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, 2008 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_PLAY
  36    * - @ref SM_PAUSE
  37    * - @ref SM_RESUME
  38    * - @ref SM_CANCEL
  39    * - @ref SM_RELOAD
  40    *
  41    * Messages from the speaker:
  42    * - @ref SM_PAUSED
  43    * - @ref SM_FINISHED
  44    * - @ref SM_PLAYING
  45    * - @ref SM_UNKNOWN
  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
  58 /** @brief Play track @c id
  59  *
  60  * The track must already have been prepared.
  61  */
  62 #define SM_PLAY 1
  63
  64 /** @brief Pause current track */
  65 #define SM_PAUSE 2
  66
  67 /** @brief Resume current track */
  68 #define SM_RESUME 3
  69
  70 /** @brief Cancel track @c id */
  71 #define SM_CANCEL 4
  72
  73 /** @brief Reload configuration */
  74 #define SM_RELOAD 5
  75
  76 /* messages from the speaker */
  77 /** @brief Paused track @c id, @c data seconds in
  78  *
  79  * There is no @c SM_RESUMED, instead @ref SM_PLAYING is sent after the track
  80  * starts playing again.
  81  */
  82 #define SM_PAUSED 128
  83
  84 /** @brief Finished playing track @c id */
  85 #define SM_FINISHED 129
  86
  87 /** @brief Never heard of track @c id */
  88 #define SM_UNKNOWN 130
  89
  90 /** @brief Currently track @c id, @c data seconds in
  91  *
  92  * This is sent from time to time while a track is playing.
  93  */
  94 #define SM_PLAYING 131
  95
  96 /** @brief Speaker process is ready
  97  *
  98  * This is sent once at startup when the speaker has finished its
  99  * initialization. */
 100 #define SM_READY 132
 101
 102 /** @brief Cancelled track @c id which wasn't playing */
 103 #define SM_STILLBORN 133
 104
 105 void speaker_send(int fd, const struct speaker_message *sm);
 106 /* Send a message. */
 107
 108 int speaker_recv(int fd, struct speaker_message *sm);
 109 /* Receive a message.  Return 0 on EOF, +ve if a message is read, -1 on EAGAIN,
 110  * terminates on any other error. */
 111
 112 /** @brief One chunk in a stream */
 113 struct stream_header {
 114   /** @brief Number of bytes */
 115   uint32_t nbytes;
 116
 117   /** @brief Frames per second */
 118   uint32_t rate;
 119
 120   /** @brief Samples per frames */
 121   uint8_t channels;
 122
 123   /** @brief Bits per sample */
 124   uint8_t bits;
 125
 126   /** @brief Endianness */
 127   uint8_t endian;
 128 #define ENDIAN_BIG 1
 129 #define ENDIAN_LITTLE 2
 130 #ifdef WORDS_BIGENDIAN
 131 # define ENDIAN_NATIVE ENDIAN_BIG
 132 #else
 133 # define ENDIAN_NATIVE ENDIAN_LITTLE
 134 #endif
 135 } attribute((packed));
 136
 137 static inline int formats_equal(const struct stream_header *a,
 138                                 const struct stream_header *b) {
 139   return (a->rate == b->rate
 140           && a->channels == b->channels
 141           && a->bits == b->bits
 142           && a->endian == b->endian);
 143 }
 144
 145 #endif /* SPEAKER_PROTOCOL_H */
 146
 147 /*
 148 Local Variables:
 149 c-basic-offset:2
 150 comment-column:40
 151 fill-column:79
 152 indent-tabs-mode:nil
 153 End:
 154 */