[FFmpeg-devel] [PATCH] move av_crc04C11DB7_update to libavutil

[Aurelien Jacobs]

Michael Niedermayer wrote:

> Hi
> 
> On Sun, Oct 28, 2007 at 06:51:19PM +0100, Baptiste Coudurier wrote:
> > Hi
> > 
> > $subject. Needed to avoid code duplication for new ogg muxer.
> > 
> > -- 
> > Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
> > SMARTJOG S.A.                                    http://www.smartjog.com
> > Key fingerprint                 8D77134D20CC9220201FC5DB0AC9325C5C1ABAAA
> > Phone: +33 1 49966312
> 
> > Index: libavutil/crc.c
> > ===================================================================
> > --- libavutil/crc.c	(revision 10867)
> > +++ libavutil/crc.c	(working copy)
> > @@ -105,6 +105,10 @@
> >      return crc;
> >  }
> >  
> > +unsigned long av_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf, unsigned int len){
> > +    return av_crc(av_crc04C11DB7, checksum, buf, len);
> > +}
> > +
> >  #ifdef TEST
> >  #undef printf
> >  main(){
> 
> libavutil is not supposed to be a place for code common between libavcodec
> and libavformat, even less so between 2 libavformat (de)muxers! but rather
> a small lib of generally usefull things av_crc04C11DB7_update() is not
> usefull outside of libavformat
> 
> so this function should stay in libavformat 

Indeed.
And I naively thought it should be moved to libavformat/crc.[ch].
But that's not possible right now. We currently can't have to .h
files with the same name in different libav* lib.
I wonder if this is intentional or if this should be fixed ?

The problems are:
 - usage of the FFMPEG_ prefix for multiple inclusion guards
     solution: use the following prefix: AVUTIL_, AVFORMAT_...
 - usage of -Ilibav* to set compiler include path
     solution: only add ffmpeg root directory to compiler include
     path, and explicitly specify directory when including files
     which are not in the same directory

I personally think it should be fixed, but if it's not, we should
probably at least add a note somewhere explaining that multiple
headers with the same name are forbidden.

Aurel