c
#include <stddef.h>

size_t xOffset = (size_t)nXDst * dstBytesPerPixel;
size_t yOffset = (size_t)nYDst * nDstStep;
if (xOffset > SIZE_MAX - yOffset) {
    // Handle overflow error
    return FALSE;
}
size_t totalOffset = xOffset + yOffset;
if (totalOffset > (size_t)(pDstData - (BYTE*)NULL)) {
    // Handle out-of-bounds error
    return FALSE;
}
const BYTE* pDstStart = &pDstData[totalOffset];
