+++ /dev/null
-/*
- * This file is part of DisOrder
- * Copyright (C) 2005-2008 Richard Kettlewell
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-/** @file server/speaker.h
- * @brief Speaker process
- */
-#ifndef SPEAKER_H
-#define SPEAKER_H
-
-#ifdef WORDS_BIGENDIAN
-# define MACHINE_AO_FMT AO_FMT_BIG
-#else
-# define MACHINE_AO_FMT AO_FMT_LITTLE
-#endif
-
-/** @brief Minimum number of frames to try to play at once
- *
- * The main loop will only attempt to play any audio when this many
- * frames are available (or the current track has reached the end).
- * The actual number of frames it attempts to play will often be
- * larger than this (up to three times).
- *
- * For ALSA we request a buffer of three times this size and set the low
- * watermark to this amount. The goal is then to keep between 1 and 3 times
- * this many frames in play.
- *
- * For other we attempt to play up to three times this many frames per
- * shot. In practice we will often only send much less than this.
- */
-#define FRAMES 4096
-
-/** @brief Bytes to send per network packet
- *
- * This is the maximum number of bytes we pass to write(2); to determine actual
- * packet sizes, add a UDP header and an IP header (and a link layer header if
- * it's the link layer size you care about).
- *
- * Don't make this too big or arithmetic will start to overflow.
- */
-#define NETWORK_BYTES (1500-8/*UDP*/-40/*IP*/-8/*conservatism*/)
-
-/** @brief Maximum number of FDs to poll for */
-#define NFDS 256
-
-/** @brief Track structure
- *
- * Known tracks are kept in a linked list. Usually there will be at most two
- * of these but rearranging the queue can cause there to be more.
- */
-struct track {
- /** @brief Next track */
- struct track *next;
-
- /** @brief Input file descriptor */
- int fd; /* input FD */
-
- /** @brief Track ID */
- char id[24];
-
- /** @brief Start position of data in buffer */
- size_t start;
-
- /** @brief Number of bytes of data in buffer */
- size_t used;
-
- /** @brief Set @c fd is at EOF */
- int eof;
-
- /** @brief Total number of frames played */
- unsigned long long played;
-
- /** @brief Slot in @ref fds */
- int slot;
-
- /** @brief Set when playable
- *
- * A track becomes playable whenever it fills its buffer or reaches EOF; it
- * stops being playable when it entirely empties its buffer. Tracks start
- * out life not playable.
- */
- int playable;
-
- /** @brief Input buffer
- *
- * 1Mbyte is enough for nearly 6s of 44100Hz 16-bit stereo
- */
- char buffer[1048576];
-};
-
-/** @brief Structure of a backend */
-struct speaker_backend {
- /** @brief Which backend this is
- *
- * @c -1 terminates the list.
- */
- int backend;
-
- /** @brief Flags
- *
- * This field is currently not used and must be 0.
- */
- unsigned flags;
-
- /** @brief Initialization
- *
- * Called once at startup. This is responsible for one-time setup
- * operations, for instance opening a network socket to transmit to.
- *
- * When writing to a native sound API this might @b not imply opening the
- * native sound device - that might be done by @c activate below.
- */
- void (*init)(void);
-
- /** @brief Activation
- * @return 0 on success, non-0 on error
- *
- * Called to activate the output device.
- *
- * On input @ref device_state may be anything. If it is @ref
- * device_open then the device is already open but might be using
- * the wrong sample format. The device should be reconfigured to
- * use the right sample format.
- *
- * If it is @ref device_error then a retry is underway and an
- * attempt to recover or re-open the device (with the right sample
- * format) should be made.
- *
- * If it is @ref device_closed then the device should be opened with
- * the right sample format.
- *
- * Some devices are effectively always open and have no error state, in which
- * case this callback can be NULL. Note that @ref device_state still
- * switches between @ref device_open and @ref device_closed in this case.
- */
- void (*activate)(void);
-
- /** @brief Play sound
- * @param frames Number of frames to play
- * @return Number of frames actually played
- *
- * If an error occurs (and it is not immediately recovered) this
- * should set @ref device_state to @ref device_error.
- */
- size_t (*play)(size_t frames);
-
- /** @brief Deactivation
- *
- * Called to deactivate the sound device. This is the inverse of @c
- * activate above.
- *
- * For sound devices that are open all the time and have no error
- * state, this callback can be NULL. Note that @ref device_state
- * still switches between @ref device_open and @ref device_closed in
- * this case.
- */
- void (*deactivate)(void);
-
- /** @brief Called before poll()
- * @param timeoutp Pointer to timeout
- *
- * Called before the call to poll().
- *
- * If desirable, should call addfd() to update the FD array and stash the
- * slot number somewhere safe. This will only be called if @ref device_state
- * is @ref device_open.
- *
- * @p timeoutp points to the poll timeout value in milliseconds. It may be
- * reduced, but never increased.
- *
- * NB you can NOT assume that @c beforepoll is always called before @c play.
- */
- void (*beforepoll)(int *timeoutp);
-
- /** @brief Called after poll()
- * @return 1 if output device ready for play, 0 otherwise
- *
- * Called after the call to poll(). This will only be called if
- * @ref device_state = @ref device_open.
- *
- * The return value should be 1 if the device was ready to play, or
- * 0 if it was not.
- */
- int (*ready)(void);
-};
-
-/** @brief Possible device states */
-enum device_states {
- /** @brief The device is closed */
- device_closed,
-
- /** @brief The device is open and ready to receive sound
- *
- * The current device sample format is potentially part of this state.
- */
- device_open,
-
- /** @brief An error has occurred on the device
- *
- * This state is used to ensure that a small interval is left
- * between retrying the device. If errors just set @ref
- * device_closed then the main loop would busy-wait on broken output
- * devices.
- *
- * The current device sample format is potentially part of this state.
- */
- device_error
-};
-
-extern enum device_states device_state;
-extern struct track *tracks;
-extern struct track *playing;
-
-extern const struct speaker_backend network_backend;
-extern const struct speaker_backend alsa_backend;
-extern const struct speaker_backend command_backend;
-extern const struct speaker_backend coreaudio_backend;
-extern const struct speaker_backend oss_backend;
-
-extern struct pollfd fds[NFDS];
-extern int fdno;
-extern size_t bpf;
-extern int idled;
-
-int addfd(int fd, int events);
-void abandon(void);
-
-#endif /* SPEAKER_H */
-
-/*
-Local Variables:
-c-basic-offset:2
-comment-column:40
-fill-column:79
-indent-tabs-mode:nil
-End:
-*/
~mdw / disorder / blobdiff