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https://github.com/shadps4-emu/ext-cryptopp.git
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108 lines
2.6 KiB
C++
108 lines
2.6 KiB
C++
// iterhash.cpp - written and placed in the public domain by Wei Dai
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#include "pch.h"
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#include "iterhash.h"
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#include "misc.h"
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NAMESPACE_BEGIN(CryptoPP)
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template <class T, class BASE> void IteratedHashBase<T, BASE>::Update(const byte *input, unsigned int len)
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{
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HashWordType tmp = m_countLo;
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if ((m_countLo = tmp + len) < tmp)
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m_countHi++; // carry from low to high
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m_countHi += SafeRightShift<8*sizeof(HashWordType)>(len);
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unsigned int blockSize = BlockSize();
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unsigned int num = ModPowerOf2(tmp, blockSize);
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if (num != 0) // process left over data
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{
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if ((num+len) >= blockSize)
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{
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memcpy((byte *)m_data.begin()+num, input, blockSize-num);
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HashBlock(m_data);
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input += (blockSize-num);
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len-=(blockSize - num);
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num=0;
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// drop through and do the rest
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}
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else
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{
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memcpy((byte *)m_data.begin()+num, input, len);
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return;
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}
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}
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// now process the input data in blocks of blockSize bytes and save the leftovers to m_data
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if (len >= blockSize)
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{
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if (input == (byte *)m_data.begin())
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{
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assert(len == blockSize);
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HashBlock(m_data);
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return;
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}
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else if (IsAligned<T>(input))
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{
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unsigned int leftOver = HashMultipleBlocks((T *)input, len);
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input += (len - leftOver);
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len = leftOver;
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}
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else
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do
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{ // copy input first if it's not aligned correctly
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memcpy(m_data, input, blockSize);
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HashBlock(m_data);
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input+=blockSize;
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len-=blockSize;
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} while (len >= blockSize);
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}
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memcpy(m_data, input, len);
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}
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template <class T, class BASE> byte * IteratedHashBase<T, BASE>::CreateUpdateSpace(unsigned int &size)
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{
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unsigned int blockSize = BlockSize();
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unsigned int num = ModPowerOf2(m_countLo, blockSize);
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size = blockSize - num;
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return (byte *)m_data.begin() + num;
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}
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template <class T, class BASE> unsigned int IteratedHashBase<T, BASE>::HashMultipleBlocks(const T *input, unsigned int length)
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{
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unsigned int blockSize = BlockSize();
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do
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{
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HashBlock(input);
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input += blockSize/sizeof(T);
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length -= blockSize;
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}
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while (length >= blockSize);
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return length;
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}
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template <class T, class BASE> void IteratedHashBase<T, BASE>::PadLastBlock(unsigned int lastBlockSize, byte padFirst)
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{
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unsigned int blockSize = BlockSize();
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unsigned int num = ModPowerOf2(m_countLo, blockSize);
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((byte *)m_data.begin())[num++]=padFirst;
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if (num <= lastBlockSize)
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memset((byte *)m_data.begin()+num, 0, lastBlockSize-num);
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else
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{
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memset((byte *)m_data.begin()+num, 0, blockSize-num);
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HashBlock(m_data);
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memset(m_data, 0, lastBlockSize);
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}
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}
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template <class T, class BASE> void IteratedHashBase<T, BASE>::Restart()
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{
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m_countLo = m_countHi = 0;
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Init();
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}
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NAMESPACE_END
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