[Ffmpeg-devel] swscale and 64 bit problem (mmx code)

[Baptiste Coudurier]

Hi

Reimar D?ffinger wrote:
> Hello,
> On Thu, Mar 01, 2007 at 01:18:12PM +0000, Giancarlo Formicuccia wrote:
>> libswscale seems to be unsafe on 64 bit platforms. The problem is 
>> the 32-bit chrMmxFilter array of SwsContext, because it stores
>> pointers to allocated memory (lumMmxFilter has probably the same
>> issue).
> [...]
>> Fixing the code is not trivial, due to the many hardcoded values in the asm code...
>> Ideas?
> 
> Well, the non-SWS_ACCURATE_RND case is trivial to fix I think, see attached
> patch.
> 
> Greetings,
> Reimar D?ffinger
> 
> 
> ------------------------------------------------------------------------
> 
> Index: libswscale/swscale_template.c
> ===================================================================
> --- libswscale/swscale_template.c	(revision 22381)
> +++ libswscale/swscale_template.c	(working copy)
> @@ -3168,14 +3168,16 @@
>              }else{
>  		for(i=0; i<vLumFilterSize; i++)
>  		{
> -			lumMmxFilter[4*i+0]= (int32_t)lumSrcPtr[i];
> +			lumMmxFilter[4*i+0]= (uintptr_t)lumSrcPtr[i];
> +			lumMmxFilter[4*i+1]= (uintptr_t)lumSrcPtr[i] >> 32;
>  			lumMmxFilter[4*i+2]= 
>  			lumMmxFilter[4*i+3]= 
>  				((uint16_t)vLumFilter[dstY*vLumFilterSize + i])*0x10001;
>  		}
>  		for(i=0; i<vChrFilterSize; i++)
>  		{
> -			chrMmxFilter[4*i+0]= (int32_t)chrSrcPtr[i];
> +			chrMmxFilter[4*i+0]= (uintptr_t)chrSrcPtr[i];
> +			chrMmxFilter[4*i+1]= (uintptr_t)chrSrcPtr[i] >> 32;
>  			chrMmxFilter[4*i+2]= 
>  			chrMmxFilter[4*i+3]= 
>  				((uint16_t)vChrFilter[chrDstY*vChrFilterSize + i])*0x10001;
> 

Isn't uintptr_t optional extended type in C99 ? I don't have specs,
but Mans said last time those types were optional:
http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2007-February/052196.html

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