iterhash.cpp

// iterhash.cpp - originally written and placed in the public domain by Wei Dai
 
#ifndef __GNUC__
#define CRYPTOPP_MANUALLY_INSTANTIATE_TEMPLATES
#endif
 
#include "iterhash.h"
#include "misc.h"
#include "cpu.h"
 
NAMESPACE_BEGIN(CryptoPP)
 
template <class T, class BASE> void IteratedHashBase<T, BASE>::Update(const byte *input, size_t length)
{
        CRYPTOPP_ASSERT(!(input == NULLPTR && length != 0));
        if (length == 0) { return; }
 
        HashWordType oldCountLo = m_countLo, oldCountHi = m_countHi;
        if ((m_countLo = oldCountLo + HashWordType(length)) < oldCountLo)
                m_countHi++;             // carry from low to high
        m_countHi += (HashWordType)SafeRightShift<8*sizeof(HashWordType)>(length);
        if (m_countHi < oldCountHi || SafeRightShift<2*8*sizeof(HashWordType)>(length) != 0)
                throw HashInputTooLong(this->AlgorithmName());
 
        const unsigned int blockSize = this->BlockSize();
        unsigned int num = ModPowerOf2(oldCountLo, blockSize);
 
        T* dataBuf = this->DataBuf();
        byte* data = (byte *)dataBuf;
 
        if (num != 0)   // process left over data
        {
                if (num+length >= blockSize)
                {
                        if (input)
                                {std::memcpy(data+num, input, blockSize-num);}
 
                        HashBlock(dataBuf);
                        input += (blockSize-num);
                        length -= (blockSize-num);
                        num = 0;
                        // drop through and do the rest
                }
                else
                {
                        if (input && length)
                                {std::memcpy(data+num, input, length);}
                        return;
                }
        }
 
        // now process the input data in blocks of blockSize bytes and save the leftovers to m_data
        if (length >= blockSize)
        {
                if (input == data)
                {
                        CRYPTOPP_ASSERT(length == blockSize);
                        HashBlock(dataBuf);
                        return;
                }
                else if (IsAligned<T>(input))
                {
                        size_t leftOver = HashMultipleBlocks((T *)(void*)input, length);
                        input += (length - leftOver);
                        length = leftOver;
                }
                else
                {
                        do
                        {   // copy input first if it's not aligned correctly
                                if (input)
                                        { std::memcpy(data, input, blockSize); }
 
                                HashBlock(dataBuf);
                                input+=blockSize;
                                length-=blockSize;
                        } while (length >= blockSize);
                }
        }
 
        if (input && data != input)
                std::memcpy(data, input, length);
}
 
template <class T, class BASE> byte * IteratedHashBase<T, BASE>::CreateUpdateSpace(size_t &size)
{
        unsigned int blockSize = this->BlockSize();
        unsigned int num = ModPowerOf2(m_countLo, blockSize);
        size = blockSize - num;
        return (byte *)DataBuf() + num;
}
 
template <class T, class BASE> size_t IteratedHashBase<T, BASE>::HashMultipleBlocks(const T *input, size_t length)
{
        const unsigned int blockSize = this->BlockSize();
        bool noReverse = NativeByteOrderIs(this->GetByteOrder());
        T* dataBuf = this->DataBuf();
 
        // Alignment checks due to http://github.com/weidai11/cryptopp/issues/690.
        // Sparc requires 8-byte aligned buffer when HashWordType is word64.
        // We also had to provide a GetAlignmentOf specialization for word64 on Sparc.
 
        do
        {
                if (noReverse)
                {
                        if (IsAligned<HashWordType>(input))
                        {
                                // Sparc bus error with non-aligned input.
                                this->HashEndianCorrectedBlock(input);
                        }
                        else
                        {
                                std::memcpy(dataBuf, input, blockSize);
                                this->HashEndianCorrectedBlock(dataBuf);
                        }
                }
                else
                {
                        if (IsAligned<HashWordType>(input))
                        {
                                // Sparc bus error with non-aligned input.
                                ByteReverse(dataBuf, input, blockSize);
                                this->HashEndianCorrectedBlock(dataBuf);
                        }
                        else
                        {
                                std::memcpy(dataBuf, input, blockSize);
                                ByteReverse(dataBuf, dataBuf, blockSize);
                                this->HashEndianCorrectedBlock(dataBuf);
                        }
                }
 
                input += blockSize/sizeof(T);
                length -= blockSize;
        }
        while (length >= blockSize);
        return length;
}
 
template <class T, class BASE> void IteratedHashBase<T, BASE>::PadLastBlock(unsigned int lastBlockSize, byte padFirst)
{
        unsigned int blockSize = this->BlockSize();
        unsigned int num = ModPowerOf2(m_countLo, blockSize);
        T* dataBuf = this->DataBuf();
        byte* data = (byte *)dataBuf;
 
        data[num++] = padFirst;
        if (num <= lastBlockSize)
                memset(data+num, 0, lastBlockSize-num);
        else
        {
                memset(data+num, 0, blockSize-num);
                HashBlock(dataBuf);
                memset(data, 0, lastBlockSize);
        }
}
 
template <class T, class BASE> void IteratedHashBase<T, BASE>::Restart()
{
        m_countLo = m_countHi = 0;
        Init();
}
 
template <class T, class BASE> void IteratedHashBase<T, BASE>::TruncatedFinal(byte *digest, size_t size)
{
        CRYPTOPP_ASSERT(digest != NULLPTR);
        this->ThrowIfInvalidTruncatedSize(size);
 
        T* dataBuf = this->DataBuf();
        T* stateBuf = this->StateBuf();
        unsigned int blockSize = this->BlockSize();
        ByteOrder order = this->GetByteOrder();
 
        PadLastBlock(blockSize - 2*sizeof(HashWordType));
        dataBuf[blockSize/sizeof(T)-2+order] = ConditionalByteReverse(order, this->GetBitCountLo());
        dataBuf[blockSize/sizeof(T)-1-order] = ConditionalByteReverse(order, this->GetBitCountHi());
 
        HashBlock(dataBuf);
 
        if (IsAligned<HashWordType>(digest) && size%sizeof(HashWordType)==0)
                ConditionalByteReverse<HashWordType>(order, (HashWordType *)(void*)digest, stateBuf, size);
        else
        {
                ConditionalByteReverse<HashWordType>(order, stateBuf, stateBuf, this->DigestSize());
                std::memcpy(digest, stateBuf, size);
        }
 
        this->Restart();                // reinit for next use
}
 
#if defined(__GNUC__) || defined(__clang__)
        template class IteratedHashBase<word64, HashTransformation>;
        template class IteratedHashBase<word64, MessageAuthenticationCode>;
 
        template class IteratedHashBase<word32, HashTransformation>;
        template class IteratedHashBase<word32, MessageAuthenticationCode>;
#endif
 
NAMESPACE_END