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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2016 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 <attributes.h>
#include <crypto/common.h>
#include <prevector.h>
#include <serialize.h>
#include <cassert>
#include <climits>
#include <cstdint>
#include <cstring>
#include <limits>
#include <stdexcept>
#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. Thresold is Tue Nov 5 00:53:20 1985 UTC
static const unsigned int LOCKTIME_THRESHOLD = 500000000;
template <typename T> std::vector<uint8_t> ToByteVector(const T &in) {
return std::vector<uint8_t>(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_SPLIT = 0x7f, // after monolith upgrade (May 2018)
OP_NUM2BIN = 0x80, // after monolith upgrade (May 2018)
OP_BIN2NUM = 0x81, // after monolith upgrade (May 2018)
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,
// More crypto
OP_CHECKDATASIG = 0xba,
OP_CHECKDATASIGVERIFY = 0xbb,
// additional byte string operations
OP_REVERSEBYTES = 0xbc,
// The first op_code value after all defined opcodes
FIRST_UNDEFINED_OP_VALUE,
// multi-byte opcodes
OP_PREFIX_BEGIN = 0xf0,
OP_PREFIX_END = 0xf7,
OP_INVALIDOPCODE = 0xff,
};
// Maximum value that an opcode can be
static const unsigned int MAX_OPCODE = FIRST_UNDEFINED_OP_VALUE - 1;
std::string GetOpName(opcodetype opcode);
/**
* Check whether the given stack element data would be minimally pushed using
* the given opcode.
*/
bool CheckMinimalPush(const std::vector<uint8_t> &data, 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:
static const size_t MAXIMUM_ELEMENT_SIZE = 4;
explicit CScriptNum(const int64_t &n) { m_value = n; }
explicit CScriptNum(const std::vector<uint8_t> &vch, bool fRequireMinimal,
const size_t nMaxNumSize = MAXIMUM_ELEMENT_SIZE) {
if (vch.size() > nMaxNumSize) {
throw scriptnum_error("script number overflow");
}
if (fRequireMinimal && !IsMinimallyEncoded(vch, nMaxNumSize)) {
throw scriptnum_error("non-minimally encoded script number");
}
m_value = set_vch(vch);
}
static bool IsMinimallyEncoded(
const std::vector<uint8_t> &vch,
const size_t nMaxNumSize = CScriptNum::MAXIMUM_ELEMENT_SIZE);
static bool MinimallyEncode(std::vector<uint8_t> &data);
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 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 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 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<uint8_t> getvch() const { return serialize(m_value); }
static std::vector<uint8_t> serialize(const int64_t &value) {
if (value == 0) {
return {};
}
std::vector<uint8_t> result;
const bool neg = value < 0;
uint64_t absvalue = neg ? ~static_cast<uint64_t>(value) + 1
: static_cast<uint64_t>(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<uint8_t> &vch) {
if (vch.empty()) {
return 0;
}
int64_t result = 0;
for (size_t i = 0; i != vch.size(); ++i) {
result |= 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, uint8_t> CScriptBase;
bool GetScriptOp(CScriptBase::const_iterator &pc,
CScriptBase::const_iterator end, opcodetype &opcodeRet,
std::vector<uint8_t> *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<uint8_t>::const_iterator pbegin,
std::vector<uint8_t>::const_iterator pend)
: CScriptBase(pbegin, pend) {}
CScript(const uint8_t *pbegin, const uint8_t *pend)
: CScriptBase(pbegin, pend) {}
SERIALIZE_METHODS(CScript, obj) { READWRITEAS(CScriptBase, obj); }
explicit CScript(int64_t b) { operator<<(b); }
explicit CScript(opcodetype b) { operator<<(b); }
explicit CScript(const CScriptNum &b) { operator<<(b); }
// delete non-existent constructor to defend against future introduction
// e.g. via prevector
explicit CScript(const std::vector<uint8_t> &b) = delete;
/** Delete non-existent operator to defend against future introduction */
CScript &operator<<(const CScript &b) = delete;
CScript &operator<<(int64_t b) LIFETIMEBOUND { return push_int64(b); }
CScript &operator<<(opcodetype opcode) LIFETIMEBOUND {
if (opcode < 0 || opcode > 0xff) {
throw std::runtime_error("CScript::operator<<(): invalid opcode");
}
insert(end(), uint8_t(opcode));
return *this;
}
CScript &operator<<(const CScriptNum &b) LIFETIMEBOUND {
*this << b.getvch();
return *this;
}
CScript &operator<<(const std::vector<uint8_t> &b) LIFETIMEBOUND {
if (b.size() < OP_PUSHDATA1) {
insert(end(), uint8_t(b.size()));
} else if (b.size() <= 0xff) {
insert(end(), OP_PUSHDATA1);
insert(end(), uint8_t(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;
}
bool GetOp(const_iterator &pc, opcodetype &opcodeRet,
std::vector<uint8_t> &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);
}
bool IsPayToScriptHash() const;
bool IsWitnessProgram(int &version, std::vector<uint8_t> &program) const;
bool IsWitnessProgram() 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();
}
};
#endif // BITCOIN_SCRIPT_SCRIPT_H

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