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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2018 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_SCRIPT_SCRIPT_H
#define BITCOIN_SCRIPT_SCRIPT_H
#include <crypto/common.h>
#include <prevector.h>
#include <serialize.h>
#include <assert.h>
#include <climits>
#include <limits>
#include <stdexcept>
#include <stdint.h>
#include <string.h>
#include <string>
#include <vector>
// Maximum number of bytes pushable to the stack
static const unsigned int MAX_SCRIPT_ELEMENT_SIZE = 520;
// Maximum number of non-push operations per script
static const int MAX_OPS_PER_SCRIPT = 201;
// Maximum number of public keys per multisig
static const int MAX_PUBKEYS_PER_MULTISIG = 20;
// Maximum script length in bytes
static const int MAX_SCRIPT_SIZE = 10000;
// Maximum number of values on script interpreter stack
static const int MAX_STACK_SIZE = 1000;
// Threshold for nLockTime: below this value it is interpreted as block number,
// otherwise as UNIX timestamp.
static const unsigned int LOCKTIME_THRESHOLD = 500000000; // Tue Nov 5 00:53:20 1985 UTC
// Maximum nLockTime. Since a lock time indicates the last invalid timestamp, a
// transaction with this lock time will never be valid unless lock time
// checking is disabled (by setting all input sequence numbers to
// SEQUENCE_FINAL).
static const uint32_t LOCKTIME_MAX = 0xFFFFFFFFU;
template <typename T>
std::vector<unsigned char> ToByteVector(const T& in)
{
return std::vector<unsigned char>(in.begin(), in.end());
}
/** Script opcodes */
enum opcodetype
{
// push value
OP_0 = 0x00,
OP_FALSE = OP_0,
OP_PUSHDATA1 = 0x4c,
OP_PUSHDATA2 = 0x4d,
OP_PUSHDATA4 = 0x4e,
OP_1NEGATE = 0x4f,
OP_RESERVED = 0x50,
OP_1 = 0x51,
OP_TRUE=OP_1,
OP_2 = 0x52,
OP_3 = 0x53,
OP_4 = 0x54,
OP_5 = 0x55,
OP_6 = 0x56,
OP_7 = 0x57,
OP_8 = 0x58,
OP_9 = 0x59,
OP_10 = 0x5a,
OP_11 = 0x5b,
OP_12 = 0x5c,
OP_13 = 0x5d,
OP_14 = 0x5e,
OP_15 = 0x5f,
OP_16 = 0x60,
// control
OP_NOP = 0x61,
OP_VER = 0x62,
OP_IF = 0x63,
OP_NOTIF = 0x64,
OP_VERIF = 0x65,
OP_VERNOTIF = 0x66,
OP_ELSE = 0x67,
OP_ENDIF = 0x68,
OP_VERIFY = 0x69,
OP_RETURN = 0x6a,
// stack ops
OP_TOALTSTACK = 0x6b,
OP_FROMALTSTACK = 0x6c,
OP_2DROP = 0x6d,
OP_2DUP = 0x6e,
OP_3DUP = 0x6f,
OP_2OVER = 0x70,
OP_2ROT = 0x71,
OP_2SWAP = 0x72,
OP_IFDUP = 0x73,
OP_DEPTH = 0x74,
OP_DROP = 0x75,
OP_DUP = 0x76,
OP_NIP = 0x77,
OP_OVER = 0x78,
OP_PICK = 0x79,
OP_ROLL = 0x7a,
OP_ROT = 0x7b,
OP_SWAP = 0x7c,
OP_TUCK = 0x7d,
// splice ops
OP_CAT = 0x7e,
OP_SUBSTR = 0x7f,
OP_LEFT = 0x80,
OP_RIGHT = 0x81,
OP_SIZE = 0x82,
// bit logic
OP_INVERT = 0x83,
OP_AND = 0x84,
OP_OR = 0x85,
OP_XOR = 0x86,
OP_EQUAL = 0x87,
OP_EQUALVERIFY = 0x88,
OP_RESERVED1 = 0x89,
OP_RESERVED2 = 0x8a,
// numeric
OP_1ADD = 0x8b,
OP_1SUB = 0x8c,
OP_2MUL = 0x8d,
OP_2DIV = 0x8e,
OP_NEGATE = 0x8f,
OP_ABS = 0x90,
OP_NOT = 0x91,
OP_0NOTEQUAL = 0x92,
OP_ADD = 0x93,
OP_SUB = 0x94,
OP_MUL = 0x95,
OP_DIV = 0x96,
OP_MOD = 0x97,
OP_LSHIFT = 0x98,
OP_RSHIFT = 0x99,
OP_BOOLAND = 0x9a,
OP_BOOLOR = 0x9b,
OP_NUMEQUAL = 0x9c,
OP_NUMEQUALVERIFY = 0x9d,
OP_NUMNOTEQUAL = 0x9e,
OP_LESSTHAN = 0x9f,
OP_GREATERTHAN = 0xa0,
OP_LESSTHANOREQUAL = 0xa1,
OP_GREATERTHANOREQUAL = 0xa2,
OP_MIN = 0xa3,
OP_MAX = 0xa4,
OP_WITHIN = 0xa5,
// crypto
OP_RIPEMD160 = 0xa6,
OP_SHA1 = 0xa7,
OP_SHA256 = 0xa8,
OP_HASH160 = 0xa9,
OP_HASH256 = 0xaa,
OP_CODESEPARATOR = 0xab,
OP_CHECKSIG = 0xac,
OP_CHECKSIGVERIFY = 0xad,
OP_CHECKMULTISIG = 0xae,
OP_CHECKMULTISIGVERIFY = 0xaf,
// expansion
OP_NOP1 = 0xb0,
OP_CHECKLOCKTIMEVERIFY = 0xb1,
OP_NOP2 = OP_CHECKLOCKTIMEVERIFY,
OP_CHECKSEQUENCEVERIFY = 0xb2,
OP_NOP3 = OP_CHECKSEQUENCEVERIFY,
OP_NOP4 = 0xb3,
OP_NOP5 = 0xb4,
OP_NOP6 = 0xb5,
OP_NOP7 = 0xb6,
OP_NOP8 = 0xb7,
OP_NOP9 = 0xb8,
OP_NOP10 = 0xb9,
OP_INVALIDOPCODE = 0xff,
};
// Maximum value that an opcode can be
static const unsigned int MAX_OPCODE = OP_NOP10;
const char* GetOpName(opcodetype opcode);
class scriptnum_error : public std::runtime_error
{
public:
explicit scriptnum_error(const std::string& str) : std::runtime_error(str) {}
};
class CScriptNum
{
/**
* Numeric opcodes (OP_1ADD, etc) are restricted to operating on 4-byte integers.
* The semantics are subtle, though: operands must be in the range [-2^31 +1...2^31 -1],
* but results may overflow (and are valid as long as they are not used in a subsequent
* numeric operation). CScriptNum enforces those semantics by storing results as
* an int64 and allowing out-of-range values to be returned as a vector of bytes but
* throwing an exception if arithmetic is done or the result is interpreted as an integer.
*/
public:
explicit CScriptNum(const int64_t& n)
{
m_value = n;
}
static const size_t nDefaultMaxNumSize = 4;
explicit CScriptNum(const std::vector<unsigned char>& vch, bool fRequireMinimal,
const size_t nMaxNumSize = nDefaultMaxNumSize)
{
if (vch.size() > nMaxNumSize) {
throw scriptnum_error("script number overflow");
}
if (fRequireMinimal && vch.size() > 0) {
// Check that the number is encoded with the minimum possible
// number of bytes.
//
// If the most-significant-byte - excluding the sign bit - is zero
// then we're not minimal. Note how this test also rejects the
// negative-zero encoding, 0x80.
if ((vch.back() & 0x7f) == 0) {
// One exception: if there's more than one byte and the most
// significant bit of the second-most-significant-byte is set
// it would conflict with the sign bit. An example of this case
// is +-255, which encode to 0xff00 and 0xff80 respectively.
// (big-endian).
if (vch.size() <= 1 || (vch[vch.size() - 2] & 0x80) == 0) {
throw scriptnum_error("non-minimally encoded script number");
}
}
}
m_value = set_vch(vch);
}
inline bool operator==(const int64_t& rhs) const { return m_value == rhs; }
inline bool operator!=(const int64_t& rhs) const { return m_value != rhs; }
inline bool operator<=(const int64_t& rhs) const { return m_value <= rhs; }
inline bool operator< (const int64_t& rhs) const { return m_value < rhs; }
inline bool operator>=(const int64_t& rhs) const { return m_value >= rhs; }
inline bool operator> (const int64_t& rhs) const { return m_value > rhs; }
inline bool operator==(const CScriptNum& rhs) const { return operator==(rhs.m_value); }
inline bool operator!=(const CScriptNum& rhs) const { return operator!=(rhs.m_value); }
inline bool operator<=(const CScriptNum& rhs) const { return operator<=(rhs.m_value); }
inline bool operator< (const CScriptNum& rhs) const { return operator< (rhs.m_value); }
inline bool operator>=(const CScriptNum& rhs) const { return operator>=(rhs.m_value); }
inline bool operator> (const CScriptNum& rhs) const { return operator> (rhs.m_value); }
inline CScriptNum operator+( const int64_t& rhs) const { return CScriptNum(m_value + rhs);}
inline CScriptNum operator-( const int64_t& rhs) const { return CScriptNum(m_value - rhs);}
inline CScriptNum operator+( const CScriptNum& rhs) const { return operator+(rhs.m_value); }
inline CScriptNum operator-( const CScriptNum& rhs) const { return operator-(rhs.m_value); }
inline CScriptNum& operator+=( const CScriptNum& rhs) { return operator+=(rhs.m_value); }
inline CScriptNum& operator-=( const CScriptNum& rhs) { return operator-=(rhs.m_value); }
inline CScriptNum operator&( const int64_t& rhs) const { return CScriptNum(m_value & rhs);}
inline CScriptNum operator&( const CScriptNum& rhs) const { return operator&(rhs.m_value); }
inline CScriptNum& operator&=( const CScriptNum& rhs) { return operator&=(rhs.m_value); }
inline CScriptNum operator-() const
{
assert(m_value != std::numeric_limits<int64_t>::min());
return CScriptNum(-m_value);
}
inline CScriptNum& operator=( const int64_t& rhs)
{
m_value = rhs;
return *this;
}
inline CScriptNum& operator+=( const int64_t& rhs)
{
assert(rhs == 0 || (rhs > 0 && m_value <= std::numeric_limits<int64_t>::max() - rhs) ||
(rhs < 0 && m_value >= std::numeric_limits<int64_t>::min() - rhs));
m_value += rhs;
return *this;
}
inline CScriptNum& operator-=( const int64_t& rhs)
{
assert(rhs == 0 || (rhs > 0 && m_value >= std::numeric_limits<int64_t>::min() + rhs) ||
(rhs < 0 && m_value <= std::numeric_limits<int64_t>::max() + rhs));
m_value -= rhs;
return *this;
}
inline CScriptNum& operator&=( const int64_t& rhs)
{
m_value &= rhs;
return *this;
}
int getint() const
{
if (m_value > std::numeric_limits<int>::max())
return std::numeric_limits<int>::max();
else if (m_value < std::numeric_limits<int>::min())
return std::numeric_limits<int>::min();
return m_value;
}
std::vector<unsigned char> getvch() const
{
return serialize(m_value);
}
static std::vector<unsigned char> serialize(const int64_t& value)
{
if(value == 0)
return std::vector<unsigned char>();
std::vector<unsigned char> result;
const bool neg = value < 0;
uint64_t absvalue = neg ? -value : value;
while(absvalue)
{
result.push_back(absvalue & 0xff);
absvalue >>= 8;
}
// - If the most significant byte is >= 0x80 and the value is positive, push a
// new zero-byte to make the significant byte < 0x80 again.
// - If the most significant byte is >= 0x80 and the value is negative, push a
// new 0x80 byte that will be popped off when converting to an integral.
// - If the most significant byte is < 0x80 and the value is negative, add
// 0x80 to it, since it will be subtracted and interpreted as a negative when
// converting to an integral.
if (result.back() & 0x80)
result.push_back(neg ? 0x80 : 0);
else if (neg)
result.back() |= 0x80;
return result;
}
private:
static int64_t set_vch(const std::vector<unsigned char>& vch)
{
if (vch.empty())
return 0;
int64_t result = 0;
for (size_t i = 0; i != vch.size(); ++i)
result |= static_cast<int64_t>(vch[i]) << 8*i;
// If the input vector's most significant byte is 0x80, remove it from
// the result's msb and return a negative.
if (vch.back() & 0x80)
return -((int64_t)(result & ~(0x80ULL << (8 * (vch.size() - 1)))));
return result;
}
int64_t m_value;
};
/**
* We use a prevector for the script to reduce the considerable memory overhead
* of vectors in cases where they normally contain a small number of small elements.
* Tests in October 2015 showed use of this reduced dbcache memory usage by 23%
* and made an initial sync 13% faster.
*/
typedef prevector<28, unsigned char> CScriptBase;
bool GetScriptOp(CScriptBase::const_iterator& pc, CScriptBase::const_iterator end, opcodetype& opcodeRet, std::vector<unsigned char>* pvchRet);
/** Serialized script, used inside transaction inputs and outputs */
class CScript : public CScriptBase
{
protected:
CScript& push_int64(int64_t n)
{
if (n == -1 || (n >= 1 && n <= 16))
{
push_back(n + (OP_1 - 1));
}
else if (n == 0)
{
push_back(OP_0);
}
else
{
*this << CScriptNum::serialize(n);
}
return *this;
}
public:
CScript() { }
CScript(const_iterator pbegin, const_iterator pend) : CScriptBase(pbegin, pend) { }
CScript(std::vector<unsigned char>::const_iterator pbegin, std::vector<unsigned char>::const_iterator pend) : CScriptBase(pbegin, pend) { }
CScript(const unsigned char* pbegin, const unsigned char* pend) : CScriptBase(pbegin, pend) { }
ADD_SERIALIZE_METHODS;
template <typename Stream, typename Operation>
inline void SerializationOp(Stream& s, Operation ser_action) {
READWRITEAS(CScriptBase, *this);
}
CScript& operator+=(const CScript& b)
{
reserve(size() + b.size());
insert(end(), b.begin(), b.end());
return *this;
}
friend CScript operator+(const CScript& a, const CScript& b)
{
CScript ret = a;
ret += b;
return ret;
}
CScript(int64_t b) { operator<<(b); }
explicit CScript(opcodetype b) { operator<<(b); }
explicit CScript(const CScriptNum& b) { operator<<(b); }
explicit CScript(const std::vector<unsigned char>& b) { operator<<(b); }
CScript& operator<<(int64_t b) { return push_int64(b); }
CScript& operator<<(opcodetype opcode)
{
if (opcode < 0 || opcode > 0xff)
throw std::runtime_error("CScript::operator<<(): invalid opcode");
insert(end(), (unsigned char)opcode);
return *this;
}
CScript& operator<<(const CScriptNum& b)
{
*this << b.getvch();
return *this;
}
CScript& operator<<(const std::vector<unsigned char>& b)
{
if (b.size() < OP_PUSHDATA1)
{
insert(end(), (unsigned char)b.size());
}
else if (b.size() <= 0xff)
{
insert(end(), OP_PUSHDATA1);
insert(end(), (unsigned char)b.size());
}
else if (b.size() <= 0xffff)
{
insert(end(), OP_PUSHDATA2);
uint8_t _data[2];
WriteLE16(_data, b.size());
insert(end(), _data, _data + sizeof(_data));
}
else
{
insert(end(), OP_PUSHDATA4);
uint8_t _data[4];
WriteLE32(_data, b.size());
insert(end(), _data, _data + sizeof(_data));
}
insert(end(), b.begin(), b.end());
return *this;
}
CScript& operator<<(const CScript& b)
{
// I'm not sure if this should push the script or concatenate scripts.
// If there's ever a use for pushing a script onto a script, delete this member fn
assert(!"Warning: Pushing a CScript onto a CScript with << is probably not intended, use + to concatenate!");
return *this;
}
bool GetOp(const_iterator& pc, opcodetype& opcodeRet, std::vector<unsigned char>& vchRet) const
{
return GetScriptOp(pc, end(), opcodeRet, &vchRet);
}
bool GetOp(const_iterator& pc, opcodetype& opcodeRet) const
{
return GetScriptOp(pc, end(), opcodeRet, nullptr);
}
/** Encode/decode small integers: */
static int DecodeOP_N(opcodetype opcode)
{
if (opcode == OP_0)
return 0;
assert(opcode >= OP_1 && opcode <= OP_16);
return (int)opcode - (int)(OP_1 - 1);
}
static opcodetype EncodeOP_N(int n)
{
assert(n >= 0 && n <= 16);
if (n == 0)
return OP_0;
return (opcodetype)(OP_1+n-1);
}
/**
* Pre-version-0.6, Bitcoin always counted CHECKMULTISIGs
* as 20 sigops. With pay-to-script-hash, that changed:
* CHECKMULTISIGs serialized in scriptSigs are
* counted more accurately, assuming they are of the form
* ... OP_N CHECKMULTISIG ...
*/
unsigned int GetSigOpCount(bool fAccurate) const;
/**
* Accurately count sigOps, including sigOps in
* pay-to-script-hash transactions:
*/
unsigned int GetSigOpCount(const CScript& scriptSig) const;
bool IsPayToScriptHash() const;
bool IsPayToWitnessScriptHash() const;
bool IsWitnessProgram(int& version, std::vector<unsigned char>& program) const;
/** Called by IsStandardTx and P2SH/BIP62 VerifyScript (which makes it consensus-critical). */
bool IsPushOnly(const_iterator pc) const;
bool IsPushOnly() const;
/** Check if the script contains valid OP_CODES */
bool HasValidOps() const;
/**
* Returns whether the script is guaranteed to fail at execution,
* regardless of the initial stack. This allows outputs to be pruned
* instantly when entering the UTXO set.
*/
bool IsUnspendable() const
{
return (size() > 0 && *begin() == OP_RETURN) || (size() > MAX_SCRIPT_SIZE);
}
void clear()
{
// The default prevector::clear() does not release memory
CScriptBase::clear();
shrink_to_fit();
}
};
struct CScriptWitness
{
// Note that this encodes the data elements being pushed, rather than
// encoding them as a CScript that pushes them.
std::vector<std::vector<unsigned char> > stack;
// Some compilers complain without a default constructor
CScriptWitness() { }
bool IsNull() const { return stack.empty(); }
void SetNull() { stack.clear(); stack.shrink_to_fit(); }
std::string ToString() const;
};
class CReserveScript
{
public:
CScript reserveScript;
virtual void KeepScript() {}
CReserveScript() {}
virtual ~CReserveScript() {}
};
#endif // BITCOIN_SCRIPT_SCRIPT_H