josephnicholas
6 years ago
6 changed files with 584 additions and 32 deletions
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// 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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#include "arith_uint256.h" |
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#include "uint256.h" |
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#include "utilstrencodings.h" |
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#include "crypto/common.h" |
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#include <stdio.h> |
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#include <string.h> |
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template <unsigned int BITS> |
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base_uint<BITS>::base_uint(const std::string& str) |
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{ |
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SetHex(str); |
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} |
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template <unsigned int BITS> |
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base_uint<BITS>& base_uint<BITS>::operator<<=(unsigned int shift) |
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{ |
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base_uint<BITS> 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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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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template <unsigned int BITS> |
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base_uint<BITS>& base_uint<BITS>::operator>>=(unsigned int shift) |
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{ |
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base_uint<BITS> 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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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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template <unsigned int BITS> |
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base_uint<BITS>& base_uint<BITS>::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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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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template <unsigned int BITS> |
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base_uint<BITS>& base_uint<BITS>::operator*=(const base_uint& b) |
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{ |
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base_uint<BITS> 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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template <unsigned int BITS> |
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base_uint<BITS>& base_uint<BITS>::operator/=(const base_uint& b) |
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{ |
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base_uint<BITS> div = b; // make a copy, so we can shift.
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base_uint<BITS> 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 num 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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template <unsigned int BITS> |
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int base_uint<BITS>::CompareTo(const base_uint<BITS>& b) const |
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{ |
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for (int i = 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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template <unsigned int BITS> |
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bool base_uint<BITS>::EqualTo(uint64_t b) const |
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{ |
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for (int i = 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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template <unsigned int BITS> |
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double base_uint<BITS>::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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template <unsigned int BITS> |
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std::string base_uint<BITS>::GetHex() const |
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{ |
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return ArithToUint256(*this).GetHex(); |
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} |
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template <unsigned int BITS> |
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void base_uint<BITS>::SetHex(const char* psz) |
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{ |
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*this = UintToArith256(uint256S(psz)); |
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} |
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template <unsigned int BITS> |
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void base_uint<BITS>::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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template <unsigned int BITS> |
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std::string base_uint<BITS>::ToString() const |
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{ |
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return (GetHex()); |
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} |
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template <unsigned int BITS> |
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unsigned int base_uint<BITS>::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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// Explicit instantiations for base_uint<256>
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template base_uint<256>::base_uint(const std::string&); |
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template base_uint<256>& base_uint<256>::operator<<=(unsigned int); |
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template base_uint<256>& base_uint<256>::operator>>=(unsigned int); |
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template base_uint<256>& base_uint<256>::operator*=(uint32_t b32); |
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template base_uint<256>& base_uint<256>::operator*=(const base_uint<256>& b); |
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template base_uint<256>& base_uint<256>::operator/=(const base_uint<256>& b); |
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template int base_uint<256>::CompareTo(const base_uint<256>&) const; |
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template bool base_uint<256>::EqualTo(uint64_t) const; |
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template double base_uint<256>::getdouble() const; |
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template std::string base_uint<256>::GetHex() const; |
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template std::string base_uint<256>::ToString() const; |
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template void base_uint<256>::SetHex(const char*); |
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template void base_uint<256>::SetHex(const std::string&); |
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template unsigned int base_uint<256>::bits() const; |
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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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arith_uint256& arith_uint256::SetCompact(uint32_t nCompact, bool* pfNegative, bool* pfOverflow) |
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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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nWord >>= 8 * (3 - nSize); |
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*this = nWord; |
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} else { |
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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 arith_uint256::GetCompact(bool fNegative) const |
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{ |
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int nSize = (bits() + 7) / 8; |
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uint32_t nCompact = 0; |
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if (nSize <= 3) { |
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nCompact = GetLow64() << 8 * (3 - nSize); |
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} else { |
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arith_uint256 bn = *this >> 8 * (nSize - 3); |
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nCompact = bn.GetLow64(); |
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} |
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// The 0x00800000 bit denotes the sign.
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// Thus, if it is already set, divide the mantissa by 256 and increase the exponent.
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if (nCompact & 0x00800000) { |
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nCompact >>= 8; |
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nSize++; |
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} |
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assert((nCompact & ~0x007fffff) == 0); |
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assert(nSize < 256); |
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nCompact |= nSize << 24; |
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nCompact |= (fNegative && (nCompact & 0x007fffff) ? 0x00800000 : 0); |
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return nCompact; |
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} |
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uint256 ArithToUint256(const arith_uint256 &a) |
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{ |
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uint256 b; |
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for(int x=0; x<a.WIDTH; ++x) |
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WriteLE32(b.begin() + x*4, a.pn[x]); |
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return b; |
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} |
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arith_uint256 UintToArith256(const uint256 &a) |
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{ |
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arith_uint256 b; |
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for(int x=0; x<b.WIDTH; ++x) |
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b.pn[x] = ReadLE32(a.begin() + x*4); |
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return b; |
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} |
@ -0,0 +1,290 @@ |
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// 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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|
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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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|
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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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Loading…
Reference in new issue