[Extractor-gtk-cvslog] SF.net SVN: extractor-gtk: [42] trunk/extractor/generic.c

[<som...@us...>]

Revision: 42
          http://extractor-gtk.svn.sourceforge.net/extractor-gtk/?rev=42&view=rev
Author:   someone-guy
Date:     2007-09-16 06:48:34 -0700 (Sun, 16 Sep 2007)

Log Message:
-----------
RIFF-check with less false positives

Modified Paths:
--------------
    trunk/extractor/generic.c

Modified: trunk/extractor/generic.c
===================================================================
--- trunk/extractor/generic.c	2007-09-16 11:43:44 UTC (rev 41)
+++ trunk/extractor/generic.c	2007-09-16 13:48:34 UTC (rev 42)
@@ -26,6 +26,18 @@
   *list = l;
 }
 
+static int is_valid_fourcc(uint32_t id) {
+  static const char valid_chars[] =
+    "0123456789abcdefghijklmnopqrstuvwxyz"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ_ ";
+  int i;
+  for (i = 0; i < 4; i++) {
+    if (!strchr(valid_chars, id)) return 0;
+    id >>= 8;
+  }
+  return 1;
+}
+
 typedef uint64_t buffer_t;
 
 static file_t *get_list(FILE *in) {
@@ -38,12 +50,17 @@
     int i;
     t = t << 8 | fgetc(in);
     switch (t & 0xffffffff) {
-      case TAG('R', 'I', 'F', 'F'):
+      case TAG('R', 'I', 'F', 'F'): {
+        uint32_t len = read_le32(in);
+        uint32_t type = read_le32(in);
+        fseek(in, -8, SEEK_CUR);
+        if (len <= 4 || !is_valid_fourcc(type)) break;
         add_entry(&list, cnt, "riff");
         list[cnt].start = ftell(in) - 4;
-        list[cnt].len = peek_le32(in);
+        list[cnt].len = len;
         cnt++;
         break;
+      }
     }
     switch (t & 0xffffff) {
       case TAG(0, 'F', 'W', 'S'):


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