| 1 | /* |
| 2 | * This file is part of DisOrder |
| 3 | * Copyright (C) 2005-2008 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 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 server/speaker.h |
| 19 | * @brief Speaker process |
| 20 | */ |
| 21 | #ifndef SPEAKER_H |
| 22 | #define SPEAKER_H |
| 23 | |
| 24 | #ifdef WORDS_BIGENDIAN |
| 25 | # define MACHINE_AO_FMT AO_FMT_BIG |
| 26 | #else |
| 27 | # define MACHINE_AO_FMT AO_FMT_LITTLE |
| 28 | #endif |
| 29 | |
| 30 | /** @brief Minimum number of frames to try to play at once |
| 31 | * |
| 32 | * The main loop will only attempt to play any audio when this many |
| 33 | * frames are available (or the current track has reached the end). |
| 34 | * The actual number of frames it attempts to play will often be |
| 35 | * larger than this (up to three times). |
| 36 | * |
| 37 | * For ALSA we request a buffer of three times this size and set the low |
| 38 | * watermark to this amount. The goal is then to keep between 1 and 3 times |
| 39 | * this many frames in play. |
| 40 | * |
| 41 | * For other we attempt to play up to three times this many frames per |
| 42 | * shot. In practice we will often only send much less than this. |
| 43 | */ |
| 44 | #define FRAMES 4096 |
| 45 | |
| 46 | /** @brief Bytes to send per network packet |
| 47 | * |
| 48 | * This is the maximum number of bytes we pass to write(2); to determine actual |
| 49 | * packet sizes, add a UDP header and an IP header (and a link layer header if |
| 50 | * it's the link layer size you care about). |
| 51 | * |
| 52 | * Don't make this too big or arithmetic will start to overflow. |
| 53 | */ |
| 54 | #define NETWORK_BYTES (1500-8/*UDP*/-40/*IP*/-8/*conservatism*/) |
| 55 | |
| 56 | /** @brief Maximum number of FDs to poll for */ |
| 57 | #define NFDS 256 |
| 58 | |
| 59 | /** @brief Track structure |
| 60 | * |
| 61 | * Known tracks are kept in a linked list. Usually there will be at most two |
| 62 | * of these but rearranging the queue can cause there to be more. |
| 63 | */ |
| 64 | struct track { |
| 65 | /** @brief Next track */ |
| 66 | struct track *next; |
| 67 | |
| 68 | /** @brief Input file descriptor */ |
| 69 | int fd; /* input FD */ |
| 70 | |
| 71 | /** @brief Track ID */ |
| 72 | char id[24]; |
| 73 | |
| 74 | /** @brief Start position of data in buffer */ |
| 75 | size_t start; |
| 76 | |
| 77 | /** @brief Number of bytes of data in buffer */ |
| 78 | size_t used; |
| 79 | |
| 80 | /** @brief Set @c fd is at EOF */ |
| 81 | int eof; |
| 82 | |
| 83 | /** @brief Total number of frames played */ |
| 84 | unsigned long long played; |
| 85 | |
| 86 | /** @brief Slot in @ref fds */ |
| 87 | int slot; |
| 88 | |
| 89 | /** @brief Set when playable |
| 90 | * |
| 91 | * A track becomes playable whenever it fills its buffer or reaches EOF; it |
| 92 | * stops being playable when it entirely empties its buffer. Tracks start |
| 93 | * out life not playable. |
| 94 | */ |
| 95 | int playable; |
| 96 | |
| 97 | /** @brief Input buffer |
| 98 | * |
| 99 | * 1Mbyte is enough for nearly 6s of 44100Hz 16-bit stereo |
| 100 | */ |
| 101 | char buffer[1048576]; |
| 102 | }; |
| 103 | |
| 104 | /** @brief Structure of a backend */ |
| 105 | struct speaker_backend { |
| 106 | /** @brief Which backend this is |
| 107 | * |
| 108 | * @c -1 terminates the list. |
| 109 | */ |
| 110 | int backend; |
| 111 | |
| 112 | /** @brief Flags |
| 113 | * |
| 114 | * This field is currently not used and must be 0. |
| 115 | */ |
| 116 | unsigned flags; |
| 117 | |
| 118 | /** @brief Initialization |
| 119 | * |
| 120 | * Called once at startup. This is responsible for one-time setup |
| 121 | * operations, for instance opening a network socket to transmit to. |
| 122 | * |
| 123 | * When writing to a native sound API this might @b not imply opening the |
| 124 | * native sound device - that might be done by @c activate below. |
| 125 | */ |
| 126 | void (*init)(void); |
| 127 | |
| 128 | /** @brief Activation |
| 129 | * @return 0 on success, non-0 on error |
| 130 | * |
| 131 | * Called to activate the output device. |
| 132 | * |
| 133 | * On input @ref device_state may be anything. If it is @ref |
| 134 | * device_open then the device is already open but might be using |
| 135 | * the wrong sample format. The device should be reconfigured to |
| 136 | * use the right sample format. |
| 137 | * |
| 138 | * If it is @ref device_error then a retry is underway and an |
| 139 | * attempt to recover or re-open the device (with the right sample |
| 140 | * format) should be made. |
| 141 | * |
| 142 | * If it is @ref device_closed then the device should be opened with |
| 143 | * the right sample format. |
| 144 | * |
| 145 | * Some devices are effectively always open and have no error state, in which |
| 146 | * case this callback can be NULL. Note that @ref device_state still |
| 147 | * switches between @ref device_open and @ref device_closed in this case. |
| 148 | */ |
| 149 | void (*activate)(void); |
| 150 | |
| 151 | /** @brief Play sound |
| 152 | * @param frames Number of frames to play |
| 153 | * @return Number of frames actually played |
| 154 | * |
| 155 | * If an error occurs (and it is not immediately recovered) this |
| 156 | * should set @ref device_state to @ref device_error. |
| 157 | */ |
| 158 | size_t (*play)(size_t frames); |
| 159 | |
| 160 | /** @brief Deactivation |
| 161 | * |
| 162 | * Called to deactivate the sound device. This is the inverse of @c |
| 163 | * activate above. |
| 164 | * |
| 165 | * For sound devices that are open all the time and have no error |
| 166 | * state, this callback can be NULL. Note that @ref device_state |
| 167 | * still switches between @ref device_open and @ref device_closed in |
| 168 | * this case. |
| 169 | */ |
| 170 | void (*deactivate)(void); |
| 171 | |
| 172 | /** @brief Called before poll() |
| 173 | * @param timeoutp Pointer to timeout |
| 174 | * |
| 175 | * Called before the call to poll(). |
| 176 | * |
| 177 | * If desirable, should call addfd() to update the FD array and stash the |
| 178 | * slot number somewhere safe. This will only be called if @ref device_state |
| 179 | * is @ref device_open. |
| 180 | * |
| 181 | * @p timeoutp points to the poll timeout value in milliseconds. It may be |
| 182 | * reduced, but never increased. |
| 183 | * |
| 184 | * NB you can NOT assume that @c beforepoll is always called before @c play. |
| 185 | */ |
| 186 | void (*beforepoll)(int *timeoutp); |
| 187 | |
| 188 | /** @brief Called after poll() |
| 189 | * @return 1 if output device ready for play, 0 otherwise |
| 190 | * |
| 191 | * Called after the call to poll(). This will only be called if |
| 192 | * @ref device_state = @ref device_open. |
| 193 | * |
| 194 | * The return value should be 1 if the device was ready to play, or |
| 195 | * 0 if it was not. |
| 196 | */ |
| 197 | int (*ready)(void); |
| 198 | }; |
| 199 | |
| 200 | /** @brief Possible device states */ |
| 201 | enum device_states { |
| 202 | /** @brief The device is closed */ |
| 203 | device_closed, |
| 204 | |
| 205 | /** @brief The device is open and ready to receive sound |
| 206 | * |
| 207 | * The current device sample format is potentially part of this state. |
| 208 | */ |
| 209 | device_open, |
| 210 | |
| 211 | /** @brief An error has occurred on the device |
| 212 | * |
| 213 | * This state is used to ensure that a small interval is left |
| 214 | * between retrying the device. If errors just set @ref |
| 215 | * device_closed then the main loop would busy-wait on broken output |
| 216 | * devices. |
| 217 | * |
| 218 | * The current device sample format is potentially part of this state. |
| 219 | */ |
| 220 | device_error |
| 221 | }; |
| 222 | |
| 223 | extern enum device_states device_state; |
| 224 | extern struct track *tracks; |
| 225 | extern struct track *playing; |
| 226 | |
| 227 | extern const struct speaker_backend network_backend; |
| 228 | extern const struct speaker_backend alsa_backend; |
| 229 | extern const struct speaker_backend command_backend; |
| 230 | extern const struct speaker_backend coreaudio_backend; |
| 231 | extern const struct speaker_backend oss_backend; |
| 232 | |
| 233 | extern struct pollfd fds[NFDS]; |
| 234 | extern int fdno; |
| 235 | extern size_t bpf; |
| 236 | extern int idled; |
| 237 | |
| 238 | int addfd(int fd, int events); |
| 239 | void abandon(void); |
| 240 | |
| 241 | #endif /* SPEAKER_H */ |
| 242 | |
| 243 | /* |
| 244 | Local Variables: |
| 245 | c-basic-offset:2 |
| 246 | comment-column:40 |
| 247 | fill-column:79 |
| 248 | indent-tabs-mode:nil |
| 249 | End: |
| 250 | */ |