[FFmpeg-devel] [PATCH] fix av_url_read_fseek

[Michael Niedermayer]

On Sat, Apr 10, 2010 at 04:37:36PM -0700, Howard Chu wrote:
> Michael Niedermayer wrote:
>> On Sat, Apr 10, 2010 at 09:26:31AM -0700, Howard Chu wrote:
>>> Index: libavformat/aviobuf.c
>>> ===================================================================
>>> --- libavformat/aviobuf.c	(revision 22813)
>>> +++ libavformat/aviobuf.c	(working copy)
>>> @@ -698,8 +698,11 @@
>>>           return AVERROR(ENOSYS);
>>>       ret = s->read_seek(h, stream_index, timestamp, flags);
>>>       if(ret>= 0) {
>>> +        int64_t pos;
>>>           s->buf_ptr = s->buf_end; // Flush buffer
>>> -        s->pos = s->seek(h, 0, SEEK_CUR);
>>> +        pos = s->seek(h, 0, SEEK_CUR);
>>> +        if (pos != AVERROR(ENOSYS))
>>> +            s->pos = pos;
>>>       }
>>>       return ret;
>>>   }
>>
>> this should be a seperate patch
>
> Protocols that implement read_seek are unlikely to also implement seek, so 
> this patch is needed to prevent the pos from getting set to a negative 
> value. Possibly it should just check for pos <= 0 instead of checking for 
> any specific error code. It's not clear that there's any real point to 
> calling seek here anyway, any stream that knows the value of SEEK_CUR would 
> have already updated itself while executing the read_seek.
> -- 
>   -- Howard Chu
>   CTO, Symas Corp.           http://www.symas.com
>   Director, Highland Sun     http://highlandsun.com/hyc/
>   Chief Architect, OpenLDAP  http://www.openldap.org/project/

> Index: libavformat/aviobuf.c
> ===================================================================
> --- libavformat/aviobuf.c	(revision 22813)
> +++ libavformat/aviobuf.c	(working copy)
> @@ -698,8 +698,11 @@
>          return AVERROR(ENOSYS);
>      ret = s->read_seek(h, stream_index, timestamp, flags);
>      if(ret >= 0) {
> +        int64_t pos;
>          s->buf_ptr = s->buf_end; // Flush buffer
> -        s->pos = s->seek(h, 0, SEEK_CUR);
> +        pos = s->seek(h, 0, SEEK_CUR);
> +        if (pos != AVERROR(ENOSYS))
> +            s->pos = pos;

should that check not be <0 ?


[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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