291 lines
8.4 KiB
C++
291 lines
8.4 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2015 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#ifndef BITCOIN_ARITH_UINT256_H
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#define BITCOIN_ARITH_UINT256_H
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#include <assert.h>
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#include <cstring>
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#include <stdexcept>
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#include <stdint.h>
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#include <string>
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#include <vector>
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class uint256;
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class uint_error : public std::runtime_error {
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public:
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explicit uint_error(const std::string& str) : std::runtime_error(str) {}
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};
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/** Template base class for unsigned big integers. */
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template<unsigned int BITS>
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class base_uint
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{
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protected:
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enum { WIDTH=BITS/32 };
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uint32_t pn[WIDTH];
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public:
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base_uint()
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{
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for (int i = 0; i < WIDTH; i++)
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pn[i] = 0;
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}
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base_uint(const base_uint& b)
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{
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for (int i = 0; i < WIDTH; i++)
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pn[i] = b.pn[i];
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}
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base_uint& operator=(const base_uint& b)
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{
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for (int i = 0; i < WIDTH; i++)
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pn[i] = b.pn[i];
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return *this;
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}
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base_uint(uint64_t b)
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{
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pn[0] = (unsigned int)b;
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pn[1] = (unsigned int)(b >> 32);
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for (int i = 2; i < WIDTH; i++)
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pn[i] = 0;
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}
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explicit base_uint(const std::string& str);
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bool operator!() const
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{
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for (int i = 0; i < WIDTH; i++)
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if (pn[i] != 0)
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return false;
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return true;
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}
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const base_uint operator~() const
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{
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base_uint ret;
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for (int i = 0; i < WIDTH; i++)
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ret.pn[i] = ~pn[i];
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return ret;
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}
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const base_uint operator-() const
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{
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base_uint ret;
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for (int i = 0; i < WIDTH; i++)
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ret.pn[i] = ~pn[i];
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ret++;
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return ret;
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}
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double getdouble() const;
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base_uint& operator=(uint64_t b)
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{
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pn[0] = (unsigned int)b;
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pn[1] = (unsigned int)(b >> 32);
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for (int i = 2; i < WIDTH; i++)
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pn[i] = 0;
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return *this;
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}
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base_uint& operator^=(const base_uint& b)
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{
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for (int i = 0; i < WIDTH; i++)
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pn[i] ^= b.pn[i];
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return *this;
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}
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base_uint& operator&=(const base_uint& b)
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{
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for (int i = 0; i < WIDTH; i++)
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pn[i] &= b.pn[i];
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return *this;
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}
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base_uint& operator|=(const base_uint& b)
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{
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for (int i = 0; i < WIDTH; i++)
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pn[i] |= b.pn[i];
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return *this;
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}
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base_uint& operator^=(uint64_t b)
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{
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pn[0] ^= (unsigned int)b;
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pn[1] ^= (unsigned int)(b >> 32);
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return *this;
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}
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base_uint& operator|=(uint64_t b)
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{
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pn[0] |= (unsigned int)b;
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pn[1] |= (unsigned int)(b >> 32);
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return *this;
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}
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base_uint& operator<<=(unsigned int shift);
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base_uint& operator>>=(unsigned int shift);
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base_uint& operator+=(const base_uint& b)
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{
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uint64_t carry = 0;
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for (int i = 0; i < WIDTH; i++)
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{
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uint64_t n = carry + pn[i] + b.pn[i];
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pn[i] = n & 0xffffffff;
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carry = n >> 32;
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}
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return *this;
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}
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base_uint& operator-=(const base_uint& b)
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{
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*this += -b;
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return *this;
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}
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base_uint& operator+=(uint64_t b64)
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{
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base_uint b;
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b = b64;
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*this += b;
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return *this;
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}
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base_uint& operator-=(uint64_t b64)
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{
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base_uint b;
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b = b64;
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*this += -b;
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return *this;
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}
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base_uint& operator*=(uint32_t b32);
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base_uint& operator*=(const base_uint& b);
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base_uint& operator/=(const base_uint& b);
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base_uint& operator++()
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{
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// prefix operator
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int i = 0;
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while (++pn[i] == 0 && i < WIDTH-1)
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i++;
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return *this;
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}
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const base_uint operator++(int)
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{
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// postfix operator
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const base_uint ret = *this;
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++(*this);
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return ret;
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}
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base_uint& operator--()
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{
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// prefix operator
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int i = 0;
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while (--pn[i] == (uint32_t)-1 && i < WIDTH-1)
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i++;
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return *this;
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}
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const base_uint operator--(int)
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{
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// postfix operator
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const base_uint ret = *this;
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--(*this);
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return ret;
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}
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int CompareTo(const base_uint& b) const;
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bool EqualTo(uint64_t b) const;
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friend inline const base_uint operator+(const base_uint& a, const base_uint& b) { return base_uint(a) += b; }
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friend inline const base_uint operator-(const base_uint& a, const base_uint& b) { return base_uint(a) -= b; }
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friend inline const base_uint operator*(const base_uint& a, const base_uint& b) { return base_uint(a) *= b; }
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friend inline const base_uint operator/(const base_uint& a, const base_uint& b) { return base_uint(a) /= b; }
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friend inline const base_uint operator|(const base_uint& a, const base_uint& b) { return base_uint(a) |= b; }
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friend inline const base_uint operator&(const base_uint& a, const base_uint& b) { return base_uint(a) &= b; }
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friend inline const base_uint operator^(const base_uint& a, const base_uint& b) { return base_uint(a) ^= b; }
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friend inline const base_uint operator>>(const base_uint& a, int shift) { return base_uint(a) >>= shift; }
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friend inline const base_uint operator<<(const base_uint& a, int shift) { return base_uint(a) <<= shift; }
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friend inline const base_uint operator*(const base_uint& a, uint32_t b) { return base_uint(a) *= b; }
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friend inline bool operator==(const base_uint& a, const base_uint& b) { return memcmp(a.pn, b.pn, sizeof(a.pn)) == 0; }
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friend inline bool operator!=(const base_uint& a, const base_uint& b) { return memcmp(a.pn, b.pn, sizeof(a.pn)) != 0; }
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friend inline bool operator>(const base_uint& a, const base_uint& b) { return a.CompareTo(b) > 0; }
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friend inline bool operator<(const base_uint& a, const base_uint& b) { return a.CompareTo(b) < 0; }
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friend inline bool operator>=(const base_uint& a, const base_uint& b) { return a.CompareTo(b) >= 0; }
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friend inline bool operator<=(const base_uint& a, const base_uint& b) { return a.CompareTo(b) <= 0; }
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friend inline bool operator==(const base_uint& a, uint64_t b) { return a.EqualTo(b); }
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friend inline bool operator!=(const base_uint& a, uint64_t b) { return !a.EqualTo(b); }
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std::string GetHex() const;
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void SetHex(const char* psz);
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void SetHex(const std::string& str);
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std::string ToString() const;
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unsigned int size() const
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{
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return sizeof(pn);
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}
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/**
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* Returns the position of the highest bit set plus one, or zero if the
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* value is zero.
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*/
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unsigned int bits() const;
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uint64_t GetLow64() const
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{
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assert(WIDTH >= 2);
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return pn[0] | (uint64_t)pn[1] << 32;
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}
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};
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/** 256-bit unsigned big integer. */
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class arith_uint256 : public base_uint<256> {
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public:
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arith_uint256() {}
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arith_uint256(const base_uint<256>& b) : base_uint<256>(b) {}
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arith_uint256(uint64_t b) : base_uint<256>(b) {}
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explicit arith_uint256(const std::string& str) : base_uint<256>(str) {}
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/**
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* The "compact" format is a representation of a whole
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* number N using an unsigned 32bit number similar to a
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* floating point format.
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* The most significant 8 bits are the unsigned exponent of base 256.
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* This exponent can be thought of as "number of bytes of N".
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* The lower 23 bits are the mantissa.
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* Bit number 24 (0x800000) represents the sign of N.
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* N = (-1^sign) * mantissa * 256^(exponent-3)
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*
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* Satoshi's original implementation used BN_bn2mpi() and BN_mpi2bn().
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* MPI uses the most significant bit of the first byte as sign.
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* Thus 0x1234560000 is compact (0x05123456)
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* and 0xc0de000000 is compact (0x0600c0de)
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*
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* Bitcoin only uses this "compact" format for encoding difficulty
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* targets, which are unsigned 256bit quantities. Thus, all the
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* complexities of the sign bit and using base 256 are probably an
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* implementation accident.
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*/
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arith_uint256& SetCompact(uint32_t nCompact, bool *pfNegative = NULL, bool *pfOverflow = NULL);
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uint32_t GetCompact(bool fNegative = false) const;
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friend uint256 ArithToUint256(const arith_uint256 &);
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friend arith_uint256 UintToArith256(const uint256 &);
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};
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uint256 ArithToUint256(const arith_uint256 &);
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arith_uint256 UintToArith256(const uint256 &);
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#endif // BITCOIN_ARITH_UINT256_H
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