void KeccakP1600times4_ExtractAndAddBytes()

in src/sha3/keccak4x/KeccakP-1600-times4-SIMD256.c [341:378]

• 35 lines of code
• 8 McCabe index (conditional complexity)

void KeccakP1600times4_ExtractAndAddBytes(const void *states, unsigned int instanceIndex, const unsigned char *input, unsigned char *output, unsigned int offset, unsigned int length)
{
    unsigned int sizeLeft = length;
    unsigned int lanePosition = offset/SnP_laneLengthInBytes;
    unsigned int offsetInLane = offset%SnP_laneLengthInBytes;
    const unsigned char *curInput = input;
    unsigned char *curOutput = output;
    const UINT64 *statesAsLanes = (const UINT64 *)states;

    if ((sizeLeft > 0) && (offsetInLane != 0)) {
        unsigned int bytesInLane = SnP_laneLengthInBytes - offsetInLane;
        UINT64 lane = statesAsLanes[laneIndex(instanceIndex, lanePosition)] >> (8 * offsetInLane);
        if (bytesInLane > sizeLeft)
            bytesInLane = sizeLeft;
        sizeLeft -= bytesInLane;
        do {
            *(curOutput++) = *(curInput++) ^ (unsigned char)lane;
            lane >>= 8;
        } while ( --bytesInLane != 0);
        lanePosition++;
    }

    while(sizeLeft >= SnP_laneLengthInBytes) {
        *((UINT64*)curOutput) = *((UINT64*)curInput) ^ statesAsLanes[laneIndex(instanceIndex, lanePosition)];
        sizeLeft -= SnP_laneLengthInBytes;
        lanePosition++;
        curInput += SnP_laneLengthInBytes;
        curOutput += SnP_laneLengthInBytes;
    }

    if (sizeLeft != 0) {
        UINT64 lane = statesAsLanes[laneIndex(instanceIndex, lanePosition)];
        do {
            *(curOutput++) = *(curInput++) ^ (unsigned char)lane;
            lane >>= 8;
        } while ( --sizeLeft != 0);
    }
}