move file signature validation to open_file() functions

CVS patchset: 3121
CVS date: 2002/11/01 03:36:24

3 files changed, 53 insertions, 104 deletions

diff --git a/src/demuxers/demux_idcin.c b/src/demuxers/demux_idcin.c
index 28dd3812d..58fef2806 100644
--- a/src/demuxers/demux_idcin.c
+++ b/src/demuxers/demux_idcin.c
@@ -63,7 +63,7 @@
  *     - if any bytes exceed 63, do not shift the bytes at all before
  *       transmitting them to the video decoder
  *
- * $Id: demux_idcin.c,v 1.24 2002/10/30 00:29:30 tmmm Exp $
+ * $Id: demux_idcin.c,v 1.25 2002/11/01 03:36:24 tmmm Exp $
  */
 
 #ifdef HAVE_CONFIG_H
@@ -133,7 +133,6 @@ static int demux_idcin_send_chunk(demux_plugin_t *this_gen) {
   demux_idcin_t *this = (demux_idcin_t *) this_gen;
   buf_element_t *buf = NULL;
   unsigned int command;
-  off_t current_file_pos;
   unsigned char preamble[8];
   unsigned char disk_palette[PALETTE_SIZE * 3];
   palette_entry_t palette[PALETTE_SIZE];
@@ -143,8 +142,6 @@ static int demux_idcin_send_chunk(demux_plugin_t *this_gen) {
   int current_audio_chunk = 1;
   int scale_bits;
 
-  current_file_pos = this->input->get_current_pos(this->input);
-
   /* figure out what the next data is */
   if (this->input->read(this->input, (unsigned char *)&command, 4) != 4) {
     this->status = DEMUX_FINISHED;
@@ -279,16 +276,49 @@ static int open_idcin_file(demux_idcin_t *this) {
   unsigned char header[IDCIN_HEADER_SIZE];
 
   this->input->seek(this->input, 0, SEEK_SET);
-  if (this->input->read(this->input, header, IDCIN_HEADER_SIZE) !=
+  if (this->input->read(this->input, header, IDCIN_HEADER_SIZE) != 
     IDCIN_HEADER_SIZE)
     return 0;
 
+  /*
+   * This is what you could call a "probabilistic" file check: Id CIN
+   * files don't have a definite file signature. In lieu of such a marker,
+   * perform sanity checks on the 5 header fields:
+   *  width, height: greater than 0, less than or equal to 1024
+   * audio sample rate: greater than or equal to 8000, less than or
+   *  equal to 48000, or 0 for no audio
+   * audio sample width (bytes/sample): 0 for no audio, or 1 or 2
+   * audio channels: 0 for no audio, or 1 or 2
+   */
+
+  /* check the width */
   this->video_width = LE_32(&header[0]);
+  if ((this->video_width == 0) || (this->video_width > 1024))
+    return 0;
+
+  /* check the height */
   this->video_height = LE_32(&header[4]);
+  if ((this->video_height == 0) || (this->video_height > 1024))
+    return 0;
+
+  /* check the audio sample rate */
   this->audio_sample_rate = LE_32(&header[8]);
+  if ((this->audio_sample_rate != 0) && 
+     ((this->audio_sample_rate < 8000) || (this->audio_sample_rate > 48000)))
+    return 0;
+
+  /* check the audio bytes/sample */
   this->audio_bytes_per_sample = LE_32(&header[12]);
+  if (this->audio_bytes_per_sample > 2)
+    return 0;
+
+  /* check the audio channels */
   this->audio_channels = LE_32(&header[16]);
-  this->filesize = this->input->get_length(this->input);
+  if (this->audio_channels > 2)
+    return 0;
+
+  /* if execution got this far, qualify it as a valid Id CIN file 
+   * and continue loading */
 
   /* read the Huffman table */
   if (this->input->read(this->input, this->huffman_table,
@@ -419,8 +449,6 @@ static demux_plugin_t *open_plugin (demux_class_t *class_gen, xine_stream_t *str
 
   input_plugin_t *input = (input_plugin_t *) input_gen;
   demux_idcin_t  *this;
-  char header[IDCIN_HEADER_SIZE];
-  unsigned int current_value;
 
   if (! (input->get_capabilities(input) & INPUT_CAP_SEEKABLE)) {
     printf(_("demux_idcin.c: input not seekable, can not handle!\n"));
@@ -445,59 +473,6 @@ static demux_plugin_t *open_plugin (demux_class_t *class_gen, xine_stream_t *str
 
   case METHOD_BY_CONTENT:
 
-    input->seek(input, 0, SEEK_SET);
-    if (input->read(input, header, IDCIN_HEADER_SIZE) != IDCIN_HEADER_SIZE)
-      return DEMUX_CANNOT_HANDLE;
-
-    /*
-     * This is what you could call a "probabilistic" file check: Id CIN
-     * files don't have a definite file signature. In lieu of such a marker,
-     * perform sanity checks on the 5 header fields:
-     *  width, height: greater than 0, less than or equal to 1024
-     * audio sample rate: greater than or equal to 8000, less than or
-     *  equal to 48000, or 0 for no audio
-     * audio sample width (bytes/sample): 0 for no audio, or 1 or 2
-     * audio channels: 0 for no audio, or 1 or 2
-     */
-
-    /* check the width */
-    current_value = LE_32(&header[0]);
-    if ((current_value == 0) || (current_value > 1024)) {
-      free (this);
-      return NULL;
-    }
-
-    /* check the height */
-    current_value = LE_32(&header[4]);
-    if ((current_value == 0) || (current_value > 1024)) {
-      free (this);
-      return NULL;
-    }
-
-    /* check the audio sample rate */
-    current_value = LE_32(&header[8]);
-    if ((current_value != 0) && 
-       ((current_value < 8000) || (current_value > 48000))) {
-      free (this);
-      return NULL;
-    }
-
-    /* check the audio bytes/sample */
-    current_value = LE_32(&header[12]);
-    if (current_value > 2) {
-      free (this);
-      return NULL;
-    }
-
-    /* check the audio channels */
-    current_value = LE_32(&header[16]);
-    if (current_value > 2) {
-      free (this);
-      return NULL;
-    }
-
-    /* if execution got this far, qualify it as a valid Id CIN file 
-     * and load it */
     if (!open_idcin_file(this)) {
       free (this);
       return NULL;
diff --git a/src/demuxers/demux_roq.c b/src/demuxers/demux_roq.c
index fc7212a8f..4f13473e8 100644
--- a/src/demuxers/demux_roq.c
+++ b/src/demuxers/demux_roq.c
@@ -21,7 +21,7 @@
  * For more information regarding the RoQ file format, visit:
  *   http://www.csse.monash.edu.au/~timf/
  *
- * $Id: demux_roq.c,v 1.26 2002/10/28 03:24:43 miguelfreitas Exp $
+ * $Id: demux_roq.c,v 1.27 2002/11/01 03:36:24 tmmm Exp $
  */
 
 #ifdef HAVE_CONFIG_H
@@ -94,13 +94,16 @@ static int open_roq_file(demux_roq_t *this) {
   unsigned int chunk_type;
   unsigned int chunk_size;
 
-  this->status = DEMUX_OK;
-
   this->input->seek(this->input, 0, SEEK_SET);
   if (this->input->read(this->input, preamble, RoQ_CHUNK_PREAMBLE_SIZE) != 
     RoQ_CHUNK_PREAMBLE_SIZE)
     return 0;
 
+  /* check for the RoQ magic numbers */
+  if ((LE_16(&preamble[0]) != RoQ_MAGIC_NUMBER) ||
+      (LE_32(&preamble[2]) != 0xFFFFFFFF))
+    return 0;
+
   this->width = this->height = 0;
   this->audio_channels = 0;  /* assume no audio at first */
 
@@ -392,7 +395,6 @@ static demux_plugin_t *open_plugin (demux_class_t *class_gen, xine_stream_t *str
 
   input_plugin_t *input = (input_plugin_t *) input_gen;
   demux_roq_t    *this;
-  char preamble[RoQ_CHUNK_PREAMBLE_SIZE];
 
   if (! (input->get_capabilities(input) & INPUT_CAP_SEEKABLE)) {
     printf(_("demux_roq.c: input not seekable, can not handle!\n"));
@@ -417,32 +419,6 @@ static demux_plugin_t *open_plugin (demux_class_t *class_gen, xine_stream_t *str
 
   case METHOD_BY_CONTENT:
 
-    input->seek(input, 0, SEEK_SET);
-    if (input->read(input, preamble, RoQ_CHUNK_PREAMBLE_SIZE) != 
-      RoQ_CHUNK_PREAMBLE_SIZE) {
-      free (this);
-      return NULL;
-    }
-
-#if 0
-    printf ("demux_roq: %02x %02x %02x %02x %02x %02x %02x %02x \n",
-	    preamble[0],
-	    preamble[1],
-	    preamble[2],
-	    preamble[3],
-	    preamble[4],
-	    preamble[5],
-	    preamble[6],
-	    preamble[7]);
-#endif
-
-    /* check for the RoQ magic numbers */
-    if ((LE_16(&preamble[0]) != RoQ_MAGIC_NUMBER) ||
-        (LE_32(&preamble[2]) != 0xFFFFFFFF)) {
-      free (this);
-      return NULL;
-    }
-
     if (!open_roq_file(this)) {
       free (this);
       return NULL;
diff --git a/src/demuxers/demux_wc3movie.c b/src/demuxers/demux_wc3movie.c
index 8b938350b..7d3f070c1 100644
--- a/src/demuxers/demux_wc3movie.c
+++ b/src/demuxers/demux_wc3movie.c
@@ -22,7 +22,7 @@
  * For more information on the MVE file format, visit:
  *   http://www.pcisys.net/~melanson/codecs/
  *
- * $Id: demux_wc3movie.c,v 1.22 2002/10/31 02:22:58 tmmm Exp $
+ * $Id: demux_wc3movie.c,v 1.23 2002/11/01 03:36:24 tmmm Exp $
  */
 
 #ifdef HAVE_CONFIG_H
@@ -381,11 +381,21 @@ static int open_mve_file(demux_mve_t *this) {
   int i, j;
   unsigned char r, g, b;
   int temp;
+  unsigned char header[16];
 
   /* these are the frame dimensions unless others are found */
   this->video_width = WC3_USUAL_WIDTH;
   this->video_height = WC3_USUAL_HEIGHT;
 
+  this->input->seek(this->input, 0, SEEK_SET);
+  if (this->input->read(this->input, header, 16) != 16)
+    return 0;
+
+  if ((BE_32(&header[0]) != FORM_TAG) ||
+      (BE_32(&header[8]) != MOVE_TAG) ||
+      (BE_32(&header[12]) != PC_TAG))
+    return 0;
+
   /* load the number of palettes, the only interesting piece of information
    * in the _PC_ chunk; take it for granted that it will always appear at
    * position 0x1C */
@@ -651,7 +661,6 @@ static demux_plugin_t *open_plugin (demux_class_t *class_gen, xine_stream_t *str
 
   input_plugin_t *input = (input_plugin_t *) input_gen;
   demux_mve_t    *this;
-  unsigned char header[16];
 
   if (! (input->get_capabilities(input) & INPUT_CAP_SEEKABLE)) {
     printf(_("demux_mve.c: input not seekable, can not handle!\n"));
@@ -676,17 +685,6 @@ static demux_plugin_t *open_plugin (demux_class_t *class_gen, xine_stream_t *str
 
   case METHOD_BY_CONTENT:
 
-    input->seek(input, 0, SEEK_SET);
-    if (input->read(input, header, 16) != 16)
-      return DEMUX_CANNOT_HANDLE;
-
-    if ((BE_32(&header[0]) != FORM_TAG) ||
-        (BE_32(&header[8]) != MOVE_TAG) ||
-        (BE_32(&header[12]) != PC_TAG)) {
-      free (this);
-      return NULL;
-    }
-
     if (!open_mve_file(this)) {
       free (this);
       return NULL;