check for "sfbk" in fluid_is_soundfont()

src/utils/fluid_sys.c

@@ -342,25 +342,32 @@ fluid_is_midifile(const char *filename)
  * @param filename Path to the file to check
  * @return TRUE if it could be a SoundFont, FALSE otherwise
  *
- * The current implementation only checks for the "RIFF" header in the file.
- * It is useful only to distinguish between SoundFont and MIDI files.
+ * @note The current implementation only checks for the "RIFF" and "sfbk" headers in
+ * the file. It is useful to distinguish between SoundFont and other (e.g. MIDI) files.
  */
 int
 fluid_is_soundfont(const char *filename)
 {
   FILE* fp = fopen(filename, "rb");
-  char id[4];
+  char riff_id[4], sfbk_id[4];
 
   if (fp == NULL) {
     return 0;
   }
-  if (fread((void*) id, 1, 4, fp) != 4) {
-    fclose(fp);
-    return 0;
+  if((fread((void*) riff_id, 1, sizeof(riff_id), fp) != sizeof(riff_id)) ||
+     (fseek(fp, 4, SEEK_CUR) != 0) || 
+     (fread((void*) sfbk_id, 1, sizeof(sfbk_id), fp) != sizeof(sfbk_id)))
+  {
+      goto error_rec;
   }
+
   fclose(fp);
-
-  return strncmp(id, "RIFF", 4) == 0;
+  return (FLUID_STRNCMP(riff_id, "RIFF", sizeof(riff_id)) == 0) &&
+         (FLUID_STRNCMP(sfbk_id, "sfbk", sizeof(sfbk_id)) == 0);
+
+error_rec:
+    fclose(fp);
+    return 0;
 }
 
 /**