[xiph-cvs] cvs commit: ices/src id3.c

[Brendan]

brendan     03/03/05 17:54:35

  Modified:    src      id3.c
  Log:
  Apparently the ID3v2.3 frame length isn't synchsafe. The official specification is
  ambiguous and iTunes disagrees, but other ID3 code I've looked at seems to think
  so, and the v2.3 files I've found in the wild confirm this.

Revision  Changes    Path
1.21      +21 -1     ices/src/id3.c

Index: id3.c
===================================================================
RCS file: /cvs/ice/ices/src/id3.c,v
retrieving revision 1.20
retrieving revision 1.21
diff -u -r1.20 -r1.21
--- id3.c	5 Mar 2003 16:15:44 -0000	1.20
+++ id3.c	5 Mar 2003 22:54:35 -0000	1.21
@@ -64,6 +64,7 @@
 static int id3v2_skip_data (input_stream_t* source, id3v2_tag* tag, size_t len);
 static int id3v2_decode_synchsafe (unsigned char* synchsafe);
 static int id3v2_decode_synchsafe3 (unsigned char* synchsafe);
+static int id3v2_decode_unsafe (unsigned char* in);
 
 /* Global function definitions */
 
@@ -177,7 +178,9 @@
     remaining -= rv;
   }
 
-  ices_metadata_set (tag.artist, tag.title);
+  /* allow fallback to ID3v1 */
+  if (tag.artist || tag.title)
+    ices_metadata_set (tag.artist, tag.title);
   ices_util_free (tag.artist);
   ices_util_free (tag.title);
 
@@ -232,6 +235,9 @@
   if (tag->major_version < 3) {
     len = id3v2_decode_synchsafe3 (hdr + 3);
     hdr[3] = '\0';
+  } else if (tag->major_version == 3) {
+    len = id3v2_decode_unsafe (hdr + 4);
+    hdr[4] = '\0';
   } else {
     len = id3v2_decode_synchsafe (hdr + 4);
     hdr[4] = '\0';
@@ -326,6 +332,20 @@
   res = synchsafe[2];
   res |= synchsafe[1] << 7;
   res |= synchsafe[0] << 14;
+
+  return res;
+}
+
+/* id3v2.3 badly specifies frame length */
+static int
+id3v2_decode_unsafe (unsigned char* in)
+{
+  int res;
+
+  res = in[3];
+  res |= in[2] << 8;
+  res |= in[1] << 16;
+  res |= in[0] << 24;
 
   return res;
 }

<p><p>--- >8 ----
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