apps/codecs/gbs.c

   1
   2 /* Ripped off from Game_Music_Emu 0.5.2. http://www.slack.net/~ant/ */
   3
   4 #include <codecs/lib/codeclib.h>
   5 #include "libgme/gbs_emu.h"
   6
   7 CODEC_HEADER
   8
   9 /* Maximum number of bytes to process in one iteration */
  10 #define CHUNK_SIZE (1024*2)
  11
  12 static int16_t samples[CHUNK_SIZE] IBSS_ATTR;
  13 static struct Gbs_Emu gbs_emu;
  14
  15 /****************** rockbox interface ******************/
  16
  17 static void set_codec_track(int t) {
  18     Gbs_start_track(&gbs_emu, t);
  19
  20     /* for loop mode we disable track limits */
  21     if (!ci->loop_track()) {
  22         Track_set_fade(&gbs_emu, Track_get_length( &gbs_emu, t ), 4000);
  23     }
  24     ci->set_elapsed(t*1000); /* t is track no to display */
  25 }
  26
  27 /* this is the codec entry point */
  28 enum codec_status codec_main(enum codec_entry_call_reason reason)
  29 {
  30     if (reason == CODEC_LOAD) {
  31         /* we only render 16 bits */
  32         ci->configure(DSP_SET_SAMPLE_DEPTH, 16);
  33
  34         /* 44 Khz, Interleaved stereo */
  35         ci->configure(DSP_SET_FREQUENCY, 44100);
  36         ci->configure(DSP_SET_STEREO_MODE, STEREO_INTERLEAVED);
  37
  38         Gbs_init(&gbs_emu);
  39         Gbs_set_sample_rate(&gbs_emu, 44100);
  40     }
  41
  42     return CODEC_OK;
  43 }
  44
  45 /* this is called for each file to process */
  46 enum codec_status codec_run(void)
  47 {
  48     blargg_err_t err;
  49     uint8_t *buf;
  50     size_t n;
  51     intptr_t param;
  52     int track = 0;
  53
  54     DEBUGF("GBS: next_track\n");
  55     if (codec_init()) {
  56         return CODEC_ERROR;
  57     }
  58
  59     codec_set_replaygain(ci->id3);
  60
  61     /* Read the entire file */
  62     DEBUGF("GBS: request file\n");
  63     ci->seek_buffer(0);
  64     buf = ci->request_buffer(&n, ci->filesize);
  65     if (!buf || n < (size_t)ci->filesize) {
  66         DEBUGF("GBS: file load failed\n");
  67         return CODEC_ERROR;
  68     }
  69
  70     if ((err = Gbs_load_mem(&gbs_emu, buf, ci->filesize))) {
  71         DEBUGF("GBS: Gbs_load_mem failed (%s)\n", err);
  72         return CODEC_ERROR;
  73     }
  74
  75     /* Update internal track count */
  76     if (gbs_emu.m3u.size > 0)
  77         gbs_emu.track_count = gbs_emu.m3u.size;
  78
  79 next_track:
  80     set_codec_track(track);
  81
  82     /* The main decoder loop */
  83     while (1) {
  84         enum codec_command_action action = ci->get_command(&param);
  85
  86         if (action == CODEC_ACTION_HALT)
  87             break;
  88
  89         if (action == CODEC_ACTION_SEEK_TIME) {
  90             track = param/1000;
  91             ci->seek_complete();
  92             if (track >= gbs_emu.track_count) break;
  93             goto next_track;
  94         }
  95
  96         /* Generate audio buffer */
  97         err = Gbs_play(&gbs_emu, CHUNK_SIZE, samples);
  98         if (err || Track_ended(&gbs_emu)) {
  99             track++;
 100             if (track >= gbs_emu.track_count) break;
 101             goto next_track;
 102         }
 103
 104         ci->pcmbuf_insert(samples, NULL, CHUNK_SIZE >> 1);
 105     }
 106
 107     return CODEC_OK;
 108 }