player.c

一个嵌入式Linux上的mp3播放器

	len = read(input->fd, allocated + count, tagsize - count);
      while (len == -1 && errno == EINTR);

      if (len == -1) {
	error("id3", ":read");
	goto fail;
      }

      if (len == 0) {
	error("id3", _("EOF while reading tag data"));
	goto fail;
      }

      count += len;
    }

    data = allocated;
  }

  tag = id3_tag_parse(data, tagsize);

 fail:
  if (allocated)
    free(allocated);

  return tag;
}

/*
 * NAME:	decode->error()
 * DESCRIPTION:	handle a decoding error
 */
static
enum mad_flow decode_error(void *data, struct mad_stream *stream,
			   struct mad_frame *frame)
{
  struct player *player = data;
  signed long tagsize;

  switch (stream->error) {
  case MAD_ERROR_BADDATAPTR:
    return MAD_FLOW_CONTINUE;

  case MAD_ERROR_LOSTSYNC:
    tagsize = id3_tag_query(stream->this_frame,
			    stream->bufend - stream->this_frame);
    if (tagsize > 0) {
      if (player->options & PLAYER_OPTION_STREAMID3) {
	struct id3_tag *tag;

	tag = get_id3(stream, tagsize, &player->input);
	if (tag) {
	  process_id3(tag, player);
	  id3_tag_delete(tag);
	}
      }
      else
	mad_stream_skip(stream, tagsize);

      if (player->stats.total_bytes >= tagsize)
	player->stats.total_bytes -= tagsize;

      return MAD_FLOW_CONTINUE;
    }

    /* fall through */

  default:
    if (player->verbosity >= -1 &&
	!(player->options & PLAYER_OPTION_SHOWTAGSONLY) &&
	((stream->error == MAD_ERROR_LOSTSYNC && !player->input.eof)
	 || stream->sync) &&
	player->stats.global_framecount != player->stats.error_frame) {
      error("error", _("frame %lu: %s"),
	    player->stats.absolute_framecount, mad_stream_errorstr(stream));
      player->stats.error_frame = player->stats.global_framecount;
    }
  }

  if (stream->error == MAD_ERROR_BADCRC) {
    if (player->stats.global_framecount == player->stats.mute_frame)
      mad_frame_mute(frame);

    player->stats.mute_frame = player->stats.global_framecount + 1;

    return MAD_FLOW_IGNORE;
  }

  return MAD_FLOW_CONTINUE;
}

/*
 * NAME:	decode()
 * DESCRIPTION:	decode and output audio for an open file
 */
static
int decode(struct player *player)
{
  struct stat stat;
  struct mad_decoder decoder;
  int options, result;

  if (fstat(player->input.fd, &stat) == -1) {
    error("decode", ":fstat");
    return -1;
  }

  if (S_ISREG(stat.st_mode))
    player->stats.total_bytes = stat.st_size;

  tag_init(&player->input.tag);

  /* prepare input buffers */

# if defined(HAVE_MMAP)
  if (S_ISREG(stat.st_mode) && stat.st_size > 0) {
    player->input.length = stat.st_size;

    player->input.fdm = map_file(player->input.fd, player->input.length);
    if (player->input.fdm == 0 && player->verbosity >= 0)
      error("decode", ":mmap");

    player->input.data = player->input.fdm;
  }
# endif

  if (player->input.data == 0) {
    player->input.data = malloc(MPEG_BUFSZ);
    if (player->input.data == 0) {
      error("decode", _("not enough memory to allocate input buffer"));
      return -1;
    }

    player->input.length = 0;
  }

  player->input.eof = 0;

  /* reset statistics */
  player->stats.absolute_timer        = mad_timer_zero;
  player->stats.play_timer            = mad_timer_zero;
  player->stats.absolute_framecount   = 0;
  player->stats.play_framecount       = 0;
  player->stats.error_frame           = -1;
  player->stats.vbr                   = 0;
  player->stats.bitrate               = 0;
  player->stats.vbr_frames            = 0;
  player->stats.vbr_rate              = 0;
  player->stats.audio.clipped_samples = 0;
  player->stats.audio.peak_clipping   = 0;
  player->stats.audio.peak_sample     = 0;

  mad_decoder_init(&decoder, player,
# if defined(HAVE_MMAP)
		   player->input.fdm ? decode_input_mmap :
# endif
		   decode_input_read,
		   decode_header, decode_filter,
		   player->output.command ? decode_output : 0,
		   decode_error, 0);

  options = 0;
  if (player->options & PLAYER_OPTION_DOWNSAMPLE)
    options |= MAD_OPTION_HALFSAMPLERATE;
  if (player->options & PLAYER_OPTION_IGNORECRC)
    options |= MAD_OPTION_IGNORECRC;

  mad_decoder_options(&decoder, options);

  result = mad_decoder_run(&decoder, MAD_DECODER_MODE_SYNC);

  mad_decoder_finish(&decoder);

# if defined(HAVE_MMAP)
  if (player->input.fdm) {
    if (unmap_file(player->input.fdm, player->input.length) == -1) {
      error("decode", ":munmap");
      result = -1;
    }

    player->input.fdm = 0;

    if (!player->input.eof)
      player->input.data = 0;
  }
# endif

  if (player->input.data) {
    free(player->input.data);
    player->input.data = 0;
  }

  tag_finish(&player->input.tag);

  return result;
}

/*
 * NAME:	play_one()
 * DESCRIPTION:	open and play a single file
 */
static
int play_one(struct player *player)
{
  char const *file = player->playlist.entries[player->playlist.current];
  int result;

  if (strcmp(file, "-") == 0) {
    if (isatty(STDIN_FILENO)) {
      error(0, "%s: %s", _("stdin"), _("is a tty"));
      return -1;
    }

    player->input.path = _("stdin");
    player->input.fd   = STDIN_FILENO;
  }
  else {
    player->input.path = file;
    player->input.fd   = open(file, O_RDONLY | O_BINARY);
    if (player->input.fd == -1) {
      error(0, ":", file);
      return -1;
    }
  }

  if (player->verbosity >= 0 &&
      player->playlist.length > 1)
    message(">> %s\n", player->input.path);

  /* reset file information */

  player->stats.total_bytes = 0;
  player->stats.total_time  = mad_timer_zero;

  if (!(player->options & PLAYER_OPTION_IGNOREVOLADJ))
    set_gain(player, GAIN_VOLADJ, 0);

  player->output.replay_gain &= ~PLAYER_RGAIN_SET;

  /* try reading ID3 tag information now (else read later from stream) */
  {
    int fd;
    struct id3_file *file;

    player->options &= ~PLAYER_OPTION_STREAMID3;

    fd = dup(player->input.fd);
    file = id3_file_fdopen(fd, ID3_FILE_MODE_READONLY);
    if (file == 0) {
      close(fd);
      player->options |= PLAYER_OPTION_STREAMID3;
    }
    else {
      process_id3(id3_file_tag(file), player);
      id3_file_close(file);
    }
  }

  result = decode(player);

  if (result == 0 && player->verbosity >= 0 &&
      !(player->options & PLAYER_OPTION_SHOWTAGSONLY)) {
    char time_str[19], db_str[7];
    char const *peak_str;
    mad_fixed_t peak;

    mad_timer_string(player->stats.play_timer, time_str, "%lu:%02u:%02u.%1u",
		     MAD_UNITS_HOURS, MAD_UNITS_DECISECONDS, 0);

# if defined(HAVE_LOCALECONV)
    {
      char *point;

      point = strchr(time_str, '.');
      if (point)
	*point = *localeconv()->decimal_point;
    }
# endif

    peak = MAD_F_ONE + player->stats.audio.peak_clipping;
    if (peak == MAD_F_ONE)
      peak = player->stats.audio.peak_sample;

    if (peak == 0)
      peak_str = "-inf";
    else {
      sprintf(db_str, "%+.1f", 20 * log10(mad_f_todouble(peak)));
      peak_str = db_str;
    }

    message("%lu %s (%s), %s dB %s, %lu %s\n",
	    player->stats.play_framecount, player->stats.play_framecount == 1 ?
	    _("frame decoded") : _("frames decoded"), time_str,
	    peak_str, _("peak amplitude"), player->stats.audio.clipped_samples,
	    player->stats.audio.clipped_samples == 1 ?
	    _("clipped sample") : _("clipped samples"));
  }

  if (player->input.fd != STDIN_FILENO &&
      close(player->input.fd) == -1 && result == 0) {
    error(0, ":", player->input.path);
    result = -1;
  }

  return result;
}

/*
 * NAME:	play_all()
 * DESCRIPTION:	run the player's playlist
 */
static
int play_all(struct player *player)
{
  int count, i, j, result = 0;
  struct playlist *playlist = &player->playlist;
  char const *tmp;

  /* set up playlist */

  count = playlist->length;

  if (player->options & PLAYER_OPTION_SHUFFLE) {
    srand(time(0));

    /* initial shuffle */
    for (i = 0; i < count; ++i) {
      j = rand() % count;

      tmp = playlist->entries[i];
      playlist->entries[i] = playlist->entries[j];
      playlist->entries[j] = tmp;
    }
  }

  /* run playlist */

  while (count && (player->repeat == -1 || player->repeat--)) {
    while (playlist->current < playlist->length) {
      i = playlist->current;

      if (playlist->entries[i] == 0) {
	++playlist->current;
	continue;
      }

      player->control = PLAYER_CONTROL_DEFAULT;

      if (play_one(player) == -1) {
	playlist->entries[i] = 0;
	--count;

	result = -1;
      }

      if ((player->options & PLAYER_OPTION_TIMED) &&
	  mad_timer_compare(player->stats.global_timer,
			    player->global_stop) > 0) {
	count = 0;
	break;
      }

      switch (player->control) {
      case PLAYER_CONTROL_DEFAULT:
	if ((player->options & PLAYER_OPTION_SHUFFLE) && player->repeat &&
	    ++i < playlist->length) {
	  /* pick something from the next half only */
	  j = (i + rand() % ((playlist->length + 1) / 2)) % playlist->length;

	  tmp = playlist->entries[i];
	  playlist->entries[i] = playlist->entries[j];
	  playlist->entries[j] = tmp;
	}
	/* fall through */

      case PLAYER_CONTROL_NEXT:
	++playlist->current;
	break;

      case PLAYER_CONTROL_PREVIOUS:
	do {
	  if (playlist->current-- == 0)
	    playlist->current = playlist->length;
	}
	while (playlist->current < playlist->length &&
	       playlist->entries[playlist->current] == 0);
	break;

      case PLAYER_CONTROL_REPLAY:
	break;

      case PLAYER_CONTROL_STOP:
	playlist->current = playlist->length;
	count = 0;
	break;
      }
    }

    playlist->current = 0;
  }

  return result;
}

/*
 * NAME:	stop_audio()
 * DESCRIPTION:	stop playing the audio device immediately
 */
static
int stop_audio(struct player *player, int flush)
{
  int result = 0;

  if (player->output.command) {
    union audio_control control;

    audio_control_init(&control, AUDIO_COMMAND_STOP);
    control.stop.flush = flush;

    result = player->output.command(&control);
  }

  return result;
}

# if defined(USE_TTY)
/*
 * NAME:	readkey()
 * DESCRIPTION:	read a keypress from the keyboard
 */
static
int readkey(int blocking)
{
# if !defined(_WIN32)
  unsigned char key;
  ssize_t count;

  if (!blocking) {
    /* tty_fd should be a tty in noncanonical mode with VMIN = VTIME = 0 */

    count = read(tty_fd, &key, 1);
    if (count == -1 && errno != EINTR) {
      error("tty", ":read");
      return -1;
    }

    return (count == 1) ? key : 0;
  }
  else {
    struct termios tty, save_tty;

    if (tcgetattr(tty_fd, &tty) == -1) {
      error("tty", ":tcgetattr");
      return -1;
    }

    save_tty = tty;

    /* change terminal temporarily to get a blocking read() */

    tty.c_cc[VMIN] = 1;

    if (tcsetattr(tty_fd, TCSANOW, &tty) == -1) {
      error("tty", ":tcsetattr");
      return -1;
    }

    do
      count = read(tty_fd, &key, 1);
    while (count == -1 && errno == EINTR);

    if (count == -1)
      error("tty", ":read");

    if (tcsetattr(tty_fd, TCSANOW, &save_tty) == -1) {
      error("tty", ":tcsetattr");
      return -1;
    }

    if (count == -1)
      return -1;

    return (count == 1) ? key : 0;
  }
# elif defined(_WIN32)
  HANDLE console;
  INPUT_RECORD input;
  DWORD count;

  console = GetStdHandle(STD_INPUT_HANDLE);

  do {
    if (GetNumberOfConsoleInputEvents(console, &count) == 0) {
      error("tty", "GetNumberOfConsoleInputEvents() failed");
      return -1;
    }

    if (count == 0) {
      if (!blocking)
	return 0;
      else {
	/* this is necessary to keep Windows from hanging (!) */
	Sleep(500);

	switch (WaitForSingleObject(console, INFINITE)) {
	case WAIT_ABANDONED:
	case WAIT_OBJECT_0:
	  continue;

	case WAIT_TIMEOUT:
	default:
	  /* ? */
	case WAIT_FAILED:
	  error("tty", "WaitForSingleObject() failed");
	  return -1;
	}
      }
    }

    if (ReadConsoleInput(console, &input, 1, &count) == 0 || count != 1) {
      error("tty", "ReadConsoleInput() failed");
      return -1;
    }
  }
  while (input.EventType != KEY_EVENT || !input.Event.KeyEvent.bKeyDown ||
	 input.Event.KeyEvent.uChar.AsciiChar == 0);

  return (unsigned char) input.Event.KeyEvent.uChar.AsciiChar;
# endif

  return blocking ? -1 : 0;
}

/*
 * NAME:	tty_filter()
 * DESCRIPTION:	process TTY commands
 */
static
enum mad_flow tty_filter(void *data, struct mad_frame *frame)
{
  struct player *player = data;
  enum mad_flow flow = MAD_FLOW_CONTINUE;
  int command, stopped = 0;

  command = readkey(0);
  if (command == -1)
    return MAD_FLOW_BREAK;

 again:
  switch (command) {
  case KEY_STOP:
    stopped = 1;

    player->control = PLAYER_CONTROL_REPLAY;
    flow = MAD_FLOW_STOP;

    /* fall through */

  case KEY_PAUSE:
    stop_audio(player, stopped);
    message(" --%s--", stopped ? _("Stopped") : _("Paused"));

    command = readkey(1);