Second part of FS#8104 by Bertrik Sikken: Simplification of audio_track_count, audio_have_tracks and audio_have_free_tracks. This hopefully won't affect anything, but the semantics of the functions have changed slightly.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@15693 a1c6a512-1295-4272-9138-f99709370657

2 files changed, 9 insertions, 21 deletions

diff --git a/apps/debug_menu.c b/apps/debug_menu.c
index f343ce6..e3f576d 100644
--- a/apps/debug_menu.c
+++ b/apps/debug_menu.c
@@ -344,7 +344,7 @@ static bool dbg_buffering_thread(void)
         snprintf(buf, sizeof(buf), "data_rem: %ld", (long)d.data_rem);
         lcd_puts(0, line++, buf);
 
-        snprintf(buf, sizeof(buf), "track count: %2d", audio_track_count()-1);
+        snprintf(buf, sizeof(buf), "track count: %2d", audio_track_count());
         lcd_puts(0, line++, buf);
 
         snprintf(buf, sizeof(buf), "handle count: %d", (int)d.num_handles);
diff --git a/apps/playback.c b/apps/playback.c
index 1ad6ce6..e136579 100644
--- a/apps/playback.c
+++ b/apps/playback.c
@@ -1422,32 +1422,20 @@ static void codec_thread(void)
 
 static bool audio_have_tracks(void)
 {
-    return track_ridx != track_widx || CUR_TI->filesize;
+    return (audio_track_count() != 0);
 }
 
-static bool audio_have_free_tracks(void)
+static int audio_free_track_count(void)
 {
-    if (track_widx < track_ridx)
-        return track_widx + 1 < track_ridx;
-    else if (track_ridx == 0)
-        return track_widx < MAX_TRACK - 1;
-
-    return true;
+    /* Used tracks + free tracks adds up to MAX_TRACK - 1 */
+    return MAX_TRACK - 1 - audio_track_count();
 }
 
 int audio_track_count(void)
 {
-    if (audio_have_tracks())
-    {
-        int relative_track_widx = track_widx;
-
-        if (track_ridx > track_widx)
-            relative_track_widx += MAX_TRACK;
-
-        return relative_track_widx - track_ridx + 1;
-    }
-
-    return 0;
+    /* Calculate difference from track_ridx to track_widx
+     * taking into account a possible wrap-around. */
+    return (MAX_TRACK + track_widx - track_ridx) & MAX_TRACK_MASK;
 }
 
 long audio_filebufused(void)
@@ -1659,7 +1647,7 @@ static bool audio_load_track(int offset, bool start_play)
     /* Stop buffer filling if there is no free track entries.
        Don't fill up the last track entry (we wan't to store next track
        metadata there). */
-    if (!audio_have_free_tracks())
+    if (!audio_free_track_count())
     {
         logf("No free tracks");
         return false;