[Ffmpeg-cvslog] r8498 - trunk/libavcodec/lzw.c

[Baptiste Coudurier]

Michael Niedermayer wrote:
> Hi
> 
> On Sun, Mar 25, 2007 at 12:23:05AM +0100, bcoudurier wrote:
>> Author: bcoudurier
>> Date: Sun Mar 25 00:23:05 2007
>> New Revision: 8498
>>
>> Modified:
>>    trunk/libavcodec/lzw.c
>>
>> Log:
>> break if eob is reached to avoid reading one too much byte
>>
>> Modified: trunk/libavcodec/lzw.c
>> ==============================================================================
>> --- trunk/libavcodec/lzw.c	(original)
>> +++ trunk/libavcodec/lzw.c	Sun Mar 25 00:23:05 2007
>> @@ -77,6 +77,7 @@ static int lzw_get_code(struct LZWState 
>>                  s->bs = sizbuf;
>>                  if(!sizbuf) {
>>                      s->eob_reached = 1;
>> +                    break;
>>                  }
> 
> * this check does not prevent reading over the end

at least it stops reading before the end.

> * this check only catches one eob case in the GIF branch of the if()
> * you are not maintainer of LZW

nobody is, it works for me (tm), and Im maintainer of gif, that case if
specific to gif, so Its like I am maintainer of that part of lzw, which
was in gifdec.c before.

> * how do you know the code isnt intended to read a byte or 2 too much for
>   simplicity and optimization reasons like almost all other code in lavc
>   too?

Because buf_size is one less than what's actually read, and that's
problematic.

> considering these, please revert it

feel free to do IF you correct the code in a better way.

-- 
Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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