Function ReadFile_Cache

src/External/CascLib/src/CascReadFile.cpp:744–772

Reads the file data from cache. Returns the number of bytes read

// Reads the file data from cache. Returns the number of bytes read
static DWORD ReadFile_Cache(TCascFile * hf, LPBYTE pbBuffer, ULONGLONG StartOffset, ULONGLONG EndOffset)
{
    // Is there a file cache at all?
    if(hf->pbFileCache != NULL && hf->FileCacheStart <= StartOffset && StartOffset < hf->FileCacheEnd)
    {
        LPBYTE pbStartBlock = hf->pbFileCache + (size_t)(StartOffset - hf->FileCacheStart);

        // Can we handle the entire request from the cache?
        if(EndOffset <= hf->FileCacheEnd)
        {
            DWORD dwBytesToCopy = (DWORD)(EndOffset - StartOffset);

            memcpy(pbBuffer, pbStartBlock, dwBytesToCopy);
            return dwBytesToCopy;
        }

        // We copy as much bytes as available. The rest is handled by normal read
        else
        {
            DWORD dwBytesToCopy = (DWORD)(hf->FileCacheEnd - StartOffset);

            memcpy(pbBuffer, pbStartBlock, dwBytesToCopy);
            return dwBytesToCopy;
        }
    }

    // Can't handle the request from the cache
    return 0;
}

// No cache at all. The entire file will be read directly to the user buffer
static DWORD ReadFile_WholeFile(TCascFile * hf, LPBYTE pbBuffer)