mdw@git.distorted.org.uk Git - disorder/blob - lib/speaker-protocol.h

   1 /*
   2  * This file is part of DisOrder
   3  * Copyright (C) 2005, 2007 Richard Kettlewell
   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, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  18  * USA
  19  */
  20 /** @file lib/speaker-protocol.h
  21  * @brief Speaker/server protocol support
  22  *
  23  * This file defines the protocol by which the main server and the speaker
  24  * process communicate.
  25  */
  26
  27 #ifndef SPEAKER_PROTOCOL_H
  28 #define SPEAKER_PROTOCOL_H
  29
  30 /** @brief A message from the main server to the speaker, or vica versa */
  31 struct speaker_message {
  32   /** @brief Message type
  33    *
  34    * Messges from the main server:
  35    * - @ref SM_PREPARE
  36    * - @ref SM_PLAY
  37    * - @ref SM_PAUSE
  38    * - @ref SM_RESUME
  39    * - @ref SM_CANCEL
  40    * - @ref SM_RELOAD
  41    *
  42    * Messages from the speaker:
  43    * - @ref SM_PAUSED
  44    * - @ref SM_FINISHED
  45    * - @ref SM_PLAYING
  46    */
  47   int type;
  48
  49   /** @brief Message-specific data */
  50   long data;
  51
  52   /** @brief Track ID (including 0 terminator) */
  53   char id[24];                          /* ID including terminator */
  54 };
  55
  56 /* messages from the main DisOrder server */
  57 /** @brief Prepare track @c id
  58  *
  59  * This message will include a file descriptor.  The speaker starts buffering
  60  * audio data read from this file against the time that it must be played.
  61  */
  62 #define SM_PREPARE 0
  63
  64 /** @brief Play track @c id
  65  *
  66  * The track must already have been prepared.
  67  */
  68 #define SM_PLAY 1
  69
  70 /** @brief Pause current track */
  71 #define SM_PAUSE 2
  72
  73 /** @brief Resume current track */
  74 #define SM_RESUME 3
  75
  76 /** @brief Cancel track @c id */
  77 #define SM_CANCEL 4
  78
  79 /** @brief Reload configuration */
  80 #define SM_RELOAD 5
  81
  82 /* messages from the speaker */
  83 /** @brief Paused track @c id, @c data seconds in
  84  *
  85  * There is no @c SM_RESUMED, instead @ref SM_PLAYING is sent after the track
  86  * starts playing again.
  87  */
  88 #define SM_PAUSED 128
  89
  90 /** @brief Finished playing track @c id */
  91 #define SM_FINISHED 129
  92
  93 /** @brief Currently track @c id, @c data seconds in
  94  *
  95  * This is sent from time to time while a track is playing.
  96  */
  97 #define SM_PLAYING 131
  98
  99 void speaker_send(int fd, const struct speaker_message *sm, int datafd);
 100 /* Send a message.  DATAFD is passed too if not -1.  Does not close DATAFD. */
 101
 102 int speaker_recv(int fd, struct speaker_message *sm, int *datafd);
 103 /* Receive a message.  If DATAFD is not null then can receive an FD.  Return 0
 104  * on EOF, +ve if a message is read, -1 on EAGAIN, terminates on any other
 105  * error. */
 106
 107 /** @brief One chunk in a stream */
 108 struct stream_header {
 109   /** @brief Frames per second */
 110   uint32_t rate;
 111
 112   /** @brief Samples per frames */
 113   uint8_t channels;
 114
 115   /** @brief Bits per sample */
 116   uint8_t bits;
 117
 118   /** @brief Endianness */
 119   uint8_t endian;
 120 #define ENDIAN_BIG 1
 121 #define ENDIAN_LITTLE 2
 122 #ifdef WORDS_BIGENDIAN
 123 # define ENDIAN_NATIVE ENDIAN_BIG
 124 #else
 125 # define ENDIAN_NATIVE ENDIAN_LITTLE
 126 #endif
 127
 128   /** @brief Number of bytes */
 129   uint32_t nbytes;
 130 } attribute((packed));
 131
 132 static inline int formats_equal(const struct stream_header *a,
 133                                 const struct stream_header *b) {
 134   return (a->rate == b->rate
 135           && a->channels == b->channels
 136           && a->bits == b->bits
 137           && a->endian == b->endian);
 138 }
 139
 140 #endif /* SPEAKER_PROTOCOL_H */
 141
 142 /*
 143 Local Variables:
 144 c-basic-offset:2
 145 comment-column:40
 146 fill-column:79
 147 indent-tabs-mode:nil
 148 End:
 149 */