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_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    */
  46   int type;
  47
  48   /** @brief Message-specific data */
  49   long data;
  50
  51   /** @brief Track ID (including 0 terminator) */
  52   char id[24];                          /* ID including terminator */
  53 };
  54
  55 /* messages from the main DisOrder server */
  56
  57 /** @brief Play track @c id
  58  *
  59  * The track must already have been prepared.
  60  */
  61 #define SM_PLAY 1
  62
  63 /** @brief Pause current track */
  64 #define SM_PAUSE 2
  65
  66 /** @brief Resume current track */
  67 #define SM_RESUME 3
  68
  69 /** @brief Cancel track @c id */
  70 #define SM_CANCEL 4
  71
  72 /** @brief Reload configuration */
  73 #define SM_RELOAD 5
  74
  75 /* messages from the speaker */
  76 /** @brief Paused track @c id, @c data seconds in
  77  *
  78  * There is no @c SM_RESUMED, instead @ref SM_PLAYING is sent after the track
  79  * starts playing again.
  80  */
  81 #define SM_PAUSED 128
  82
  83 /** @brief Finished playing track @c id */
  84 #define SM_FINISHED 129
  85
  86 /** @brief Currently track @c id, @c data seconds in
  87  *
  88  * This is sent from time to time while a track is playing.
  89  */
  90 #define SM_PLAYING 131
  91
  92 /** @brief Speaker process is ready
  93  *
  94  * This is sent once at startup when the speaker has finished its
  95  * initialization. */
  96 #define SM_READY 132
  97
  98 void speaker_send(int fd, const struct speaker_message *sm);
  99 /* Send a message. */
 100
 101 int speaker_recv(int fd, struct speaker_message *sm);
 102 /* Receive a message.  Return 0 on EOF, +ve if a message is read, -1 on EAGAIN,
 103  * terminates on any other error. */
 104
 105 /** @brief One chunk in a stream */
 106 struct stream_header {
 107   /** @brief Number of bytes */
 108   uint32_t nbytes;
 109
 110   /** @brief Frames per second */
 111   uint32_t rate;
 112
 113   /** @brief Samples per frames */
 114   uint8_t channels;
 115
 116   /** @brief Bits per sample */
 117   uint8_t bits;
 118
 119   /** @brief Endianness */
 120   uint8_t endian;
 121 #define ENDIAN_BIG 1
 122 #define ENDIAN_LITTLE 2
 123 #ifdef WORDS_BIGENDIAN
 124 # define ENDIAN_NATIVE ENDIAN_BIG
 125 #else
 126 # define ENDIAN_NATIVE ENDIAN_LITTLE
 127 #endif
 128 } attribute((packed));
 129
 130 static inline int formats_equal(const struct stream_header *a,
 131                                 const struct stream_header *b) {
 132   return (a->rate == b->rate
 133           && a->channels == b->channels
 134           && a->bits == b->bits
 135           && a->endian == b->endian);
 136 }
 137
 138 #endif /* SPEAKER_PROTOCOL_H */
 139
 140 /*
 141 Local Variables:
 142 c-basic-offset:2
 143 comment-column:40
 144 fill-column:79
 145 indent-tabs-mode:nil
 146 End:
 147 */