[FFmpeg-devel] [PATCH] Mask away AVSEEK_FORCE properly in some checks in url_fseek()

[Michael Niedermayer]

On Tue, Mar 23, 2010 at 01:20:58PM +0100, Tomas H?rdin wrote:
> Hi
> 
> I've a bug in url_fseek(): it always returns AVERROR(EINVAL) when whence
> has AVSEEK_FORCE. The solution is to simply mask away AVSEEK_FORCE in
> the three places whence is tested for equality. Patch attached.
> 
> /Tomas

>  aviobuf.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> a9aec82352efcaf60fa32c246de99219439aa769  whencefix.patch
> diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
> index da05251..b3d055d 100644
> --- a/libavformat/aviobuf.c
> +++ b/libavformat/aviobuf.c
> @@ -136,10 +136,10 @@ int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence)
>  
>      pos = s->pos - (s->write_flag ? 0 : (s->buf_end - s->buffer));
>  
> -    if (whence != SEEK_CUR && whence != SEEK_SET)
> +    if ((whence & ~AVSEEK_FORCE) != SEEK_CUR && (whence & ~AVSEEK_FORCE) != SEEK_SET)
>          return AVERROR(EINVAL);
>  
> -    if (whence == SEEK_CUR) {
> +    if ((whence & ~AVSEEK_FORCE) == SEEK_CUR) {
>          offset1 = pos + (s->buf_ptr - s->buffer);
>          if (offset == 0)
>              return offset1;

int force= whence & AVSEEK_FORCE;
whence &= ~AVSEEK_FORCE;
seems more readable to me

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Breaking DRM is a little like attempting to break through a door even
though the window is wide open and the only thing in the house is a bunch
of things you dont want and which you would get tomorrow for free anyway
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