mpeg.c

编译后直接运行的ＭＰ３播放器全部Ｃ语言源代码 一个包含FAT文件系统、系统引导 Boot、FLASH Driver等内容的

    /* Stop the current stream */
    mp3_play_stop();
    playing = false;
    filling = false;
    if(mpeg_file >= 0)
        close(mpeg_file);
    mpeg_file = -1;
    remove_all_tags();
}

static void update_playlist(void)
{
    int index;

    if (num_tracks_in_memory() > 0)
    {
        index = playlist_next(id3tags[tag_read_idx]->id3.index);
        id3tags[tag_read_idx]->id3.index = index;
    }
}

static void track_change(void)
{
    DEBUGF("Track change\n");

#ifdef HAVE_MAS3587F
    /* Reset the AVC */
    mpeg_sound_set(SOUND_AVC, -1);
#endif /* #ifdef HAVE_MAS3587F */
    remove_current_tag();

    update_playlist();
    current_track_counter++;
}

#ifdef DEBUG
void hexdump(unsigned char *buf, int len)
{
    int i;

    for(i = 0;i < len;i++)
    {
        if(i && (i & 15) == 0)
        {
            DEBUGF("\n");
        }
        DEBUGF("%02x ", buf[i]);
    }
    DEBUGF("\n");
}
#endif /* #ifdef DEBUG */

static void start_playback_if_ready(void)
{
    int playable_space;

    playable_space = mp3buf_swapwrite - mp3buf_read;
    if(playable_space < 0)
        playable_space += mp3buflen;
    
    /* See if we have started playing yet. If not, do it. */
    if(play_pending || dma_underrun)
    {
        /* If the filling has stopped, and we still haven't reached
           the watermark, the file must be smaller than the
           watermark. We must still play it. */
        if((playable_space >= MPEG_PLAY_PENDING_THRESHOLD) ||
           !filling || dma_underrun)
        {
            DEBUGF("P\n");
            play_pending = false;
            playing = true;
			
            if (!paused)
            {
                last_dma_chunk_size = MIN(0x2000, get_unplayed_space_current_song());
                mp3_play_data(mp3buf + mp3buf_read, last_dma_chunk_size, transfer_end);
                dma_underrun = false;

                last_dma_tick = current_tick;
                mp3_play_pause(true);
            }

            /* Tell ourselves that we need more data */
            queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);
        }
    }
}

static bool swap_one_chunk(void)
{
    int free_space_left;
    int amount_to_swap;

    free_space_left = get_unswapped_space();

    if(free_space_left == 0 && !play_pending)
        return false;

    /* Swap in larger chunks when the user is waiting for the playback
       to start, or when there is dangerously little playable data left */
    if(play_pending)
        amount_to_swap = MIN(MPEG_PLAY_PENDING_SWAPSIZE, free_space_left);
    else
    {
        if(get_playable_space() < low_watermark)
            amount_to_swap = MIN(MPEG_LOW_WATER_SWAP_CHUNKSIZE,
                                 free_space_left);
        else
            amount_to_swap = MIN(MPEG_SWAP_CHUNKSIZE, free_space_left);
    }
    
    if(mp3buf_write < mp3buf_swapwrite)
        amount_to_swap = MIN(mp3buflen - mp3buf_swapwrite,
                             amount_to_swap);
    else
        amount_to_swap = MIN(mp3buf_write - mp3buf_swapwrite,
                             amount_to_swap);

    bitswap(mp3buf + mp3buf_swapwrite, amount_to_swap);

    mp3buf_swapwrite += amount_to_swap;
    if(mp3buf_swapwrite >= mp3buflen)
    {
        mp3buf_swapwrite = 0;
    }

    return true;
}

static const unsigned char empty_id3_header[] =
{
    'I', 'D', '3', 0x04, 0x00, 0x00,
    0x00, 0x00, 0x1f, 0x76 /* Size is 4096 minus 10 bytes for the header */
};

#ifdef HAVE_MAS3587F
static unsigned long get_last_recorded_header(void)
{
    unsigned long tmp[2];

    /* Read the frame data from the MAS and reconstruct it with the
       frame sync and all */
    mas_readmem(MAS_BANK_D0, 0xfd1, tmp, 2);
    return 0xffe00000 | ((tmp[0] & 0x7c00) << 6) | (tmp[1] & 0xffff);
}
#endif /* #ifdef HAVE_MAS3587F */

static void mpeg_thread(void)
{
    static int pause_tick = 0;
    static unsigned int pause_track = 0;
    struct event ev;
    int len;
    int free_space_left;
    int unplayed_space_left;
    int amount_to_read;
    int t1, t2;
    int start_offset;
#ifdef HAVE_MAS3587F
    int amount_to_save;
    int writelen;
    int framelen;
    unsigned long saved_header = 0;
    int startpos;
    int rc;
    int offset;
    int countdown;
#endif /* #ifdef HAVE_MAS3587F */
    
    is_playing = false;
    play_pending = false;
    playing = false;
    mpeg_file = -1;

    while(1)
    {
#ifdef HAVE_MAS3587F
        if(mpeg_mode == MPEG_DECODER)
        {
#endif /* #ifdef HAVE_MAS3587F */
        yield();

        /* Swap if necessary, and don't block on the queue_wait() */
        if(swap_one_chunk())
        {
            queue_wait_w_tmo(&mpeg_queue, &ev, 0);
        }
        else
        {
            DEBUGF("S R:%x W:%x SW:%x\n",
                   mp3buf_read, mp3buf_write, mp3buf_swapwrite);
            queue_wait(&mpeg_queue, &ev);
        }

        start_playback_if_ready();
        
        switch(ev.id)
        {
            case MPEG_PLAY:
                DEBUGF("MPEG_PLAY\n");

#ifdef HAVE_FMRADIO
                /* Silence the A/D input, it may be on because the radio
                   may be playing */
                mas_codec_writereg(6, 0x0000);
#endif /* #ifdef HAVE_FMRADIO */

                /* Stop the current stream */
                play_pending = false;
                playing = false;
                paused = false;
                mp3_play_pause(false);

                reset_mp3_buffer();
                remove_all_tags();

                if(mpeg_file >= 0)
                    close(mpeg_file);

                if ( new_file(0) == -1 )
                {
                    is_playing = false;
                    track_change();
                    break;
                }

                start_offset = (int)ev.data;

                /* mid-song resume? */
                if (start_offset) {
                    struct mp3entry* id3 = &id3tags[tag_read_idx]->id3;
                    lseek(mpeg_file, start_offset, SEEK_SET);
                    id3->offset = start_offset;
                    set_elapsed(id3);
                }
                else {
                    /* skip past id3v2 tag */
                    lseek(mpeg_file, 
                          id3tags[tag_read_idx]->id3.first_frame_offset, 
                          SEEK_SET);

                }

                /* Make it read more data */
                filling = true;
                queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);

                /* Tell the file loading code that we want to start playing
                   as soon as we have some data */
                play_pending = true;

                update_playlist();
                current_track_counter++;
                break;

            case MPEG_STOP:
                DEBUGF("MPEG_STOP\n");
                is_playing = false;
                paused = false;
                stop_playing();
                mpeg_stop_done = true;
                break;

            case MPEG_PAUSE:
                DEBUGF("MPEG_PAUSE\n");
                /* Stop the current stream */
                paused = true;
                playing = false;
                pause_tick = current_tick;
                pause_track = current_track_counter;
                mp3_play_pause(false);
                break;

            case MPEG_RESUME:
                DEBUGF("MPEG_RESUME\n");
                /* Continue the current stream */
                paused = false;
                if (!play_pending)
                {
                    playing = true;
                    if ( current_track_counter == pause_track )
                        last_dma_tick += current_tick - pause_tick;
                    else
                        last_dma_tick = current_tick;                        
                    pause_tick = 0;
                    mp3_play_pause(true);
                }
                break;

            case MPEG_NEXT:
                DEBUGF("MPEG_NEXT\n");
                /* is next track in ram? */
                if ( num_tracks_in_memory() > 1 ) {
                    int unplayed_space_left, unswapped_space_left;

                    /* stop the current stream */
                    play_pending = false;
                    playing = false;
                    mp3_play_pause(false);

                    track_change();
                    mp3buf_read = id3tags[tag_read_idx]->mempos;
                    last_dma_chunk_size = MIN(0x2000, get_unplayed_space_current_song());
                    mp3_play_data(mp3buf + mp3buf_read, last_dma_chunk_size, transfer_end);
                    dma_underrun = false;
                    last_dma_tick = current_tick;

                    unplayed_space_left  = get_unplayed_space();
                    unswapped_space_left = get_unswapped_space();

                    /* should we start reading more data? */
                    if(!filling && (unplayed_space_left < low_watermark)) {
                        filling = true;
                        queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);
                        play_pending = true;
                    } else if(unswapped_space_left &&
                              unswapped_space_left > unplayed_space_left) {
                        /* Stop swapping the data from the previous file */
                        mp3buf_swapwrite = mp3buf_read;
                        play_pending = true;
                    } else {
                        playing = true;
                        if (!paused)
                            mp3_play_pause(true);
                    }
                }
                else {
                    if (!playlist_check(1))
                        break;

                    /* stop the current stream */
                    play_pending = false;
                    playing = false;
                    mp3_play_pause(false);

                    reset_mp3_buffer();
                    remove_all_tags();

                    /* Open the next file */
                    if (mpeg_file >= 0)
                        close(mpeg_file);
                    
                    if (new_file(1) < 0) {
                        DEBUGF("No more files to play\n");
                        filling = false;
                    } else {
                        /* Make it read more data */
                        filling = true;
                        queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);
                        
                        /* Tell the file loading code that we want
                           to start playing as soon as we have some data */
                        play_pending = true;

                        update_playlist();
                        current_track_counter++;
                    }
                }
                break;

            case MPEG_PREV: {
                DEBUGF("MPEG_PREV\n");

                if (!playlist_check(-1))
                    break;
                
                /* stop the current stream */
                play_pending = false;
                playing = false;
                mp3_play_pause(false);

                reset_mp3_buffer();
                remove_all_tags();

                /* Open the next file */
                if (mpeg_file >= 0)
                    close(mpeg_file);

                if (new_file(-1) < 0) {
                    DEBUGF("No more files to play\n");
                    filling = false;
                } else {
                    /* Make it read more data */
                    filling = true;
                    queue_post(&mpeg_queue, MPEG_NEED_DATA, 0);

                    /* Tell the file loading code that we want to
                       start playing as soon as we have some data */
                    play_pending = true;

                    update_playlist();
                    current_track_counter++;
                }
                break;
            }

            case MPEG_FF_REWIND: {
                struct mp3entry *id3  = mpeg_current_track();
                unsigned int oldtime  = id3->elapsed;
                unsigned int newtime  = (unsigned int)ev.data;
                int curpos, newpos, diffpos;
                DEBUGF("MPEG_FF_REWIND\n");

                id3->elapsed = newtime;