lbrycrd/src/test/scriptnum10.h
2018-07-27 07:15:02 -04:00

183 lines
6.6 KiB
C++

// 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_TEST_SCRIPTNUM10_H
#define BITCOIN_TEST_SCRIPTNUM10_H
#include <algorithm>
#include <limits>
#include <stdexcept>
#include <stdint.h>
#include <string>
#include <vector>
#include <assert.h>
class scriptnum10_error : public std::runtime_error
{
public:
explicit scriptnum10_error(const std::string& str) : std::runtime_error(str) {}
};
class CScriptNum10
{
/**
* The ScriptNum implementation from Bitcoin Core 0.10.0, for cross-comparison.
*/
public:
explicit CScriptNum10(const int64_t& n)
{
m_value = n;
}
static const size_t nDefaultMaxNumSize = 4;
explicit CScriptNum10(const std::vector<unsigned char>& vch, bool fRequireMinimal,
const size_t nMaxNumSize = nDefaultMaxNumSize)
{
if (vch.size() > nMaxNumSize) {
throw scriptnum10_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 scriptnum10_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 CScriptNum10& rhs) const { return operator==(rhs.m_value); }
inline bool operator!=(const CScriptNum10& rhs) const { return operator!=(rhs.m_value); }
inline bool operator<=(const CScriptNum10& rhs) const { return operator<=(rhs.m_value); }
inline bool operator< (const CScriptNum10& rhs) const { return operator< (rhs.m_value); }
inline bool operator>=(const CScriptNum10& rhs) const { return operator>=(rhs.m_value); }
inline bool operator> (const CScriptNum10& rhs) const { return operator> (rhs.m_value); }
inline CScriptNum10 operator+( const int64_t& rhs) const { return CScriptNum10(m_value + rhs);}
inline CScriptNum10 operator-( const int64_t& rhs) const { return CScriptNum10(m_value - rhs);}
inline CScriptNum10 operator+( const CScriptNum10& rhs) const { return operator+(rhs.m_value); }
inline CScriptNum10 operator-( const CScriptNum10& rhs) const { return operator-(rhs.m_value); }
inline CScriptNum10& operator+=( const CScriptNum10& rhs) { return operator+=(rhs.m_value); }
inline CScriptNum10& operator-=( const CScriptNum10& rhs) { return operator-=(rhs.m_value); }
inline CScriptNum10 operator-() const
{
assert(m_value != std::numeric_limits<int64_t>::min());
return CScriptNum10(-m_value);
}
inline CScriptNum10& operator=( const int64_t& rhs)
{
m_value = rhs;
return *this;
}
inline CScriptNum10& 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 CScriptNum10& 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;
}
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;
};
#endif // BITCOIN_TEST_BIGNUM_H