Fixed some potential and actual segfaults: a lot of readers did not check if the packetizer for a track had been initialized.

ChangeLog

@@ -1,3 +1,9 @@
+2005-11-12  Moritz Bunkus  <moritz@bunkus.org>
+
+	* mkvmerge: bug fix: Fixed a couple of potential (and actual)
+	segmentation faults by accessing invalid memory addresses. Initial
+	patch for the VobSub reader by Issa on Doom9's forum.
+
 2005-11-04  Moritz Bunkus  <moritz@bunkus.org>
 
 	* mkvmerge, mmg: new feature: The names of attached files can be

src/input/r_avi.cpp

@@ -469,7 +469,7 @@ avi_reader_c::read(generic_packetizer_c *ptzr,
     return read_video();
 
   foreach(demuxer, ademuxers)
-    if (PTZR(demuxer->ptzr) == ptzr)
+    if ((-1 != demuxer->ptzr) && (PTZR(demuxer->ptzr) == ptzr))
       return read_audio(*demuxer);
 
   return FILE_STATUS_DONE;

src/input/r_matroska.cpp

@@ -173,7 +173,7 @@ kax_reader_c::packets_available() {
   int i;
 
   for (i = 0; i < tracks.size(); i++)
-    if (tracks[i]->ok && (!PTZR(tracks[i]->ptzr)->packet_available()))
+    if ((-1 != tracks[i]->ptzr) && !PTZR(tracks[i]->ptzr)->packet_available())
       return 0;
 
   if (tracks.size() == 0)

src/input/r_ogm.cpp

@@ -613,7 +613,8 @@ ogm_reader_c::packet_available() {
     return 0;
 
   for (i = 0; i < sdemuxers.size(); i++)
-    if (!PTZR(sdemuxers[i]->ptzr)->packet_available())
+    if ((-1 != sdemuxers[i]->ptzr) &&
+        !PTZR(sdemuxers[i]->ptzr)->packet_available())
       return 0;
 
   return 1;
@@ -804,7 +805,7 @@ ogm_reader_c::process_page(ogg_page *og) {
 
   duration = 0;
   dmx = find_demuxer(ogg_page_serialno(og));
-  if (dmx == NULL)
+  if ((NULL == dmx) || (-1 == dmx->ptzr))
     return;
 
   debug_enter("ogm_reader_c::process_page");

src/input/r_qtmp4.cpp

@@ -1071,7 +1071,7 @@ qtmp4_reader_c::read(generic_packetizer_c *ptzr,
   for (i = 0; i < demuxers.size(); i++) {
     qtmp4_demuxer_ptr &dmx = demuxers[i];
 
-    if (PTZR(dmx->ptzr) != ptzr)
+    if ((-1 == dmx->ptzr) || (PTZR(dmx->ptzr) != ptzr))
       continue;
 
     if (dmx->sample_size != 0) {

src/input/r_real.cpp

@@ -501,7 +501,7 @@ real_reader_c::read(generic_packetizer_c *,
 
   timecode = (int64_t)frame->timecode * 1000000ll;
   dmx = find_demuxer(frame->id);
-  if (dmx.get() == NULL) {
+  if ((dmx.get() == NULL) || (-1 == dmx->ptzr)) {
     rmff_release_frame(frame);
     return FILE_STATUS_MOREDATA;
   }
@@ -568,7 +568,7 @@ real_reader_c::deliver_audio_frames(real_demuxer_cptr dmx,
   uint32_t i;
   rv_segment_cptr segment;
 
-  if (dmx->segments.empty())
+  if (dmx->segments.empty() || (-1 == dmx->ptzr))
     return;
 
   for (i = 0; i < dmx->segments.size(); i++) {

src/input/r_usf.cpp

@@ -291,7 +291,7 @@ usf_reader_c::read(generic_packetizer_c *ptzr,
 
   track = NULL;
   for (i = 0; m_tracks.size() > i; ++i)
-    if (PTZR(m_tracks[i].m_ptzr) == ptzr) {
+    if ((-1 != m_tracks[i].m_ptzr) && (PTZR(m_tracks[i].m_ptzr) == ptzr)) {
       track = &m_tracks[i];
       break;
     }

src/input/r_vobbtn.cpp

@@ -86,6 +86,7 @@ vobbtn_reader_c::~vobbtn_reader_c() {
 void
 vobbtn_reader_c::create_packetizer(int64_t tid) {
   ti.id = tid;
+  if (demuxing_requested('s', tid))
     add_packetizer(new vobbtn_packetizer_c(this, width, height, ti));
 }
 

src/input/r_vobsub.cpp

@@ -561,7 +561,7 @@ vobsub_reader_c::read(generic_packetizer_c *ptzr,
 
   track = NULL;
   for (i = 0; i < tracks.size(); i++)
-    if (PTZR(tracks[i]->ptzr) == ptzr) {
+    if ((-1 != tracks[i]->ptzr) && (PTZR(tracks[i]->ptzr) == ptzr)) {
       track = tracks[i];
       break;
     }