6bd0dc2a84
Remove initialization from vector (as this is only used in the tests). Also implement SetHex and GetHex in terms of uint256, to avoid duplicate code as well as avoid endianness issues (as they work in term of bytes).
291 lines
8.4 KiB
C++
291 lines
8.4 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2014 The Bitcoin 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_UINT256_H
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