gif library incompatibility fixes and prefere libungif over libgif. Patch by Joey Parrish <joey@nicewarrior.org>

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@9464 b3059339-0415-0410-9bf9-f77b7e298cf2

2 files changed, 42 insertions, 7 deletions

diff --git a/configure b/configure
index f70152c68f..4333a03052 100755
--- a/configure
+++ b/configure
@@ -2916,18 +2916,18 @@ int main(void) {
   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
 
@@ -2965,6 +2965,27 @@ fi
 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
@@ -5293,6 +5314,7 @@ $_def_jpg
 /* enable GIF support */
 $_def_gif
 $_def_gif_4
+$_def_gif_tvt_hack
 
 /* enable FreeType support */
 $_def_freetype
diff --git a/libmpdemux/demux_gif.c b/libmpdemux/demux_gif.c
index dbc6841212..e5dcb47b9b 100644
--- a/libmpdemux/demux_gif.c
+++ b/libmpdemux/demux_gif.c
@@ -24,9 +24,12 @@ static unsigned char *pallete = NULL;
 
 #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 @@ demuxer_t* demux_open_gif(demuxer_t* demuxer)
   // 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;