FS#13497: '0' is sometimes a valid track number

Most notably for CD rips that use a track number of 0 for
the leadin.

Therefore change our "invalid track number" canary to -1 instead
of 0.  Additionally don't try to parse an empty string.

In the process, get rid of redudant 'discnum = 0' as well.

NOTE: While not strictly necessary, we recommend rebuilding the
      database to ensure files without track numbers are
      updated with the new canary.

Change-Id: I543f98ca49cec7b5eeffa7c14c1eca57171f345a

apps/gui/skin_engine/skin_tokens.c

@@ -263,7 +263,7 @@ const char *get_id3_token(struct wps_token *token, struct mp3entry *id3,
             case SKIN_TOKEN_METADATA_TRACK_NUMBER:
                 if (id3->track_string)
                     return id3->track_string;
-                if (id3->tracknum) {
+                if (id3->tracknum >= 0) {
                     itoa_buf(buf, buf_size, id3->tracknum);
                     return buf;
                 }

apps/plugins/lib/mul_id3.c

@@ -173,7 +173,7 @@ void finalize_id3(struct mp3entry *id3)
     id3->codectype = mul_id3.codectype;
     id3->vbr = mul_id3.vbr;
     id3->discnum = 0;
-    id3->tracknum = 0;
+    id3->tracknum = -1;
     id3->track_level = 0;
     id3->album_level = 0;
 }

apps/screens.c

@@ -571,7 +571,7 @@ static const char * id3_get_or_speak_info(int selected_item, void* data,
                     if(say_it)
                         say_number_and_spell(val, true);
                 }
-                else if (id3->tracknum)
+                else if (id3->tracknum >= 0)
                 {
                     itoa_buf(buffer, buffer_len, id3->tracknum);
                     val = buffer;

apps/tagcache.c

@@ -2322,7 +2322,7 @@ static void NO_INLINE add_tagcache(char *path, unsigned long mtime)
 
     logf("-> %s", path);
 
-    if (id3.tracknum <= 0)              /* Track number missing? */
+    if (id3.tracknum < 0)              /* Track number missing? */
     {
         id3.tracknum = -1;
     }

lib/rbcodec/metadata/aac.c

@@ -70,8 +70,6 @@ bool get_aac_metadata(int fd, struct mp3entry *entry)
     unsigned char buf[5];
 
     entry->title = NULL;
-    entry->tracknum = 0;
-    entry->discnum = 0;
     entry->id3v1len = 0;
     entry->id3v2len = getid3v2len(fd);
     entry->first_frame_offset = entry->id3v2len;

lib/rbcodec/metadata/aiff.c

@@ -36,8 +36,6 @@
 
 static void read_id3_tags(int fd, struct mp3entry* id3)
 {
-    id3->tracknum = 0;
-    id3->discnum  = 0;
     setid3v2title(fd, id3);
 }
 

lib/rbcodec/metadata/asf.c

@@ -24,6 +24,7 @@
 #include <stdlib.h>
 #include <ctype.h>
 #include <inttypes.h>
+#include <errno.h>
 #include "platform.h"
 
 #include "metadata.h"
@@ -473,7 +474,12 @@ static int asf_parse_header(int fd, struct mp3entry* id3,
                             if (type == 0) {
                                 id3->track_string = id3buf;
                                 asf_utf16LEdecode(fd, length, &id3buf, &id3buf_remaining);
-                                id3->tracknum = atoi(id3->track_string);
+                                if (strlen(id3->track_string)) {
+                                    char *p = NULL;
+                                    int tracknum = strtol(id3->track_string, &p, 0);
+                                    if (!(tracknum == 0 && (errno || *p)))
+                                        id3->tracknum = tracknum;
+                                }
                             } else if ((type >=2) && (type <= 5)) {
                                 id3->tracknum = asf_intdecode(fd, type, length);
                             } else {

lib/rbcodec/metadata/id3tags.c

@@ -243,7 +243,12 @@ static int skip_unsynched(int fd, int len)
 /* parse numeric value from string */
 static int parsetracknum( struct mp3entry* entry, char* tag, int bufferpos )
 {
-    entry->tracknum = atoi( tag );
+    if (strlen(tag)) {
+        char *p = NULL;
+        int tracknum = strtol(tag, &p, 0);
+        if (!(tracknum == 0 && (errno || *p)))
+            entry->tracknum = tracknum;
+    }
     return bufferpos;
 }
 
@@ -826,7 +831,7 @@ void setid3v2title(int fd, struct mp3entry *entry)
             return;
     }
     entry->id3version = version;
-    entry->tracknum = entry->year = entry->discnum = 0;
+    entry->year = entry->discnum = 0;
     entry->title = entry->artist = entry->album = NULL; /* FIXME incomplete */
 
     global_flags = header[5];

lib/rbcodec/metadata/metadata.c

@@ -452,6 +452,8 @@ bool get_metadata_ex(struct mp3entry* id3, int fd, const char* trackname, int fl
     id3->has_embedded_cuesheet = false;
     id3->embedded_cuesheet.pos = 0;
 
+    id3->tracknum = -1;
+
     entry = &audio_formats[id3->codectype];
 
     /* Load codec specific track tag information and confirm the codec type. */

lib/rbcodec/metadata/metadata_common.c

@@ -23,6 +23,7 @@
 #include <stdlib.h>
 #include <ctype.h>
 #include <inttypes.h>
+#include <errno.h>
 
 #include "platform.h"
 #include "metadata.h"
@@ -315,7 +316,12 @@ long parse_tag(const char* name, char* value, struct mp3entry* id3,
     if (((item == eTRACK && (type == TAGTYPE_APE)))
         || (item == eTRACKNUMBER && (type == TAGTYPE_VORBIS)))
     {
-        id3->tracknum = atoi(value);
+        if (strlen(value)) {
+            char *p = NULL;
+            int tracknum = strtol(value, &p, 0);
+            if (!(tracknum == 0 && (errno || *p)))
+                id3->tracknum = tracknum;
+        }
         p = &(id3->track_string);
     }
     else if (item == eDISCNUMBER || item == eDISC)

lib/rbcodec/metadata/mp3.c

@@ -166,8 +166,6 @@ bool get_mp3_metadata(int fd, struct mp3entry *entry)
     entry->filesize = filesize(fd);
     entry->id3v1len = getid3v1len(fd);
     entry->id3v2len = getid3v2len(fd);
-    entry->tracknum = 0;
-    entry->discnum = 0;
 
     if (entry->id3v2len)
         setid3v2title(fd, entry);

lib/rbcodec/metadata/mp4.c

@@ -481,10 +481,14 @@ static bool read_mp4_tags(int fd, struct mp3entry* id3,
             read_mp4_tag_i_from_n(fd, &id3->discnum, &id3->disc_string, size, &buffer_left, &buffer);
             break;
 
-        case MP4_trkn:
+        case MP4_trkn: {
-            read_mp4_tag_i_from_n(fd, &id3->tracknum, &id3->track_string, size, &buffer_left, &buffer);
+            char *p = NULL;
+            int tracknum = 0;
+            read_mp4_tag_i_from_n(fd, &tracknum, &id3->track_string, size, &buffer_left, &buffer);
+            if (!(tracknum == 0 && (errno || *p)))
+                id3->tracknum = tracknum;
             break;
-
+        }
 #ifdef HAVE_ALBUMART
         case MP4_covr:
             {

lib/rbcodec/metadata/tta.c

@@ -56,8 +56,6 @@ static void read_id3_tags(int fd, struct mp3entry* id3)
     id3->title    = NULL;
     id3->filesize = filesize(fd);
     id3->id3v2len = getid3v2len(fd);
-    id3->tracknum = 0;
-    id3->discnum  = 0;
     id3->vbr      = false;   /* All TTA files are CBR */
 
     /* first get id3v2 tags. if no id3v2 tags ware found, get id3v1 tags */

lib/rbcodec/test/warble.c

@@ -732,7 +732,7 @@ static void print_mp3entry(const struct mp3entry *id3, FILE *f)
     if (id3->album) fprintf(f, "Album: %s\n", id3->album);
     if (id3->genre_string) fprintf(f, "Genre: %s\n", id3->genre_string);
     if (id3->disc_string || id3->discnum) fprintf(f, "Disc: %s (%d)\n", id3->disc_string, id3->discnum);
-    if (id3->track_string || id3->tracknum) fprintf(f, "Track: %s (%d)\n", id3->track_string, id3->tracknum);
+    if (id3->track_string || id3->tracknum >= 0) fprintf(f, "Track: %s (%d)\n", id3->track_string, id3->tracknum);
     if (id3->year_string || id3->year) fprintf(f, "Year: %s (%d)\n", id3->year_string, id3->year);
     if (id3->composer) fprintf(f, "Composer: %s\n", id3->composer);
     if (id3->comment) fprintf(f, "Comment: %s\n", id3->comment);