main.cpp

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin developers
// Copyright (c) 2011-2013 The Litecoin developers
// Copyright (c) 2013-2014 The Dogecoin developers
// Copyright (c)      2014 The Inutoshi developers
// Copyright (c)      2014 The Freshcoin developers
// Distributed under the MIT/X11 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 "chainparams.h"
#include "checkpoints.h"
#include "checkqueue.h"
#include "init.h"
#include "net.h"
#include "txdb.h"
#include "txmempool.h"
#include "ui_interface.h"
#include "util.h"

#include <sstream>

#include <boost/algorithm/string/replace.hpp>
#include <boost/filesystem.hpp>
#include <boost/filesystem/fstream.hpp>
#include <boost/random/mersenne_twister.hpp>
#include <boost/random/uniform_int.hpp>

using namespace std;
using namespace boost;

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

#define MINUTE      60   // 60 seconds
#define HOUR        60   // 60 minutes
#define DAY         24   // 24 hours
#define HOUR_SEC    (HOUR * MINUTE)
#define DAY_SEC     (DAY * HOUR_SEC)
//
// Global state
//

CCriticalSection cs_main;

CTxMemPool mempool;

map<uint256, CBlockIndex*> mapBlockIndex;
CChain chainActive;
CChain chainMostWork;
int64_t nTimeBestReceived = 0;
int nScriptCheckThreads = 0;
bool fImporting = false;
bool fReindex = false;
bool fBenchmark = false;
bool fTxIndex = false;
unsigned int nCoinCacheSize = 5000;

/** Fees smaller than this (in satoshi) are considered zero fee (for transaction creation) */
//                              0.00000123
int64_t CTransaction::nMinTxFee = 10000;  // Override with -mintxfee
/** Fees smaller than this (in satoshi) are considered zero fee (for relaying and mining) */
int64_t CTransaction::nMinRelayTxFee = 5000;

static CMedianFilter<int> cPeerBlockCounts(8, 0); // Amount of blocks that other nodes claim to hav

struct COrphanBlock {
    uint256 hashBlock;
    uint256 hashPrev;
    vector<unsigned char> vchBlock;
};
map<uint256, COrphanBlock*> mapOrphanBlocks;
multimap<uint256, COrphanBlock*> mapOrphanBlocksByPrev;

map<uint256, CTransaction> mapOrphanTransactions;
map<uint256, set<uint256> > mapOrphanTransactionsByPrev;

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

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

// Internal stuff
namespace {
struct CBlockIndexWorkComparator
{
    bool operator()(CBlockIndex *pa, CBlockIndex *pb) {
        // 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;
set<CBlockIndex*, CBlockIndexWorkComparator> setBlockIndexValid; // may contain all CBlockIndex*'s that have validness >=BLOCK_VALID_TRANSACTIONS, and must contain those who aren't failed

CCriticalSection cs_LastBlockFile;
CBlockFileInfo infoLastBlockFile;
int nLastBlockFile = 0;

// 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;
}

//////////////////////////////////////////////////////////////////////////////
//
// dispatching functions
//

// These functions dispatch to one or all registered wallets

namespace {
struct CMainSignals {
    // Notifies listeners of updated transaction data (passing hash, transaction, and optionally the block it is found in.
    boost::signals2::signal<void (const uint256 &, const CTransaction &, const CBlock *)> SyncTransaction;
    // Notifies listeners of an erased transaction (currently disabled, requires transaction replacement).
    boost::signals2::signal<void (const uint256 &)> EraseTransaction;
    // Notifies listeners of an updated transaction without new data (for now: a coinbase potentially becoming visible).
    boost::signals2::signal<void (const uint256 &)> UpdatedTransaction;
    // Notifies listeners of a new active block chain.
    boost::signals2::signal<void (const CBlockLocator &)> SetBestChain;
    // Notifies listeners about an inventory item being seen on the network.
    boost::signals2::signal<void (const uint256 &)> Inventory;
    // Tells listeners to broadcast their data.
    boost::signals2::signal<void ()> Broadcast;
} g_signals;
}

void RegisterWallet(CWalletInterface* pwalletIn) {
    g_signals.SyncTransaction.connect(boost::bind(&CWalletInterface::SyncTransaction, pwalletIn, _1, _2, _3));
    g_signals.EraseTransaction.connect(boost::bind(&CWalletInterface::EraseFromWallet, pwalletIn, _1));
    g_signals.UpdatedTransaction.connect(boost::bind(&CWalletInterface::UpdatedTransaction, pwalletIn, _1));
    g_signals.SetBestChain.connect(boost::bind(&CWalletInterface::SetBestChain, pwalletIn, _1));
    g_signals.Inventory.connect(boost::bind(&CWalletInterface::Inventory, pwalletIn, _1));
    g_signals.Broadcast.connect(boost::bind(&CWalletInterface::ResendWalletTransactions, pwalletIn));
}

void UnregisterWallet(CWalletInterface* pwalletIn) {
    g_signals.Broadcast.disconnect(boost::bind(&CWalletInterface::ResendWalletTransactions, pwalletIn));
    g_signals.Inventory.disconnect(boost::bind(&CWalletInterface::Inventory, pwalletIn, _1));
    g_signals.SetBestChain.disconnect(boost::bind(&CWalletInterface::SetBestChain, pwalletIn, _1));
    g_signals.UpdatedTransaction.disconnect(boost::bind(&CWalletInterface::UpdatedTransaction, pwalletIn, _1));
    g_signals.EraseTransaction.disconnect(boost::bind(&CWalletInterface::EraseFromWallet, pwalletIn, _1));
    g_signals.SyncTransaction.disconnect(boost::bind(&CWalletInterface::SyncTransaction, pwalletIn, _1, _2, _3));
}

void UnregisterAllWallets() {
    g_signals.Broadcast.disconnect_all_slots();
    g_signals.Inventory.disconnect_all_slots();
    g_signals.SetBestChain.disconnect_all_slots();
    g_signals.UpdatedTransaction.disconnect_all_slots();
    g_signals.EraseTransaction.disconnect_all_slots();
    g_signals.SyncTransaction.disconnect_all_slots();
}

void SyncWithWallets(const uint256 &hash, const CTransaction &tx, const CBlock *pblock) {
    g_signals.SyncTransaction(hash, tx, pblock);
}

//////////////////////////////////////////////////////////////////////////////
//
// 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 {
    // Accumulated misbehaviour score for this peer.
    int nMisbehavior;
    // Whether this peer should be disconnected and banned.
    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;

    CNodeState() {
        nMisbehavior = 0;
        fShouldBan = 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()
{
    LOCK(cs_main);
    return chainActive.Height();
}

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;
}

void FinalizeNode(NodeId nodeid) {
    LOCK(cs_main);
    mapNodeState.erase(nodeid);
}
}

bool GetNodeStateStats(NodeId nodeid, CNodeStateStats &stats) {
    LOCK(cs_main);
    CNodeState *state = State(nodeid);
    if (state == NULL)
        return false;
    stats.nMisbehavior = state->nMisbehavior;
    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);
}

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

//////////////////////////////////////////////////////////////////////////////
//
// CChain implementation
//

CBlockIndex *CChain::SetTip(CBlockIndex *pindex) {
    if (pindex == NULL) {
        vChain.clear();
        return NULL;
    }
    vChain.resize(pindex->nHeight + 1);
    while (pindex && vChain[pindex->nHeight] != pindex) {
        vChain[pindex->nHeight] = pindex;
        pindex = pindex->pprev;
    }
    return pindex;
}

CBlockLocator CChain::GetLocator(const CBlockIndex *pindex) const {
    int nStep = 1;
    std::vector<uint256> vHave;
    vHave.reserve(32);

    if (!pindex)
        pindex = Tip();
    while (pindex) {
        vHave.push_back(pindex->GetBlockHash());
        // Stop when we have added the genesis block.
        if (pindex->nHeight == 0)
            break;
        // Exponentially larger steps back, plus the genesis block.
        int nHeight = std::max(pindex->nHeight - nStep, 0);
        // In case pindex is not in this chain, iterate pindex->pprev to find blocks.
        while (pindex->nHeight > nHeight && !Contains(pindex))
            pindex = pindex->pprev;
        // If pindex is in this chain, use direct height-based access.
        if (pindex->nHeight > nHeight)
            pindex = (*this)[nHeight];
        if (vHave.size() > 10)
            nStep *= 2;
    }

    return CBlockLocator(vHave);
}

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

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

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

bool AddOrphanTx(const CTransaction& tx)
{
    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, CTransaction::CURRENT_VERSION);
    if (sz > 5000)
    {
        LogPrint("mempool", "ignoring large orphan tx (size: %u, hash: %s)\n", sz, hash.ToString());
        return false;
    }

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

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

void static EraseOrphanTx(uint256 hash)
{
    if (!mapOrphanTransactions.count(hash))
        return;
    const CTransaction& tx = mapOrphanTransactions[hash];
    BOOST_FOREACH(const CTxIn& txin, tx.vin)
    {
        mapOrphanTransactionsByPrev[txin.prevout.hash].erase(hash);
        if (mapOrphanTransactionsByPrev[txin.prevout.hash].empty())
            mapOrphanTransactionsByPrev.erase(txin.prevout.hash);
    }
    mapOrphanTransactions.erase(hash);
}

unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans)
{
    unsigned int nEvicted = 0;
    while (mapOrphanTransactions.size() > nMaxOrphans)
    {
        // Evict a random orphan:
        uint256 randomhash = GetRandHash();
        map<uint256, CTransaction>::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)
{
    if (tx.nVersion > CTransaction::CURRENT_VERSION || tx.nVersion < 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 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, CTransaction::CURRENT_VERSION);
    if (sz >= MAX_STANDARD_TX_SIZE) {
        reason = "tx-size";
        return false;
    }

    BOOST_FOREACH(const CTxIn& txin, tx.vin)
    {
        // Biggest 'standard' txin is a 3-signature 3-of-3 CHECKMULTISIG
        // pay-to-script-hash, which is 3 ~80-byte signatures, 3
        // ~65-byte public keys, plus a few script ops.
        if (txin.scriptSig.size() > 500) {
            reason = "scriptsig-size";
            return false;
        }
        if (!txin.scriptSig.IsPushOnly()) {
            reason = "scriptsig-not-pushonly";
            return false;
        }
        if (!txin.scriptSig.HasCanonicalPushes()) {
            reason = "scriptsig-non-canonical-push";
            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 (txout.IsDust(CTransaction::nMinRelayTxFee)) {
            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)
{
    // 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, 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]);

        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, tx, i, false, 0))
            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;
}

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, 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 CMerkleTx::SetMerkleBranch(const CBlock* pblock)
{
    CBlock blockTmp;

    if (pblock == NULL) {
        CCoins coins;
        if (pcoinsTip->GetCoins(GetHash(), coins)) {
            CBlockIndex *pindex = chainActive[coins.nHeight];
            if (pindex) {
                if (!ReadBlockFromDisk(blockTmp, pindex))
                    return 0;
                pblock = &blockTmp;
            }
        }
    }

    if (pblock) {
        // Update the tx's hashBlock
        hashBlock = pblock->GetHash();

        // Locate the transaction
        for (nIndex = 0; nIndex < (int)pblock->vtx.size(); nIndex++)
            if (pblock->vtx[nIndex] == *(CTransaction*)this)
                break;
        if (nIndex == (int)pblock->vtx.size())
        {
            vMerkleBranch.clear();
            nIndex = -1;
            LogPrintf("ERROR: SetMerkleBranch() : couldn't find tx in block\n");
            return 0;
        }

        // Fill in merkle branch
        vMerkleBranch = pblock->GetMerkleBranch(nIndex);
    }

    // Is the tx in a block that's in the main chain
    map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hashBlock);
    if (mi == mapBlockIndex.end())
        return 0;
    CBlockIndex* pindex = (*mi).second;
    if (!pindex || !chainActive.Contains(pindex))
        return 0;

    return chainActive.Height() - pindex->nHeight + 1;
}







bool CheckTransaction(const CTransaction& tx, CValidationState &state)
{
    // Basic checks that don't depend on any context
    if (tx.vin.empty())
        return state.DoS(10, error("CheckTransaction() : vin empty"),
                         REJECT_INVALID, "bad-txns-vin-empty");
    if (tx.vout.empty())
        return state.DoS(10, error("CheckTransaction() : vout empty"),
                         REJECT_INVALID, "bad-txns-vout-empty");
    // Size limits
    if (::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION) > MAX_BLOCK_SIZE)
        return state.DoS(100, error("CheckTransaction() : size limits failed"),
                         REJECT_INVALID, "bad-txns-oversize");

    // Check for negative or overflow output values
    int64_t nValueOut = 0;
    BOOST_FOREACH(const CTxOut& txout, tx.vout)
    {
        if (txout.nValue < 0)
            return state.DoS(100, error("CheckTransaction() : txout.nValue negative"),
                             REJECT_INVALID, "bad-txns-vout-negative");
        if (txout.nValue > MAX_MONEY)
            return state.DoS(100, error("CheckTransaction() : txout.nValue too high"),
                             REJECT_INVALID, "bad-txns-vout-toolarge");
        nValueOut += txout.nValue;
        if (!MoneyRange(nValueOut))
            return state.DoS(100, error("CheckTransaction() : txout total out of range"),
                             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, error("CheckTransaction() : duplicate inputs"),
                             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, error("CheckTransaction() : coinbase script size"),
                             REJECT_INVALID, "bad-cb-length");
    }
    else
    {
        BOOST_FOREACH(const CTxIn& txin, tx.vin)
            if (txin.prevout.IsNull())
                return state.DoS(10, error("CheckTransaction() : prevout is null"),
                                 REJECT_INVALID, "bad-txns-prevout-null");
    }

    return true;
}

static const int64_t TransactionFeeDivider = 200; //divider for outputs to specify transaction fee percentage (in this case, 0.5%)
static const int64_t TransactionFeeDividerSelf = 10000000; //divider for sending an input to output by same address to specify transaction fee percentage
//the fee for sending to self equates to almost nothing
//The time when to begin sending transactions out with percentage based transaction fees


static const time_t CoinLaunchTime=1404748800L; // 7 Jul 2014 16:00:00 GMT
static const time_t PercentageFeeSendingBegin = CoinLaunchTime+(DAY_SEC*6); //6 days after launch
//The time when to stop relaying free/cheap transactions and only relay ones with percentage fees
static const time_t PercentageFeeRelayBegin = CoinLaunchTime+(DAY_SEC*7); //7 days after launch


// send Fee from wallet fix
int64_t GetMinSendFee(const int64_t nValue)
{
    int64_t nMinFee = 100000;

    time_t t=time(NULL);
    if(t > PercentageFeeRelayBegin || (t > PercentageFeeSendingBegin))
    {
        nMinFee = nValue / 100; // 1% send fee
    }
    
    return nMinFee;
}


int64_t GetMinFee(const CTransaction& tx, unsigned int nBytes, bool fAllowFree, enum GetMinFee_mode mode)
{    
    // Base fee is either nMinTxFee or nMinRelayTxFee
    int64_t nBaseFee = (mode == GMF_RELAY) ? tx.nMinRelayTxFee : tx.nMinTxFee;

    int64_t nMinFee = (1 + (int64_t)nBytes / 1000) * nBaseFee;

    // Freshcoin
    // To limit dust spam, add nBaseFee for each output less than DUST_SOFT_LIMIT
    BOOST_FOREACH(const CTxOut& txout, tx.vout)
        if (txout.nValue < DUST_SOFT_LIMIT)
            nMinFee += nBaseFee;



        // BOOST_FOREACH(const CTxOut& txout2, tx.vout)
        // {
        //     BOOST_FOREACH(const CTxIn& txin2, tx.vin)
        //     {
        //         if(txin2.prevout.hash == txout2.GetHash())
        //         {        
        //             LogPrintf("GetMinFee: FOUND");
        //         }
        //         else
        //         {
        //             LogPrintf("GetMinFee: NOT FOUND");
                    
        //         }
        //     }
        //     LogPrintf("nValue: %lld\n", txout2.nValue);
        // }



    time_t t=time(NULL);
    if(t > PercentageFeeRelayBegin || (t > PercentageFeeSendingBegin && mode==GMF_SEND) )  
    {
        int64_t nNewMinFee = 0;
        int64_t prevNvalue = 0;
    
        /*XXX this could contain a loophole. 
        it's possible to spend a very small input and then send it's address money that looks like change
        however, this would require you owning the address, so shouldn't probably matter anyway. 
        if someone wants to avoid fees that strongly, they can mine a block themselves even or arrange for a pool to
        */
        // freshcoin percentage fee implementation
        BOOST_FOREACH(const CTxOut& txout, tx.vout)
        {
            bool found=false; //do not add fees when sending to the same address (this can be used for restructuring large single inputs)
            BOOST_FOREACH(const CTxIn& txin, tx.vin)
            {
                if(txin.prevout.hash == txout.GetHash())
                {        
                    found=true;
                  //  LogPrintf("GetMinFee: FOUND");
                }
                else
                {
                  //  LogPrintf("GetMinFee: NOT FOUND");
                }
            }
            if(!found)
            {
                // TODO IMPROVE
                if( (prevNvalue == 0) || (txout.nValue < prevNvalue) )
                {
                    prevNvalue = txout.nValue;
                    nNewMinFee = txout.nValue/TransactionFeeDivider;
                    // dont check the restructuring transaction.
                }

            }
            else
            {
                nMinFee+=txout.nValue/TransactionFeeDividerSelf;
            }

           // LogPrintf("GetMinFee: %lld\n", nMinFee);
        }
        nMinFee += nNewMinFee;
    }
    if(nMinFee > COIN*500) // max 500 coins fee.
    {
        nMinFee=COIN*500;
    }
    if (!MoneyRange(nMinFee))
        nMinFee = MAX_MONEY;
    return nMinFee;
}


bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransaction &tx, bool fLimitFree,
                        bool* pfMissingInputs, bool fRejectInsaneFee)
{
    fRejectInsaneFee=false;
    fLimitFree=true;
    if (pfMissingInputs)
        *pfMissingInputs = false;

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

    // 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");

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

    // 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);

        {
        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).
        BOOST_FOREACH(const CTxIn txin, tx.vin) {
            if (!view.HaveCoins(txin.prevout.hash)) {
                if (pfMissingInputs)
                    *pfMissingInputs = true;
                return false;
            }
        }

        // 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();

        // 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
        if (Params().NetworkID() == CChainParams::MAIN && !AreInputsStandard(tx, view))
            return error("AcceptToMemoryPool: : nonstandard transaction input");

        // Note: if you modify this code to accept non-standard transactions, then
        // you should add code here to check that the transaction does a
        // reasonable number of ECDSA signature verifications.

        int64_t nValueIn = view.GetValueIn(tx);
        int64_t nValueOut = tx.GetValueOut();
        int64_t nFees = nValueIn-nValueOut;
        double dPriority = view.GetPriority(tx, chainActive.Height());

        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
        int64_t txMinFee = GetMinFee(tx, nSize, true, GMF_RELAY);
        if (fLimitFree && nFees < txMinFee)
            return state.DoS(0, error("AcceptToMemoryPool : not enough fees %s, %d < %d",
                                      hash.ToString(), nFees, txMinFee),
                             REJECT_INSUFFICIENTFEE, "insufficient fee");

        // Continuously rate-limit free 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 < CTransaction::nMinRelayTxFee)
        {
            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/(MINUTE * 10.0), (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", 15)*10*1000)
                return state.DoS(0, error("AcceptToMemoryPool : free transaction rejected by rate limiter"),
                                 REJECT_INSUFFICIENTFEE, "insufficient priority");
            LogPrint("mempool", "Rate limit dFreeCount: %g => %g\n", dFreeCount, dFreeCount+nSize);
            dFreeCount += nSize;
        }

        if (fRejectInsaneFee && nFees > CTransaction::nMinRelayTxFee * 10000)
            return error("AcceptToMemoryPool: : insane fees %s, %d > %d",
                         hash.ToString(),
                         nFees, CTransaction::nMinRelayTxFee * 10000);

        // Check against previous transactions
        // This is done last to help prevent CPU exhaustion denial-of-service attacks.
        if (!CheckInputs(tx, state, view, true, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC))
        {
            return error("AcceptToMemoryPool: : ConnectInputs failed %s", hash.ToString());
        }
        // Store transaction in memory
        pool.addUnchecked(hash, entry);
    }

    g_signals.SyncTransaction(hash, tx, NULL);

    return true;
}


int CMerkleTx::GetDepthInMainChainINTERNAL(CBlockIndex* &pindexRet) const
{
    if (hashBlock == 0 || nIndex == -1)
        return 0;

    // Find the block it claims to be in
    map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(hashBlock);
    if (mi == mapBlockIndex.end())
        return 0;
    CBlockIndex* pindex = (*mi).second;
    if (!pindex || !chainActive.Contains(pindex))
        return 0;

    // Make sure the merkle branch connects to this block
    if (!fMerkleVerified)
    {
        if (CBlock::CheckMerkleBranch(GetHash(), vMerkleBranch, nIndex) != pindex->hashMerkleRoot)
            return 0;
        fMerkleVerified = true;
    }

    pindexRet = pindex;
    return chainActive.Height() - pindex->nHeight + 1;
}

int CMerkleTx::GetDepthInMainChain(CBlockIndex* &pindexRet) const
{
    int nResult = GetDepthInMainChainINTERNAL(pindexRet);
    if (nResult == 0 && !mempool.exists(GetHash()))
        return -1; // Not in chain, not in mempool

    return nResult;
}

int CMerkleTx::GetHeightInMainChain(CBlockIndex* &pindexRet) const
{
    return chainActive.Height() - GetDepthInMainChain(pindexRet) + 1;
}

int CMerkleTx::GetBlocksToMaturity() const
{
    if (!IsCoinBase())
        return 0;

    int nHeight = GetHeightInMainChain();
    int nMaturity = GetRequiredMaturityDepth(nHeight);

    return max(0, (nMaturity+1) - GetDepthInMainChain());

}


bool CMerkleTx::AcceptToMemoryPool(bool fLimitFree)
{
    CValidationState state;
    return ::AcceptToMemoryPool(mempool, state, *this, fLimitFree, NULL);
}


// 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);
                CBlockHeader header;
                try {
                    file >> header;
                    fseek(file, postx.nTxOffset, SEEK_CUR);
                    file >> txOut;
                } catch (std::exception &e) {
                    return error("%s : Deserialize or I/O error - %s", __PRETTY_FUNCTION__, e.what());
                }
                hashBlock = header.GetHash();
                if (txOut.GetHash() != hash)
                    return error("%s : txid mismatch", __PRETTY_FUNCTION__);
                return true;
            }
        }

        if (fAllowSlow) { // use coin database to locate block that contains transaction, and scan it
            int nHeight = -1;
            {
                CCoinsViewCache &view = *pcoinsTip;
                CCoins coins;
                if (view.GetCoins(hash, 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(CBlock& block, CDiskBlockPos& pos)
{
    // Open history file to append
    CAutoFile fileout = CAutoFile(OpenBlockFile(pos), SER_DISK, CLIENT_VERSION);
    if (!fileout)
        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);
    if (fileOutPos < 0)
        return error("WriteBlockToDisk : ftell failed");
    pos.nPos = (unsigned int)fileOutPos;
    fileout << block;

    // Flush stdio buffers and commit to disk before returning
    fflush(fileout);
    if (!IsInitialBlockDownload())
        FileCommit(fileout);

    return true;
}

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

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

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

    // Check the header
    if (!CheckProofOfWork(block.GetPoWHash(), 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())
        return error("ReadBlockFromDisk(CBlock&, CBlockIndex*) : GetHash() doesn't match index");
    return true;
}

uint256 static GetOrphanRoot(const uint256& hash)
{
    map<uint256, COrphanBlock*>::iterator it = mapOrphanBlocks.find(hash);
    if (it == mapOrphanBlocks.end())
        return hash;

    // Work back to the first block in the orphan chain
    do {
        map<uint256, COrphanBlock*>::iterator it2 = mapOrphanBlocks.find(it->second->hashPrev);
        if (it2 == mapOrphanBlocks.end())
            return it->first;
        it = it2;
    } while(true);
}

// Remove a random orphan block (which does not have any dependent orphans).
void static PruneOrphanBlocks()
{
    if (mapOrphanBlocksByPrev.size() <= MAX_ORPHAN_BLOCKS)
        return;

    // Pick a random orphan block.
    int pos = insecure_rand() % mapOrphanBlocksByPrev.size();
    std::multimap<uint256, COrphanBlock*>::iterator it = mapOrphanBlocksByPrev.begin();
    while (pos--) it++;

    // As long as this block has other orphans depending on it, move to one of those successors.
    do {
        std::multimap<uint256, COrphanBlock*>::iterator it2 = mapOrphanBlocksByPrev.find(it->second->hashBlock);
        if (it2 == mapOrphanBlocksByPrev.end())
            break;
        it = it2;
    } while(1);

    uint256 hash = it->second->hashBlock;
    delete it->second;
    mapOrphanBlocksByPrev.erase(it);
    mapOrphanBlocks.erase(hash);
}

int static generateMTRandom(unsigned int s, int range)
{
    boost::mt19937 gen(s);
    boost::uniform_int<> dist(1, range);
    return dist(gen);
}


int64_t GetBlockValue(int nHeight, int64_t nFees, uint256 prevHash)
{
    //1M coins total. 50000 premine, 40 per block after, etc etc
    int64_t reward = 10 * COIN;
    int adjust=30+1; //30 blocks of zero rewards, to adjust difficulty and ensure fair launch (plus 1 for premine)
    int firstreward=adjust+1*HOUR*DAY; //first day of mining 
    int secondreward=firstreward+(2*HOUR*DAY); //next 13 days of mining
    int thirdreward=secondreward+(3*HOUR*DAY); //next 13 days of mining
    int fourthreward=thirdreward+(1*HOUR*DAY); //last day of "primary mining"
    int finalreward=fourthreward+((HOUR*DAY*300)-40); //final reward phase (after this, nothing)
    int64_t sub=0;
    if(nHeight==1)
    {
        sub=5000*reward; //premine of 50000 coins, 0.5% of cap
    }
    else if(nHeight < adjust)
    {
        sub=0;
    }
    else if(nHeight < firstreward)
    {
        sub=reward*100; //bonus phase of 1000 coins 
    }
    else if(nHeight<secondreward)
    {
        sub=reward*50; //normal first phase of 500 coins
    }
    else if(nHeight<thirdreward)
    {
        sub=reward*25; //normal first phase of 250 coins
    }
    else if(nHeight<fourthreward)
    {
        sub=reward*100; //end primary mining with a bang round of 1000 coins
    }
    else if(nHeight<finalreward)
    {
        sub=reward; //final phase is 10 coin reward
    }
    else
    {
        sub=0; //no coins
    }

    return (sub+nFees); // oops wrong branch

}

// New Difficulty adjustement and reward scheme by /u/lleti, rog1121, and DigiByte (DigiShield Developers).
static const int64_t nTargetTimespan = 60 ; // Freshcoin: every 1 minute
static const int64_t nTargetSpacing = 60; // Freshcoin: 1 minute
static const int64_t nInterval = nTargetTimespan / nTargetSpacing;

//
// minimum amount of work that could possibly be required nTime after
// minimum work required was nBase. This is only an estimate!
//
unsigned int ComputeMinWork(unsigned int nBase, int64_t nTime)
{
    const CBigNum &bnLimit = Params().ProofOfWorkLimit();
    // Testnet has min-difficulty blocks
    // after nTargetSpacing*30 time between blocks:
    if (TestNet() && nTime > nTargetSpacing*30)
        return bnLimit.GetCompact();

    CBigNum bnResult;
    bnResult.SetCompact(nBase);
    while (nTime > 0 && bnResult < bnLimit)
    { 
        if(chainActive.Height()+1<10){ //just in case
            bnResult *= 4;
            // ... in best-case exactly 4-times-normal target time
            nTime -= nTargetTimespan*4;
        } else {
            // Maximum 10% adjustment...
            bnResult = (bnResult * 110) / 100;
            // ... in best-case exactly 4-times-normal target time
            nTime -= nTargetTimespan*4;
        }
    }
    if (bnResult > bnLimit)
        bnResult = bnLimit;
    return bnResult.GetCompact();
}

unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlock *pblock)
{
    unsigned int nProofOfWorkLimit = Params().ProofOfWorkLimit().GetCompact();

    int nHeight = pindexLast->nHeight + 1;
    
    int64_t retargetTimespan = nTargetTimespan;
    int64_t retargetSpacing = nTargetSpacing;
    int64_t retargetInterval = nInterval;
    
    retargetInterval = nTargetTimespan / nTargetSpacing;
    retargetTimespan = nTargetTimespan;
    
    // Genesis block
    if (pindexLast == NULL)
        return nProofOfWorkLimit;

    // Only change once per interval
    if ((pindexLast->nHeight+1) % retargetInterval != 0)
    {
        if (TestNet())
        {
            // Special difficulty rule for testnet:
            // If the new block's timestamp is more than 2* nTargetSpacing minutes
            // then allow mining of a min-difficulty block.
            if (pblock->nTime > pindexLast->nTime + nTargetSpacing*30)
                return nProofOfWorkLimit;
            else
            {
                // Return the last non-special-min-difficulty-rules-block
                const CBlockIndex* pindex = pindexLast;
                while (pindex->pprev && pindex->nHeight % retargetInterval != 0 && pindex->nBits == nProofOfWorkLimit)
                    pindex = pindex->pprev;
                return pindex->nBits;
            }
        }
        return pindexLast->nBits;
    }

    // Freshcoin: This fixes an issue where a 51% attack can change difficulty at will.
    // Go back the full period unless it's the first retarget after genesis. Code courtesy of Art Forz
    int blockstogoback = retargetInterval-1;
    if ((pindexLast->nHeight+1) != retargetInterval)
        blockstogoback = retargetInterval;

    // Go back by what we want to be 14 days worth of blocks
    const CBlockIndex* pindexFirst = pindexLast;
    for (int i = 0; pindexFirst && i < blockstogoback; i++)
        pindexFirst = pindexFirst->pprev;
    assert(pindexFirst);

    // Limit adjustment step
    int64_t nActualTimespan = pindexLast->GetBlockTime() - pindexFirst->GetBlockTime();
    LogPrintf("  nActualTimespan = %d  before bounds\n", nActualTimespan);
    
    //DigiShield implementation - thanks to RealSolid & WDC for this code
    // amplitude filter - thanks to daft27 for this code
    nActualTimespan = retargetTimespan + (nActualTimespan - retargetTimespan)/8;

    if (nActualTimespan < (retargetTimespan - (retargetTimespan/4)) ) nActualTimespan = (retargetTimespan - (retargetTimespan/4));
    if (nActualTimespan > (retargetTimespan + (retargetTimespan/2)) ) nActualTimespan = (retargetTimespan + (retargetTimespan/2));


    //freshcoin slingshield modification:
    /*intentions:
    This will make it so that blocks with many coins spent will be harder to solve.
    This serves two purposes:
    1. It's pretty much certain that when the block reward goes up significantly from percentage transaction fees, multipools will hop on
       This makes it so that when the reward is higher, the difficulty is automatically a bit higher, ensuring multipools can't instamine the high value block
    2. This increases overall network security, given the certainty that multipools won't always be mining this. 
       If trying to do a signficant double spend, you'd have to spend the coins on both sides of the double-spend fork attempt. 
       To comply with network rules, both sides would therefore be of higher difficulty(up to 20% higher). This is not a problem
       for the legitimate fork though, because when the big spend and it's fees are seen, multipools would hop on.
       This effectively makes it so that a significant network attack would require a 71% hashrate, rather than just 51%
       Given that multipools will always mine big transaction blocks, that is. 

       This effectively makes mining big fees slightly less profitable. So, when fees increase by 2%, difficulty of the block increases by 1%, 3% is 2%, etc. 
       It's possible you could make a transaction with only mining fees to circumvent this, but this block would be less difficult, and as such, 
       if the block containing your spend was mined, it would replace your weaker block. So, this makes 1 confirmation transactions significantly safer.
    */
    int64_t adjust=0;
    if(pindexLast->nHeight > (HOUR*DAY*7)) //don't activate til rewards drop
    {
        const static int64_t stepcount=12;
        //min fees: 0.1, 0.2, etc etc corresponding to 1% increase, 2% increase etc
        const static int64_t steps[stepcount]={100*COIN,200*COIN,300*COIN,400*COIN,500*COIN,600*COIN,700*COIN,800*COIN,900*COIN,1000*COIN,1100*COIN,2100*COIN};
        //difficulty increase in milliseconds. Corresponds to 0.5% increase, 1%, 2%, etc
        const static int64_t adjusts[stepcount]={300,600,1200,1800,2400,3000,3600,4200,4800,5400,6000,12000};
        int64_t sum=0;
        BOOST_FOREACH(const CTransaction &tx, pblock->vtx)
        {
            sum+=tx.GetValueOut();
        }
        for(int i=0;i<stepcount;i++)
        {
            if(sum>steps[i])
            {
                adjust=adjusts[i];
            }else
            {
                break;
            }
        }
    }

    // Retarget
    CBigNum bnNew;
    bnNew.SetCompact(pindexLast->nBits);
    //scale up for millisecond granularity
    int64_t scale=1000;
    bnNew *= nActualTimespan*scale;
    //slingshield effectively works by making the target block time longer temporarily
    bnNew /= (retargetTimespan*scale)+adjust; 



    if (bnNew > Params().ProofOfWorkLimit())
        bnNew = Params().ProofOfWorkLimit();

    /// debug print
    LogPrintf("GetNextWorkRequired RETARGET\n");
    LogPrintf("nTargetTimespan = %d    nActualTimespan = %d\n", retargetTimespan, nActualTimespan);
    LogPrintf("Before: %08x  %s\n", pindexLast->nBits, CBigNum().SetCompact(pindexLast->nBits).getuint256().ToString());
    LogPrintf("After:  %08x  %s\n", bnNew.GetCompact(), bnNew.getuint256().ToString());

    return bnNew.GetCompact();
}

bool CheckProofOfWork(uint256 hash, unsigned int nBits)
{
    CBigNum bnTarget;
    bnTarget.SetCompact(nBits);

    // Check range
    if (bnTarget <= 0 || bnTarget > Params().ProofOfWorkLimit())
        return error("CheckProofOfWork() : nBits below minimum work");

    // Check proof of work matches claimed amount
    if (hash > bnTarget.getuint256())
        return error("CheckProofOfWork() : hash doesn't match nBits");

    return true;
}

// Return maximum amount of blocks that other nodes claim to have
int GetNumBlocksOfPeers()
{
    return std::max(cPeerBlockCounts.median(), Checkpoints::GetTotalBlocksEstimate());
}

bool IsInitialBlockDownload()
{
    if (fImporting || fReindex || chainActive.Height() < Checkpoints::GetTotalBlocksEstimate())
        return true;
    static int64_t nLastUpdate;
    static CBlockIndex* pindexLastBest;
    if (chainActive.Tip() != pindexLastBest)
    {
        pindexLastBest = chainActive.Tip();
        nLastUpdate = GetTime();
    }
    return (GetTime() - nLastUpdate < 10 &&
            chainActive.Tip()->GetBlockTime() < GetTime() - DAY_SEC);
}

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

void CheckForkWarningConditions()
{
    // 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 + (chainActive.Tip()->GetBlockWork() * 6).getuint256()))
    {
        if (!fLargeWorkForkFound)
        {
            std::string strCmd = GetArg("-alertnotify", "");
            if (!strCmd.empty())
            {
                std::string warning = std::string("'Warning: Large-work fork detected, forking after block ") +
                                      pindexBestForkBase->phashBlock->ToString() + std::string("'");
                boost::replace_all(strCmd, "%s", warning);
                boost::thread t(runCommand, strCmd); // thread runs free
            }
        }
        if (pindexBestForkTip)
        {
            LogPrintf("CheckForkWarningConditions: 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",
                   pindexBestForkBase->nHeight, pindexBestForkBase->phashBlock->ToString(),
                   pindexBestForkTip->nHeight, pindexBestForkTip->phashBlock->ToString());
            fLargeWorkForkFound = true;
        }
        else
        {
            LogPrintf("CheckForkWarningConditions: Warning: Found invalid chain at least ~6 blocks longer than our best chain.\nChain state database corruption likely.\n");
            fLargeWorkInvalidChainFound = true;
        }
    }
    else
    {
        fLargeWorkForkFound = false;
        fLargeWorkInvalidChainFound = false;
    }
}

void CheckForkWarningConditionsOnNewFork(CBlockIndex* pindexNewForkTip)
{
    // 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 (+/- 12 hours if no one mines it) of ours
    // We use 7 blocks rather arbitrarily as it represents just under 10% of sustained network
    // hash rate operating on the fork.
    // or a chain that is entirely longer than ours and invalid (note that this should be detected by both)
    // 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 > (pfork->GetBlockWork() * 7).getuint256() &&
            chainActive.Height() - pindexNewForkTip->nHeight < 72)
    {
        pindexBestForkTip = pindexNewForkTip;
        pindexBestForkBase = pfork;
    }

    CheckForkWarningConditions();
}

void Misbehaving(NodeId pnode, int howmuch)
{
    if (howmuch == 0)
        return;

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

    state->nMisbehavior += howmuch;
    if (state->nMisbehavior >= GetArg("-banscore", 100))
    {
        LogPrintf("Misbehaving: %s (%d -> %d) BAN THRESHOLD EXCEEDED\n", state->name, state->nMisbehavior-howmuch, state->nMisbehavior);
        state->fShouldBan = true;
    } else
        LogPrintf("Misbehaving: %s (%d -> %d)\n", state->name, state->nMisbehavior-howmuch, state->nMisbehavior);
}

void static InvalidChainFound(CBlockIndex* pindexNew)
{
    if (!pindexBestInvalid || pindexNew->nChainWork > pindexBestInvalid->nChainWork)
    {
        pindexBestInvalid = pindexNew;
        // The current code doesn't actually read the BestInvalidWork entry in
        // the block database anymore, as it is derived from the flags in block
        // index entry. We only write it for backward compatibility.
        pblocktree->WriteBestInvalidWork(CBigNum(pindexBestInvalid->nChainWork));
        uiInterface.NotifyBlocksChanged();
    }
    LogPrintf("InvalidChainFound: invalid block=%s  height=%d  log2_work=%.8g  date=%s\n",
      pindexNew->GetBlockHash().ToString(), pindexNew->nHeight,
      log(pindexNew->nChainWork.getdouble())/log(2.0), DateTimeStrFormat("%Y-%m-%d %H:%M:%S",
      pindexNew->GetBlockTime()));
    LogPrintf("InvalidChainFound:  current best=%s  height=%d  log2_work=%.8g  date=%s\n",
      chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(), log(chainActive.Tip()->nChainWork.getdouble())/log(2.0),
      DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.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(), pindex->GetBlockHash()};
            State(it->second)->rejects.push_back(reject);
            if (nDoS > 0)
                Misbehaving(it->second, nDoS);
        }
    }
    if (!state.CorruptionPossible()) {
        pindex->nStatus |= BLOCK_FAILED_VALID;
        pblocktree->WriteBlockIndex(CDiskBlockIndex(pindex));
        setBlockIndexValid.erase(pindex);
        InvalidChainFound(pindex);
    }
}

void UpdateTime(CBlock& block, const CBlockIndex* pindexPrev)
{
    block.nTime = max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());

    // Updating time can change work required on testnet:
    if (TestNet())
        block.nBits = GetNextWorkRequired(pindexPrev, &block);
}











void UpdateCoins(const CTransaction& tx, CValidationState &state, CCoinsViewCache &inputs, CTxUndo &txundo, int nHeight, const uint256 &txhash)
{
    bool ret;
    // mark inputs spent
    if (!tx.IsCoinBase()) {
        BOOST_FOREACH(const CTxIn &txin, tx.vin) {
            CCoins &coins = inputs.GetCoins(txin.prevout.hash);
            CTxInUndo undo;
            ret = coins.Spend(txin.prevout, undo);
            assert(ret);
            txundo.vprevout.push_back(undo);
        }
    }

    // add outputs
    ret = inputs.SetCoins(txhash, CCoins(tx, nHeight));
    assert(ret);
}

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

bool VerifySignature(const CCoins& txFrom, const CTransaction& txTo, unsigned int nIn, unsigned int flags, int nHashType)
{
    return CScriptCheck(txFrom, txTo, nIn, flags, nHashType)();
}

int GetRequiredMaturityDepth(int nHeight)
{
    return COINBASE_MATURITY;
}

bool CheckInputs(const CTransaction& tx, CValidationState &state, CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, 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.
        CBlockIndex *pindexPrev = mapBlockIndex.find(inputs.GetBestBlock())->second;
        int nSpendHeight = pindexPrev->nHeight + 1;
        int64_t nValueIn = 0;
        int64_t nFees = 0;
        for (unsigned int i = 0; i < tx.vin.size(); i++)
        {
            const COutPoint &prevout = tx.vin[i].prevout;
            const CCoins &coins = inputs.GetCoins(prevout.hash);

            // If prev is coinbase, check that it's matured
            if (coins.IsCoinBase()) {

                int minDepth = GetRequiredMaturityDepth(coins.nHeight);

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

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

        // Tally transaction fees
        int64_t 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.GetCoins(prevout.hash);

                // Verify signature
                CScriptCheck check(coins, tx, i, flags, 0);
                if (pvChecks) {
                    pvChecks->push_back(CScriptCheck());
                    check.swap(pvChecks->back());
                } else if (!check()) {
                    if (flags & SCRIPT_VERIFY_STRICTENC) {
                        // For now, check whether the failure was caused by non-canonical
                        // encodings or not; if so, don't trigger DoS protection.
                        CScriptCheck check(coins, tx, i, flags & (~SCRIPT_VERIFY_STRICTENC), 0);
                        if (check())
                            return state.Invalid(false, REJECT_NONSTANDARD, "non-canonical");
                    }
                    return state.DoS(100,false, REJECT_NONSTANDARD, "non-canonical");
                }
            }
        }
    }

    return true;
}



bool DisconnectBlock(CBlock& block, CValidationState& state, 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 (!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;
        CCoins &outs = view.HaveCoins(hash) ? view.GetCoins(hash) : outsEmpty;
        outs.ClearUnspendable();

        CCoins outsBlock = CCoins(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 = CCoins();

        // 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];
                CCoins coins;
                view.GetCoins(out.hash, coins); // this can fail if the prevout was already entirely spent
                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 = CCoins();
                    coins.fCoinBase = undo.fCoinBase;
                    coins.nHeight = undo.nHeight;
                    coins.nVersion = undo.nVersion;
                } 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;
                if (!view.SetCoins(out.hash, coins))
                    return error("DisconnectBlock() : cannot restore coin inputs");
            }
        }
    }

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

    if (pfClean) {
        *pfClean = fClean;
        return true;
    } else {
        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, infoLastBlockFile.nSize);
        FileCommit(fileOld);
        fclose(fileOld);
    }

    fileOld = OpenUndoFile(posOld);
    if (fileOld) {
        if (fFinalize)
            TruncateFile(fileOld, infoLastBlockFile.nUndoSize);
        FileCommit(fileOld);
        fclose(fileOld);
    }
}

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

static CCheckQueue<CScriptCheck> scriptcheckqueue(128);

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

bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, CCoinsViewCache& view, bool fJustCheck)
{
    // Check it again in case a previous version let a bad block in
    if (!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();
    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;
    }

    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 October 1, 2012, 0:00 UTC.
    // Now that the whole chain is irreversibly beyond that time it is applied to all blocks,
    // this prevents exploiting the issue against nodes in their initial block download.
    bool fEnforceBIP30 = true;

    if (fEnforceBIP30) {
        for (unsigned int i = 0; i < block.vtx.size(); i++) {
            uint256 hash = block.GetTxHash(i);
            if (view.HaveCoins(hash) && !view.GetCoins(hash).IsPruned())
                return state.DoS(100, error("ConnectBlock() : tried to overwrite transaction"),
                                 REJECT_INVALID, "bad-txns-BIP30");
        }
    }

    // BIP16 was always active in Freshcoin
    bool fStrictPayToScriptHash = true;

    unsigned int flags = SCRIPT_VERIFY_NOCACHE |
                         (fStrictPayToScriptHash ? SCRIPT_VERIFY_P2SH : SCRIPT_VERIFY_NONE);

    CBlockUndo blockundo;

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

    int64_t nStart = GetTimeMicros();
    int64_t 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());
    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)
            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");

            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)
                    return state.DoS(100, error("ConnectBlock() : too many sigops"),
                                     REJECT_INVALID, "bad-blk-sigops");
            }

            nFees += view.GetValueIn(tx)-tx.GetValueOut();

            std::vector<CScriptCheck> vChecks;
            if (!CheckInputs(tx, state, view, fScriptChecks, flags, nScriptCheckThreads ? &vChecks : NULL))
                return false;
            control.Add(vChecks);
        }

        CTxUndo txundo;
        UpdateCoins(tx, state, view, txundo, pindex->nHeight, block.GetTxHash(i));
        if (!tx.IsCoinBase())
            blockundo.vtxundo.push_back(txundo);

        vPos.push_back(std::make_pair(block.GetTxHash(i), pos));
        pos.nTxOffset += ::GetSerializeSize(tx, SER_DISK, CLIENT_VERSION);
    }
    int64_t nTime = GetTimeMicros() - nStart;
    if (fBenchmark)
        LogPrintf("- Connect %u transactions: %.2fms (%.3fms/tx, %.3fms/txin)\n", (unsigned)block.vtx.size(), 0.001 * nTime, 0.001 * nTime / block.vtx.size(), nInputs <= 1 ? 0 : 0.001 * nTime / (nInputs-1));

    uint256 prevHash = 0;
    if(pindex->pprev)
    {
        prevHash = pindex->pprev->GetBlockHash();
    }
    
    if (block.vtx[0].GetValueOut() > GetBlockValue(pindex->nHeight, nFees, prevHash))
        return state.DoS(100,
                         error("ConnectBlock() : coinbase pays too much (actual=%d vs limit=%d)",
                               block.vtx[0].GetValueOut(), GetBlockValue(pindex->nHeight, nFees, prevHash)),
                         REJECT_INVALID, "bad-cb-amount");

    if (!control.Wait())
        return state.DoS(100, false);
    int64_t nTime2 = GetTimeMicros() - nStart;
    if (fBenchmark)
        LogPrintf("- Verify %u txins: %.2fms (%.3fms/txin)\n", nInputs - 1, 0.001 * nTime2, nInputs <= 1 ? 0 : 0.001 * nTime2 / (nInputs-1));

    if (fJustCheck)
        return true;

    // Write undo information to disk
    if (pindex->GetUndoPos().IsNull() || (pindex->nStatus & BLOCK_VALID_MASK) < 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->nStatus = (pindex->nStatus & ~BLOCK_VALID_MASK) | BLOCK_VALID_SCRIPTS;

        CDiskBlockIndex blockindex(pindex);
        if (!pblocktree->WriteBlockIndex(blockindex))
            return state.Abort(_("Failed to write block index"));
    }

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

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

    // Watch for transactions paying to me
    for (unsigned int i = 0; i < block.vtx.size(); i++)
        g_signals.SyncTransaction(block.GetTxHash(i), block.vtx[i], &block);

    return true;
}

// Update the on-disk chain state.
bool static WriteChainState(CValidationState &state) {
    static int64_t nLastWrite = 0;
    if (!IsInitialBlockDownload() || pcoinsTip->GetCacheSize() > nCoinCacheSize || GetTimeMicros() > nLastWrite + 600*1000000) {
        // Typical CCoins structures on disk are around 100 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(100 * 2 * 2 * pcoinsTip->GetCacheSize()))
            return state.Error("out of disk space");
        FlushBlockFile();
        pblocktree->Sync();
        if (!pcoinsTip->Flush())
            return state.Abort(_("Failed to write to coin database"));
        nLastWrite = GetTimeMicros();
    }
    return true;
}

// Update chainActive and related internal data structures.
void static UpdateTip(CBlockIndex *pindexNew) {
    chainActive.SetTip(pindexNew);

    // Update best block in wallet (so we can detect restored wallets)
    bool fIsInitialDownload = IsInitialBlockDownload();
    if ((chainActive.Height() % 20160) == 0 || (!fIsInitialDownload && (chainActive.Height() % 144) == 0))
        g_signals.SetBestChain(chainActive.GetLocator());

    // New best block
    nTimeBestReceived = GetTime();
    mempool.AddTransactionsUpdated(1);
    LogPrintf("UpdateTip: new best=%s  height=%d  log2_work=%.8g  tx=%lu  date=%s progress=%f\n",
      chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(), log(chainActive.Tip()->nChainWork.getdouble())/log(2.0), (unsigned long)chainActive.Tip()->nChainTx,
      DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()),
      Checkpoints::GuessVerificationProgress(chainActive.Tip()));

    // Check the version of the last 100 blocks to see if we need to upgrade:
    if (!fIsInitialDownload)
    {
        int nUpgraded = 0;
        const CBlockIndex* pindex = chainActive.Tip();
        for (int i = 0; i < 100 && pindex != NULL; i++)
        {
            if (pindex->nVersion > CBlock::CURRENT_VERSION)
                ++nUpgraded;
            pindex = pindex->pprev;
        }
        if (nUpgraded > 0)
            LogPrintf("SetBestChain: %d of last 100 blocks above version %d\n", nUpgraded, (int)CBlock::CURRENT_VERSION);
        if (nUpgraded > 100/2)
            // strMiscWarning is read by GetWarnings(), called by Qt and the JSON-RPC code to warn the user:
            strMiscWarning = _("Warning: This version is obsolete, upgrade required!");
    }
}

// Disconnect chainActive's tip.
bool static DisconnectTip(CValidationState &state) {
    CBlockIndex *pindexDelete = chainActive.Tip();
    assert(pindexDelete);
    mempool.check(pcoinsTip);
    // Read block from disk.
    CBlock block;
    if (!ReadBlockFromDisk(block, pindexDelete))
        return state.Abort(_("Failed to read block"));
    // Apply the block atomically to the chain state.
    int64_t nStart = GetTimeMicros();
    {
        CCoinsViewCache view(*pcoinsTip, true);
        if (!DisconnectBlock(block, state, pindexDelete, view))
            return error("DisconnectTip() : DisconnectBlock %s failed", pindexDelete->GetBlockHash().ToString());
        assert(view.Flush());
    }
    if (fBenchmark)
        LogPrintf("- Disconnect: %.2fms\n", (GetTimeMicros() - nStart) * 0.001);
    // Write the chain state to disk, if necessary.
    if (!WriteChainState(state))
        return false;
    // Resurrect mempool transactions from the disconnected block.
    BOOST_FOREACH(const CTransaction &tx, block.vtx) {
        // ignore validation errors in resurrected transactions
        list<CTransaction> removed;
        CValidationState stateDummy; 
        if (!tx.IsCoinBase())
            if (!AcceptToMemoryPool(mempool, stateDummy, tx, false, NULL))
                mempool.remove(tx, removed, true);
    }
    mempool.check(pcoinsTip);
    // 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.GetHash(), tx, NULL);
    }
    return true;
}

// Connect a new block to chainActive.
bool static ConnectTip(CValidationState &state, CBlockIndex *pindexNew) {
    assert(pindexNew->pprev == chainActive.Tip());
    mempool.check(pcoinsTip);
    // Read block from disk.
    CBlock block;
    if (!ReadBlockFromDisk(block, pindexNew))
        return state.Abort(_("Failed to read block"));
    // Apply the block atomically to the chain state.
    int64_t nStart = GetTimeMicros();
    {
        CCoinsViewCache view(*pcoinsTip, true);
        CInv inv(MSG_BLOCK, pindexNew->GetBlockHash());
        if (!ConnectBlock(block, state, pindexNew, view)) {
            if (state.IsInvalid())
                InvalidBlockFound(pindexNew, state);
            return error("ConnectTip() : ConnectBlock %s failed", pindexNew->GetBlockHash().ToString());
        }
        mapBlockSource.erase(inv.hash);
        assert(view.Flush());
    }
    if (fBenchmark)
        LogPrintf("- Connect: %.2fms\n", (GetTimeMicros() - nStart) * 0.001);
    // Write the chain state to disk, if necessary.
    if (!WriteChainState(state))
        return false;
    // Remove conflicting transactions from the mempool.
    list<CTransaction> txConflicted;
    BOOST_FOREACH(const CTransaction &tx, block.vtx) {
        list<CTransaction> unused;
        mempool.remove(tx, unused);
        mempool.removeConflicts(tx, txConflicted);
    }
    mempool.check(pcoinsTip);
    // Update chainActive & related variables.
    UpdateTip(pindexNew);
    // Tell wallet about transactions that went from mempool
    // to conflicted:
    BOOST_FOREACH(const CTransaction &tx, txConflicted) {
        SyncWithWallets(tx.GetHash(), tx, NULL);
    }
    // ... and about transactions that got confirmed:
    BOOST_FOREACH(const CTransaction &tx, block.vtx) {
        SyncWithWallets(tx.GetHash(), tx, &block);
    }
    return true;
}

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

    // In case the current best is invalid, do not consider it.
    while (chainMostWork.Tip() && (chainMostWork.Tip()->nStatus & BLOCK_FAILED_MASK)) {
        setBlockIndexValid.erase(chainMostWork.Tip());
        chainMostWork.SetTip(chainMostWork.Tip()->pprev);
    }

    do {
        // Find the best candidate header.
        {
            std::set<CBlockIndex*, CBlockIndexWorkComparator>::reverse_iterator it = setBlockIndexValid.rbegin();
            if (it == setBlockIndexValid.rend())
                return;
            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)) {
            if (pindexTest->nStatus & BLOCK_FAILED_MASK) {
                // Candidate has an invalid ancestor, remove entire chain from the set.
                if (pindexBestInvalid == NULL || pindexNew->nChainWork > pindexBestInvalid->nChainWork)
                    pindexBestInvalid = pindexNew;                CBlockIndex *pindexFailed = pindexNew;
                while (pindexTest != pindexFailed) {
                    pindexFailed->nStatus |= BLOCK_FAILED_CHILD;
                    setBlockIndexValid.erase(pindexFailed);
                    pindexFailed = pindexFailed->pprev;
                }
                fInvalidAncestor = true;
                break;
            }
            pindexTest = pindexTest->pprev;
        }
        if (fInvalidAncestor)
            continue;

        break;
    } while(true);

    // Check whether it's actually an improvement.
    if (chainMostWork.Tip() && !CBlockIndexWorkComparator()(chainMostWork.Tip(), pindexNew))
        return;

    // We have a new best.
    chainMostWork.SetTip(pindexNew);
}

// Try to activate to the most-work chain (thereby connecting it).
bool ActivateBestChain(CValidationState &state) {
    CBlockIndex *pindexOldTip = chainActive.Tip();
    bool fComplete = false;
    while (!fComplete) {
        FindMostWorkChain();
        fComplete = true;

        // Check whether we have something to do.
        if (chainMostWork.Tip() == NULL) break;

        // Disconnect active blocks which are no longer in the best chain.
        while (chainActive.Tip() && !chainMostWork.Contains(chainActive.Tip())) {
            if (!DisconnectTip(state))
                return false;
        }

        // Connect new blocks.
        while (!chainActive.Contains(chainMostWork.Tip())) {
            CBlockIndex *pindexConnect = chainMostWork[chainActive.Height() + 1];
            if (!ConnectTip(state, pindexConnect)) {
                if (state.IsInvalid()) {
                    // The block violates a consensus rule.
                    if (!state.CorruptionPossible())
                        InvalidChainFound(chainMostWork.Tip());
                    fComplete = false;
                    state = CValidationState();
                    break;
                } else {
                    // A system error occurred (disk space, database error, ...).
                    return false;
                }
            }
        }
    }

    if (chainActive.Tip() != pindexOldTip) {
        std::string strCmd = GetArg("-blocknotify", "");
        if (!IsInitialBlockDownload() && !strCmd.empty())
        {
            boost::replace_all(strCmd, "%s", chainActive.Tip()->GetBlockHash().GetHex());
            boost::thread t(runCommand, strCmd); // thread runs free
        }
    }

    return true;
}

bool AddToBlockIndex(CBlock& block, CValidationState& state, const CDiskBlockPos& pos)
{
    // Check for duplicate
    uint256 hash = block.GetHash();
    if (mapBlockIndex.count(hash))
        return state.Invalid(error("AddToBlockIndex() : %s already exists", hash.ToString()), 0, "duplicate");

    // Construct new block index object
    CBlockIndex* pindexNew = new CBlockIndex(block);
    {
         LOCK(cs_nBlockSequenceId);
         pindexNew->nSequenceId = nBlockSequenceId++;
    }
    assert(pindexNew);
    mapAlreadyAskedFor.erase(CInv(MSG_BLOCK, hash));
    map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.insert(make_pair(hash, pindexNew)).first;
    pindexNew->phashBlock = &((*mi).first);
    map<uint256, CBlockIndex*>::iterator miPrev = mapBlockIndex.find(block.hashPrevBlock);
    if (miPrev != mapBlockIndex.end())
    {
        pindexNew->pprev = (*miPrev).second;
        pindexNew->nHeight = pindexNew->pprev->nHeight + 1;
    }
    pindexNew->nTx = block.vtx.size();
    pindexNew->nChainWork = (pindexNew->pprev ? pindexNew->pprev->nChainWork : 0) + pindexNew->GetBlockWork().getuint256();
    pindexNew->nChainTx = (pindexNew->pprev ? pindexNew->pprev->nChainTx : 0) + pindexNew->nTx;
    pindexNew->nFile = pos.nFile;
    pindexNew->nDataPos = pos.nPos;
    pindexNew->nUndoPos = 0;
    pindexNew->nStatus = BLOCK_VALID_TRANSACTIONS | BLOCK_HAVE_DATA;
    setBlockIndexValid.insert(pindexNew);

    if (!pblocktree->WriteBlockIndex(CDiskBlockIndex(pindexNew)))
        return state.Abort(_("Failed to write block index"));

    // New best?
    if (!ActivateBestChain(state))
        return false;

    if (pindexNew == chainActive.Tip())
    {
        // Clear fork warning if its no longer applicable
        CheckForkWarningConditions();
        // Notify UI to display prev block's coinbase if it was ours
        static uint256 hashPrevBestCoinBase;
        g_signals.UpdatedTransaction(hashPrevBestCoinBase);
        hashPrevBestCoinBase = block.GetTxHash(0);
    } else
        CheckForkWarningConditionsOnNewFork(pindexNew);

    if (!pblocktree->Flush())
        return state.Abort(_("Failed to sync block index"));

    uiInterface.NotifyBlocksChanged();
    return true;
}


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

    LOCK(cs_LastBlockFile);

    if (fKnown) {
        if (nLastBlockFile != pos.nFile) {
            nLastBlockFile = pos.nFile;
            infoLastBlockFile.SetNull();
            pblocktree->ReadBlockFileInfo(nLastBlockFile, infoLastBlockFile);
            fUpdatedLast = true;
        }
    } else {
        while (infoLastBlockFile.nSize + nAddSize >= MAX_BLOCKFILE_SIZE) {
            LogPrintf("Leaving block file %i: %s\n", nLastBlockFile, infoLastBlockFile.ToString());
            FlushBlockFile(true);
            nLastBlockFile++;
            infoLastBlockFile.SetNull();
            pblocktree->ReadBlockFileInfo(nLastBlockFile, infoLastBlockFile); // check whether data for the new file somehow already exist; can fail just fine
            fUpdatedLast = true;
        }
        pos.nFile = nLastBlockFile;
        pos.nPos = infoLastBlockFile.nSize;
    }

    infoLastBlockFile.nSize += nAddSize;
    infoLastBlockFile.AddBlock(nHeight, nTime);

    if (!fKnown) {
        unsigned int nOldChunks = (pos.nPos + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
        unsigned int nNewChunks = (infoLastBlockFile.nSize + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
        if (nNewChunks > nOldChunks) {
            if (CheckDiskSpace(nNewChunks * BLOCKFILE_CHUNK_SIZE - pos.nPos)) {
                FILE *file = OpenBlockFile(pos);
                if (file) {
                    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");
        }
    }

    if (!pblocktree->WriteBlockFileInfo(nLastBlockFile, infoLastBlockFile))
        return state.Abort(_("Failed to write file info"));
    if (fUpdatedLast)
        pblocktree->WriteLastBlockFile(nLastBlockFile);

    return true;
}

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

    LOCK(cs_LastBlockFile);

    unsigned int nNewSize;
    if (nFile == nLastBlockFile) {
        pos.nPos = infoLastBlockFile.nUndoSize;
        nNewSize = (infoLastBlockFile.nUndoSize += nAddSize);
        if (!pblocktree->WriteBlockFileInfo(nLastBlockFile, infoLastBlockFile))
            return state.Abort(_("Failed to write block info"));
    } else {
        CBlockFileInfo info;
        if (!pblocktree->ReadBlockFileInfo(nFile, info))
            return state.Abort(_("Failed to read block info"));
        pos.nPos = info.nUndoSize;
        nNewSize = (info.nUndoSize += nAddSize);
        if (!pblocktree->WriteBlockFileInfo(nFile, info))
            return state.Abort(_("Failed to write block info"));
    }

    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) {
                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 CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW, bool fCheckMerkleRoot)
{
    // These are checks that are independent of context
    // that can be verified before saving an orphan block.

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

    // Check proof of work matches claimed amount
    if (fCheckPOW && !CheckProofOfWork(block.GetPoWHash(), block.nBits))
        return state.DoS(50, error("CheckBlock() : proof of work failed"),
                         REJECT_INVALID, "high-hash");

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

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

    // Build the merkle tree already. We need it anyway later, and it makes the
    // block cache the transaction hashes, which means they don't need to be
    // recalculated many times during this block's validation.
    block.BuildMerkleTree();

    // Check for duplicate txids. This is caught by ConnectInputs(),
    // but catching it earlier avoids a potential DoS attack:
    set<uint256> uniqueTx;
    for (unsigned int i = 0; i < block.vtx.size(); i++) {
        uniqueTx.insert(block.GetTxHash(i));
    }
    if (uniqueTx.size() != block.vtx.size())
        return state.DoS(100, error("CheckBlock() : duplicate transaction"),
                         REJECT_INVALID, "bad-txns-duplicate", true);

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

    // Check merkle root
    if (fCheckMerkleRoot && block.hashMerkleRoot != block.vMerkleTree.back())
        return state.DoS(100, error("CheckBlock() : hashMerkleRoot mismatch"),
                         REJECT_INVALID, "bad-txnmrklroot", true);

    return true;
}

bool AcceptBlock(CBlock& block, CValidationState& state, CDiskBlockPos* dbp)
{
    // Check for duplicate
    uint256 hash = block.GetHash();
    if (mapBlockIndex.count(hash))
        return state.Invalid(error("AcceptBlock() : block already in mapBlockIndex"), 0, "duplicate");

    // Get prev block index
    CBlockIndex* pindexPrev = NULL;
    int nHeight = 0;
    if (hash != Params().HashGenesisBlock()) {
        map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(block.hashPrevBlock);
        if (mi == mapBlockIndex.end())
            return state.DoS(10, error("AcceptBlock() : prev block not found"), 0, "bad-prevblk");
        pindexPrev = (*mi).second;
        nHeight = pindexPrev->nHeight+1;

        // Check proof of work
        if (block.nBits != GetNextWorkRequired(pindexPrev, &block))
            return state.DoS(100, error("AcceptBlock() : incorrect proof of work"),
                             REJECT_INVALID, "bad-diffbits");

        // Check timestamp against prev
        if (block.GetBlockTime() <= pindexPrev->GetMedianTimePast())
            return state.Invalid(error("AcceptBlock() : block's timestamp is too early"),
                                 REJECT_INVALID, "time-too-old");

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

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

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

        // Reject block.nVersion=1 blocks when 95% (75% on testnet) of the network has upgraded:
        if (block.nVersion < 2)
        {
            if ((!TestNet() && CBlockIndex::IsSuperMajority(2, pindexPrev, 950, 1000)) ||
                (TestNet() && CBlockIndex::IsSuperMajority(2, pindexPrev, 75, 100)))
            {
                return state.Invalid(error("AcceptBlock() : rejected nVersion=1 block"),
                                     REJECT_OBSOLETE, "bad-version");
            }
        }
        // Enforce block.nVersion=2 rule that the coinbase starts with serialized block height
        if (block.nVersion >= 2)
        {
            // if 750 of the last 1,000 blocks are version 2 or greater (51/100 if testnet):
            if ((!TestNet() && CBlockIndex::IsSuperMajority(2, pindexPrev, 750, 1000)) ||
                (TestNet() && CBlockIndex::IsSuperMajority(2, pindexPrev, 51, 100)))
            {
                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("AcceptBlock() : block height mismatch in coinbase"),
                                     REJECT_INVALID, "bad-cb-height");
            }
        }
    }

    // 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.nTime, dbp != NULL))
            return error("AcceptBlock() : FindBlockPos failed");
        if (dbp == NULL)
            if (!WriteBlockToDisk(block, blockPos))
                return state.Abort(_("Failed to write block"));
        if (!AddToBlockIndex(block, state, blockPos))
            return error("AcceptBlock() : AddToBlockIndex failed");
    } catch(std::runtime_error &e) {
        return state.Abort(_("System error: ") + e.what());
    }

    // Relay inventory, but don't relay old inventory during initial block download
    int nBlockEstimate = Checkpoints::GetTotalBlocksEstimate();
    if (chainActive.Tip()->GetBlockHash() == hash)
    {
        LOCK(cs_vNodes);
        BOOST_FOREACH(CNode* pnode, vNodes)
            if (chainActive.Height() > (pnode->nStartingHeight != -1 ? pnode->nStartingHeight - 2000 : nBlockEstimate))
                pnode->PushInventory(CInv(MSG_BLOCK, hash));
    }

    return true;
}

bool CBlockIndex::IsSuperMajority(int minVersion, const CBlockIndex* pstart, unsigned int nRequired, unsigned int nToCheck)
{
    // Freshcoin: temporarily disable v2 block lockin until we are ready for v2 transition
    return false;

    unsigned int nFound = 0;
    for (unsigned int i = 0; i < nToCheck && nFound < nRequired && pstart != NULL; i++)
    {
        if (pstart->nVersion >= minVersion)
            ++nFound;
        pstart = pstart->pprev;
    }
    return (nFound >= nRequired);
}

int64_t CBlockIndex::GetMedianTime() const
{
    const CBlockIndex* pindex = this;
    for (int i = 0; i < nMedianTimeSpan/2; i++)
    {
        if (!chainActive.Next(pindex))
            return GetBlockTime();
        pindex = chainActive.Next(pindex);
    }
    return pindex->GetMedianTimePast();
}

void PushGetBlocks(CNode* pnode, CBlockIndex* pindexBegin, uint256 hashEnd)
{
    // Filter out duplicate requests
    if (pindexBegin == pnode->pindexLastGetBlocksBegin && hashEnd == pnode->hashLastGetBlocksEnd)
        return;
    pnode->pindexLastGetBlocksBegin = pindexBegin;
    pnode->hashLastGetBlocksEnd = hashEnd;

    pnode->PushMessage("getblocks", chainActive.GetLocator(pindexBegin), hashEnd);
}

bool ProcessBlock(CValidationState &state, CNode* pfrom, CBlock* pblock, CDiskBlockPos *dbp)
{
    AssertLockHeld(cs_main);

    // Check for duplicate
    uint256 hash = pblock->GetHash();
    if (mapBlockIndex.count(hash))
        return state.Invalid(error("ProcessBlock() : already have block %d %s", mapBlockIndex[hash]->nHeight, hash.ToString()), 0, "duplicate");
    if (mapOrphanBlocks.count(hash))
        return state.Invalid(error("ProcessBlock() : already have block (orphan) %s", hash.ToString()), 0, "duplicate");

    // Preliminary checks
    if (!CheckBlock(*pblock, state)) {
        if (state.CorruptionPossible())
            mapAlreadyAskedFor.erase(CInv(MSG_BLOCK, hash));
        return error("ProcessBlock() : CheckBlock FAILED");
    }

    CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint(mapBlockIndex);
    if (pcheckpoint && pblock->hashPrevBlock != (chainActive.Tip() ? chainActive.Tip()->GetBlockHash() : uint256(0)))
    {
        // Extra checks to prevent "fill up memory by spamming with bogus blocks"
        int64_t deltaTime = pblock->GetBlockTime() - pcheckpoint->nTime;
        if (deltaTime < 0)
        {
            return state.DoS(100, error("ProcessBlock() : block with timestamp before last checkpoint"),
                             REJECT_CHECKPOINT, "time-too-old");
        }
        CBigNum bnNewBlock;
        bnNewBlock.SetCompact(pblock->nBits);
        CBigNum bnRequired;
        bnRequired.SetCompact(ComputeMinWork(pcheckpoint->nBits, deltaTime));
        if (bnNewBlock > bnRequired)
        {
            return state.DoS(100, error("ProcessBlock() : block with too little proof-of-work"),
                             REJECT_INVALID, "bad-diffbits");
        }
    }


    // If we don't already have its previous block, shunt it off to holding area until we get it
    if (pblock->hashPrevBlock != 0 && !mapBlockIndex.count(pblock->hashPrevBlock))
    {
        LogPrintf("ProcessBlock: ORPHAN BLOCK %lu, prev=%s\n", (unsigned long)mapOrphanBlocks.size(), pblock->hashPrevBlock.ToString());

        // Accept orphans as long as there is a node to request its parents from
        if (pfrom) {
            PruneOrphanBlocks();
            COrphanBlock* pblock2 = new COrphanBlock();
            {
                CDataStream ss(SER_DISK, CLIENT_VERSION);
                ss << *pblock;
                pblock2->vchBlock = std::vector<unsigned char>(ss.begin(), ss.end());
            }
            pblock2->hashBlock = hash;
            pblock2->hashPrev = pblock->hashPrevBlock;
            mapOrphanBlocks.insert(make_pair(hash, pblock2));
            mapOrphanBlocksByPrev.insert(make_pair(pblock2->hashPrev, pblock2));

            // Ask this guy to fill in what we're missing
            PushGetBlocks(pfrom, chainActive.Tip(), GetOrphanRoot(hash));
        }
        return true;
    }

    // Store to disk
    if (!AcceptBlock(*pblock, state, dbp))
        return error("ProcessBlock() : AcceptBlock FAILED");

    // Recursively process any orphan blocks that depended on this one
    vector<uint256> vWorkQueue;
    vWorkQueue.push_back(hash);
    for (unsigned int i = 0; i < vWorkQueue.size(); i++)
    {
        uint256 hashPrev = vWorkQueue[i];
        for (multimap<uint256, COrphanBlock*>::iterator mi = mapOrphanBlocksByPrev.lower_bound(hashPrev);
             mi != mapOrphanBlocksByPrev.upper_bound(hashPrev);
             ++mi)
        {
            CBlock block;
            {
                CDataStream ss(mi->second->vchBlock, SER_DISK, CLIENT_VERSION);
                ss >> block;
            }
            block.BuildMerkleTree();
            // Use a dummy CValidationState so someone can't setup nodes to counter-DoS based on orphan resolution (that is, feeding people an invalid block based on LegitBlockX in order to get anyone relaying LegitBlockX banned)
            CValidationState stateDummy;
            if (AcceptBlock(block, stateDummy))
                vWorkQueue.push_back(mi->second->hashBlock);
            mapOrphanBlocks.erase(mi->second->hashBlock);
            delete mi->second;
        }
        mapOrphanBlocksByPrev.erase(hashPrev);
    }

    LogPrintf("ProcessBlock: ACCEPTED\n");
    return true;
}








CMerkleBlock::CMerkleBlock(const CBlock& block, CBloomFilter& filter)
{
    header = block.GetBlockHeader();

    vector<bool> vMatch;
    vector<uint256> vHashes;

    vMatch.reserve(block.vtx.size());
    vHashes.reserve(block.vtx.size());

    for (unsigned int i = 0; i < block.vtx.size(); i++)
    {
        uint256 hash = block.vtx[i].GetHash();
        if (filter.IsRelevantAndUpdate(block.vtx[i], hash))
        {
            vMatch.push_back(true);
            vMatchedTxn.push_back(make_pair(i, hash));
        }
        else
            vMatch.push_back(false);
        vHashes.push_back(hash);
    }

    txn = CPartialMerkleTree(vHashes, vMatch);
}








uint256 CPartialMerkleTree::CalcHash(int height, unsigned int pos, const std::vector<uint256> &vTxid) {
    if (height == 0) {
        // hash at height 0 is the txids themself
        return vTxid[pos];
    } else {
        // calculate left hash
        uint256 left = CalcHash(height-1, pos*2, vTxid), right;
        // calculate right hash if not beyong the end of the array - copy left hash otherwise1
        if (pos*2+1 < CalcTreeWidth(height-1))
            right = CalcHash(height-1, pos*2+1, vTxid);
        else
            right = left;
        // combine subhashes
        return Hash(BEGIN(left), END(left), BEGIN(right), END(right));
    }
}

void CPartialMerkleTree::TraverseAndBuild(int height, unsigned int pos, const std::vector<uint256> &vTxid, const std::vector<bool> &vMatch) {
    // determine whether this node is the parent of at least one matched txid
    bool fParentOfMatch = false;
    for (unsigned int p = pos << height; p < (pos+1) << height && p < nTransactions; p++)
        fParentOfMatch |= vMatch[p];
    // store as flag bit
    vBits.push_back(fParentOfMatch);
    if (height==0 || !fParentOfMatch) {
        // if at height 0, or nothing interesting below, store hash and stop
        vHash.push_back(CalcHash(height, pos, vTxid));
    } else {
        // otherwise, don't store any hash, but descend into the subtrees
        TraverseAndBuild(height-1, pos*2, vTxid, vMatch);
        if (pos*2+1 < CalcTreeWidth(height-1))
            TraverseAndBuild(height-1, pos*2+1, vTxid, vMatch);
    }
}

uint256 CPartialMerkleTree::TraverseAndExtract(int height, unsigned int pos, unsigned int &nBitsUsed, unsigned int &nHashUsed, std::vector<uint256> &vMatch) {
    if (nBitsUsed >= vBits.size()) {
        // overflowed the bits array - failure
        fBad = true;
        return 0;
    }
    bool fParentOfMatch = vBits[nBitsUsed++];
    if (height==0 || !fParentOfMatch) {
        // if at height 0, or nothing interesting below, use stored hash and do not descend
        if (nHashUsed >= vHash.size()) {
            // overflowed the hash array - failure
            fBad = true;
            return 0;
        }
        const uint256 &hash = vHash[nHashUsed++];
        if (height==0 && fParentOfMatch) // in case of height 0, we have a matched txid
            vMatch.push_back(hash);
        return hash;
    } else {
        // otherwise, descend into the subtrees to extract matched txids and hashes
        uint256 left = TraverseAndExtract(height-1, pos*2, nBitsUsed, nHashUsed, vMatch), right;
        if (pos*2+1 < CalcTreeWidth(height-1))
            right = TraverseAndExtract(height-1, pos*2+1, nBitsUsed, nHashUsed, vMatch);
        else
            right = left;
        // and combine them before returning
        return Hash(BEGIN(left), END(left), BEGIN(right), END(right));
    }
}

CPartialMerkleTree::CPartialMerkleTree(const std::vector<uint256> &vTxid, const std::vector<bool> &vMatch) : nTransactions(vTxid.size()), fBad(false) {
    // reset state
    vBits.clear();
    vHash.clear();

    // calculate height of tree
    int nHeight = 0;
    while (CalcTreeWidth(nHeight) > 1)
        nHeight++;

    // traverse the partial tree
    TraverseAndBuild(nHeight, 0, vTxid, vMatch);
}

CPartialMerkleTree::CPartialMerkleTree() : nTransactions(0), fBad(true) {}

uint256 CPartialMerkleTree::ExtractMatches(std::vector<uint256> &vMatch) {
    vMatch.clear();
    // An empty set will not work
    if (nTransactions == 0)
        return 0;
    // check for excessively high numbers of transactions
    if (nTransactions > MAX_BLOCK_SIZE / 60) // 60 is the lower bound for the size of a serialized CTransaction
        return 0;
    // there can never be more hashes provided than one for every txid
    if (vHash.size() > nTransactions)
        return 0;
    // there must be at least one bit per node in the partial tree, and at least one node per hash
    if (vBits.size() < vHash.size())
        return 0;
    // calculate height of tree
    int nHeight = 0;
    while (CalcTreeWidth(nHeight) > 1)
        nHeight++;
    // traverse the partial tree
    unsigned int nBitsUsed = 0, nHashUsed = 0;
    uint256 hashMerkleRoot = TraverseAndExtract(nHeight, 0, nBitsUsed, nHashUsed, vMatch);
    // verify that no problems occured during the tree traversal
    if (fBad)
        return 0;
    // verify that all bits were consumed (except for the padding caused by serializing it as a byte sequence)
    if ((nBitsUsed+7)/8 != (vBits.size()+7)/8)
        return 0;
    // verify that all hashes were consumed
    if (nHashUsed != vHash.size())
        return 0;
    return hashMerkleRoot;
}







bool AbortNode(const std::string &strMessage) {
    strMiscWarning = strMessage;
    LogPrintf("*** %s\n", strMessage);
    uiInterface.ThreadSafeMessageBox(strMessage, "", CClientUIInterface::MSG_ERROR);
    StartShutdown();
    return false;
}

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

    // Check for nMinDiskSpace bytes (currently 50MB)
    if (nFreeBytesAvailable < nMinDiskSpace + nAdditionalBytes)
        return AbortNode(_("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 = GetDataDir() / "blocks" / strprintf("%s%05u.dat", prefix, pos.nFile);
    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) {
        LogPrintf("Unable to open file %s\n", path.string());
        return NULL;
    }
    if (pos.nPos) {
        if (fseek(file, pos.nPos, SEEK_SET)) {
            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);
}

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

    // Return existing
    map<uint256, CBlockIndex*>::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) + pindex->GetBlockWork().getuint256();
        pindex->nChainTx = (pindex->pprev ? pindex->pprev->nChainTx : 0) + pindex->nTx;
        if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TRANSACTIONS && !(pindex->nStatus & BLOCK_FAILED_MASK))
            setBlockIndexValid.insert(pindex);
        if (pindex->nStatus & BLOCK_FAILED_MASK && (!pindexBestInvalid || pindex->nChainWork > pindexBestInvalid->nChainWork))
            pindexBestInvalid = pindex;
    }

    // Load block file info
    pblocktree->ReadLastBlockFile(nLastBlockFile);
    LogPrintf("LoadBlockIndexDB(): last block file = %i\n", nLastBlockFile);
    if (pblocktree->ReadBlockFileInfo(nLastBlockFile, infoLastBlockFile))
        LogPrintf("LoadBlockIndexDB(): last block file info: %s\n", infoLastBlockFile.ToString());

    // 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);
    LogPrintf("LoadBlockIndexDB(): transaction index %s\n", fTxIndex ? "enabled" : "disabled");

    // Load pointer to end of best chain
    std::map<uint256, CBlockIndex*>::iterator it = mapBlockIndex.find(pcoinsTip->GetBestBlock());
    if (it == mapBlockIndex.end())
        return true;
    chainActive.SetTip(it->second);
    LogPrintf("LoadBlockIndexDB(): hashBestChain=%s height=%d date=%s progress=%f\n",
        chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(),
        DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()),
        Checkpoints::GuessVerificationProgress(chainActive.Tip()));

    return true;
}

bool VerifyDB(int nCheckLevel, int nCheckDepth)
{
    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));
    LogPrintf("Verifying last %i blocks at level %i\n", nCheckDepth, nCheckLevel);
    CCoinsViewCache coins(*pcoinsTip, true);
    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();
        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()) <= 2*nCoinCacheSize + 32000) {
            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 (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();
            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))
                return error("VerifyDB() : *** found unconnectable block at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
        }
    }

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

    return true;
}

void UnloadBlockIndex()
{
    mapBlockIndex.clear();
    setBlockIndexValid.clear();
    chainActive.SetTip(NULL);
    pindexBestInvalid = NULL;
}

bool LoadBlockIndex()
{
    // Load block index from databases
    if (!fReindex && !LoadBlockIndexDB())
        return false;
    return true;
}


bool InitBlockIndex() {
    // 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", false);
    pblocktree->WriteFlag("txindex", fTxIndex);
    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.nTime))
                return error("LoadBlockIndex() : FindBlockPos failed");
            if (!WriteBlockToDisk(block, blockPos))
                return error("LoadBlockIndex() : writing genesis block to disk failed");
            if (!AddToBlockIndex(block, state, blockPos))
                return error("LoadBlockIndex() : genesis block not accepted");
        } catch(std::runtime_error &e) {
            return error("LoadBlockIndex() : failed to initialize block database: %s", e.what());
        }
    }

    return true;
}



void PrintBlockTree()
{
    // pre-compute tree structure
    map<CBlockIndex*, vector<CBlockIndex*> > mapNext;
    for (map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.begin(); mi != mapBlockIndex.end(); ++mi)
    {
        CBlockIndex* pindex = (*mi).second;
        mapNext[pindex->pprev].push_back(pindex);
        // test
        //while (rand() % 3 == 0)
        //    mapNext[pindex->pprev].push_back(pindex);
    }

    vector<pair<int, CBlockIndex*> > vStack;
    vStack.push_back(make_pair(0, chainActive.Genesis()));

    int nPrevCol = 0;
    while (!vStack.empty())
    {
        int nCol = vStack.back().first;
        CBlockIndex* pindex = vStack.back().second;
        vStack.pop_back();

        // print split or gap
        if (nCol > nPrevCol)
        {
            for (int i = 0; i < nCol-1; i++)
                LogPrintf("| ");
            LogPrintf("|\\\n");
        }
        else if (nCol < nPrevCol)
        {
            for (int i = 0; i < nCol; i++)
                LogPrintf("| ");
            LogPrintf("|\n");
       }
        nPrevCol = nCol;

        // print columns
        for (int i = 0; i < nCol; i++)
            LogPrintf("| ");

        // print item
        CBlock block;
        ReadBlockFromDisk(block, pindex);
        LogPrintf("%d (blk%05u.dat:0x%x)  %s  tx %" PRIszu"",
            pindex->nHeight,
            pindex->GetBlockPos().nFile, pindex->GetBlockPos().nPos,
            DateTimeStrFormat("%Y-%m-%d %H:%M:%S", block.GetBlockTime()),
            block.vtx.size());

        // put the main time-chain first
        vector<CBlockIndex*>& vNext = mapNext[pindex];
        for (unsigned int i = 0; i < vNext.size(); i++)
        {
            if (chainActive.Next(vNext[i]))
            {
                swap(vNext[0], vNext[i]);
                break;
            }
        }

        // iterate children
        for (unsigned int i = 0; i < vNext.size(); i++)
            vStack.push_back(make_pair(nCol+i, vNext[i]));
    }
}

bool LoadExternalBlockFile(FILE* fileIn, CDiskBlockPos *dbp)
{
    int64_t nStart = GetTimeMillis();

    int nLoaded = 0;
    try {
        CBufferedFile blkdat(fileIn, 2*MAX_BLOCK_SIZE, MAX_BLOCK_SIZE+8, SER_DISK, CLIENT_VERSION);
        uint64_t nStartByte = 0;
        if (dbp) {
            // (try to) skip already indexed part
            CBlockFileInfo info;
            if (pblocktree->ReadBlockFileInfo(dbp->nFile, info)) {
                nStartByte = info.nSize;
                blkdat.Seek(info.nSize);
            }
        }
        uint64_t nRewind = blkdat.GetPos();
        while (blkdat.good() && !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[4];
                blkdat.FindByte(Params().MessageStart()[0]);
                nRewind = blkdat.GetPos()+1;
                blkdat >> FLATDATA(buf);
                if (memcmp(buf, Params().MessageStart(), 4))
                    continue;
                // read size
                blkdat >> nSize;
                if (nSize < 80 || nSize > MAX_BLOCK_SIZE)
                    continue;
            } catch (std::exception &e) {
                // no valid block header found; don't complain
                break;
            }
            try {
                // read block
                uint64_t nBlockPos = blkdat.GetPos();
                blkdat.SetLimit(nBlockPos + nSize);
                CBlock block;
                blkdat >> block;
                nRewind = blkdat.GetPos();

                // process block
                if (nBlockPos >= nStartByte) {
                    LOCK(cs_main);
                    if (dbp)
                        dbp->nPos = nBlockPos;
                    CValidationState state;
                    if (ProcessBlock(state, NULL, &block, dbp))
                        nLoaded++;
                    if (state.IsError())
                        break;
                }
            } catch (std::exception &e) {
                LogPrintf("%s : Deserialize or I/O error - %s", __PRETTY_FUNCTION__, e.what());
            }
        }
        fclose(fileIn);
    } catch(std::runtime_error &e) {
        AbortNode(_("Error: system error: ") + e.what());
    }
    if (nLoaded > 0)
        LogPrintf("Loaded %i blocks from external file in %dms\n", nLoaded, GetTimeMillis() - nStart);
    return nLoaded > 0;
}










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

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

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

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

    // 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: Displayed transactions may not be correct! 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:
        {
            bool txInMap = false;
            txInMap = mempool.exists(inv.hash);
            return txInMap || mapOrphanTransactions.count(inv.hash) ||
                pcoinsTip->HaveCoins(inv.hash);
        }
    case MSG_BLOCK:
        return mapBlockIndex.count(inv.hash) ||
               mapOrphanBlocks.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;
                map<uint256, CBlockIndex*>::iterator mi = mapBlockIndex.find(inv.hash);
                if (mi != mapBlockIndex.end())
                {
                    // If the requested block is at a height below our last
                    // checkpoint, only serve it if it's in the checkpointed chain
                    int nHeight = mi->second->nHeight;
                    CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint(mapBlockIndex);
                    if (pcheckpoint && nHeight < pcheckpoint->nHeight) {
                       if (!chainActive.Contains(mi->second))
                       {
                         LogPrintf("ProcessGetData(): ignoring request for old block that isn't in the main chain\n");
                       } else {
                         send = true;
                       }
                    } else {
                      send = true;
                    }
                }
                if (send)
                {
                    // Send block from disk
                    CBlock block;
                    ReadBlockFromDisk(block, (*mi).second);
                    if (inv.type == MSG_BLOCK)
                        pfrom->PushMessage("block", block);
                    else // MSG_FILTERED_BLOCK)
                    {
                        LOCK(pfrom->cs_filter);
                        if (pfrom->pfilter)
                        {
                            CMerkleBlock merkleBlock(block, *pfrom->pfilter);
                            pfrom->PushMessage("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 didnt 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)
                                if (!pfrom->setInventoryKnown.count(CInv(MSG_TX, pair.second)))
                                    pfrom->PushMessage("tx", block.vtx[pair.first]);
                        }
                        // else
                            // no response
                    }

                    // Trigger them 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("inv", vInv);
                        pfrom->hashContinue = 0;
                    }
                }
            }
            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("tx", ss);
                        pushed = true;
                    }
                }
                if (!pushed) {
                    vNotFound.push_back(inv);
                }
            }

            // Track requests for our stuff.
            g_signals.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("notfound", vNotFound);
    }
}

bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
{
    RandAddSeedPerfmon();
    LogPrint("net", "received: %s (%" PRIszu" bytes)\n", strCommand, vRecv.size());
    if (mapArgs.count("-dropmessagestest") && GetRand(atoi(mapArgs["-dropmessagestest"])) == 0)
    {
        LogPrintf("dropmessagestest DROPPING RECV MESSAGE\n");
        return true;
    }





    if (strCommand == "version")
    {
        // Each connection can only send one version message
        if (pfrom->nVersion != 0)
        {
            pfrom->PushMessage("reject", strCommand, REJECT_DUPLICATE, string("Duplicate version message"));
            Misbehaving(pfrom->GetId(), 1);
            return false;
        }

        int64_t nTime;
        CAddress addrMe;
        CAddress addrFrom;
        uint64_t nNonce = 1;
        vRecv >> pfrom->nVersion >> pfrom->nServices >> nTime >> addrMe;
        if (pfrom->nVersion < MIN_PEER_PROTO_VERSION)
        {
            // disconnect from peers older than this proto version
            LogPrintf("partner %s using obsolete version %i; disconnecting\n", pfrom->addr.ToString(), pfrom->nVersion);
            pfrom->PushMessage("reject", strCommand, REJECT_OBSOLETE,
                               strprintf("Version must be %d or greater", MIN_PEER_PROTO_VERSION));
            pfrom->fDisconnect = true;
            return false;
        }

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

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

        // 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;
        }

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

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


        // Change version
        pfrom->PushMessage("verack");
        pfrom->ssSend.SetVersion(min(pfrom->nVersion, PROTOCOL_VERSION));

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

            // Get recent addresses
            if (pfrom->fOneShot || pfrom->nVersion >= CADDR_TIME_VERSION || addrman.size() < 1000)
            {
                pfrom->PushMessage("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;

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

        AddTimeData(pfrom->addr, nTime);

        LOCK(cs_main);
        cPeerBlockCounts.input(pfrom->nStartingHeight);
    }


    else if (pfrom->nVersion == 0)
    {
        // Must have a version message before anything else
        Misbehaving(pfrom->GetId(), 1);
        return false;
    }


    else if (strCommand == "verack")
    {
        pfrom->SetRecvVersion(min(pfrom->nVersion, PROTOCOL_VERSION));
    }


    else if (strCommand == "addr")
    {
        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)
        {
            Misbehaving(pfrom->GetId(), 20);
            return error("message addr size() = %" PRIszu"", vAddr.size());
        }

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

            if (addr.nTime <= 100000000 || addr.nTime > nNow + 10 * MINUTE)
                addr.nTime = nNow - 5 * DAY_SEC;
            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 setAddrKnowns of the chosen nodes prevent repeats
                    static uint256 hashSalt;
                    if (hashSalt == 0)
                        hashSalt = GetRandHash();
                    uint64_t hashAddr = addr.GetHash();
                    uint256 hashRand = hashSalt ^ (hashAddr<<32) ^ ((GetTime()+hashAddr)/DAY_SEC);
                    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 = 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 * MINUTE * HOUR);
        if (vAddr.size() < 1000)
            pfrom->fGetAddr = false;
        if (pfrom->fOneShot)
            pfrom->fDisconnect = true;
    }


    else if (strCommand == "inv")
    {
        vector<CInv> vInv;
        vRecv >> vInv;
        if (vInv.size() > MAX_INV_SZ)
        {
            Misbehaving(pfrom->GetId(), 20);
            return error("message inv size() = %" PRIszu"", vInv.size());
        }

        // find last block in inv vector
        unsigned int nLastBlock = (unsigned int)(-1);
        for (unsigned int nInv = 0; nInv < vInv.size(); nInv++) {
            if (vInv[vInv.size() - 1 - nInv].type == MSG_BLOCK) {
                nLastBlock = vInv.size() - 1 - nInv;
                break;
            }
        }

        LOCK(cs_main);

        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 inventory: %s  %s\n", inv.ToString(), fAlreadyHave ? "have" : "new");

            if (!fAlreadyHave) {
                if (!fImporting && !fReindex)
                    pfrom->AskFor(inv);
            } else if (inv.type == MSG_BLOCK && mapOrphanBlocks.count(inv.hash)) {
                PushGetBlocks(pfrom, chainActive.Tip(), GetOrphanRoot(inv.hash));
            } else if (nInv == nLastBlock) {
                // In case we are on a very long side-chain, it is possible that we already have
                // the last block in an inv bundle sent in response to getblocks. Try to detect
                // this situation and push another getblocks to continue.
                PushGetBlocks(pfrom, mapBlockIndex[inv.hash], uint256(0));
                if (fDebug)
                    LogPrintf("force request: %s\n", inv.ToString());
            }

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


    else if (strCommand == "getdata")
    {
        vector<CInv> vInv;
        vRecv >> vInv;
        if (vInv.size() > MAX_INV_SZ)
        {
            Misbehaving(pfrom->GetId(), 20);
            return error("message getdata size() = %" PRIszu"", vInv.size());
        }

        if (fDebug || (vInv.size() != 1))
            LogPrint("net", "received getdata (%" PRIszu" invsz)\n", vInv.size());

        if ((fDebug && vInv.size() > 0) || (vInv.size() == 1))
            LogPrint("net", "received getdata for: %s\n", vInv[0].ToString());

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


    else if (strCommand == "getblocks")
    {
        CBlockLocator locator;
        uint256 hashStop;
        vRecv >> locator >> hashStop;

        LOCK(cs_main);

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

        // Send the rest of the chain
        if (pindex)
            pindex = chainActive.Next(pindex);
        int nLimit = 500;
        LogPrint("net", "getblocks %d to %s limit %d\n", (pindex ? pindex->nHeight : -1), hashStop.ToString(), nLimit);
        for (; pindex; pindex = chainActive.Next(pindex))
        {
            if (pindex->GetBlockHash() == hashStop)
            {
                LogPrint("net", "  getblocks stopping 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 make them
                // 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;
            }
        }
    }


    else if (strCommand == "getheaders")
    {
        CBlockLocator locator;
        uint256 hashStop;
        vRecv >> locator >> hashStop;

        LOCK(cs_main);

        CBlockIndex* pindex = NULL;
        if (locator.IsNull())
        {
            // If locator is null, return the hashStop block
            map<uint256, CBlockIndex*>::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 = chainActive.FindFork(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 = 2000;
        LogPrint("net", "getheaders %d to %s\n", (pindex ? pindex->nHeight : -1), hashStop.ToString());
        for (; pindex; pindex = chainActive.Next(pindex))
        {
            vHeaders.push_back(pindex->GetBlockHeader());
            if (--nLimit <= 0 || pindex->GetBlockHash() == hashStop)
                break;
        }
        pfrom->PushMessage("headers", vHeaders);
    }


    else if (strCommand == "tx")
    {
        vector<uint256> vWorkQueue;
        vector<uint256> vEraseQueue;
        CTransaction tx;
        vRecv >> tx;

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

        LOCK(cs_main);

        bool fMissingInputs = false;
        CValidationState state;
        if (AcceptToMemoryPool(mempool, state, tx, true, &fMissingInputs))
        {
            mempool.check(pcoinsTip);
            RelayTransaction(tx, inv.hash);
            mapAlreadyAskedFor.erase(inv);
            vWorkQueue.push_back(inv.hash);
            vEraseQueue.push_back(inv.hash);


            LogPrint("mempool", "AcceptToMemoryPool: %s %s : accepted %s (poolsz %" PRIszu")\n",
                pfrom->addr.ToString(), pfrom->cleanSubVer,
                tx.GetHash().ToString(),
                mempool.mapTx.size());

            // Recursively process any orphan transactions that depended on this one
            for (unsigned int i = 0; i < vWorkQueue.size(); i++)
            {
                uint256 hashPrev = vWorkQueue[i];
                for (set<uint256>::iterator mi = mapOrphanTransactionsByPrev[hashPrev].begin();
                     mi != mapOrphanTransactionsByPrev[hashPrev].end();
                     ++mi)
                {
                    const uint256& orphanHash = *mi;
                    const CTransaction& orphanTx = mapOrphanTransactions[orphanHash];
                    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 (AcceptToMemoryPool(mempool, stateDummy, orphanTx, true, &fMissingInputs2))
                    {
                        LogPrint("mempool", "   accepted orphan tx %s\n", orphanHash.ToString());
                        RelayTransaction(orphanTx, orphanHash);
                        mapAlreadyAskedFor.erase(CInv(MSG_TX, orphanHash));
                        vWorkQueue.push_back(orphanHash);
                        vEraseQueue.push_back(orphanHash);
                    }
                    else if (!fMissingInputs2)
                    {
                        // invalid or too-little-fee orphan
                        vEraseQueue.push_back(orphanHash);
                        LogPrint("mempool", "   removed orphan tx %s\n", orphanHash.ToString());
                    }
                    mempool.check(pcoinsTip);
                }
            }

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

            // DoS prevention: do not allow mapOrphanTransactions to grow unbounded
            unsigned int nEvicted = LimitOrphanTxSize(MAX_ORPHAN_TRANSACTIONS);
            if (nEvicted > 0)
                LogPrint("mempool", "mapOrphan overflow, removed %u tx\n", nEvicted);
        }
        int nDoS = 0;
        if (state.IsInvalid(nDoS))
        { 
            LogPrint("mempool", "%s from %s %s was not accepted into the memory pool: %s\n", tx.GetHash().ToString(),
                pfrom->addr.ToString(), pfrom->cleanSubVer,
                state.GetRejectReason());
            pfrom->PushMessage("reject", strCommand, state.GetRejectCode(),
                               state.GetRejectReason(), inv.hash);
            if (nDoS > 0)
                Misbehaving(pfrom->GetId(), nDoS);
        }
    }


    else if (strCommand == "block" && !fImporting && !fReindex) // Ignore blocks received while importing
    {
        CBlock block;
        vRecv >> block;

        LogPrint("net", "received block %s\n", block.GetHash().ToString());
        // block.print();

        CInv inv(MSG_BLOCK, block.GetHash());
        pfrom->AddInventoryKnown(inv);

        LOCK(cs_main);
        // Remember who we got this block from.
        mapBlockSource[inv.hash] = pfrom->GetId();

        CValidationState state;
        ProcessBlock(state, pfrom, &block);
    }


    else if (strCommand == "getaddr")
    {
        pfrom->vAddrToSend.clear();
        vector<CAddress> vAddr = addrman.GetAddr();
        BOOST_FOREACH(const CAddress &addr, vAddr)
            pfrom->PushAddress(addr);
    }


    else if (strCommand == "mempool")
    {
        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);
            CTransaction tx;
            bool fInMemPool = mempool.lookup(hash, tx);
            if (!fInMemPool) continue; // another thread removed since queryHashes, maybe...
            if ((pfrom->pfilter && pfrom->pfilter->IsRelevantAndUpdate(tx, hash)) ||
               (!pfrom->pfilter))
                vInv.push_back(inv);
            if (vInv.size() == MAX_INV_SZ) {
                pfrom->PushMessage("inv", vInv);
                vInv.clear();
            }
        }
        if (vInv.size() > 0)
            pfrom->PushMessage("inv", vInv);
    }


    else if (strCommand == "ping")
    {
        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("pong", nonce);
        }
    }


    else if (strCommand == "pong")
    {
        int64_t pingUsecEnd = GetTimeMicros();
        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;
                    } 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 %s %s: %s, %x expected, %x received, %" PRIszu" bytes\n",
                pfrom->addr.ToString(),
                pfrom->cleanSubVer,
                sProblem,
                pfrom->nPingNonceSent,
                nonce,
                nAvail);
        }
        if (bPingFinished) {
            pfrom->nPingNonceSent = 0;
        }
    }


    else if (strCommand == "alert")
    {
        CAlert alert;
        vRecv >> alert;

        uint256 alertHash = alert.GetHash();
        if (pfrom->setKnown.count(alertHash) == 0)
        {
            if (alert.ProcessAlert())
            {
                // Relay
                pfrom->setKnown.insert(alertHash);
                {
                    LOCK(cs_vNodes);
                    BOOST_FOREACH(CNode* pnode, vNodes)
                        alert.RelayTo(pnode);
                }
            }
            else {
                // Small DoS penalty so peers that send us lots of
                // duplicate/expired/invalid-signature/whatever alerts
                // eventually get banned.
                // This isn't a Misbehaving(100) (immediate ban) because the
                // peer might be an older or different implementation with
                // a different signature key, etc.
                Misbehaving(pfrom->GetId(), 10);
            }
        }
    }

    else if (!fBloomFilters &&
             (strCommand == "filterload" ||
              strCommand == "filteradd" ||
              strCommand == "filterclear"))
    {
        pfrom->CloseSocketDisconnect();
        return error("peer %s attempted to set a bloom filter even though we do not advertise that service",
                     pfrom->addr.ToString().c_str());
    }

    else if (strCommand == "filterload")
    {
        CBloomFilter filter;
        vRecv >> filter;

        if (!filter.IsWithinSizeConstraints())
            // There is no excuse for sending a too-large filter
            Misbehaving(pfrom->GetId(), 100);
        else
        {
            LOCK(pfrom->cs_filter);
            delete pfrom->pfilter;
            pfrom->pfilter = new CBloomFilter(filter);
            pfrom->pfilter->UpdateEmptyFull();
        }
        pfrom->fRelayTxes = true;
    }


    else if (strCommand == "filteradd")
    {
        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);
        } else {
            LOCK(pfrom->cs_filter);
            if (pfrom->pfilter)
                pfrom->pfilter->insert(vData);
            else
                Misbehaving(pfrom->GetId(), 100);
        }
    }


    else if (strCommand == "filterclear")
    {
        LOCK(pfrom->cs_filter);
        delete pfrom->pfilter;
        pfrom->pfilter = new CBloomFilter();
        pfrom->fRelayTxes = true;
    }


    else if (strCommand == "reject")
    {
        if (fDebug)
        {
            string strMsg; unsigned char ccode; string strReason;
            vRecv >> strMsg >> ccode >> strReason;

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

            if (strMsg == "block" || strMsg == "tx")
            {
                uint256 hash;
                vRecv >> hash;
                ss << ": hash " << hash.ToString();
            }
            // Truncate to reasonable length and sanitize before printing:
            string s = ss.str();
            if (s.size() > 111) s.erase(111, string::npos);
            LogPrint("net", "Reject %s\n", SanitizeString(s));
        }
    }

    else
    {
        // Ignore unknown commands for extensibility
    }


    // Update the last seen time for this node's address
    if (pfrom->fNetworkNode)
        if (strCommand == "version" || strCommand == "addr" || strCommand == "inv" || strCommand == "getdata" || strCommand == "ping")
            AddressCurrentlyConnected(pfrom->addr);


    return true;
}

// requires LOCK(cs_vRecvMsg)
bool ProcessMessages(CNode* pfrom)
{
    //if (fDebug)
    //    LogPrintf("ProcessMessages(%"PRIszu" messages)\n", pfrom->vRecvMsg.size());

    //
    // 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;

        //if (fDebug)
        //    LogPrintf("ProcessMessages(message %u msgsz, %"PRIszu" bytes, complete:%s)\n",
        //            msg.hdr.nMessageSize, msg.vRecv.size(),
        //            msg.complete() ? "Y" : "N");

        // 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) {
            LogPrintf("\n\nPROCESSMESSAGE: INVALID MESSAGESTART\n\n");
            fOk = false;
            break;
        }

        // Read header
        CMessageHeader& hdr = msg.hdr;
        if (!hdr.IsValid())
        {
            LogPrintf("\n\nPROCESSMESSAGE: ERRORS IN HEADER %s\n\n\n", hdr.GetCommand());
            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)
        {
            LogPrintf("ProcessMessages(%s, %u bytes) : CHECKSUM ERROR nChecksum=%08x hdr.nChecksum=%08x\n",
               strCommand, nMessageSize, nChecksum, hdr.nChecksum);
            continue;
        }

        // Process message
        bool fRet = false;
        try
        {
            fRet = ProcessMessage(pfrom, strCommand, vRecv);
            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"))
            {
                // Allow exceptions from under-length message on vRecv
                LogPrintf("ProcessMessages(%s, %u bytes) : Exception '%s' caught, normally caused by a message being shorter than its stated length\n", strCommand, nMessageSize, e.what());
            }
            else if (strstr(e.what(), "size too large"))
            {
                // Allow exceptions from over-long size
                LogPrintf("ProcessMessages(%s, %u bytes) : Exception '%s' caught\n", 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)
            LogPrintf("ProcessMessage(%s, %u bytes) FAILED\n", strCommand, nMessageSize);

        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 SendMessages(CNode* pto, bool fSendTrickle)
{
    {
        // Don't send anything until we get their 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->nLastSend && GetTime() - pto->nLastSend > 30 * MINUTE && pto->vSendMsg.empty()) {
            // Ping automatically sent as a keepalive
            pingSend = true;
        }
        if (pingSend) {
            uint64_t nonce = 0;
            while (nonce == 0) {
                RAND_bytes((unsigned char*)&nonce, sizeof(nonce));
            }
            pto->nPingNonceSent = nonce;
            pto->fPingQueued = false;
            if (pto->nVersion > BIP0031_VERSION) {
                // Take timestamp as close as possible before transmitting ping
                pto->nPingUsecStart = GetTimeMicros();
                pto->PushMessage("ping", nonce);
            } else {
                // Peer is too old to support ping command with nonce, pong will never arrive, disable timing
                pto->nPingUsecStart = 0;
                pto->PushMessage("ping");
            }
        }

        // Address refresh broadcast
        static int64_t nLastRebroadcast;
        if (!IsInitialBlockDownload() && (GetTime() - nLastRebroadcast > DAY_SEC))
        {
            {
                LOCK(cs_vNodes);
                BOOST_FOREACH(CNode* pnode, vNodes)
                {
                    // Periodically clear setAddrKnown to allow refresh broadcasts
                    if (nLastRebroadcast)
                        pnode->setAddrKnown.clear();

                    // Rebroadcast our address
                    if (!fNoListen)
                    {
                        CAddress addr = GetLocalAddress(&pnode->addr);
                        if (addr.IsRoutable())
                            pnode->PushAddress(addr);
                    }
                }
            }
            nLastRebroadcast = GetTime();
        }

        //
        // Message: addr
        //
        if (fSendTrickle)
        {
            vector<CAddress> vAddr;
            vAddr.reserve(pto->vAddrToSend.size());
            BOOST_FOREACH(const CAddress& addr, pto->vAddrToSend)
            {
                // returns true if wasn't already contained in the set
                if (pto->setAddrKnown.insert(addr).second)
                {
                    vAddr.push_back(addr);
                    // receiver rejects addr messages larger than 1000
                    if (vAddr.size() >= 1000)
                    {
                        pto->PushMessage("addr", vAddr);
                        vAddr.clear();
                    }
                }
            }
            pto->vAddrToSend.clear();
            if (!vAddr.empty())
                pto->PushMessage("addr", vAddr);
        }

        TRY_LOCK(cs_main, lockMain);
        if (!lockMain)
            return true;

        CNodeState &state = *State(pto->GetId());
        if (state.fShouldBan) {
            if (pto->addr.IsLocal())
                LogPrintf("Warning: not banning local node %s!\n", pto->addr.ToString());
            else {
                pto->fDisconnect = true;
                CNode::Ban(pto->addr);
            }
            state.fShouldBan = false;
        }

        BOOST_FOREACH(const CBlockReject& reject, state.rejects)
            pto->PushMessage("reject", (string)"block", reject.chRejectCode, reject.strRejectReason, reject.hashBlock);
        state.rejects.clear();

        // Start block sync
        if (pto->fStartSync && !fImporting && !fReindex) {
            pto->fStartSync = false;
            PushGetBlocks(pto, chainActive.Tip(), uint256(0));
        }

        // 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())
        {
            g_signals.Broadcast();
        }

        //
        // Message: inventory
        //
        vector<CInv> vInv;
        vector<CInv> vInvWait;
        {
            LOCK(pto->cs_inventory);
            vInv.reserve(pto->vInventoryToSend.size());
            vInvWait.reserve(pto->vInventoryToSend.size());
            BOOST_FOREACH(const CInv& inv, pto->vInventoryToSend)
            {
                if (pto->setInventoryKnown.count(inv))
                    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 == 0)
                        hashSalt = GetRandHash();
                    uint256 hashRand = inv.hash ^ hashSalt;
                    hashRand = Hash(BEGIN(hashRand), END(hashRand));
                    bool fTrickleWait = ((hashRand & 3) != 0);

                    if (fTrickleWait)
                    {
                        vInvWait.push_back(inv);
                        continue;
                    }
                }

                // returns true if wasn't already contained in the set
                if (pto->setInventoryKnown.insert(inv).second)
                {
                    vInv.push_back(inv);
                    if (vInv.size() >= 1000)
                    {
                        pto->PushMessage("inv", vInv);
                        vInv.clear();
                    }
                }
            }
            pto->vInventoryToSend = vInvWait;
        }
        if (!vInv.empty())
            pto->PushMessage("inv", vInv);


        //
        // Message: getdata
        //
        vector<CInv> vGetData;
        int64_t nNow = GetTime() * 1000000;
        while (!pto->mapAskFor.empty() && (*pto->mapAskFor.begin()).first <= nNow)
        {
            const CInv& inv = (*pto->mapAskFor.begin()).second;
            if (!AlreadyHave(inv))
            {
                if (fDebug)
                    LogPrint("net", "sending getdata: %s\n", inv.ToString());
                vGetData.push_back(inv);
                if (vGetData.size() >= 1000)
                {
                    pto->PushMessage("getdata", vGetData);
                    vGetData.clear();
                }
            }
            pto->mapAskFor.erase(pto->mapAskFor.begin());
        }
        if (!vGetData.empty())
            pto->PushMessage("getdata", vGetData);

    }
    return true;
}






class CMainCleanup
{
public:
    CMainCleanup() {}
    ~CMainCleanup() {
        // block headers
        std::map<uint256, CBlockIndex*>::iterator it1 = mapBlockIndex.begin();
        for (; it1 != mapBlockIndex.end(); it1++)
            delete (*it1).second;
        mapBlockIndex.clear();

        // orphan blocks
        std::map<uint256, COrphanBlock*>::iterator it2 = mapOrphanBlocks.begin();
        for (; it2 != mapOrphanBlocks.end(); it2++)
            delete (*it2).second;
        mapOrphanBlocks.clear();

        // orphan transactions
        mapOrphanTransactions.clear();
    }
} instance_of_cmaincleanup;