Correct two more corner case problems with #1486:

1) single-page streams will have no bisection; handle the special case explicitly
2) if the bisection fails without ever successfully grabbing a page, the first-page-special-case check is unprotected and will look at uninitialized memory.

svn path=/trunk/vorbis/; revision=19171

diff --git a/lib/vorbisfile.c b/lib/vorbisfile.c
index 1b7f80a..93f663c 100644 (file)
--- a/lib/vorbisfile.c
+++ b/lib/vorbisfile.c
@@ -1437,8 +1437,21 @@ int ov_pcm_seek_page(OggVorbis_File *vf,ogg_int64_t pos){
     ogg_int64_t endtime = vf->pcmlengths[link*2+1]+begintime;
     ogg_int64_t target=pos-total+begintime;
     ogg_int64_t best=-1;
+    int         got_page=0;
 
     ogg_page og;
+
+    /* if we have only one page, there will be no bisection.  Grab the page here */
+    if(begin==end){
+      result=_seek_helper(vf,begin);
+      if(result) goto seek_error;
+
+      result=_get_next_page(vf,&og,1);
+      if(result<0) goto seek_error;
+
+      got_page=1;
+    }
+
     /* bisection loop */
     while(begin<end){
       ogg_int64_t bisect;
@@ -1482,6 +1495,7 @@ int ov_pcm_seek_page(OggVorbis_File *vf,ogg_int64_t pos){
           }
         }else{
           ogg_int64_t granulepos;
+          got_page=1;
 
           /* got a page. analyze it */
           /* only consider pages from primary vorbis stream */
@@ -1544,7 +1558,8 @@ int ov_pcm_seek_page(OggVorbis_File *vf,ogg_int64_t pos){
          bisection would 'fail' because our search target was before the
          first PCM granule position fencepost. */
 
-      if(begin == vf->dataoffsets[link] &&
+      if(got_page &&
+         begin == vf->dataoffsets[link] &&
          ogg_page_serialno(&og)==vf->serialnos[link]){
 
         /* Yes, this is the beginning-of-stream case. We already have