[MPlayer-dev-eng] [BUG][PATCH] gif library incompatibility fixes

[Joey Parrish]

Hello,

Attached below are two patches to help fix incompatibilities between gif
library versions.  The first adds an extra check to configure that looks
for advanced functionality preferred by demux_gif.  If no such function
is found, then a workaround is enabled.  The second patch will make
configure check for libungif before libgif.  Since I am now aware of the
need for libungif's special functions, I believe configure should prefer
libungif over libgif in all cases.  These patches are intended for both
0_90 and main.

Thanks,
--Joey
-------------- next part --------------
diff -ur 0_90.cvs/configure 0_90.dev/configure
--- 0_90.cvs/configure	Thu Feb 13 15:57:26 2003
+++ 0_90.dev/configure	Thu Feb 13 16:37:06 2003
@@ -2960,6 +2960,27 @@
 echores "$_gif"
 
 
+if test "$_gif" = yes ; then
+  echocheck "broken giflib workaround"
+  _def_gif_tvt_hack='#define HAVE_GIF_TVT_HACK 1'
+
+  cat > $TMPC << EOF
+#include <gif_lib.h>
+int main(void) {
+  GifFileType gif;
+  printf("UserData is at address %p\n", gif.UserData);
+  return 0;
+}
+EOF
+  if cc_check "$_ld_gif" && ( "$TMPO" ) >>"$TMPLOG" 2>&1 ; then
+    _def_gif_tvt_hack='#undef HAVE_GIF_TVT_HACK'
+    echores "disabled"
+  else
+    echores "enabled"
+  fi
+fi
+
+
 if test "$_vesa" != no ; then
 echocheck "VESA support"
 if x86 && linux ; then
@@ -5275,6 +5296,7 @@
 /* enable GIF support */
 $_def_gif
 $_def_gif_4
+$_def_gif_tvt_hack
 
 /* enable FreeType support */
 $_def_freetype
diff -ur 0_90.cvs/libmpdemux/demux_gif.c 0_90.dev/libmpdemux/demux_gif.c
--- 0_90.cvs/libmpdemux/demux_gif.c	Sat Feb  8 11:29:43 2003
+++ 0_90.dev/libmpdemux/demux_gif.c	Thu Feb 13 16:37:36 2003
@@ -24,9 +24,12 @@
 
 #define GIF_SIGNATURE (('G' << 16) | ('I' << 8) | 'F')
 
+#ifndef HAVE_GIF_TVT_HACK
+// not supported by certain versions of the library
 int my_read_gif(GifFileType *gif, uint8_t *buf, int len) {
   return stream_read(gif->UserData, buf, len);
 }
+#endif
   
 int gif_check_file(demuxer_t *demuxer)
 {
@@ -156,7 +159,17 @@
   // go back to the beginning
   stream_seek(demuxer->stream,demuxer->stream->start_pos);
 
+#ifdef HAVE_GIF_TVT_HACK
+  // without the TVT functionality of libungif, a hard seek must be
+  // done to the beginning of the file.  this is because libgif is
+  // unable to use mplayer's cache, and without this lseek libgif will
+  // not read from the beginning of the file and the command will fail.
+  // with this hack enabled, you will lose the ability to stream a GIF.
+  lseek(demuxer->stream->fd, 0, SEEK_SET);
+  gif = DGifOpenFileHandle(demuxer->stream->fd);
+#else
   gif = DGifOpen(demuxer->stream, my_read_gif);
+#endif
   if (!gif) {
     PrintGifError();
     return NULL;
-------------- next part --------------
diff -ur 0_90.cvs/configure 0_90.dev/configure
--- 0_90.cvs/configure	Thu Feb 13 15:57:26 2003
+++ 0_90.dev/configure	Sat Feb 15 11:50:32 2003
@@ -2911,18 +2911,18 @@
   return 0;
 }
 EOF
-  if cc_check -lgif && "$TMPO" >> "$TMPLOG" ; then
-    _gif=yes
-    _ld_gif="-lgif"
-  elif cc_check -lungif && "$TMPO" >> "$TMPLOG" ; then
+  if cc_check -lungif && "$TMPO" >> "$TMPLOG" ; then
     _gif=yes
     _ld_gif="-lungif"
-  elif cc_check -lgif $_ld_x11 && "$TMPO" >> "$TMPLOG" ; then
-    _gif=yes
-    _ld_gif="-lgif $_ld_x11"
   elif cc_check -lungif $_ld_x11 && "$TMPO" >> "$TMPLOG" ; then
     _gif=yes
     _ld_gif="-lungif $_ld_x11"
+  elif cc_check -lgif && "$TMPO" >> "$TMPLOG" ; then
+    _gif=yes
+    _ld_gif="-lgif"
+  elif cc_check -lgif $_ld_x11 && "$TMPO" >> "$TMPLOG" ; then
+    _gif=yes
+    _ld_gif="-lgif $_ld_x11"
   fi
 fi