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, 2013 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 3 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
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18 /** @file lib/speaker-protocol.h
  19  * @brief Speaker/server protocol support
  20  *
  21  * This file defines the protocol by which the main server and the speaker
  22  * process communicate.
  23  */
  24
  25 #ifndef SPEAKER_PROTOCOL_H
  26 #define SPEAKER_PROTOCOL_H
  27
  28 #include "byte-order.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    * Messages 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    * - @ref SM_ARRIVED
  47    */
  48   int type;
  49
  50   /** @brief Message-specific data */
  51   long data;
  52
  53   union {
  54     /** @brief Track ID (including 0 terminator) */
  55     char id[24];                          /* ID including terminator */
  56   } u;
  57 };
  58
  59 /* messages from the main DisOrder server */
  60
  61 /** @brief Play track @c id
  62  *
  63  * The track must already have been prepared.
  64  */
  65 #define SM_PLAY 1
  66
  67 /** @brief Pause current track */
  68 #define SM_PAUSE 2
  69
  70 /** @brief Resume current track */
  71 #define SM_RESUME 3
  72
  73 /** @brief Cancel track @c id */
  74 #define SM_CANCEL 4
  75
  76 /** @brief Reload configuration */
  77 #define SM_RELOAD 5
  78
  79 /* messages from the speaker */
  80 /** @brief Paused track @c id, @c data seconds in
  81  *
  82  * There is no @c SM_RESUMED, instead @ref SM_PLAYING is sent after the track
  83  * starts playing again.
  84  */
  85 #define SM_PAUSED 128
  86
  87 /** @brief Finished playing track @c id */
  88 #define SM_FINISHED 129
  89
  90 /** @brief Never heard of track @c id */
  91 #define SM_UNKNOWN 130
  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 /** @brief Speaker process is ready
 100  *
 101  * This is sent once at startup when the speaker has finished its
 102  * initialization. */
 103 #define SM_READY 132
 104
 105 /** @brief Cancelled track @c id which wasn't playing */
 106 #define SM_STILLBORN 133
 107
 108 /** @brief A connection for track @c id arrived */
 109 #define SM_ARRIVED 134
 110
 111 void speaker_send(int fd, const struct speaker_message *sm);
 112 /* Send a message. */
 113
 114 int speaker_recv(int fd, struct speaker_message *sm);
 115 /* Receive a message.  Return 0 on EOF, +ve if a message is read, -1 on EAGAIN,
 116  * terminates on any other error. */
 117
 118 /** @brief One chunk in a stream */
 119 struct stream_header {
 120   /** @brief Number of bytes */
 121   uint32_t nbytes;
 122
 123   /** @brief Frames per second */
 124   uint32_t rate;
 125
 126   /** @brief Samples per frames */
 127   uint8_t channels;
 128
 129   /** @brief Bits per sample */
 130   uint8_t bits;
 131
 132   /** @brief Endianness */
 133   uint8_t endian;
 134 } attribute((packed));
 135
 136 static inline int formats_equal(const struct stream_header *a,
 137                                 const struct stream_header *b) {
 138   return (a->rate == b->rate
 139           && a->channels == b->channels
 140           && a->bits == b->bits
 141           && a->endian == b->endian);
 142 }
 143
 144 #endif /* SPEAKER_PROTOCOL_H */
 145
 146 /*
 147 Local Variables:
 148 c-basic-offset:2
 149 comment-column:40
 150 fill-column:79
 151 indent-tabs-mode:nil
 152 End:
 153 */