mirror of
https://github.com/dashpay/dash.git
synced 2024-12-25 12:02:48 +01:00
93027376bf
fa99e108e778b5169b3de2ce557af68f1fe0ac0b Fix implicit-integer-sign-change in arith_uint256 (MarcoFalke)
Pull request description:
This refactor doesn't change behaviour, but clarifies that the numbers being dealt with aren't supposed to be negative. This helps when reading the code and allows to remove a sanitizer suppression for the whole file.
ACKs for top commit:
PastaPastaPasta:
utACK fa99e108e778b5169b3de2ce557af68f1fe0ac0b
shaavan:
ACK fa99e108e778b5169b3de2ce557af68f1fe0ac0b
Tree-SHA512: f227e2fd22021e39f0445ec041f4a299d13477c23cef0fc06c53fb3313cbe550cec329336224a7e8775d9045b8009423052b394e83d42a1e40772085dfcdd471
255 lines
6.6 KiB
C++
255 lines
6.6 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
|
|
// Copyright (c) 2009-2019 The Bitcoin Core developers
|
|
// Distributed under the MIT software license, see the accompanying
|
|
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
|
|
|
|
#include <arith_uint256.h>
|
|
|
|
#include <uint256.h>
|
|
#include <crypto/common.h>
|
|
|
|
|
|
template <unsigned int BITS>
|
|
base_uint<BITS>::base_uint(const std::string& str)
|
|
{
|
|
static_assert(BITS/32 > 0 && BITS%32 == 0, "Template parameter BITS must be a positive multiple of 32.");
|
|
|
|
SetHex(str);
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
base_uint<BITS>& base_uint<BITS>::operator<<=(unsigned int shift)
|
|
{
|
|
base_uint<BITS> a(*this);
|
|
for (int i = 0; i < WIDTH; i++)
|
|
pn[i] = 0;
|
|
int k = shift / 32;
|
|
shift = shift % 32;
|
|
for (int i = 0; i < WIDTH; i++) {
|
|
if (i + k + 1 < WIDTH && shift != 0)
|
|
pn[i + k + 1] |= (a.pn[i] >> (32 - shift));
|
|
if (i + k < WIDTH)
|
|
pn[i + k] |= (a.pn[i] << shift);
|
|
}
|
|
return *this;
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
base_uint<BITS>& base_uint<BITS>::operator>>=(unsigned int shift)
|
|
{
|
|
base_uint<BITS> a(*this);
|
|
for (int i = 0; i < WIDTH; i++)
|
|
pn[i] = 0;
|
|
int k = shift / 32;
|
|
shift = shift % 32;
|
|
for (int i = 0; i < WIDTH; i++) {
|
|
if (i - k - 1 >= 0 && shift != 0)
|
|
pn[i - k - 1] |= (a.pn[i] << (32 - shift));
|
|
if (i - k >= 0)
|
|
pn[i - k] |= (a.pn[i] >> shift);
|
|
}
|
|
return *this;
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
base_uint<BITS>& base_uint<BITS>::operator*=(uint32_t b32)
|
|
{
|
|
uint64_t carry = 0;
|
|
for (int i = 0; i < WIDTH; i++) {
|
|
uint64_t n = carry + (uint64_t)b32 * pn[i];
|
|
pn[i] = n & 0xffffffff;
|
|
carry = n >> 32;
|
|
}
|
|
return *this;
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
base_uint<BITS>& base_uint<BITS>::operator*=(const base_uint& b)
|
|
{
|
|
base_uint<BITS> a;
|
|
for (int j = 0; j < WIDTH; j++) {
|
|
uint64_t carry = 0;
|
|
for (int i = 0; i + j < WIDTH; i++) {
|
|
uint64_t n = carry + a.pn[i + j] + (uint64_t)pn[j] * b.pn[i];
|
|
a.pn[i + j] = n & 0xffffffff;
|
|
carry = n >> 32;
|
|
}
|
|
}
|
|
*this = a;
|
|
return *this;
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
base_uint<BITS>& base_uint<BITS>::operator/=(const base_uint& b)
|
|
{
|
|
base_uint<BITS> div = b; // make a copy, so we can shift.
|
|
base_uint<BITS> num = *this; // make a copy, so we can subtract.
|
|
*this = 0; // the quotient.
|
|
int num_bits = num.bits();
|
|
int div_bits = div.bits();
|
|
if (div_bits == 0)
|
|
throw uint_error("Division by zero");
|
|
if (div_bits > num_bits) // the result is certainly 0.
|
|
return *this;
|
|
int shift = num_bits - div_bits;
|
|
div <<= shift; // shift so that div and num align.
|
|
while (shift >= 0) {
|
|
if (num >= div) {
|
|
num -= div;
|
|
pn[shift / 32] |= (1U << (shift & 31)); // set a bit of the result.
|
|
}
|
|
div >>= 1; // shift back.
|
|
shift--;
|
|
}
|
|
// num now contains the remainder of the division.
|
|
return *this;
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
int base_uint<BITS>::CompareTo(const base_uint<BITS>& b) const
|
|
{
|
|
for (int i = WIDTH - 1; i >= 0; i--) {
|
|
if (pn[i] < b.pn[i])
|
|
return -1;
|
|
if (pn[i] > b.pn[i])
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
bool base_uint<BITS>::EqualTo(uint64_t b) const
|
|
{
|
|
for (int i = WIDTH - 1; i >= 2; i--) {
|
|
if (pn[i])
|
|
return false;
|
|
}
|
|
if (pn[1] != (b >> 32))
|
|
return false;
|
|
if (pn[0] != (b & 0xfffffffful))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
double base_uint<BITS>::getdouble() const
|
|
{
|
|
double ret = 0.0;
|
|
double fact = 1.0;
|
|
for (int i = 0; i < WIDTH; i++) {
|
|
ret += fact * pn[i];
|
|
fact *= 4294967296.0;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
std::string base_uint<BITS>::GetHex() const
|
|
{
|
|
base_blob<BITS> b;
|
|
for (int x = 0; x < this->WIDTH; ++x) {
|
|
WriteLE32(b.begin() + x*4, this->pn[x]);
|
|
}
|
|
return b.GetHex();
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
void base_uint<BITS>::SetHex(const char* psz)
|
|
{
|
|
base_blob<BITS> b;
|
|
b.SetHex(psz);
|
|
for (int x = 0; x < this->WIDTH; ++x) {
|
|
this->pn[x] = ReadLE32(b.begin() + x*4);
|
|
}
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
void base_uint<BITS>::SetHex(const std::string& str)
|
|
{
|
|
SetHex(str.c_str());
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
std::string base_uint<BITS>::ToString() const
|
|
{
|
|
return GetHex();
|
|
}
|
|
|
|
template <unsigned int BITS>
|
|
unsigned int base_uint<BITS>::bits() const
|
|
{
|
|
for (int pos = WIDTH - 1; pos >= 0; pos--) {
|
|
if (pn[pos]) {
|
|
for (int nbits = 31; nbits > 0; nbits--) {
|
|
if (pn[pos] & 1U << nbits)
|
|
return 32 * pos + nbits + 1;
|
|
}
|
|
return 32 * pos + 1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
// Explicit instantiations for base_uint<256>
|
|
template class base_uint<256>;
|
|
|
|
// This implementation directly uses shifts instead of going
|
|
// through an intermediate MPI representation.
|
|
arith_uint256& arith_uint256::SetCompact(uint32_t nCompact, bool* pfNegative, bool* pfOverflow)
|
|
{
|
|
int nSize = nCompact >> 24;
|
|
uint32_t nWord = nCompact & 0x007fffff;
|
|
if (nSize <= 3) {
|
|
nWord >>= 8 * (3 - nSize);
|
|
*this = nWord;
|
|
} else {
|
|
*this = nWord;
|
|
*this <<= 8 * (nSize - 3);
|
|
}
|
|
if (pfNegative)
|
|
*pfNegative = nWord != 0 && (nCompact & 0x00800000) != 0;
|
|
if (pfOverflow)
|
|
*pfOverflow = nWord != 0 && ((nSize > 34) ||
|
|
(nWord > 0xff && nSize > 33) ||
|
|
(nWord > 0xffff && nSize > 32));
|
|
return *this;
|
|
}
|
|
|
|
uint32_t arith_uint256::GetCompact(bool fNegative) const
|
|
{
|
|
int nSize = (bits() + 7) / 8;
|
|
uint32_t nCompact = 0;
|
|
if (nSize <= 3) {
|
|
nCompact = GetLow64() << 8 * (3 - nSize);
|
|
} else {
|
|
arith_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 & ~0x007fffffU) == 0);
|
|
assert(nSize < 256);
|
|
nCompact |= nSize << 24;
|
|
nCompact |= (fNegative && (nCompact & 0x007fffff) ? 0x00800000 : 0);
|
|
return nCompact;
|
|
}
|
|
|
|
uint256 ArithToUint256(const arith_uint256 &a)
|
|
{
|
|
uint256 b;
|
|
for(int x=0; x<a.WIDTH; ++x)
|
|
WriteLE32(b.begin() + x*4, a.pn[x]);
|
|
return b;
|
|
}
|
|
arith_uint256 UintToArith256(const uint256 &a)
|
|
{
|
|
arith_uint256 b;
|
|
for(int x=0; x<b.WIDTH; ++x)
|
|
b.pn[x] = ReadLE32(a.begin() + x*4);
|
|
return b;
|
|
}
|