music_ogg.c: revise parsing loop info

According to Vitaly Novichkov [1], there are broken vorbis files in the wild which has bad looping info with leading and/or trailing non-digits that fool strtoull() [2] [3]. Therefore, strip those non-digits before feeding to SDL_strtoull. Based on code from SDL_mixer-X fork by Vitaly Novichkov [1]. [1] WohlSoft/SDL-Mixer-X@a67d8fd#comments [2] https://github.com/WohlSoft/SDL-Mixer-X/files/3808096/Not.So.Heavenly.Boss.Battle.ogg.zip [3] https://github.com/WohlSoft/SDL-Mixer-X/files/3808099/Not.So.Heavenly.Preparation.Room.ogg.zip
libsdl-org · Nov 10, 2019 · c5df1d5 · c5df1d5
1 parent 50432fd
commit c5df1d5
Showing 1 changed file with 27 additions and 12 deletions.
diff --git a/music_ogg.c b/music_ogg.c
@@ -223,6 +223,25 @@ static int OGG_UpdateSection(OGG_music *music)
     return 0;
 }
 
+/* Convert string into integer with clean-up from junk and leading zeroes */
+static ogg_int64_t str_to_int64(char *param)
+{
+    char *front = param;
+    char *back;
+
+    /* Find digit between of 1 and 9 at begin */
+    while (*front != '\0' && (*front < '1' || *front > '9')) {
+        front++;
+    }
+    /* Find any non-digit character or NULL */
+    back = front;
+    while (*back != '\0' && (*back >= '0' && *back <= '9')) {
+        back++;
+    }
+    *back = '\0';
+    return (ogg_int64_t)SDL_strtoull(front, NULL, 0);
+}
+
 /* Parse time string of the form HH:MM:SS.mmm and return equivalent sample
  * position */
 static ogg_int64_t parse_time(char *time, long samplerate_hz)
@@ -231,29 +250,25 @@ static ogg_int64_t parse_time(char *time, long samplerate_hz)
     ogg_int64_t result = 0;
     char c;
 
-    // Time is directly expressed as a sample position
-    if (SDL_strchr(time, ':') == NULL)
-    {
-        return SDL_strtoull(time, NULL, 0);
+    /* Time is directly expressed as a sample position */
+    if (SDL_strchr(time, ':') == NULL) {
+        return str_to_int64(time);
     }
 
     result = 0;
     num_start = time;
 
-    for (p = time; *p != '\0'; ++p)
-    {
-        if (*p == '.' || *p == ':')
-        {
+    for (p = time; *p != '\0'; ++p) {
+        if (*p == '.' || *p == ':') {
             c = *p; *p = '\0';
             result = result * 60 + SDL_atoi(num_start);
             num_start = p + 1;
             *p = c;
         }
 
-        if (*p == '.')
-        {
+        if (*p == '.') {
             return result * samplerate_hz
-            + (ogg_int64_t) (SDL_atof(p) * samplerate_hz);
+                + (ogg_int64_t) (SDL_atof(p) * samplerate_hz);
         }
     }
 
@@ -321,7 +336,7 @@ static void *OGG_CreateFromRW(SDL_RWops *src, int freesrc)
         if (SDL_strcasecmp(argument, "LOOPSTART") == 0)
             music->loop_start = parse_time(value, rate);
         else if (SDL_strcasecmp(argument, "LOOPLENGTH") == 0) {
-            music->loop_len = SDL_strtoull(value, NULL, 0);
+            music->loop_len = str_to_int64(value);
             isLoopLength = 1;
         } else if (SDL_strcasecmp(argument, "LOOPEND") == 0) {
             isLoopLength = 0;