBlockPos pos = pindex->GetUndoPos();
            if (!pos.IsNull()) {
                if (!undo.ReadFromDisk(pos, pindex->pprev->GetBlockHash()))
                    return error("VerifyDB() : *** found bad undo data at %d, hash=%s\n", pindex->nHeight, pindex->GetBlockHash().ToString());
            }
        }
        // check level 3: check for inconsistencies during memory-only disconnect of tip blocks
        if (nCheckLevel >= 3 && pindex == pindexState && (coins.GetCacheSize() + pcoinsTip->GetCacheSize()) <= nCoinCacheSize) {
            bool fClean = true;
            if (!DisconnectBlock(block, state, pindex, coins, &fClean))
                return error("VerifyDB() : *** irrecoverable inconsistency in block data at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
            pindexState = pindex->pprev;
            if (!fClean) {
                nGoodTransactions = 0;
                pindexFailure = pindex;
            } else
                nGoodTransactions += block.vtx.size();
        }
        if (ShutdownRequested())
            return true;
    }
    if (pindexFailure)
        return error("VerifyDB() : *** coin database inconsistencies found (last %i blocks, %i good transactions before that)\n", chainActive.Height() - pindexFailure->nHeight + 1, nGoodTransactions);

    // check level 4: try reconnecting blocks
    if (nCheckLevel >= 4) {
        CBlockIndex* pindex = pindexState;
        while (pindex != chainActive.Tip()) {
            boost::this_thread::interruption_point();
            uiInterface.ShowProgress(_("Verifying blocks..."), std::max(1, std::min(99, 100 - (int)(((double)(chainActive.Height() - pindex->nHeight)) / (double)nCheckDepth * 50))));
            pindex = chainActive.Next(pindex);
            CBlock block;
            if (!ReadBlockFromDisk(block, pindex))
                return error("VerifyDB() : *** ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
            if (!ConnectBlock(block, state, pindex, coins, false))
                return error("VerifyDB() : *** found unconnectable block at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
        }
    }

    if (fDebug)
        LogPrintf("No coin database inconsistencies in last %i blocks (%i transactions)\n", chainActive.Height() - pindexState->nHeight, nGoodTransactions);

    return true;
}

void UnloadBlockIndex_Legacy()
{
    LOCK(cs_main);
    setBlockIndexCandidates.clear();
    chainActive.SetTip(NULL);
    pindexBestInvalid = NULL;
    pindexBestHeader = NULL;
    mempool.clear();
    mapOrphanTransactions.clear();
    mapOrphanTransactionsByPrev.clear();
    nSyncStarted = 0;
    mapBlocksUnlinked.clear();
    vinfoBlockFile.clear();
    nLastBlockFile = 0;
    nBlockSequenceId = 1;
    mapBlockSource.clear();
    mapBlocksInFlight.clear();
    nPreferredDownload = 0;
    setDirtyBlockIndex.clear();
    setDirtyFileInfo.clear();
    mapNodeState.clear();
    recentRejects.reset(NULL);
    versionbitscache.Clear();
    for (int b = 0; b < VERSIONBITS_NUM_BITS; b++) {
        warningcache[b].clear();
    }

    BOOST_FOREACH (BlockMap::value_type& entry, mapBlockIndex) {
        delete entry.second;
    }
    mapBlockIndex.clear();
    fHavePruned = false;
}

void UnloadBlockIndex()
{
    mapBlockIndex.clear();
    setBlockIndexCandidates.clear();
    chainActive.SetTip(NULL);
    pindexBestInvalid = NULL;
    versionbitscache.Clear();
    UnloadBlockIndex_Legacy();
}


bool LoadBlockIndex()
{
    if (!fReindex && !LoadBlockIndexDB())
        return false;
    return true;
}


bool InitBlockIndex()
{
    LOCK(cs_main);

    // Initialize global variables that cannot be constructed at startup.
    recentRejects.reset(new CRollingBloomFilter(120000, 0.000001));

    // Check whether we're already initialized
    if (chainActive.Genesis() != NULL)
        return true;

    // Use the provided setting for -txindex in the new database
    fTxIndex = GetBoolArg("-txindex", true);
    pblocktree->WriteFlag("txindex", fTxIndex);
    fAddrIndex = GetBoolArg("-addrindex", DEFAULT_ADDRINDEX);
    pblocktree->WriteFlag("addrindex", fAddrIndex);
    if (fDebug)
        LogPrintf("Initializing databases...\n");

    // Only add the genesis block if not reindexing (in which case we reuse the one already on disk)
    if (!fReindex) {
        try {
            CBlock& block = const_cast<CBlock&>(Params().GenesisBlock());
            // Start new block file
            unsigned int nBlockSize = ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
            CDiskBlockPos blockPos;
            CValidationState state;
            if (!FindBlockPos(state, blockPos, nBlockSize + 8, 0, block.GetBlockTime()))
                return error("LoadBlockIndex() : FindBlockPos failed");
            if (!WriteBlockToDisk(block, blockPos))
                return error("LoadBlockIndex() : writing genesis block to disk failed");
            CBlockIndex* pindex = AddToBlockIndex(block);
            if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
                return error("LoadBlockIndex() : genesis block not accepted");
            if (!ActivateBestChain(state, &block, true))
                return error("LoadBlockIndex() : genesis block cannot be activated");
            // Force a chainstate write so that when we VerifyDB in a moment, it doesnt check stale data
            return FlushStateToDisk(state, FLUSH_STATE_ALWAYS);
        } catch (std::runtime_error& e) {
            return error("LoadBlockIndex() : failed to initialize block database: %s", e.what());
        }
    }

    return true;
}

bool LoadExternalBlockFile(FILE* fileIn, CDiskBlockPos* dbp)
{
    // Map of disk positions for blocks with unknown parent (only used for reindex)
    static std::multimap<uint256, CDiskBlockPos> mapBlocksUnknownParent;
    int64_t nStart = GetTimeMillis();
    const CChainParams& chainparams = Params();

    int nLoaded = 0;
    try {
        // This takes over fileIn and calls fclose() on it in the CBufferedFile destructor
        CBufferedFile blkdat(fileIn, 2 * MAX_BLOCK_SIZE, MAX_BLOCK_SIZE + 8, SER_DISK, CLIENT_VERSION);
        uint64_t nRewind = blkdat.GetPos();
        while (!blkdat.eof()) {
            boost::this_thread::interruption_point();

            blkdat.SetPos(nRewind);
            nRewind++;         // start one byte further next time, in case of failure
            blkdat.SetLimit(); // remove former limit
            unsigned int nSize = 0;
            try {
                // locate a header
                unsigned char buf[MESSAGE_START_SIZE];
                blkdat.FindByte(Params().MessageStart()[0]);
                nRewind = blkdat.GetPos() + 1;
                blkdat >> FLATDATA(buf);
                if (memcmp(buf, Params().MessageStart(), MESSAGE_START_SIZE))
                    continue;
                // read size
                blkdat >> nSize;
                if (nSize < 80 || nSize > MAX_BLOCK_SIZE)
                    continue;
            } catch (const std::exception&) {
                // no valid block header found; don't complain
                break;
            }
            try {
                // read block
                uint64_t nBlockPos = blkdat.GetPos();
                if (dbp)
                    dbp->nPos = nBlockPos;
                blkdat.SetLimit(nBlockPos + nSize);
                blkdat.SetPos(nBlockPos);
                CBlock block;
                blkdat >> block;
                nRewind = blkdat.GetPos();

                // detect out of order blocks, and store them for later
                uint256 hash = block.GetHash();
                if (hash != Params().HashGenesisBlock() && mapBlockIndex.find(block.hashPrevBlock) == mapBlockIndex.end()) {
                    if (dbp)
                        mapBlocksUnknownParent.insert(std::make_pair(block.hashPrevBlock, *dbp));
                    continue;
                }

                // process in case the block isn't known yet
                if (mapBlockIndex.count(hash) == 0 || (mapBlockIndex[hash]->nStatus & BLOCK_HAVE_DATA) == 0) {
                    CValidationState state;
                    if (UseLegacyCode(block)) {
                        if (ProcessNewBlock_Legacy(state, chainparams, NULL, &block, true, dbp))
                            nLoaded++;
                    } else {
                        if (ProcessNewBlock(state, NULL, &block, dbp))
                            nLoaded++;
                    }
                    if (state.IsError())
                        break;
                } else if (hash != Params().HashGenesisBlock() && mapBlockIndex[hash]->nHeight % 1000 == 0 && fDebug)
                    LogPrintf("Block Import: already had block %s at height %d\n", hash.ToString(), mapBlockIndex[hash]->nHeight);

                // Recursively process earlier encountered successors of this block
                deque<uint256> queue;
                queue.push_back(hash);
                while (!queue.empty()) {
                    uint256 head = queue.front();
                    queue.pop_front();
                    std::pair<std::multimap<uint256, CDiskBlockPos>::iterator, std::multimap<uint256, CDiskBlockPos>::iterator> range = mapBlocksUnknownParent.equal_range(head);
                    while (range.first != range.second) {
                        std::multimap<uint256, CDiskBlockPos>::iterator it = range.first;
                        if (ReadBlockFromDisk(block, it->second)) {
                            if (fDebug)
                                LogPrintf("%s: Processing out of order child %s of %s\n", __func__, block.GetHash().ToString(), head.ToString());
                            
                            CValidationState dummy;
                            if (UseLegacyCode(block)) {
                                if (ProcessNewBlock_Legacy(dummy, chainparams, NULL, &block, true, &it->second))
                                    nLoaded++;
                            } else if (ProcessNewBlock(dummy, NULL, &block, &it->second))
                                nLoaded++;
                            queue.push_back(block.GetHash());
                        }
                        range.first++;
                        mapBlocksUnknownParent.erase(it);
                    }
                }
            } catch (std::exception& e) {
                LogPrintf("%s : Deserialize or I/O error - %s", __func__, e.what());
            }
        }
    } catch (std::runtime_error& e) {
        AbortNode(std::string("System error: ") + e.what());
    }
    if (fDebug)
        LogPrintf("LoadExternalBlockFile Loaded %i blocks from external file in %dms\n", nLoaded, GetTimeMillis() - nStart);
    
    return nLoaded > 0;
}


void static CheckBlockIndex()
{
    if (!fCheckBlockIndex) {
        return;
    }

    LOCK(cs_main);

    // During a reindex, we read the genesis block and call CheckBlockIndex before ActivateBestChain,
    // so we have the genesis block in mapBlockIndex but no active chain.  (A few of the tests when
    // iterating the block tree require that chainActive has been initialized.)
    if (chainActive.Height() < 0) {
        assert(mapBlockIndex.size() <= 1);
        return;
    }

    // Build forward-pointing map of the entire block tree.
    std::multimap<CBlockIndex*, CBlockIndex*> forward;
    for (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); it++) {
        forward.insert(std::make_pair(it->second->pprev, it->second));
    }

    assert(forward.size() == mapBlockIndex.size());

    std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> rangeGenesis = forward.equal_range(NULL);
    CBlockIndex* pindex = rangeGenesis.first->second;
    rangeGenesis.first++;
    assert(rangeGenesis.first == rangeGenesis.second); // There is only one index entry with parent NULL.

    // Iterate over the entire block tree, using depth-first search.
    // Along the way, remember whether there are blocks on the path from genesis
    // block being explored which are the first to have certain properties.
    size_t nNodes = 0;
    int nHeight = 0;
    CBlockIndex* pindexFirstInvalid = NULL;              // Oldest ancestor of pindex which is invalid.
    CBlockIndex* pindexFirstMissing = NULL;              // Oldest ancestor of pindex which does not have BLOCK_HAVE_DATA.
    CBlockIndex* pindexFirstNeverProcessed = NULL;       // Oldest ancestor of pindex for which nTx == 0.
    CBlockIndex* pindexFirstNotTreeValid = NULL;         // Oldest ancestor of pindex which does not have BLOCK_VALID_TREE (regardless of being valid or not).
    CBlockIndex* pindexFirstNotTransactionsValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_TRANSACTIONS (regardless of being valid or not).
    CBlockIndex* pindexFirstNotChainValid = NULL;        // Oldest ancestor of pindex which does not have BLOCK_VALID_CHAIN (regardless of being valid or not).
    CBlockIndex* pindexFirstNotScriptsValid = NULL;      // Oldest ancestor of pindex which does not have BLOCK_VALID_SCRIPTS (regardless of being valid or not).
    while (pindex != NULL) {
        nNodes++;
        if (pindexFirstInvalid == NULL && pindex->nStatus & BLOCK_FAILED_VALID) pindexFirstInvalid = pindex;
        if (pindexFirstMissing == NULL && !(pindex->nStatus & BLOCK_HAVE_DATA)) pindexFirstMissing = pindex;
        if (pindexFirstNeverProcessed == NULL && pindex->nTx == 0) pindexFirstNeverProcessed = pindex;
        if (pindex->pprev != NULL && pindexFirstNotTreeValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TREE) pindexFirstNotTreeValid = pindex;
        if (pindex->pprev != NULL && pindexFirstNotTransactionsValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TRANSACTIONS) pindexFirstNotTransactionsValid = pindex;
        if (pindex->pprev != NULL && pindexFirstNotChainValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_CHAIN) pindexFirstNotChainValid = pindex;
        if (pindex->pprev != NULL && pindexFirstNotScriptsValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_SCRIPTS) pindexFirstNotScriptsValid = pindex;

        // Begin: actual consistency checks.
        if (pindex->pprev == NULL) {
            // Genesis block checks.
            assert(pindex->GetBlockHash() == Params().HashGenesisBlock()); // Genesis block's hash must match.
            assert(pindex == chainActive.Genesis());                       // The current active chain's genesis block must be this block.
        }
        if (pindex->nChainTx == 0) assert(pindex->nSequenceId == 0); // nSequenceId can't be set for blocks that aren't linked
        // VALID_TRANSACTIONS is equivalent to nTx > 0 for all nodes (whether or not pruning has occurred).
        // HAVE_DATA is only equivalent to nTx > 0 (or VALID_TRANSACTIONS) if no pruning has occurred.
        if (!fHavePruned) {
            // If we've never pruned, then HAVE_DATA should be equivalent to nTx > 0
            assert(!(pindex->nStatus & BLOCK_HAVE_DATA) == (pindex->nTx == 0));
            assert(pindexFirstMissing == pindexFirstNeverProcessed);
        } else {
            // If we have pruned, then we can only say that HAVE_DATA implies nTx > 0
            if (pindex->nStatus & BLOCK_HAVE_DATA) assert(pindex->nTx > 0);
        }
        if (pindex->nStatus & BLOCK_HAVE_UNDO) assert(pindex->nStatus & BLOCK_HAVE_DATA);
        assert(((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TRANSACTIONS) == (pindex->nTx > 0)); // This is pruning-independent.
        // All parents having had data (at some point) is equivalent to all parents being VALID_TRANSACTIONS, which is equivalent to nChainTx being set.
        assert((pindexFirstNeverProcessed != NULL) == (pindex->nChainTx == 0)); // nChainTx != 0 is used to signal that all parent blocks have been processed (but may have been pruned).
        assert((pindexFirstNotTransactionsValid != NULL) == (pindex->nChainTx == 0));
        assert(pindex->nHeight == nHeight);                                                                          // nHeight must be consistent.
        assert(pindex->pprev == NULL || pindex->nChainWork >= pindex->pprev->nChainWork);                            // For every block except the genesis block, the chainwork must be larger than the parent's.
        assert(nHeight < 2 || (pindex->pskip && (pindex->pskip->nHeight < nHeight)));                                // The pskip pointer must point back for all but the first 2 blocks.
        assert(pindexFirstNotTreeValid == NULL);                                                                     // All mapBlockIndex entries must at least be TREE valid
        if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TREE) assert(pindexFirstNotTreeValid == NULL);       // TREE valid implies all parents are TREE valid
        if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_CHAIN) assert(pindexFirstNotChainValid == NULL);     // CHAIN valid implies all parents are CHAIN valid
        if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_SCRIPTS) assert(pindexFirstNotScriptsValid == NULL); // SCRIPTS valid implies all parents are SCRIPTS valid
        if (pindexFirstInvalid == NULL) {
            // Checks for not-invalid blocks.
            assert((pindex->nStatus & BLOCK_FAILED_MASK) == 0); // The failed mask cannot be set for blocks without invalid parents.
        }
        if (!CBlockIndexWorkComparator()(pindex, chainActive.Tip()) && pindexFirstNeverProcessed == NULL) {
            if (pindexFirstInvalid == NULL) {
                // If this block sorts at least as good as the current tip and
                // is valid and we have all data for its parents, it must be in
                // setBlockIndexCandidates.  chainActive.Tip() must also be there
                // even if some data has been pruned.
                if (pindexFirstMissing == NULL || pindex == chainActive.Tip()) {
                    assert(setBlockIndexCandidates.count(pindex));
                }
                // If some parent is missing, then it could be that this block was in
                // setBlockIndexCandidates but had to be removed because of the missing data.
                // In this case it must be in mapBlocksUnlinked -- see test below.
            }
        } else { // If this block sorts worse than the current tip or some ancestor's block has never been seen, it cannot be in setBlockIndexCandidates.
            assert(setBlockIndexCandidates.count(pindex) == 0);
        }
        // Check whether this block is in mapBlocksUnlinked.
        std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> rangeUnlinked = mapBlocksUnlinked.equal_range(pindex->pprev);
        bool foundInUnlinked = false;
        while (rangeUnlinked.first != rangeUnlinked.second) {
            assert(rangeUnlinked.first->first == pindex->pprev);
            if (rangeUnlinked.first->second == pindex) {
                foundInUnlinked = true;
                break;
            }
            rangeUnlinked.first++;
        }
        if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed != NULL && pindexFirstInvalid == NULL) {
            // If this block has block data available, some parent was never received, and has no invalid parents, it must be in mapBlocksUnlinked.
            assert(foundInUnlinked);
        }
        if (!(pindex->nStatus & BLOCK_HAVE_DATA)) assert(!foundInUnlinked); // Can't be in mapBlocksUnlinked if we don't HAVE_DATA
        if (pindexFirstMissing == NULL) assert(!foundInUnlinked);           // We aren't missing data for any parent -- cannot be in mapBlocksUnlinked.
        if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed == NULL && pindexFirstMissing != NULL) {
            // We HAVE_DATA for this block, have received data for all parents at some point, but we're currently missing data for some parent.
            assert(fHavePruned); // We must have pruned.
            // This block may have entered mapBlocksUnlinked if:
            //  - it has a descendant that at some point had more work than the
            //    tip, and
            //  - we tried switching to that descendant but were missing
            //    data for some intermediate block between chainActive and the
            //    tip.
            // So if this block is itself better than chainActive.Tip() and it wasn't in
            // setBlockIndexCandidates, then it must be in mapBlocksUnlinked.
            if (!CBlockIndexWorkComparator()(pindex, chainActive.Tip()) && setBlockIndexCandidates.count(pindex) == 0) {
                if (pindexFirstInvalid == NULL) {
                    assert(foundInUnlinked);
                }
            }
        }
        // TODO: Remove?
        // assert(pindex->GetBlockHash() == pindex->GetBlockHeader().GetHash()); // Perhaps too slow
        // End: actual consistency checks.

        // Try descending into the first subnode.
        std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> range = forward.equal_range(pindex);
        if (range.first != range.second) {
            // A subnode was found.
            pindex = range.first->second;
            nHeight++;
            continue;
        }
        // This is a leaf node.
        // Move upwards until we reach a node of which we have not yet visited the last child.
        while (pindex) {
            // We are going to either move to a parent or a sibling of pindex.
            // If pindex was the first with a certain property, unset the corresponding variable.
            if (pindex == pindexFirstInvalid) pindexFirstInvalid = NULL;
            if (pindex == pindexFirstMissing) pindexFirstMissing = NULL;
            if (pindex == pindexFirstNeverProcessed) pindexFirstNeverProcessed = NULL;
            if (pindex == pindexFirstNotTreeValid) pindexFirstNotTreeValid = NULL;
            if (pindex == pindexFirstNotTransactionsValid) pindexFirstNotTransactionsValid = NULL;
            if (pindex == pindexFirstNotChainValid) pindexFirstNotChainValid = NULL;
            if (pindex == pindexFirstNotScriptsValid) pindexFirstNotScriptsValid = NULL;
            // Find our parent.
            CBlockIndex* pindexPar = pindex->pprev;
            // Find which child we just visited.
            std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> rangePar = forward.equal_range(pindexPar);
            while (rangePar.first->second != pindex) {
                assert(rangePar.first != rangePar.second); // Our parent must have at least the node we're coming from as child.
                rangePar.first++;
            }
            // Proceed to the next one.
            rangePar.first++;
            if (rangePar.first != rangePar.second) {
                // Move to the sibling.
                pindex = rangePar.first->second;
                break;
            } else {
                // Move up further.
                pindex = pindexPar;
                nHeight--;
                continue;
            }
        }
    }

    // Check that we actually traversed the entire map.
    assert(nNodes == forward.size());
}

//////////////////////////////////////////////////////////////////////////////
//
// CAlert
//

string GetWarnings(string strFor)
{
    int nPriority = 0;
    string strStatusBar;
    string strRPC;

    if (!CLIENT_VERSION_IS_RELEASE)
        strStatusBar = _("This is a pre-release test build - use at your own risk - do not use for staking or merchant applications!");

    if (GetBoolArg("-testsafemode", false))
        strStatusBar = strRPC = "testsafemode enabled";

    // Misc warnings like out of disk space and clock is wrong
    if (strMiscWarning != "") {
        nPriority = 1000;
        strStatusBar = strMiscWarning;
    }

    if (fLargeWorkForkFound) {
        nPriority = 2000;
        strStatusBar = strRPC = _("Warning: The network does not appear to fully agree! Some miners appear to be experiencing issues.");
    } else if (fLargeWorkInvalidChainFound) {
        nPriority = 2000;
        strStatusBar = strRPC = _("Warning: We do not appear to fully agree with our peers! You may need to upgrade, or other nodes may need to upgrade.");
    }

    // Alerts
    {
        LOCK(cs_mapAlerts);
        BOOST_FOREACH (PAIRTYPE(const uint256, CAlert) & item, mapAlerts) {
            const CAlert& alert = item.second;
            if (alert.AppliesToMe() && alert.nPriority > nPriority) {
                nPriority = alert.nPriority;
                strStatusBar = alert.strStatusBar;
            }
        }
    }

    if (strFor == "statusbar")
        return strStatusBar;
    else if (strFor == "rpc")
        return strRPC;
    assert(!"GetWarnings() : invalid parameter");
    return "error";
}


//////////////////////////////////////////////////////////////////////////////
//
// Messages
//


bool static AlreadyHave(const CInv& inv)
{
    switch (inv.type) {
    case MSG_TX: {
        if (fDebug)
            LogPrintf("AlreadyHave inv.type = MSG_TX \n");
        
        assert(recentRejects);
        if (chainActive.Tip()->GetBlockHash() != hashRecentRejectsChainTip) {
            // If the chain tip has changed previously rejected transactions
            // might be now valid, e.g. due to a nLockTime'd tx becoming valid,
            // or a double-spend. Reset the rejects filter and give those
            // txs a second chance.
            hashRecentRejectsChainTip = chainActive.Tip()->GetBlockHash();
            recentRejects->reset();
        }

        return recentRejects->contains(inv.hash) ||
               mempool.exists(inv.hash) ||
               mapOrphanTransactions.count(inv.hash) ||
               pcoinsTip->HaveCoins(inv.hash);
    }
    case MSG_BLOCK:
        if (fDebug)
            LogPrintf("AlreadyHave inv.type = MSG_BLOCK \n");
        return mapBlockIndex.count(inv.hash);
    }
    // Don't know what it is, just say we already got one
    return true;
}


void static ProcessGetData(CNode* pfrom)
{
    std::deque<CInv>::iterator it = pfrom->vRecvGetData.begin();

    vector<CInv> vNotFound;

    LOCK(cs_main);

    while (it != pfrom->vRecvGetData.end()) {
        // Don't bother if send buffer is too full to respond anyway
        if (pfrom->nSendSize >= SendBufferSize())
            break;

        const CInv& inv = *it;
        {
            boost::this_thread::interruption_point();
            it++;

            if (inv.type == MSG_BLOCK || inv.type == MSG_FILTERED_BLOCK) {
                bool send = false;
                BlockMap::iterator mi = mapBlockIndex.find(inv.hash);
                if (mi != mapBlockIndex.end()) {
                    if (chainActive.Contains(mi->second)) {
                        send = true;
                    } else {
                        // To prevent fingerprinting attacks, only send blocks outside of the active
                        // chain if they are valid, and no more than the max reorganization depth older.
                        send = mi->second->IsValid(BLOCK_VALID_SCRIPTS) && (pindexBestHeader != NULL) &&
                               (chainActive.Height() - mi->second->nHeight < Params().GetMaxReorganizationDepth());
                        if (!send && fDebug)
                            LogPrintf("%s: ignoring request from peer=%i for old block that isn't in the main chain\n", __func__, pfrom->GetId());
                    }
                }
                // disconnect node in case we have reached the outbound limit for serving historical blocks
                // never disconnect whitelisted nodes
                static const int nOneWeek = 7 * 24 * 60 * 60; // assume > 1 week = historical
                if (send && CNode::OutboundTargetReached(true) && (((pindexBestHeader != NULL) && (pindexBestHeader->GetBlockTime() - mi->second->GetBlockTime() > nOneWeek)) || inv.type == MSG_FILTERED_BLOCK) && !pfrom->fWhitelisted) {
                    if (fDebug)
                        LogPrint("net", "historical block serving limit reached, disconnect peer=%d\n", pfrom->GetId());

                    //disconnect node
                    pfrom->fDisconnect = true;
                    send = false;
                }
                // Pruned nodes may have deleted the block, so check whether
                // it's available before trying to send.
                if (send && (mi->second->nStatus & BLOCK_HAVE_DATA)) {
                    // Send block from disk
                    CBlock block;
                    if (!ReadBlockFromDisk(block, (*mi).second))
                        assert(!"cannot load block from disk");
                    if (inv.type == MSG_BLOCK)
                        pfrom->PushMessage(NetMsgType::BLOCK, block);
                    else // MSG_FILTERED_BLOCK)
                    {
                        LOCK(pfrom->cs_filter);
                        if (pfrom->pfilter) {
                            CMerkleBlock merkleBlock(block, *pfrom->pfilter);
                            pfrom->PushMessage(NetMsgType::MERKLEBLOCK, merkleBlock);
                            // CMerkleBlock just contains hashes, so also push any transactions in the block the client did not see
                            // This avoids hurting performance by pointlessly requiring a round-trip
                            // Note that there is currently no way for a node to request any single transactions we didn't send here -
                            // they must either disconnect and retry or request the full block.
                            // Thus, the protocol spec specified allows for us to provide duplicate txn here,
                            // however we MUST always provide at least what the remote peer needs
                            typedef std::pair<unsigned int, uint256> PairType;
                            BOOST_FOREACH (PairType& pair, merkleBlock.vMatchedTxn)
                                pfrom->PushMessage(NetMsgType::TX, block.vtx[pair.first]);
                        }
                        // else
                        // no response
                    }

                    // Trigger the peer node to send a getblocks request for the next batch of inventory
                    if (inv.hash == pfrom->hashContinue) {
                        // Bypass PushInventory, this must send even if redundant,
                        // and we want it right after the last block so they don't
                        // wait for other stuff first.
                        vector<CInv> vInv;
                        vInv.push_back(CInv(MSG_BLOCK, chainActive.Tip()->GetBlockHash()));
                        pfrom->PushMessage(NetMsgType::INV, vInv);
                        pfrom->hashContinue.SetNull();
                    }
                }
            } else if (inv.IsKnownType()) {
                // Send stream from relay memory
                bool pushed = false;
                {
                    LOCK(cs_mapRelay);
                    map<CInv, CDataStream>::iterator mi = mapRelay.find(inv);
                    if (mi != mapRelay.end()) {
                        pfrom->PushMessage(inv.GetCommand(), (*mi).second);
                        pushed = true;
                    }
                }
                if (!pushed && inv.type == MSG_TX) {
                    CTransaction tx;
                    if (mempool.lookup(inv.hash, tx)) {
                        CDataStream ss(SER_NETWORK, PROTOCOL_VERSION);
                        ss.reserve(1000);
                        ss << tx;
                        pfrom->PushMessage(NetMsgType::TX, ss);
                        pushed = true;
                    }
                }

                if (!pushed) {
                    vNotFound.push_back(inv);
                }
            }

            // Track requests for our stuff.
            GetMainSignals().Inventory(inv.hash);

            if (inv.type == MSG_BLOCK || inv.type == MSG_FILTERED_BLOCK)
                break;
        }
    }

    pfrom->vRecvGetData.erase(pfrom->vRecvGetData.begin(), it);

    if (!vNotFound.empty()) {
        // Let the peer know that we didn't find what it asked for, so it doesn't
        // have to wait around forever. Currently only SPV clients actually care
        // about this message: it's needed when they are recursively walking the
        // dependencies of relevant unconfirmed transactions. SPV clients want to
        // do that because they want to know about (and store and rebroadcast and
        // risk analyze) the dependencies of transactions relevant to them, without
        // having to download the entire memory pool.
        pfrom->PushMessage(NetMsgType::NOTFOUND, vNotFound);
    }
}

bool static ProcessMessageBlock(CNode* pfrom, string strCommand, CDataStream& vRecv)
{
    const CChainParams& chainparams = Params();

    // If we are in the last block and a new block has arrived
    // than it need to be processed by the new chain
    CBlock block;
    vRecv >> block;
    uint256 hashBlock = block.GetHash();
    CInv inv(MSG_BLOCK, hashBlock);
    LogPrint("net", "received block %s peer=%d\n", inv.hash.ToString(), pfrom->id);

    //sometimes we will be sent their most recent block and its not the one we want, in that case tell where we are
    if (!mapBlockIndex.count(block.hashPrevBlock)) {
        if (find(pfrom->vBlockRequested.begin(), pfrom->vBlockRequested.end(), hashBlock) != pfrom->vBlockRequested.end()) {
            //we already asked for this block, so lets work backwards and ask for the previous block
            pfrom->PushMessage("getblocks", chainActive.GetLocator(), block.hashPrevBlock);
            pfrom->vBlockRequested.push_back(block.hashPrevBlock);
        } else {
            //ask to sync to this block
            pfrom->PushMessage("getblocks", chainActive.GetLocator(), hashBlock);
            pfrom->vBlockRequested.push_back(hashBlock);
        }
    } else {
        pfrom->AddInventoryKnown(inv);

        CValidationState state;
        CBlockIndex* prevBlockIndex = mapBlockIndex[block.hashPrevBlock];
        if (UseLegacyCode(prevBlockIndex->nHeight + 1)) {
            // Process all blocks from whitelisted peers, even if not requested,
            // unless we're still syncing with the network.
            // Such an unrequested block may still be processed, subject to the
            // conditions in AcceptBlock().
            bool forceProcessing = pfrom->fWhitelisted && !IsInitialBlockDownload();
            ProcessNewBlock_Legacy(state, chainparams, pfrom, &block, forceProcessing, NULL);
        } else
            ProcessNewBlock(state, pfrom, &block, NULL);

        int nDoS;
        if (state.IsInvalid(nDoS)) {
            assert(state.GetRejectCode() < REJECT_INTERNAL_LEGACY); // Blocks are never rejected with internal reject codes
            pfrom->PushMessage(NetMsgType::REJECT, strCommand, (unsigned char)state.GetRejectCode(),
                state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), inv.hash);
            if (nDoS > 0) {
                LOCK(cs_main);
                Misbehaving(pfrom->GetId(), nDoS, state.GetRejectReason());
            }
        }
    }

    return true;
}

bool static ProcessMessageReject(CNode* pfrom, string strCommand, CDataStream& vRecv, int64_t nTimeReceived)
{
    try {
        string strMsg;
        unsigned char ccode;
        string strReason;
        vRecv >> LIMITED_STRING(strMsg, CMessageHeader::COMMAND_SIZE) >> ccode >> LIMITED_STRING(strReason, MAX_REJECT_MESSAGE_LENGTH);

        ostringstream ss;
        ss << strMsg << " code " << itostr(ccode) << ": " << strReason;

        if (strMsg == NetMsgType::BLOCK || strMsg == NetMsgType::TX) {
            uint256 hash;
            vRecv >> hash;
            ss << ": hash " << hash.ToString();
        }
        LogPrint("net", "Reject %s\n", SanitizeString(ss.str()));
    } catch (const std::ios_base::failure&) {
        // Avoid feedback loops by preventing reject messages from triggering a new reject message.
        LogPrint("net", "Unparseable reject message received\n");
    }
}

bool static ProcessMessagePing(CNode* pfrom, string strCommand, CDataStream& vRecv, int64_t nTimeReceived)
{
    if (pfrom->nVersion > BIP0031_VERSION) {
        uint64_t nonce = 0;
        vRecv >> nonce;
        // Echo the message back with the nonce. This allows for two useful features:
        //
        // 1) A remote node can quickly check if the connection is operational
        // 2) Remote nodes can measure the latency of the network thread. If this node
        //    is overloaded it won't respond to pings quickly and the remote node can
        //    avoid sending us more work, like chain download requests.
        //
        // The nonce stops the remote getting confused between different pings: without
        // it, if the remote node sends a ping once per second and this node takes 5
        // seconds to respond to each, the 5th ping the remote sends would appear to
        // return very quickly.
        pfrom->PushMessage(NetMsgType::PONG, nonce);
        LogPrint("net", "%s has version : %d\n", pfrom->addr.ToString().c_str(), pfrom->nVersion);
        if (pfrom->nVersion >= PING_INCLUDES_HEIGHT_VERSION) {
            int nPeerHeight;
            vRecv >> nPeerHeight;

            LOCK(cs_main);
            cPeerBlockCounts.input(nPeerHeight);
            pfrom->nChainHeight = nPeerHeight;

            LogPrint("net", "%s has chain height %d\n", pfrom->addr.ToString().c_str(), nPeerHeight);
        }
    }
    return true;
}

bool static ProcessMessagePong(CNode* pfrom, string strCommand, CDataStream& vRecv, int64_t nTimeReceived)
{
    int64_t pingUsecEnd = nTimeReceived;
    uint64_t nonce = 0;
    size_t nAvail = vRecv.in_avail();
    bool bPingFinished = false;
    std::string sProblem;

    if (nAvail >= sizeof(nonce)) {
        vRecv >> nonce;

        // Only process pong message if there is an outstanding ping (old ping without nonce should never pong)
        if (pfrom->nPingNonceSent != 0) {
            if (nonce == pfrom->nPingNonceSent) {
                // Matching pong received, this ping is no longer outstanding
                bPingFinished = true;
                int64_t pingUsecTime = pingUsecEnd - pfrom->nPingUsecStart;
                if (pingUsecTime > 0) {
                    // Successful ping time measurement, replace previous
                    pfrom->nPingUsecTime = pingUsecTime;
                    pfrom->nMinPingUsecTime = std::min(pfrom->nMinPingUsecTime, pingUsecTime);
                } else {
                    // This should never happen
                    sProblem = "Timing mishap";
                }
            } else {
                // Nonce mismatches are normal when pings are overlapping
                sProblem = "Nonce mismatch";
                if (nonce == 0) {
                    // This is most likely a bug in another implementation somewhere; cancel this ping
                    bPingFinished = true;
                    sProblem = "Nonce zero";
                }
            }
        } else {
            sProblem = "Unsolicited pong without ping";
        }
    } else {
        // This is most likely a bug in another implementation somewhere; cancel this ping
        bPingFinished = true;
        sProblem = "Short payload";
    }

    if (!(sProblem.empty())) {
        LogPrint("net", "pong peer=%d %s: %s, %x expected, %x received, %u bytes\n",
            pfrom->id,
            pfrom->cleanSubVer,
            sProblem,
            pfrom->nPingNonceSent,
            nonce,
            nAvail);
    }
    if (bPingFinished) {
        pfrom->nPingNonceSent = 0;
    }
    return true;
}

bool static ProcessMessageGetBlocks(CNode* pfrom, string strCommand, CDataStream& vRecv, int64_t nTimeReceived)
{
    const CChainParams& chainparams = Params();
    CBlockLocator locator;
    uint256 hashStop;
    vRecv >> locator >> hashStop;

    LOCK(cs_main);

    // Find the last block the caller has in the main chain
    CBlockIndex* pindex = FindForkInGlobalIndex(chainActive, locator);

    // Send the rest of the chain
    if (pindex)
        pindex = chainActive.Next(pindex);
    int nLimit = 500;
    LogPrint("net", "getblocks %d to %s limit %d from peer=%d\n", (pindex ? pindex->nHeight : -1), hashStop.IsNull() ? "end" : hashStop.ToString(), nLimit, pfrom->id);
    for (; pindex; pindex = chainActive.Next(pindex)) {
        if (pindex->GetBlockHash() == hashStop) {
            LogPrint("net", "  getblocks stopping at %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString());
            break;
        }
        // If pruning, don't inv blocks unless we have on disk and are likely to still have
        // for some reasonable time window (1 hour) that block relay might require.
        const int nPrunedBlocksLikelyToHave = MIN_BLOCKS_TO_KEEP - 3600 / chainparams.GetTargetSpacing();
        if (fPruneMode && (!(pindex->nStatus & BLOCK_HAVE_DATA) || pindex->nHeight <= chainActive.Tip()->nHeight - nPrunedBlocksLikelyToHave)) {
            LogPrint("net", " getblocks stopping, pruned or too old block at %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString());
            break;
        }
        pfrom->PushInventory(CInv(MSG_BLOCK, pindex->GetBlockHash()));
        if (--nLimit <= 0) {
            // When this block is requested, we'll send an inv that'll
            // trigger the peer to getblocks the next batch of inventory.
            LogPrint("net", "  getblocks stopping at limit %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString());
            pfrom->hashContinue = pindex->GetBlockHash();
            break;
        }
    }
    return true;
}

bool CanDirectFetch()
{
    return chainActive.Tip()->GetBlockTime() > GetAdjustedTime() - Params().GetTargetTimespan() * 20;
}

bool ProcessMessageHeaders(CNode* pfrom, string strCommand, CDataStream& vRecv, int64_t nTimeReceived)
{
    std::vector<CBlockHeader> headers;

    // Bypass the normal CBlock deserialization, as we don't want to risk deserializing 2000 full blocks.
    unsigned int nCount = ReadCompactSize(vRecv);
    if (nCount > MAX_HEADERS_RESULTS) {
        Misbehaving(pfrom->GetId(), 20, "Header too big");
        return error("headers message size = %u", nCount);
    }
    headers.resize(nCount);
    for (unsigned int n = 0; n < nCount; n++) {
        vRecv >> headers[n];
        ReadCompactSize(vRecv); // ignore tx count; assume it is 0.
    }

    LOCK(cs_main);

    if (nCount == 0) {
        // Nothing interesting. Stop asking this peers for more headers.
        return true;
    }

    CBlockIndex* pindexLast = NULL;
    BOOST_FOREACH (const CBlockHeader& header, headers) {
        CValidationState state;
        if (pindexLast != NULL && header.hashPrevBlock != pindexLast->GetBlockHash()) {
            Misbehaving(pfrom->GetId(), 20, "Non-continuous headers sequence");
            return error("non-continuous headers sequence");
        }
        if (!AcceptBlockHeader(header, state, &pindexLast)) {
            int nDoS;
            if (state.IsInvalid(nDoS)) {
                if (nDoS > 0)
                    Misbehaving(pfrom->GetId(), nDoS, "Invalid header");
                return error("invalid header received");
            }
        }
    }

    if (pindexLast)
        UpdateBlockAvailability(pfrom->GetId(), pindexLast->GetBlockHash());

    if (nCount == MAX_HEADERS_RESULTS && pindexLast) {
        // Headers message had its maximum size; the peer may have more headers.
        // TODO: optimize: if pindexLast is an ancestor of chainActive.Tip or pindexBestHeader, continue
        // from there instead.
        LogPrint("net", "more getheaders (%d) to end to peer=%d (startheight:%d)\n", pindexLast->nHeight, pfrom->id, pfrom->nStartingHeight);
        pfrom->PushMessage(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexLast), uint256());
    }

    bool fCanDirectFetch = CanDirectFetch();
    CNodeState* nodestate = State(pfrom->GetId());
    // If this set of headers is valid and ends in a block with at least as
    // much work as our tip, download as much as possible.
    if (fCanDirectFetch && pindexLast->IsValid(BLOCK_VALID_TREE) && chainActive.Tip()->nChainWork <= pindexLast->nChainWork) {
        vector<CBlockIndex*> vToFetch;
        CBlockIndex* pindexWalk = pindexLast;
        // Calculate all the blocks we'd need to switch to pindexLast, up to a limit.
        while (pindexWalk && !chainActive.Contains(pindexWalk) && vToFetch.size() <= MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
            if (!(pindexWalk->nStatus & BLOCK_HAVE_DATA) &&
                !mapBlocksInFlight.count(pindexWalk->GetBlockHash())) {
                // We don't have this block, and it's not yet in flight.
                vToFetch.push_back(pindexWalk);
            }
            pindexWalk = pindexWalk->pprev;
        }
        // If pindexWalk still isn't on our main chain, we're looking at a
        // very large reorg at a time we think we're close to caught up to
        // the main chain -- this shouldn't really happen.  Bail out on the
        // direct fetch and rely on parallel download instead.
        if (!chainActive.Contains(pindexWalk)) {
            LogPrint("net", "Large reorg, won't direct fetch to %s (%d)\n",
                pindexLast->GetBlockHash().ToString(),
                pindexLast->nHeight);
        } else {
            vector<CInv> vGetData;
            // Download as much as possible, from earliest to latest.
            BOOST_REVERSE_FOREACH (CBlockIndex* pindex, vToFetch) {
                if (nodestate->nBlocksInFlight >= MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
                    // Can't download any more from this peer
                    break;
                }
                vGetData.push_back(CInv(MSG_BLOCK, pindex->GetBlockHash()));
                MarkBlockAsInFlight_Legacy(pfrom->GetId(), pindex->GetBlockHash(), pindex);
                LogPrint("net", "Requesting block %s from  peer=%d\n",
                    pindex->GetBlockHash().ToString(), pfrom->id);
            }
            if (vGetData.size() > 1) {
                LogPrint("net", "Downloading blocks toward %s (%d) via headers direct fetch\n",
                    pindexLast->GetBlockHash().ToString(), pindexLast->nHeight);
            }
            if (vGetData.size() > 0) {
                pfrom->PushMessage(NetMsgType::GETDATA, vGetData);
            }
        }
    }

    CheckBlockIndex();

    return true;
}

bool static ProcessMessageGetHeaders(CNode* pfrom, string strCommand, CDataStream& vRecv, int64_t nTimeReceived)
{
    CBlockLocator locator;
    uint256 hashStop;
    vRecv >> locator >> hashStop;

    LOCK(cs_main);
    
    if (IsInitialBlockDownload() && !pfrom->fWhitelisted) {
        LogPrint("net", "Ignoring getheaders from peer=%d because node is in initial block download\n", pfrom->id);
        return true;
    }

    CNodeState* nodestate = State(pfrom->GetId());
    CBlockIndex* pindex = NULL;
    if (locator.IsNull()) {
        // If locator is null, return the hashStop block
        BlockMap::iterator mi = mapBlockIndex.find(hashStop);
        if (mi == mapBlockIndex.end())
            return true;
        pindex = (*mi).second;
    } else {
        // Find the last block the caller has in the main chain
        pindex = FindForkInGlobalIndex(chainActive, locator);
        if (pindex)
            pindex = chainActive.Next(pindex);
    }

    // we must use CBlocks, as CBlockHeaders won't include the 0x00 nTx count at the end
    vector<CBlock> vHeaders;
    int nLimit = MAX_HEADERS_RESULTS;
    if (pindex != NULL)
        LogPrint("net", "getheaders for block %d with hash %s from peerId=%d\n", pindex->nHeight, (locator.IsNull() ? hashStop.ToString() : pindex->GetBlockHash().ToString()), pfrom->id);
    for (; pindex; pindex = chainActive.Next(pindex)) {
        vHeaders.push_back(pindex->GetBlockHeader());
        if (--nLimit <= 0 || pindex->GetBlockHash() == hashStop)
            break;
    }
    // pindex can be NULL either if we sent chainActive.Tip() OR
    // if our peer has chainActive.Tip() (and thus we are sending an empty
    // headers message). In both cases it's safe to update
    // pindexBestHeaderSent to be our tip.
    nodestate->pindexBestHeaderSent_Legacy = pindex ? pindex : chainActive.Tip();
    pfrom->PushMessage(NetMsgType::HEADERS, vHeaders);
    return true;
}

bool static ProcessMessageAddress(CNode* pfrom, CDataStream& vRecv)
{
    vector<CAddress> vAddr;
    vRecv >> vAddr;

    // Don't want addr from older versions unless seeding
    if (pfrom->nVersion < CADDR_TIME_VERSION && addrman.size() > 1000)
        return true;
    if (vAddr.size() > 1000) {
        LOCK(cs_main);
        Misbehaving(pfrom->GetId(), 20, "Address message too big");
        return error("message addr size() = %u", vAddr.size());
    }

    // Store the new addresses
    vector<CAddress> vAddrOk;
    int64_t nNow = GetAdjustedTime();
    int64_t nSince = nNow - 10 * 60;
    BOOST_FOREACH (CAddress& addr, vAddr) {
        boost::this_thread::interruption_point();

        if (addr.nTime <= 100000000 || addr.nTime > nNow + 10 * 60)
            addr.nTime = nNow - 5 * 24 * 60 * 60;
        pfrom->AddAddressKnown(addr);
        bool fReachable = IsReachable(addr);
        if (addr.nTime > nSince && !pfrom->fGetAddr && vAddr.size() <= 10 && addr.IsRoutable()) {
            // Relay to a limited number of other nodes
            {
                LOCK(cs_vNodes);
                // Use deterministic randomness to send to the same nodes for 24 hours
                // at a time so the addrKnowns of the chosen nodes prevent repeats
                static uint256 hashSalt;
                if (hashSalt.IsNull())
                    hashSalt = GetRandHash();
                uint64_t hashAddr = addr.GetHash();
                uint256 hashRand = ArithToUint256(UintToArith256(hashSalt) ^ (hashAddr << 32) ^ ((GetTime() + hashAddr) / (24 * 60 * 60)));
                hashRand = Hash(BEGIN(hashRand), END(hashRand));
                multimap<uint256, CNode*> mapMix;
                BOOST_FOREACH (CNode* pnode, vNodes) {
                    if (pnode->nVersion < CADDR_TIME_VERSION)
                        continue;
                    unsigned int nPointer;
                    memcpy(&nPointer, &pnode, sizeof(nPointer));
                    uint256 hashKey = ArithToUint256(UintToArith256(hashRand) ^ nPointer);
                    hashKey = Hash(BEGIN(hashKey), END(hashKey));
                    mapMix.insert(make_pair(hashKey, pnode));
                }
                int nRelayNodes = fReachable ? 2 : 1; // limited relaying of addresses outside our network(s)
                for (multimap<uint256, CNode*>::iterator mi = mapMix.begin(); mi != mapMix.end() && nRelayNodes-- > 0; ++mi)
                    ((*mi).second)->PushAddress(addr);
            }
        }
        // Do not store addresses outside our network
        if (fReachable)
            vAddrOk.push_back(addr);
    }
    addrman.Add(vAddrOk, pfrom->addr, 2 * 60 * 60);
    if (vAddr.size() < 1000)
        pfrom->fGetAddr = false;
    if (pfrom->fOneShot)
        pfrom->fDisconnect = true;

    return true;
}

bool static ProcessMessageVerAck(CNode* pfrom)
{
    pfrom->SetRecvVersion(min(pfrom->nVersion, PROTOCOL_VERSION));

    // Mark this node as currently connected, so we update its timestamp later.
    if (pfrom->fNetworkNode) {
        LOCK(cs_main);
        State(pfrom->GetId())->fCurrentlyConnected = true;
    }

    if (pfrom->nVersion >= SENDHEADERS_VERSION_LEGACY) {
        // Tell our peer we prefer to receive headers rather than inv's
        // We send this to non-NODE NETWORK peers as well, because even
        // non-NODE NETWORK peers can announce blocks (such as pruning
        // nodes)
        pfrom->PushMessage(NetMsgType::SENDHEADERS);
    }

    return true;
}

bool static ProcessMessageGetData(CNode* pfrom, CDataStream& vRecv)
{
    vector<CInv> vInv;
    vRecv >> vInv;
    if (vInv.size() > MAX_INV_SZ) {
        LOCK(cs_main);
        Misbehaving(pfrom->GetId(), 20, "Get data message too big");
        return error("message getdata size() = %u", vInv.size());
    }

    if (fDebug)
        LogPrint("net", "received getdata (%u invsz) peer=%d\n", vInv.size(), pfrom->id);

    if ((fDebug && vInv.size() > 0))
        LogPrint("net", "received getdata for: %s peer=%d\n", vInv[0].ToString(), pfrom->id);

    pfrom->vRecvGetData.insert(pfrom->vRecvGetData.end(), vInv.begin(), vInv.end());

    ProcessGetData(pfrom);

    return true;
}

bool static ProcessMessageTx(CNode* pfrom, string strCommand, CDataStream& vRecv)
{
    // Stop processing the transaction early if
    // We are in blocks only mode and peer is either not whitelisted or whitelistrelay is off
    if (GetBoolArg("-blocksonly", DEFAULT_BLOCKSONLY) && (!pfrom->fWhitelisted || !GetBoolArg("-whitelistrelay", DEFAULT_WHITELISTRELAY_LEGACY))) {
        LogPrint("net", "transaction sent in violation of protocol peer=%d\n", pfrom->id);
        return true;
    }

    vector<uint256> vWorkQueue;
    vector<uint256> vEraseQueue;
    CTransaction tx;
    CTxIn vin;
    vector<unsigned char> vchSig;
    int64_t sigTime;

    vRecv >> tx;

    CInv inv(MSG_TX, tx.GetHash());
    pfrom->AddInventoryKnown(inv);

    LOCK(cs_main);

    bool fMissingInputs = false;
    CValidationState state;

    pfrom->setAskFor.erase(inv.hash);
    mapAlreadyAskedFor.erase(inv.hash);

    if (!AlreadyHave(inv) && AcceptToMemoryPool(mempool, state, tx, true, &fMissingInputs)) {
        mempool.check(pcoinsTip);
        RelayTransaction(tx);
        vWorkQueue.push_back(inv.hash);

        LogPrint("mempool", "AcceptToMemoryPool: peer=%d: accepted %s (poolsz %u txn, %u kB)\n",
            pfrom->id,
            tx.GetHash().ToString(),
            mempool.size(), mempool.DynamicMemoryUsage() / 1000);

        // Recursively process any orphan transactions that depended on this one
        set<NodeId> setMisbehaving;
        for (unsigned int i = 0; i < vWorkQueue.size(); i++) {
            map<uint256, set<uint256> >::iterator itByPrev = mapOrphanTransactionsByPrev.find(vWorkQueue[i]);
            if (itByPrev == mapOrphanTransactionsByPrev.end())
                continue;
            for (set<uint256>::iterator mi = itByPrev->second.begin();
                 mi != itByPrev->second.end();
                 ++mi) {
                const uint256& orphanHash = *mi;
                const CTransaction& orphanTx = mapOrphanTransactions[orphanHash].tx;
                NodeId fromPeer = mapOrphanTransactions[orphanHash].fromPeer;
                bool fMissingInputs2 = false;
                // Use a dummy CValidationState so someone can't setup nodes to counter-DoS based on orphan
                // resolution (that is, feeding people an invalid transaction based on LegitTxX in order to get
                // anyone relaying LegitTxX banned)
                CValidationState stateDummy;


                if (setMisbehaving.count(fromPeer))
                    continue;
                if (AcceptToMemoryPool(mempool, stateDummy, orphanTx, true, &fMissingInputs2)) {
                    LogPrint("mempool", "   accepted orphan tx %s\n", orphanHash.ToString());
                    RelayTransaction(orphanTx);
                    vWorkQueue.push_back(orphanHash);
                    vEraseQueue.push_back(orphanHash);
                } else if (!fMissingInputs2) {
                    int nDos = 0;
                    if (stateDummy.IsInvalid(nDos) && nDos > 0) {
                        // Punish peer that gave us an invalid orphan tx
                        Misbehaving(fromPeer, nDos, "TX is invalid");
                        setMisbehaving.insert(fromPeer);
                        LogPrint("mempool", "   invalid orphan tx %s\n", orphanHash.ToString());
                    }
                    // Has inputs but not accepted to mempool
                    // Probably non-standard or insufficient fee/priority
                    LogPrint("mempool", "   removed orphan tx %s\n", orphanHash.ToString());
                    vEraseQueue.push_back(orphanHash);
                    assert(recentRejects);
                    recentRejects->insert(orphanHash);
                }
                mempool.check(pcoinsTip);
            }
        }

        BOOST_FOREACH (uint256 hash, vEraseQueue)
            EraseOrphanTx(hash);
    } else if (fMissingInputs) {
        AddOrphanTx(tx, pfrom->GetId());

        // DoS prevention: do not allow mapOrphanTransactions to grow unbounded
        unsigned int nMaxOrphanTx = (unsigned int)std::max((int64_t)0, GetArg("-maxorphantx", DEFAULT_MAX_ORPHAN_TRANSACTIONS));
        unsigned int nEvicted = LimitOrphanTxSize(nMaxOrphanTx);
        if (nEvicted > 0)
            LogPrint("mempool", "mapOrphan overflow, removed %u tx\n", nEvicted);
    } else {
        assert(recentRejects);
        recentRejects->insert(tx.GetHash());

        if (pfrom->fWhitelisted && GetBoolArg("-whitelistforcerelay", DEFAULT_WHITELISTFORCERELAY_LEGACY)) {
            // Always relay transactions received from whitelisted peers, even
            // if they were already in the mempool or rejected from it due
            // to policy, allowing the node to function as a gateway for
            // nodes hidden behind it.
            //
            // Never relay transactions that we would assign a non-zero DoS
            // score for, as we expect peers to do the same with us in that
            // case.
            int nDoS = 0;
            if (!state.IsInvalid(nDoS) || nDoS == 0) {
                if (fDebug)
                    LogPrintf("Force relaying tx %s from whitelisted peer=%d\n", tx.GetHash().ToString(), pfrom->id);
                
                RelayTransaction(tx);
            } else if (fDebug)
                LogPrintf("Not relaying invalid transaction %s from whitelisted peer=%d (%s)\n", tx.GetHash().ToString(), pfrom->id, FormatStateMessage_Legacy(state));
        }
    }

    int nDoS = 0;
    if (state.IsInvalid(nDoS)) {
        LogPrint("mempoolrej", "%s from peer=%d was not accepted: %s\n", tx.GetHash().ToString(),
            pfrom->id,
            FormatStateMessage_Legacy(state));
        if (state.GetRejectCode() < REJECT_INTERNAL_LEGACY) // Never send AcceptToMemoryPool's internal codes over P2P
            pfrom->PushMessage(NetMsgType::REJECT, strCommand, (unsigned char)state.GetRejectCode(),
                state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), inv.hash);
        if (nDoS > 0)
            Misbehaving(pfrom->GetId(), nDoS, state.GetRejectReason());
    }
    FlushStateToDisk(state, FLUSH_STATE_PERIODIC);
    return true;
}

bool static ProcessMessageMemPool(CNode* pfrom)
{
    if (CNode::OutboundTargetReached(false) && !pfrom->fWhitelisted) {
        LogPrint("net", "mempool request with bandwidth limit reached, disconnect peer=%d\n", pfrom->GetId());
        pfrom->fDisconnect = true;
        return true;
    }
    LOCK2(cs_main, pfrom->cs_filter);

    std::vector<uint256> vtxid;
    mempool.queryHashes(vtxid);
    vector<CInv> vInv;
    BOOST_FOREACH (uint256& hash, vtxid) {
        CInv inv(MSG_TX, hash);
        if (pfrom->pfilter) {
            CTransaction tx;
            bool fInMemPool = mempool.lookup(hash, tx);
            if (!fInMemPool) continue; // another thread removed since queryHashes, maybe...
            if (!pfrom->pfilter->IsRelevantAndUpdate(tx)) continue;
        }
        vInv.push_back(inv);
        if (vInv.size() == MAX_INV_SZ) {
            pfrom->PushMessage(NetMsgType::INV, vInv);
            vInv.clear();
        }
    }
    if (vInv.size() > 0)
        pfrom->PushMessage(NetMsgType::INV, vInv);

    return true;
}

bool static ProcessMessageVersion(CNode* pfrom, string strCommand, CDataStream& vRecv, int64_t nTimeReceived)
{
    // Each connection can only send one version message
    if (pfrom->nVersion != 0) {
        pfrom->PushMessage(NetMsgType::REJECT, strCommand, REJECT_DUPLICATE, string("Duplicate version message"));
        Misbehaving(pfrom->GetId(), 1, "Duplicated version message");
        return false;
    }

    int64_t nTime;
    CAddress addrMe;
    CAddress addrFrom;
    uint64_t nNonce = 1;
    vRecv >> pfrom->nVersion >> pfrom->nServices >> nTime >> addrMe;

    int minVersion = UseLegacyCode() ? MIN_PEER_PROTO_VERSION_PRE_FORK : MIN_PEER_PROTO_VERSION;
    if (pfrom->nVersion < minVersion) {
        // disconnect from peers older than this proto version
        LogPrintf("peer=%d using obsolete version %i; disconnecting\n", pfrom->id, pfrom->nVersion);
        
        pfrom->PushMessage(NetMsgType::REJECT, strCommand, REJECT_OBSOLETE,
            strprintf("Version must be %d or greater", minVersion));
        pfrom->fDisconnect = true;
        return false;
    }

    if (pfrom->nVersion == 10300)
        pfrom->nVersion = 300;
    if (!vRecv.empty())
        vRecv >> addrFrom >> nNonce;
    if (!vRecv.empty()) {
        vRecv >> LIMITED_STRING(pfrom->strSubVer, MAX_SUBVERSION_LENGTH);
        pfrom->cleanSubVer = SanitizeString(pfrom->strSubVer);
        pfrom->SetClientVersion();
    }
    if (!vRecv.empty()) {
        vRecv >> pfrom->nStartingHeight;
        pfrom->nChainHeight = pfrom->nStartingHeight;
    }
    if (!vRecv.empty())
        vRecv >> pfrom->fRelayTxes; // set to true after we get the first filter* message
    else
        pfrom->fRelayTxes = true;

    // Disconnect if we connected to ourself
    if (nNonce == nLocalHostNonce && nNonce > 1) {
        LogPrintf("connected to self at %s, disconnecting\n", pfrom->addr.ToString());
        pfrom->fDisconnect = true;
        return true;
    }

    pfrom->addrLocal = addrMe;
    if (pfrom->fInbound && addrMe.IsRoutable()) {
        SeenLocal(addrMe);
    }

    // Be shy and don't send version until we hear
    if (pfrom->fInbound)
        pfrom->PushVersion();

    pfrom->fClient = !(pfrom->nServices & NODE_NETWORK);

    // Potentially mark this peer as a preferred download peer.
    UpdatePreferredDownload(pfrom, State(pfrom->GetId()));

    // Change version
    pfrom->PushMessage(NetMsgType::VERACK);
    pfrom->ssSend.SetVersion(min(pfrom->nVersion, PROTOCOL_VERSION));

    if (!pfrom->fInbound) {
        // Advertise our address
        if (fListen && !IsInitialBlockDownload()) {
            CAddress addr = GetLocalAddress(&pfrom->addr);
            if (addr.IsRoutable()) {
                pfrom->PushAddress(addr);
            } else if (IsPeerAddrLocalGood(pfrom)) {
                addr.SetIP(pfrom->addrLocal);
                pfrom->PushAddress(addr);
            }
        }

        // Get recent addresses
        if (pfrom->fOneShot || pfrom->nVersion >= CADDR_TIME_VERSION || addrman.size() < 1000) {
            pfrom->PushMessage(NetMsgType::GETADDR);
            pfrom->fGetAddr = true;
        }
        addrman.Good(pfrom->addr);
    } else {
        if (((CNetAddr)pfrom->addr) == (CNetAddr)addrFrom) {
            addrman.Add(addrFrom, addrFrom);
            addrman.Good(addrFrom);
        }
    }

    // Relay alerts
    {
        LOCK(cs_mapAlerts);
        BOOST_FOREACH (PAIRTYPE(const uint256, CAlert) & item, mapAlerts)
            item.second.RelayTo(pfrom);
    }

    pfrom->fSuccessfullyConnected = true;

    string remoteAddr;
    if (fLogIPs)
        remoteAddr = ", peeraddr=" + pfrom->addr.ToString();

    if (fDebug)
        LogPrintf("receive version message: %s: version %d, blocks=%d, us=%s, peer=%d%s\n", pfrom->cleanSubVer, pfrom->nVersion, pfrom->nStartingHeight, addrMe.ToString(), pfrom->id, remoteAddr);

    cPeerBlockCounts.input(pfrom->nChainHeight);

    int64_t nTimeOffset = nTime - GetTime();
    pfrom->nTimeOffset = nTimeOffset;
    AddTimeData(pfrom->addr, nTimeOffset);
    return true;
}

bool static ProcessMessageFilterLoad(CNode* pfrom, CDataStream& vRecv)
{
    CBloomFilter filter;
    vRecv >> filter;

    if (!filter.IsWithinSizeConstraints())
        // There is no excuse for sending a too-large filter

        Misbehaving(pfrom->GetId(), 100, "Filter too large to load");
    else {
        LOCK(pfrom->cs_filter);
        delete pfrom->pfilter;
        pfrom->pfilter = new CBloomFilter(filter);
        pfrom->pfilter->UpdateEmptyFull();
    }
    pfrom->fRelayTxes = true;
}

bool static ProcessMessageFilterAdd(CNode* pfrom, CDataStream& vRecv)
{
    vector<unsigned char> vData;
    vRecv >> vData;

    // Nodes must NEVER send a data item > 520 bytes (the max size for a script data object,
    // and thus, the maximum size any matched object can have) in a filteradd message
    if (vData.size() > MAX_SCRIPT_ELEMENT_SIZE) {
        Misbehaving(pfrom->GetId(), 100, "Filter too large to add");
    } else {
        LOCK(pfrom->cs_filter);
        if (pfrom->pfilter)
            pfrom->pfilter->insert(vData);
        else
            Misbehaving(pfrom->GetId(), 100, "Error adding filter");
    }
}

bool static ProcessMessageFilterClear(CNode* pfrom, CDataStream& vRecv)
{
    LOCK(pfrom->cs_filter);
    delete pfrom->pfilter;
    pfrom->pfilter = new CBloomFilter();
    pfrom->fRelayTxes = true;
}

bool static ProcessMessageInventory(CNode* pfrom, CDataStream& vRecv)
{
    vector<CInv> vInv;
    vRecv >> vInv;
    if (vInv.size() > MAX_INV_SZ) {
        LOCK(cs_main);
        Misbehaving(pfrom->GetId(), 20, "Inventory too large");
        return error("message inv size() = %u", vInv.size());
    }

    bool fBlocksOnly = GetBoolArg("-blocksonly", DEFAULT_BLOCKSONLY_LEGACY);

    // Allow whitelisted peers to send data other than blocks in blocks only mode if whitelistrelay is true
    if (pfrom->fWhitelisted && GetBoolArg("-whitelistrelay", DEFAULT_WHITELISTRELAY_LEGACY))
        fBlocksOnly = false;

    LOCK(cs_main);

    std::vector<CInv> vToFetch;

    for (unsigned int nInv = 0; nInv < vInv.size(); nInv++) {
        const CInv& inv = vInv[nInv];

        boost::this_thread::interruption_point();
        pfrom->AddInventoryKnown(inv);

        bool fAlreadyHave = AlreadyHave(inv);
        LogPrint("net", "got inv: %s  %s peer=%d\n", inv.ToString(), fAlreadyHave ? "have" : "new", pfrom->id);

        if (inv.type == MSG_BLOCK) {
            UpdateBlockAvailability(pfrom->GetId(), inv.hash);
            if (!fAlreadyHave && !fImporting && !fReindex && !mapBlocksInFlight.count(inv.hash)) {
                // First request the headers preceding the announced block. In the normal fully-synced
                // case where a new block is announced that succeeds the current tip (no reorganization),
                // there are no such headers.
                // Secondly, and only when we are close to being synced, we request the announced block directly,
                // to avoid an extra round-trip. Note that we must *first* ask for the headers, so by the
                // time the block arrives, the header chain leading up to it is already validated. Not
                // doing this will result in the received block being rejected as an orphan in case it is
                // not a direct successor.
                pfrom->PushMessage(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexBestHeader), inv.hash);
                CNodeState* nodestate = State(pfrom->GetId());
                if (CanDirectFetch() &&
                    nodestate->nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
                    vToFetch.push_back(inv);
                    // Mark block as in flight already, even though the actual "getdata" message only goes out
                    // later (within the same cs_main lock, though).
                    MarkBlockAsInFlight_Legacy(pfrom->GetId(), inv.hash);
                }
                LogPrint("net", "getheaders (%d) %s to peer=%d\n", pindexBestHeader->nHeight, inv.hash.ToString(), pfrom->id);
            }
        } else {
            if (fBlocksOnly)
                LogPrint("net", "transaction (%s) inv sent in violation of protocol peer=%d\n", inv.hash.ToString(), pfrom->id);
            else if (!fAlreadyHave && !fImporting && !fReindex && !IsInitialBlockDownload())
                pfrom->AskFor(inv);
        }

        // Track requests for our stuff
        GetMainSignals().Inventory(inv.hash);

        if (pfrom->nSendSize > (SendBufferSize() * 2)) {
            Misbehaving(pfrom->GetId(), 50, "Inventory buffer too large");
            return error("send buffer size() = %u", pfrom->nSendSize);
        }
    }

    if (!vToFetch.empty())
        pfrom->PushMessage(NetMsgType::GETDATA, vToFetch);
    return true;
}

/* This asymmetric behavior for inbound and outbound connections was introduced
 * to prevent a fingerprinting attack: an attacker can send specific fake addresses
 * to users' AddrMan and later request them by sending getaddr messages.
 * Making users (which are behind NAT and can only make outgoing connections) ignore
 * getaddr message mitigates the attack.
 */
bool static ProcessMessageGetAddr(CNode* pfrom)
{
    if (!pfrom->fInbound) {
        LogPrint("net", "Ignoring \"getaddr\" from outbound connection. peer=%d\n", pfrom->id);
        return true;
    }

    pfrom->vAddrToSend.clear();
    vector<CAddress> vAddr = addrman.GetAddr();
    BOOST_FOREACH (const CAddress& addr, vAddr)
        pfrom->PushAddress(addr);
    return true;
}

bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv, int64_t nTimeReceived)
{
    RandAddSeedPerfmon();

    LogPrint("net", "received: %s (%u bytes) peer=%d\n", SanitizeString(strCommand), vRecv.size(), pfrom->id);
    if (mapArgs.count("-dropmessagestest") && GetRand(atoi(mapArgs["-dropmessagestest"])) == 0) {
        if (fDebug)
            LogPrintf("dropmessagestest DROPPING RECV MESSAGE\n");

        return true;
    }

    if (!(nLocalServices & NODE_BLOOM) &&
        (strCommand == NetMsgType::FILTERLOAD ||
            strCommand == NetMsgType::FILTERADD ||
            strCommand == NetMsgType::FILTERCLEAR)) {
        if (pfrom->nVersion >= NO_BLOOM_VERSION) {
            Misbehaving(pfrom->GetId(), 100, "We have no bloom");
            return false;
        } else if (GetBoolArg("-enforcenodebloom", false)) {
            pfrom->fDisconnect = true;
            return false;
        }
    }

    if (strCommand == NetMsgType::VERSION)
        return ProcessMessageVersion(pfrom, strCommand, vRecv, nTimeReceived);

    else if (pfrom->nVersion == 0) {
        // Must have a version message before anything else
        LOCK(cs_main);
        Misbehaving(pfrom->GetId(), 1, "Didn't send a version first");
        return false;
    }

     else if (pfrom->clientVersion < MIM_CLIENT_VERSION) {
        pfrom->PushMessage(NetMsgType::REJECT, strCommand, REJECT_OBSOLETE, strprintf("Version must be %d or greater", MIM_CLIENT_VERSION));
        Misbehaving(pfrom->GetId(), 100, "Ban due to fork");
        pfrom->fDisconnect = true;
        return false;
    }

    else if (strCommand == NetMsgType::VERACK)
        return ProcessMessageVerAck(pfrom);

    else if (strCommand == NetMsgType::ADDR)
        return ProcessMessageAddress(pfrom, vRecv);

    else if (strCommand == NetMsgType::SENDHEADERS) {
        LOCK(cs_main);
        State(pfrom->GetId())->fPreferHeaders = true;
    }

    else if (strCommand == NetMsgType::INV)
        return ProcessMessageInventory(pfrom, vRecv);

    else if (strCommand == NetMsgType::GETDATA)
        return ProcessMessageGetData(pfrom, vRecv);

    else if (strCommand == NetMsgType::GETBLOCKS)
        return ProcessMessageGetBlocks(pfrom, strCommand, vRecv, nTimeReceived);

    else if (strCommand == NetMsgType::GETHEADERS)
        return ProcessMessageGetHeaders(pfrom, strCommand, vRecv, nTimeReceived);

    else if (strCommand == NetMsgType::TX)
        return ProcessMessageTx(pfrom, strCommand, vRecv);

    else if (strCommand == NetMsgType::HEADERS && !fImporting && !fReindex) // Ignore headers received while importing
        return ProcessMessageHeaders(pfrom, strCommand, vRecv, nTimeReceived);

    else if (strCommand == NetMsgType::BLOCK && !fImporting && !fReindex) // Ignore blocks received while importing
        return ProcessMessageBlock(pfrom, strCommand, vRecv);

    else if (strCommand == NetMsgType::GETADDR)
        return ProcessMessageGetAddr(pfrom);

    else if (strCommand == NetMsgType::MEMPOOL)
        return ProcessMessageMemPool(pfrom);

    else if (strCommand == NetMsgType::PING)
        return ProcessMessagePing(pfrom, strCommand, vRecv, nTimeReceived);

    else if (strCommand == NetMsgType::PONG)
        return ProcessMessagePong(pfrom, strCommand, vRecv, nTimeReceived);

    else if (strCommand == NetMsgType::FILTERLOAD)
        return ProcessMessageFilterLoad(pfrom, vRecv);

    else if (strCommand == NetMsgType::FILTERADD)
        return ProcessMessageFilterAdd(pfrom, vRecv);

    else if (strCommand == NetMsgType::FILTERCLEAR)
        return ProcessMessageFilterClear(pfrom, vRecv);

    else if (strCommand == NetMsgType::REJECT)
        return ProcessMessageReject(pfrom, strCommand, vRecv, nTimeReceived);

    return true;
}

int ActiveProtocol()
{
    return UseLegacyCode() ? MIN_PEER_PROTO_VERSION_PRE_FORK : MIN_PEER_PROTO_VERSION;
}

// requires LOCK(cs_vRecvMsg)
bool ProcessMessages(CNode* pfrom)
{
    // Message format
    //  (4) message start
    //  (12) command
    //  (4) size
    //  (4) checksum
    //  (x) data
    
    bool fOk = true;

    if (!pfrom->vRecvGetData.empty())
        ProcessGetData(pfrom);

    // this maintains the order of responses
    if (!pfrom->vRecvGetData.empty()) return fOk;

    std::deque<CNetMessage>::iterator it = pfrom->vRecvMsg.begin();
    while (!pfrom->fDisconnect && it != pfrom->vRecvMsg.end()) {
        // Don't bother if send buffer is too full to respond anyway
        if (pfrom->nSendSize >= SendBufferSize())
            break;

        // get next message
        CNetMessage& msg = *it;

        // end, if an incomplete message is found
        if (!msg.complete())
            break;

        // at this point, any failure means we can delete the current message
        it++;

        // Scan for message start
        if (memcmp(msg.hdr.pchMessageStart, Params().MessageStart(), MESSAGE_START_SIZE) != 0) {
            if (fDebug)
                LogPrintf("PROCESSMESSAGE: INVALID MESSAGESTART %s peer=%d\n", SanitizeString(msg.hdr.GetCommand()), pfrom->id);
            
            fOk = false;
            break;
        }

        // Read header
        CMessageHeader& hdr = msg.hdr;
        if (!hdr.IsValid()) {
            if (fDebug)
                LogPrintf("PROCESSMESSAGE: ERRORS IN HEADER %s peer=%d\n", SanitizeString(hdr.GetCommand()), pfrom->id);
            
            continue;
        }
        string strCommand = hdr.GetCommand();

        // Message size
        unsigned int nMessageSize = hdr.nMessageSize;

        // Checksum
        CDataStream& vRecv = msg.vRecv;
        uint256 hash = Hash(vRecv.begin(), vRecv.begin() + nMessageSize);
        unsigned int nChecksum = 0;
        memcpy(&nChecksum, &hash, sizeof(nChecksum));
        if (nChecksum != hdr.nChecksum) {
            if (fDebug) 
                LogPrintf("ProcessMessages(%s, %u bytes): CHECKSUM ERROR nChecksum=%08x hdr.nChecksum=%08x\n", SanitizeString(strCommand), nMessageSize, nChecksum, hdr.nChecksum);
            
            continue;
        }

        // Process message
        bool fRet = false;
        try {
            fRet = ProcessMessage(pfrom, strCommand, vRecv, msg.nTime);

            boost::this_thread::interruption_point();
        } catch (std::ios_base::failure& e) {
            pfrom->PushMessage("reject", strCommand, REJECT_MALFORMED, string("error parsing message"));
            if (strstr(e.what(), "end of data") && fDebug)
                LogPrintf("ProcessMessages(%s, %u bytes): Exception '%s' caught, normally caused by a message being shorter than its stated length\n", SanitizeString(strCommand), nMessageSize, e.what());
            else if (strstr(e.what(), "size too large") && fDebug)
                LogPrintf("ProcessMessages(%s, %u bytes): Exception '%s' caught\n", SanitizeString(strCommand), nMessageSize, e.what());
            else
                PrintExceptionContinue(&e, "ProcessMessages()");
        } catch (boost::thread_interrupted) {
            throw;
        } catch (std::exception& e) {
            PrintExceptionContinue(&e, "ProcessMessages()");
        } catch (...) {
            PrintExceptionContinue(NULL, "ProcessMessages()");
        }

        if (!fRet && fDebug)
            LogPrintf("ProcessMessage(%s, %u bytes) FAILED peer=%d\n", SanitizeString(strCommand), nMessageSize, pfrom->id);

        break;
    }

    // In case the connection got shut down, its receive buffer was wiped
    if (!pfrom->fDisconnect)
        pfrom->vRecvMsg.erase(pfrom->vRecvMsg.begin(), it);

    return fOk;
}

bool PeerHasHeader_Legacy(CNodeState* state, CBlockIndex* pindex)
{
    if (state->pindexBestKnownBlock && pindex == state->pindexBestKnownBlock->GetAncestor(pindex->nHeight))
        return true;
    if (state->pindexBestHeaderSent_Legacy && pindex == state->pindexBestHeaderSent_Legacy->GetAncestor(pindex->nHeight))
        return true;
    return false;
}

bool SendMessages(CNode* pto)
{
    // Don't send anything until we get its version message
    if (pto->nVersion == 0)
        return true;

    //
    // Message: ping
    //
    bool pingSend = false;
    if (pto->fPingQueued) {
        // RPC ping request by user
        pingSend = true;
    }
    if (pto->nPingNonceSent == 0 && pto->nPingUsecStart + PING_INTERVAL * 1000000 < GetTimeMicros()) {
        // Ping automatically sent as a latency probe & keepalive.
        pingSend = true;
    }
    if (pingSend) {
        uint64_t nonce = 0;
        while (nonce == 0) {
            GetRandBytes((unsigned char*)&nonce, sizeof(nonce));
        }
        pto->fPingQueued = false;
        pto->nPingUsecStart = GetTimeMicros();
        if (pto->nVersion > BIP0031_VERSION) {
            pto->nPingNonceSent = nonce;
            if (pto->nVersion >= PING_INCLUDES_HEIGHT_VERSION) {
                pto->PushMessage(NetMsgType::PING, nonce, nChainHeight);
            } else {
                pto->PushMessage(NetMsgType::PING, nonce);
            }
        } else {
            // Peer is too old to support ping command with nonce, pong will never arrive.
            pto->nPingNonceSent = 0;
            pto->PushMessage(NetMsgType::PING);
        }
    }

    TRY_LOCK(cs_main, lockMain); // Acquire cs_main for IsInitialBlockDownload() and CNodeState()
    if (!lockMain)
        return true;

    // Address refresh broadcast
    int64_t nNow = GetTimeMicros();
    if (!IsInitialBlockDownload() && pto->nNextLocalAddrSend < nNow) {
        AdvertizeLocal(pto);
        pto->nNextLocalAddrSend = PoissonNextSend_Legacy(nNow, AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL_LEGACY);
    }

    //
    // Message: addr
    //
    if (pto->nNextAddrSend < nNow) {
        pto->nNextAddrSend = PoissonNextSend_Legacy(nNow, AVG_ADDRESS_BROADCAST_INTERVAL_LEGACY);
        vector<CAddress> vAddr;
        vAddr.reserve(pto->vAddrToSend.size());
        BOOST_FOREACH (const CAddress& addr, pto->vAddrToSend) {
            if (!pto->addrKnown.contains(addr.GetKey())) {
                pto->addrKnown.insert(addr.GetKey());
                vAddr.push_back(addr);
                // receiver rejects addr messages larger than 1000
                if (vAddr.size() >= 1000) {
                    pto->PushMessage(NetMsgType::ADDR, vAddr);
                    vAddr.clear();
                }
            }
        }
        pto->vAddrToSend.clear();
        if (!vAddr.empty())
            pto->PushMessage(NetMsgType::ADDR, vAddr);
    }

    CNodeState& state = *State(pto->GetId());
    if (state.fShouldBan) {
        if (pto->fWhitelisted && fDebug)
            LogPrintf("Warning: not punishing whitelisted peer %s!\n", pto->addr.ToString());
        else {
            pto->fDisconnect = true;
            if (pto->addr.IsLocal() && fDebug)
                LogPrintf("Warning: not banning local peer %s!\n", pto->addr.ToString());
            else
                CNode::Ban(pto->addr, BanReasonNodeMisbehaving);
        }
        state.fShouldBan = false;
    }

    BOOST_FOREACH (const CBlockReject& reject, state.rejects)
        pto->PushMessage(NetMsgType::REJECT, (string)NetMsgType::BLOCK, reject.chRejectCode, reject.strRejectReason, reject.hashBlock);
    state.rejects.clear();

    // Start block sync
    if (pindexBestHeader == NULL)
        pindexBestHeader = chainActive.Tip();
    bool fFetch = state.fPreferredDownload || (nPreferredDownload == 0 && !pto->fClient && !pto->fOneShot); // Download if this is a nice peer, or we have no nice peers and this one might do.
    if (!state.fSyncStarted && !pto->fClient && !fImporting && !fReindex) {
        // Only actively request headers from a single peer, unless we're close to today.
        if ((nSyncStarted == 0 && fFetch) || pindexBestHeader->GetBlockTime() > GetAdjustedTime() - 24 * 60 * 60) {
            state.fSyncStarted = true;
            nSyncStarted++;
            const CBlockIndex* pindexStart = pindexBestHeader;
            /* If possible, start at the block preceding the currently
                best known header.  This ensures that we always get a
                non-empty list of headers back as long as the peer
                is up-to-date.  With a non-empty response, we can initialise
                the peer's known best block.  This wouldn't be possible
                if we requested starting at pindexBestHeader and
                got back an empty response.  */
            if (pindexStart->pprev)
                pindexStart = pindexStart->pprev;
            LogPrint("net", "initial getheaders (%d) to peer=%d (startheight:%d)\n", pindexStart->nHeight, pto->id, pto->nStartingHeight);
            pto->PushMessage(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexStart), uint256());
        }
    }

    // Resend wallet transactions that haven't gotten in a block yet
    // Except during reindex, importing and IBD, when old wallet
    // transactions become unconfirmed and spams other nodes.
    if (!fReindex && !fImporting && !IsInitialBlockDownload()) {
        //GetMainSignals().Broadcast(nTimeBestReceived);
        GetMainSignals().Broadcast();
    }

    //
    // Try sending block announcements via headers
    //
    {
        // If we have less than MAX_BLOCKS_TO_ANNOUNCE in our
        // list of block hashes we're relaying, and our peer wants
        // headers announcements, then find the first header
        // not yet known to our peer but would connect, and send.
        // If no header would connect, or if we have too many
        // blocks, or if the peer doesn't want headers, just
        // add all to the inv queue.
        LOCK(pto->cs_inventory);
        vector<CBlock> vHeaders;
        bool fRevertToInv = (!state.fPreferHeaders || pto->vBlockHashesToAnnounce.size() > MAX_BLOCKS_TO_ANNOUNCE_LEGACY);
        CBlockIndex* pBestIndex = NULL;    // last header queued for delivery
        ProcessBlockAvailability(pto->id); // ensure pindexBestKnownBlock is up-to-date

        if (!fRevertToInv) {
            bool fFoundStartingHeader = false;
            // Try to find first header that our peer doesn't have, and
            // then send all headers past that one.  If we come across any
            // headers that aren't on chainActive, give up.
            BOOST_FOREACH (const uint256& hash, pto->vBlockHashesToAnnounce) {
                BlockMap::iterator mi = mapBlockIndex.find(hash);
                assert(mi != mapBlockIndex.end());
                CBlockIndex* pindex = mi->second;
                if (chainActive[pindex->nHeight] != pindex) {
                    // Bail out if we reorged away from this block
                    fRevertToInv = true;
                    break;
                }
                if (pBestIndex != NULL && pindex->pprev != pBestIndex) {
                    // This means that the list of blocks to announce don't
                    // connect to each other.
                    // This shouldn't really be possible to hit during
                    // regular operation (because reorgs should take us to
                    // a chain that has some block not on the prior chain,
                    // which should be caught by the prior check), but one
                    // way this could happen is by using invalidateblock /
                    // reconsiderblock repeatedly on the tip, causing it to
                    // be added multiple times to vBlockHashesToAnnounce.
                    // Robustly deal with this rare situation by reverting
                    // to an inv.
                    fRevertToInv = true;
                    break;
                }
                pBestIndex = pindex;
                if (fFoundStartingHeader) {
                    // add this to the headers message
                    vHeaders.push_back(pindex->GetBlockHeader());
                } else if (PeerHasHeader_Legacy(&state, pindex)) {
                    continue; // keep looking for the first new block
                } else if (pindex->pprev == NULL || PeerHasHeader_Legacy(&state, pindex->pprev)) {
                    // Peer doesn't have this header but they do have the prior one.
                    // Start sending headers.
                    fFoundStartingHeader = true;
                    vHeaders.push_back(pindex->GetBlockHeader());
                } else {
                    // Peer doesn't have this header or the prior one -- nothing will
                    // connect, so bail out.
                    fRevertToInv = true;
                    break;
                }
            }
        }
        if (fRevertToInv) {
            // If falling back to using an inv, just try to inv the tip.
            // The last entry in vBlockHashesToAnnounce was our tip at some point
            // in the past.
            if (!pto->vBlockHashesToAnnounce.empty()) {
                const uint256& hashToAnnounce = pto->vBlockHashesToAnnounce.back();
                BlockMap::iterator mi = mapBlockIndex.find(hashToAnnounce);
                assert(mi != mapBlockIndex.end());
                CBlockIndex* pindex = mi->second;

                // Warn if we're announcing a block that is not on the main chain.
                // This should be very rare and could be optimized out.
                // Just log for now.
                if (chainActive[pindex->nHeight] != pindex) {
                    LogPrint("net", "Announcing block %s not on main chain (tip=%s)\n",
                        hashToAnnounce.ToString(), chainActive.Tip()->GetBlockHash().ToString());
                }

                // If the peer announced this block to us, don't inv it back.
                // (Since block announcements may not be via inv's, we can't solely rely on
                // setInventoryKnown to track this.)
                if (!PeerHasHeader_Legacy(&state, pindex)) {
                    pto->PushInventory(CInv(MSG_BLOCK, hashToAnnounce));
                    LogPrint("net", "%s: sending inv peer=%d hash=%s\n", __func__,
                        pto->id, hashToAnnounce.ToString());
                }
            }
        } else if (!vHeaders.empty()) {
            if (vHeaders.size() > 1) {
                LogPrint("net", "%s: %u headers, range (%s, %s), to peer=%d\n", __func__,
                    vHeaders.size(),
                    vHeaders.front().GetHash().ToString(),
                    vHeaders.back().GetHash().ToString(), pto->id);
            } else {
                LogPrint("net", "%s: sending header %s to peer=%d\n", __func__,
                    vHeaders.front().GetHash().ToString(), pto->id);
            }
            pto->PushMessage(NetMsgType::HEADERS, vHeaders);
            state.pindexBestHeaderSent_Legacy = pBestIndex;
        }
        pto->vBlockHashesToAnnounce.clear();
    }

    //
    // Message: inventory
    //
    vector<CInv> vInv;
    vector<CInv> vInvWait;
    {
        bool fSendTrickle = pto->fWhitelisted;
        if (pto->nNextInvSend < nNow) {
            fSendTrickle = true;
            pto->nNextInvSend = PoissonNextSend_Legacy(nNow, AVG_INVENTORY_BROADCAST_INTERVAL_LEGACY);
        }
        LOCK(pto->cs_inventory);
        vInv.reserve(std::min<size_t>(1000, pto->vInventoryToSend.size()));
        vInvWait.reserve(pto->vInventoryToSend.size());
        BOOST_FOREACH (const CInv& inv, pto->vInventoryToSend) {
            if (inv.type == MSG_TX && pto->filterInventoryKnown.contains(inv.hash))
                continue;

            // trickle out tx inv to protect privacy
            if (inv.type == MSG_TX && !fSendTrickle) {
                // 1/4 of tx invs blast to all immediately
                static uint256 hashSalt;
                if (hashSalt.IsNull())
                    hashSalt = GetRandHash();
                uint256 hashRand = ArithToUint256(UintToArith256(inv.hash) ^ UintToArith256(hashSalt));
                hashRand = Hash(BEGIN(hashRand), END(hashRand));
                bool fTrickleWait = ((UintToArith256(hashRand) & 3) != 0);

                if (fTrickleWait) {
                    vInvWait.push_back(inv);
                    continue;
                }
            }

            pto->filterInventoryKnown.insert(inv.hash);
            vInv.push_back(inv);
            if (vInv.size() >= 1000) {
                pto->PushMessage(NetMsgType::INV, vInv);
                vInv.clear();
            }
        }
        pto->vInventoryToSend = vInvWait;
    }
    if (!vInv.empty())
        pto->PushMessage(NetMsgType::INV, vInv);

    // Detect whether we're stalling
    nNow = GetTimeMicros();
    if (!pto->fDisconnect && state.nStallingSince && state.nStallingSince < nNow - 1000000 * BLOCK_STALLING_TIMEOUT) {
        // Stalling only triggers when the block download window cannot move. During normal steady state,
        // the download window should be much larger than the to-be-downloaded set of blocks, so disconnection
        // should only happen during initial block download.
        if (fDebug)
            LogPrintf("Peer=%d is stalling block download, disconnecting\n", pto->id);
        
        pto->fDisconnect = true;
    }
    // In case there is a block that has been in flight from this peer for 2 + 0.5 * N times the block interval
    // (with N the number of peers from which we're downloading validated blocks), disconnect due to timeout.
    // We compensate for other peers to prevent killing off peers due to our own downstream link
    // being saturated. We only count validated in-flight blocks so peers can't advertise non-existing block hashes
    // to unreasonably increase our timeout.
    if (!pto->fDisconnect && state.vBlocksInFlight.size() > 0) {
        QueuedBlock& queuedBlock = state.vBlocksInFlight.front();
        int nOtherPeersWithValidatedDownloads = nPeersWithValidatedDownloads - (state.nBlocksInFlightValidHeaders > 0);
        if (nNow > state.nDownloadingSince + Params().GetTargetSpacing() * (BLOCK_DOWNLOAD_TIMEOUT_BASE_LEGACY + BLOCK_DOWNLOAD_TIMEOUT_BASE_LEGACY * nOtherPeersWithValidatedDownloads)) {
            if (fDebug)
                LogPrintf("Timeout downloading block %s from peer=%d, disconnecting\n", queuedBlock.hash.ToString(), pto->id);
            
            pto->fDisconnect = true;
        }
    }

    //
    // Message: getdata (blocks)
    //
    vector<CInv> vGetData;
    if (!pto->fDisconnect && !pto->fClient && (fFetch || !IsInitialBlockDownload()) && state.nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
        vector<CBlockIndex*> vToDownload;
        NodeId staller = -1;
        FindNextBlocksToDownload(pto->GetId(), MAX_BLOCKS_IN_TRANSIT_PER_PEER - state.nBlocksInFlight, vToDownload, staller);
        BOOST_FOREACH (CBlockIndex* pindex, vToDownload) {
            vGetData.push_back(CInv(MSG_BLOCK, pindex->GetBlockHash()));
            MarkBlockAsInFlight_Legacy(pto->GetId(), pindex->GetBlockHash(), pindex);
            LogPrint("net", "Requesting block %s (%d) peer=%d\n", pindex->GetBlockHash().ToString(),
                pindex->nHeight, pto->id);
        }
        if (state.nBlocksInFlight == 0 && staller != -1) {
            if (State(staller)->nStallingSince == 0) {
                State(staller)->nStallingSince = nNow;
                LogPrint("net", "Stall started peer=%d\n", staller);
            }
        }
    }

    //
    // Message: getdata (non-blocks)
    //
    while (!pto->fDisconnect && !pto->mapAskFor.empty() && (*pto->mapAskFor.begin()).first <= nNow) {
        const CInv& inv = (*pto->mapAskFor.begin()).second;
        if (!AlreadyHave(inv)) {
            if (fDebug)
                LogPrint("net", "Requesting %s peer=%d\n", inv.ToString(), pto->id);
            
            vGetData.push_back(inv);
            if (vGetData.size() >= 1000) {
                pto->PushMessage(NetMsgType::GETDATA, vGetData);
                vGetData.clear();
            }
        } else {
            //If we're not going to ask, don't expect a response.
            pto->setAskFor.erase(inv.hash);
        }
        pto->mapAskFor.erase(pto->mapAskFor.begin());
    }
    if (!vGetData.empty())
        pto->PushMessage(NetMsgType::GETDATA, vGetData);

    return true;
}

bool CBlockUndo::WriteToDisk(CDiskBlockPos& pos, const uint256& hashBlock)
{
    // Open history file to append
    CAutoFile fileout(OpenUndoFile(pos), SER_DISK, CLIENT_VERSION);
    if (fileout.IsNull())
        return error("CBlockUndo::WriteToDisk : OpenUndoFile failed");

    // Write index header
    unsigned int nSize = fileout.GetSerializeSize(*this);
    fileout << FLATDATA(Params().MessageStart()) << nSize;

    // Write undo data
    long fileOutPos = ftell(fileout.Get());
    if (fileOutPos < 0)
        return error("CBlockUndo::WriteToDisk : ftell failed");
    pos.nPos = (unsigned int)fileOutPos;
    fileout << *this;

    // calculate & write checksum
    CHashWriter hasher(SER_GETHASH, PROTOCOL_VERSION);
    hasher << hashBlock;
    hasher << *this;
    fileout << hasher.GetHash();

    return true;
}

bool CBlockUndo::ReadFromDisk(const CDiskBlockPos& pos, const uint256& hashBlock)
{
    // Open history file to read
    CAutoFile filein(OpenUndoFile(pos, true), SER_DISK, CLIENT_VERSION);
    if (filein.IsNull())
        return error("CBlockUndo::ReadFromDisk : OpenBlockFile failed");

    // Read block
    uint256 hashChecksum;
    try {
        filein >> *this;
        filein >> hashChecksum;
    } catch (std::exception& e) {
        return error("%s : Deserialize or I/O error - %s", __func__, e.what());
    }

    // Verify checksum
    CHashWriter hasher(SER_GETHASH, PROTOCOL_VERSION);
    hasher << hashBlock;
    hasher << *this;
    if (hashChecksum != hasher.GetHash())
        return error("CBlockUndo::ReadFromDisk : Checksum mismatch");

    return true;
}

std::string CBlockFileInfo::ToString() const
{
    return strprintf("CBlockFileInfo(blocks=%u, size=%u, heights=%u...%u, time=%s...%s)", nBlocks, nSize, nHeightFirst, nHeightLast, DateTimeStrFormat("%Y-%m-%d", nTimeFirst), DateTimeStrFormat("%Y-%m-%d", nTimeLast));
}


class CMainCleanup
{
public:
    CMainCleanup() {}
    ~CMainCleanup()
    {
        // block headers
        BlockMap::iterator it1 = mapBlockIndex.begin();
        for (; it1 != mapBlockIndex.end(); it1++)
            delete (*it1).second;
        mapBlockIndex.clear();

        // orphan transactions
        mapOrphanTransactions.clear();
        mapOrphanTransactionsByPrev.clear();
    }
} instance_of_cmaincleanup;