556 lines
15 KiB
C++
556 lines
15 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2014 The Bitcoin developers
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// Distributed under the MIT/X11 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_UINT256_H
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#define BITCOIN_UINT256_H
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#include <assert.h>
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#include <stdexcept>
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#include <stdint.h>
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#include <stdio.h>
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#include <string>
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#include <string.h>
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#include <vector>
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extern const signed char p_util_hexdigit[256]; // defined in util.cpp
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inline signed char HexDigit(char c)
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{
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return p_util_hexdigit[(unsigned char)c];
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}
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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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private:
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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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{
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SetHex(str);
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}
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explicit base_uint(const std::vector<unsigned char>& vch)
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{
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if (vch.size() != sizeof(pn))
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throw uint_error("Converting vector of wrong size to base_uint");
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memcpy(pn, &vch[0], sizeof(pn));
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}
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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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{
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double ret = 0.0;
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double fact = 1.0;
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for (int i = 0; i < WIDTH; i++) {
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ret += fact * pn[i];
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fact *= 4294967296.0;
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}
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return ret;
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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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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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{
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base_uint a(*this);
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for (int i = 0; i < WIDTH; i++)
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pn[i] = 0;
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int k = shift / 32;
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shift = shift % 32;
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for (int i = 0; i < WIDTH; i++)
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{
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if (i+k+1 < WIDTH && shift != 0)
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pn[i+k+1] |= (a.pn[i] >> (32-shift));
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if (i+k < WIDTH)
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pn[i+k] |= (a.pn[i] << shift);
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}
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return *this;
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}
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base_uint& operator>>=(unsigned int shift)
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{
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base_uint a(*this);
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for (int i = 0; i < WIDTH; i++)
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pn[i] = 0;
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int k = shift / 32;
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shift = shift % 32;
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for (int i = 0; i < WIDTH; i++)
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{
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if (i-k-1 >= 0 && shift != 0)
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pn[i-k-1] |= (a.pn[i] << (32-shift));
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if (i-k >= 0)
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pn[i-k] |= (a.pn[i] >> shift);
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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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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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{
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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 + (uint64_t)b32 * 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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base_uint a = *this;
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*this = 0;
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for (int j = 0; j < WIDTH; j++) {
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uint64_t carry = 0;
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for (int i = 0; i + j < WIDTH; i++) {
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uint64_t n = carry + pn[i + j] + (uint64_t)a.pn[j] * b.pn[i];
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pn[i + j] = n & 0xffffffff;
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carry = n >> 32;
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}
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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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base_uint div = b; // make a copy, so we can shift.
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base_uint num = *this; // make a copy, so we can subtract.
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*this = 0; // the quotient.
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int num_bits = num.bits();
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int div_bits = div.bits();
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if (div_bits == 0)
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throw uint_error("Division by zero");
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if (div_bits > num_bits) // the result is certainly 0.
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return *this;
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int shift = num_bits - div_bits;
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div <<= shift; // shift so that div and nun align.
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while (shift >= 0) {
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if (num >= div) {
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num -= div;
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pn[shift / 32] |= (1 << (shift & 31)); // set a bit of the result.
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}
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div >>= 1; // shift back.
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shift--;
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}
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// num now contains the remainder of the division.
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return *this;
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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] == 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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for (int i = base_uint::WIDTH-1; i >= 0; i--) {
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if (pn[i] < b.pn[i])
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return -1;
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if (pn[i] > b.pn[i])
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return 1;
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}
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return 0;
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}
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bool EqualTo(uint64_t b) const {
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for (int i = base_uint::WIDTH-1; i >= 2; i--) {
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if (pn[i])
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return false;
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}
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if (pn[1] != (b >> 32))
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return false;
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if (pn[0] != (b & 0xfffffffful))
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return false;
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return true;
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}
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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 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, 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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{
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char psz[sizeof(pn)*2 + 1];
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for (unsigned int i = 0; i < sizeof(pn); i++)
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sprintf(psz + i*2, "%02x", ((unsigned char*)pn)[sizeof(pn) - i - 1]);
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return std::string(psz, psz + sizeof(pn)*2);
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}
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void SetHex(const char* psz)
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{
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memset(pn,0,sizeof(pn));
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// skip leading spaces
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while (isspace(*psz))
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psz++;
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// skip 0x
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if (psz[0] == '0' && tolower(psz[1]) == 'x')
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psz += 2;
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// hex string to uint
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const char* pbegin = psz;
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while (::HexDigit(*psz) != -1)
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psz++;
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psz--;
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unsigned char* p1 = (unsigned char*)pn;
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unsigned char* pend = p1 + WIDTH * 4;
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while (psz >= pbegin && p1 < pend)
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{
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*p1 = ::HexDigit(*psz--);
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if (psz >= pbegin)
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{
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*p1 |= ((unsigned char)::HexDigit(*psz--) << 4);
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p1++;
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}
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}
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}
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void SetHex(const std::string& str)
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{
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SetHex(str.c_str());
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}
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std::string ToString() const
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{
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return (GetHex());
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}
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unsigned char* begin()
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{
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return (unsigned char*)&pn[0];
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}
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unsigned char* end()
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{
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return (unsigned char*)&pn[WIDTH];
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}
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const unsigned char* begin() const
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{
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return (unsigned char*)&pn[0];
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}
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const unsigned char* end() const
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{
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return (unsigned char*)&pn[WIDTH];
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}
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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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// 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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unsigned int bits() const
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{
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for (int pos = WIDTH-1; pos >= 0; pos--) {
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if (pn[pos]) {
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for (int bits = 31; bits > 0; bits--) {
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if (pn[pos] & 1<<bits)
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return 32*pos + bits + 1;
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}
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return 32*pos + 1;
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}
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}
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return 0;
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}
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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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unsigned int GetSerializeSize(int nType, int nVersion) const
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{
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return sizeof(pn);
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}
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template<typename Stream>
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void Serialize(Stream& s, int nType, int nVersion) const
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{
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s.write((char*)pn, sizeof(pn));
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}
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template<typename Stream>
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void Unserialize(Stream& s, int nType, int nVersion)
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{
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s.read((char*)pn, sizeof(pn));
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}
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};
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/** 160-bit unsigned big integer. */
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class uint160 : public base_uint<160> {
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public:
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uint160() {}
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uint160(const base_uint<160>& b) : base_uint<160>(b) {}
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uint160(uint64_t b) : base_uint<160>(b) {}
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explicit uint160(const std::string& str) : base_uint<160>(str) {}
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explicit uint160(const std::vector<unsigned char>& vch) : base_uint<160>(vch) {}
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};
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/** 256-bit unsigned big integer. */
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class uint256 : public base_uint<256> {
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public:
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uint256() {}
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uint256(const base_uint<256>& b) : base_uint<256>(b) {}
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uint256(uint64_t b) : base_uint<256>(b) {}
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explicit uint256(const std::string& str) : base_uint<256>(str) {}
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explicit uint256(const std::vector<unsigned char>& vch) : base_uint<256>(vch) {}
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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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// (0x05c0de00) would be -0x40de000000
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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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// This implementation directly uses shifts instead of going
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// through an intermediate MPI representation.
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uint256& SetCompact(uint32_t nCompact, bool *pfNegative = NULL, bool *pfOverflow = NULL)
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{
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int nSize = nCompact >> 24;
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uint32_t nWord = nCompact & 0x007fffff;
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if (nSize <= 3)
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{
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nWord >>= 8*(3-nSize);
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*this = nWord;
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}
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else
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{
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*this = nWord;
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*this <<= 8*(nSize-3);
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}
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if (pfNegative)
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*pfNegative = nWord != 0 && (nCompact & 0x00800000) != 0;
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if (pfOverflow)
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*pfOverflow = nWord != 0 && ((nSize > 34) ||
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(nWord > 0xff && nSize > 33) ||
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(nWord > 0xffff && nSize > 32));
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return *this;
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}
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uint32_t GetCompact(bool fNegative = false) const
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{
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|
int nSize = (bits() + 7) / 8;
|
|
uint32_t nCompact = 0;
|
|
if (nSize <= 3)
|
|
nCompact = GetLow64() << 8*(3-nSize);
|
|
else
|
|
{
|
|
uint256 bn = *this >> 8*(nSize-3);
|
|
nCompact = bn.GetLow64();
|
|
}
|
|
// The 0x00800000 bit denotes the sign.
|
|
// Thus, if it is already set, divide the mantissa by 256 and increase the exponent.
|
|
if (nCompact & 0x00800000)
|
|
{
|
|
nCompact >>= 8;
|
|
nSize++;
|
|
}
|
|
assert((nCompact & ~0x007fffff) == 0);
|
|
assert(nSize < 256);
|
|
nCompact |= nSize << 24;
|
|
nCompact |= (fNegative && (nCompact & 0x007fffff) ? 0x00800000 : 0);
|
|
return nCompact;
|
|
}
|
|
};
|
|
|
|
#endif
|