Method CreateHashFromInput

src/KnownFile.cpp:888–967

void CKnownFile::CreateHashFromInput(const uint8_t* input, uint32 Length, CMD4Hash* Output, CAICHHashTree* pShaHashOut )
{
	wxASSERT_MSG(Output || pShaHashOut, "Nothing to do in CreateHashFromInput");
	{ wxCHECK_RET(input, "No input to hash from in CreateHashFromInput"); }
	wxASSERT(Length <= PARTSIZE); // We never hash more than one PARTSIZE

	CMemFile data(input, Length);

	uint32 Required = Length;
	uint8  X[64*128];

	uint32	posCurrentEMBlock = 0;
	uint32	nIACHPos = 0;
	CScopedPtr<CAICHHashAlgo> pHashAlg(CAICHHashSet::GetNewHashAlgo());

	// This is all AICH.
	while (Required >= 64) {
		uint32 len = Required / 64;
		if (len > sizeof(X)/(64 * sizeof(X[0]))) {
			len = sizeof(X)/(64 * sizeof(X[0]));
		}

		data.Read(&X, len * 64);

		// SHA hash needs 180KB blocks
		if (pShaHashOut) {
			if (nIACHPos + len*64 >= EMBLOCKSIZE) {
				uint32 nToComplete = EMBLOCKSIZE - nIACHPos;
				pHashAlg->Add(X, nToComplete);
				wxASSERT( nIACHPos + nToComplete == EMBLOCKSIZE );
				pShaHashOut->SetBlockHash(EMBLOCKSIZE, posCurrentEMBlock, pHashAlg.get());
				posCurrentEMBlock += EMBLOCKSIZE;
				pHashAlg->Reset();
				pHashAlg->Add(X+nToComplete,(len*64) - nToComplete);
				nIACHPos = (len*64) - nToComplete;
			}
			else{
				pHashAlg->Add(X, len*64);
				nIACHPos += len*64;
			}
		}

		Required -= len*64;
	}
	// bytes to read
	Required = Length % 64;
	if (Required != 0){
		data.Read(&X,Required);

		if (pShaHashOut != NULL){
			if (nIACHPos + Required >= EMBLOCKSIZE){
				uint32 nToComplete = EMBLOCKSIZE - nIACHPos;
				pHashAlg->Add(X, nToComplete);
				wxASSERT( nIACHPos + nToComplete == EMBLOCKSIZE );
				pShaHashOut->SetBlockHash(EMBLOCKSIZE, posCurrentEMBlock, pHashAlg.get());
				posCurrentEMBlock += EMBLOCKSIZE;
				pHashAlg->Reset();
				pHashAlg->Add(X+nToComplete, Required - nToComplete);