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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_ARITH_UINT256_H
#define BITCOIN_ARITH_UINT256_H
#include <cassert>
#include <cstdint>
#include <cstring>
#include <limits>
#include <stdexcept>
#include <string>
#include <vector>
class uint256;
class uint_error : public std::runtime_error {
public:
explicit uint_error(const std::string &str) : std::runtime_error(str) {}
};
/** Template base class for unsigned big integers. */
template <unsigned int BITS> class base_uint {
protected:
static constexpr int WIDTH = BITS / 32;
uint32_t pn[WIDTH];
public:
base_uint() {
static_assert(
BITS / 32 > 0 && BITS % 32 == 0,
"Template parameter BITS must be a positive multiple of 32.");
for (int i = 0; i < WIDTH; i++) {
pn[i] = 0;
}
}
base_uint(const base_uint &b) {
static_assert(
BITS / 32 > 0 && BITS % 32 == 0,
"Template parameter BITS must be a positive multiple of 32.");
for (int i = 0; i < WIDTH; i++) {
pn[i] = b.pn[i];
}
}
base_uint &operator=(const base_uint &b) {
for (int i = 0; i < WIDTH; i++) {
pn[i] = b.pn[i];
}
return *this;
}
base_uint(uint64_t b) {
static_assert(
BITS / 32 > 0 && BITS % 32 == 0,
"Template parameter BITS must be a positive multiple of 32.");
pn[0] = (unsigned int)b;
pn[1] = (unsigned int)(b >> 32);
for (int i = 2; i < WIDTH; i++) {
pn[i] = 0;
}
}
explicit base_uint(const std::string &str);
const base_uint operator~() const {
base_uint ret;
for (int i = 0; i < WIDTH; i++) {
ret.pn[i] = ~pn[i];
}
return ret;
}
const base_uint operator-() const {
base_uint ret;
for (int i = 0; i < WIDTH; i++) {
ret.pn[i] = ~pn[i];
}
++ret;
return ret;
}
double getdouble() const;
base_uint &operator=(uint64_t b) {
pn[0] = (unsigned int)b;
pn[1] = (unsigned int)(b >> 32);
for (int i = 2; i < WIDTH; i++) {
pn[i] = 0;
}
return *this;
}
base_uint &operator^=(const base_uint &b) {
for (int i = 0; i < WIDTH; i++) {
pn[i] ^= b.pn[i];
}
return *this;
}
base_uint &operator&=(const base_uint &b) {
for (int i = 0; i < WIDTH; i++) {
pn[i] &= b.pn[i];
}
return *this;
}
base_uint &operator|=(const base_uint &b) {
for (int i = 0; i < WIDTH; i++) {
pn[i] |= b.pn[i];
}
return *this;
}
base_uint &operator^=(uint64_t b) {
pn[0] ^= (unsigned int)b;
pn[1] ^= (unsigned int)(b >> 32);
return *this;
}
base_uint &operator|=(uint64_t b) {
pn[0] |= (unsigned int)b;
pn[1] |= (unsigned int)(b >> 32);
return *this;
}
base_uint &operator<<=(unsigned int shift);
base_uint &operator>>=(unsigned int shift);
base_uint &operator+=(const base_uint &b) {
uint64_t carry = 0;
for (int i = 0; i < WIDTH; i++) {
uint64_t n = carry + pn[i] + b.pn[i];
pn[i] = n & 0xffffffff;
carry = n >> 32;
}
return *this;
}
base_uint &operator-=(const base_uint &b) {
*this += -b;
return *this;
}
base_uint &operator+=(uint64_t b64) {
base_uint b;
b = b64;
*this += b;
return *this;
}
base_uint &operator-=(uint64_t b64) {
base_uint b;
b = b64;
*this += -b;
return *this;
}
base_uint &operator*=(uint32_t b32);
base_uint &operator*=(const base_uint &b);
base_uint &operator/=(const base_uint &b);
base_uint &operator++() {
// prefix operator
int i = 0;
while (i < WIDTH && ++pn[i] == 0) {
i++;
}
return *this;
}
const base_uint operator++(int) {
// postfix operator
const base_uint ret = *this;
++(*this);
return ret;
}
base_uint &operator--() {
// prefix operator
int i = 0;
while (i < WIDTH && --pn[i] == std::numeric_limits<uint32_t>::max()) {
i++;
}
return *this;
}
const base_uint operator--(int) {
// postfix operator
const base_uint ret = *this;
--(*this);
return ret;
}
int CompareTo(const base_uint &b) const;
bool EqualTo(uint64_t b) const;
friend inline const base_uint operator+(const base_uint &a,
const base_uint &b) {
return base_uint(a) += b;
}
friend inline const base_uint operator-(const base_uint &a,
const base_uint &b) {
return base_uint(a) -= b;
}
friend inline const base_uint operator*(const base_uint &a,
const base_uint &b) {
return base_uint(a) *= b;
}
friend inline const base_uint operator/(const base_uint &a,
const base_uint &b) {
return base_uint(a) /= b;
}
friend inline const base_uint operator|(const base_uint &a,
const base_uint &b) {
return base_uint(a) |= b;
}
friend inline const base_uint operator&(const base_uint &a,
const base_uint &b) {
return base_uint(a) &= b;
}
friend inline const base_uint operator^(const base_uint &a,
const base_uint &b) {
return base_uint(a) ^= b;
}
friend inline const base_uint operator>>(const base_uint &a, int shift) {
return base_uint(a) >>= shift;
}
friend inline const base_uint operator<<(const base_uint &a, int shift) {
return base_uint(a) <<= shift;
}
friend inline const base_uint operator*(const base_uint &a, uint32_t b) {
return base_uint(a) *= b;
}
friend inline bool operator==(const base_uint &a, const base_uint &b) {
return memcmp(a.pn, b.pn, sizeof(a.pn)) == 0;
}
friend inline bool operator!=(const base_uint &a, const base_uint &b) {
return memcmp(a.pn, b.pn, sizeof(a.pn)) != 0;
}
friend inline bool operator>(const base_uint &a, const base_uint &b) {
return a.CompareTo(b) > 0;
}
friend inline bool operator<(const base_uint &a, const base_uint &b) {
return a.CompareTo(b) < 0;
}
friend inline bool operator>=(const base_uint &a, const base_uint &b) {
return a.CompareTo(b) >= 0;
}
friend inline bool operator<=(const base_uint &a, const base_uint &b) {
return a.CompareTo(b) <= 0;
}
friend inline bool operator==(const base_uint &a, uint64_t b) {
return a.EqualTo(b);
}
friend inline bool operator!=(const base_uint &a, uint64_t b) {
return !a.EqualTo(b);
}
std::string GetHex() const;
void SetHex(const char *psz);
void SetHex(const std::string &str);
std::string ToString() const;
unsigned int size() const { return sizeof(pn); }
/**
* Returns the position of the highest bit set plus one, or zero if the
* value is zero.
*/
unsigned int bits() const;
uint64_t GetLow64() const {
static_assert(WIDTH >= 2, "Assertion WIDTH >= 2 failed (WIDTH = BITS / "
"32). BITS is a template parameter.");
return pn[0] | uint64_t(pn[1]) << 32;
}
};
/** 256-bit unsigned big integer. */
class arith_uint256 : public base_uint<256> {
public:
arith_uint256() {}
arith_uint256(const base_uint<256> &b) : base_uint<256>(b) {}
arith_uint256(uint64_t b) : base_uint<256>(b) {}
explicit arith_uint256(const std::string &str) : base_uint<256>(str) {}
/**
* The "compact" format is a representation of a whole number N using an
* unsigned 32bit number similar to a floating point format.
* The most significant 8 bits are the unsigned exponent of base 256.
* This exponent can be thought of as "number of bytes of N".
* The lower 23 bits are the mantissa.
* Bit number 24 (0x800000) represents the sign of N.
* N = (-1^sign) * mantissa * 256^(exponent-3)
*
* Satoshi's original implementation used BN_bn2mpi() and BN_mpi2bn().
* MPI uses the most significant bit of the first byte as sign.
* Thus 0x1234560000 is compact (0x05123456)
* and 0xc0de000000 is compact (0x0600c0de)
*
* Bitcoin only uses this "compact" format for encoding difficulty targets,
* which are unsigned 256bit quantities. Thus, all the complexities of the
* sign bit and using base 256 are probably an implementation accident.
*/
arith_uint256 &SetCompact(uint32_t nCompact, bool *pfNegative = nullptr,
bool *pfOverflow = nullptr);
uint32_t GetCompact(bool fNegative = false) const;
friend uint256 ArithToUint256(const arith_uint256 &);
friend arith_uint256 UintToArith256(const uint256 &);
};
uint256 ArithToUint256(const arith_uint256 &);
arith_uint256 UintToArith256(const uint256 &);
#endif // BITCOIN_ARITH_UINT256_H

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