c
size_t bufferSize = ...; // Total size of pDstData buffer
size_t offset = (size_t)nXDst * dstBytesPerPixel + (size_t)nYDst * nDstStep;

if (offset >= bufferSize) {
    // Handle overflow error
    return NULL;
}

const BYTE* pDstStart = &pDstData[offset];
