读取资源中的GIF文件相应像素宽高度

代码参考了如下网页的实现：

https://www.cnblogs.com/zy791976083/p/9921069.html

整理成一个函数：

BOOL GetResGifSize(long nResId, LPCTSTR name, long *lnWidth, long *lnHeight)
{
    HRSRC hRsrc = FindResource(NULL, MAKEINTRESOURCE(nResId), name);
    if (NULL == hRsrc) {
        return FALSE;
    }

    DWORD dwSize = SizeofResource(NULL, hRsrc);
    HGLOBAL hGlobal = LoadResource(NULL, hRsrc);
    if (NULL == hGlobal) {
        CloseHandle(hRsrc);
        return FALSE;
    }

    unsigned char* pBuffer = (unsigned char*)LockResource(hGlobal);
    if (NULL == pBuffer) {
        CloseHandle(hRsrc);
        FreeResource(hGlobal);
        return FALSE;
    }

    //判断是否为GIF文件
    if(pBuffer[0] != 0x47 && pBuffer[1] != 0x49 && pBuffer[2] != 0x46 && pBuffer[3] != 0x38){
        return FALSE;
    }

    //读取宽高
    for(int i = 4; i < dwSize ; i++)
    {
        if(pBuffer[i] == 0x00 && pBuffer[i+1] == 0x2c)
        {
            *lnWidth = (pBuffer[i+7]<<8) | pBuffer[i+6];
            *lnHeight = (pBuffer[i+9]<<8) | pBuffer[i+8];
            UnlockResource(hGlobal);
            FreeResource(hGlobal);
            return TRUE;
        }
    }

    UnlockResource(hGlobal);
    FreeResource(hGlobal);

    return FALSE;
}