src/pipe.h

   1 /*
   2  * Copyright (C) 2003-2010 The Music Player Daemon Project
   3  * http://www.musicpd.org
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #ifndef MPD_PIPE_H
  21 #define MPD_PIPE_H
  22
  23 #ifndef NDEBUG
  24 #include <stdbool.h>
  25
  26 struct audio_format;
  27 #endif
  28
  29 struct music_chunk;
  30 struct music_buffer;
  31
  32 /**
  33  * A queue of #music_chunk objects.  One party appends chunks at the
  34  * tail, and the other consumes them from the head.
  35  */
  36 struct music_pipe;
  37
  38 /**
  39  * Creates a new #music_pipe object.  It is empty.
  40  */
  41 struct music_pipe *
  42 music_pipe_new(void);
  43
  44 /**
  45  * Frees the object.  It must be empty now.
  46  */
  47 void
  48 music_pipe_free(struct music_pipe *mp);
  49
  50 #ifndef NDEBUG
  51
  52 /**
  53  * Checks if the audio format if the chunk is equal to the specified
  54  * audio_format.
  55  */
  56 bool
  57 music_pipe_check_format(const struct music_pipe *pipe,
  58                         const struct audio_format *audio_format);
  59
  60 /**
  61  * Checks if the specified chunk is enqueued in the music pipe.
  62  */
  63 bool
  64 music_pipe_contains(const struct music_pipe *mp,
  65                     const struct music_chunk *chunk);
  66
  67 #endif
  68
  69 /**
  70  * Returns the first #music_chunk from the pipe.  Returns NULL if the
  71  * pipe is empty.
  72  */
  73 const struct music_chunk *
  74 music_pipe_peek(const struct music_pipe *mp);
  75
  76 /**
  77  * Removes the first chunk from the head, and returns it.
  78  */
  79 struct music_chunk *
  80 music_pipe_shift(struct music_pipe *mp);
  81
  82 /**
  83  * Clears the whole pipe and returns the chunks to the buffer.
  84  *
  85  * @param buffer the buffer object to return the chunks to
  86  */
  87 void
  88 music_pipe_clear(struct music_pipe *mp, struct music_buffer *buffer);
  89
  90 /**
  91  * Pushes a chunk to the tail of the pipe.
  92  */
  93 void
  94 music_pipe_push(struct music_pipe *mp, struct music_chunk *chunk);
  95
  96 /**
  97  * Returns the number of chunks currently in this pipe.
  98  */
  99 unsigned
 100 music_pipe_size(const struct music_pipe *mp);
 101
 102 #endif