e9060e7e |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: ausys-sdl.c,v 1.1 2002/02/02 19:16:28 mdw Exp $ |
4 | * |
5 | * Unix-specific (SDL) audio handling |
6 | * |
7 | * (c) 2002 Mark Wooding |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Jog: Programming for a jogging machine. |
13 | * |
14 | * Jog is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
19 | * Jog is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
25 | * along with Jog; if not, write to the Free Software Foundation, |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | */ |
28 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: ausys-sdl.c,v $ |
32 | * Revision 1.1 2002/02/02 19:16:28 mdw |
33 | * New audio subsystem. |
34 | * |
35 | */ |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
39 | #ifdef HAVE_CONFIG_H |
40 | # include "config.h" |
41 | #endif |
42 | |
43 | #include <errno.h> |
44 | #include <stdio.h> |
45 | #include <string.h> |
46 | |
47 | #include <sys/types.h> |
48 | #include <sys/time.h> |
49 | #include <unistd.h> |
50 | #include <pthread.h> |
51 | |
52 | #include <SDL.h> |
53 | |
54 | #include <mLib/alloc.h> |
55 | #include <mLib/bits.h> |
56 | #include <mLib/sub.h> |
57 | #include <mLib/trace.h> |
58 | |
59 | #include "au.h" |
60 | #include "ausys.h" |
61 | #include "err.h" |
62 | #include "jog.h" |
63 | |
64 | /*----- Data structures ---------------------------------------------------*/ |
65 | |
66 | /* --- Queue of samples to play --- */ |
67 | |
68 | typedef struct qnode { |
69 | struct qnode *next; /* Next item in the queue */ |
70 | au_data *a; /* Pointer to sample data */ |
71 | } qnode; |
72 | |
73 | /*----- Global variables --------------------------------------------------*/ |
74 | |
75 | const char *const ausys_suffix = "wav"; |
76 | |
77 | /*----- Static data -------------------------------------------------------*/ |
78 | |
79 | static SDL_AudioSpec auspec; /* Driver's selected parameters */ |
80 | static qnode *qhead = 0, *qtail = 0; /* Queue of samples to play */ |
81 | static qnode *qfree = 0; /* Queue of samples to free */ |
82 | |
83 | static pthread_t tid_free; /* The sample-freeing thread */ |
84 | static pthread_mutex_t mx_free; /* Mutex for @qfree@ */ |
85 | static pthread_cond_t cv_free; /* More sample data to free */ |
86 | |
87 | static pthread_mutex_t mx_sub; /* Protects mLib @sub@ functions */ |
88 | |
89 | /*----- Thread structure --------------------------------------------------* |
90 | * |
91 | * SDL makes a buffer-stuffing thread that @fill@ is run from. This function |
92 | * reads samples to play from the queue at @qhead@. Hence @qhead@ must be |
93 | * locked when it's modified, using @SDL_LockAudio@. |
94 | * |
95 | * In order to keep latency down when new sample data is wanted, we don't do |
96 | * potentially tedious things like freeing sample data blocks in the @fill@ |
97 | * thread. Instead, there's a queue of sample blocks which need freeing, and |
98 | * a separate thread @dofree@ which processes the queue. The queue, @qfree@ |
99 | * is locked by @mx_free@. When new nodes are added to @qfree@, the |
100 | * condition @cv_free@ is signalled. |
101 | * |
102 | * Finally, the mLib `sub' module isn't thread-safe, so it's locked |
103 | * separately by @mx_sub@. |
104 | * |
105 | * There's an ordering on mutexes. If you want more than one mutex at a |
106 | * time, you must lock the greatest first. The ordering is: |
107 | * |
108 | * SDL_Audio > free > sub |
109 | */ |
110 | |
111 | /*----- Main code ---------------------------------------------------------*/ |
112 | |
113 | /* --- @fill@ --- * |
114 | * |
115 | * Arguments: @void *u@ = user data (ignored) |
116 | * @octet *q@ = pointer to buffer to fill in |
117 | * @int qsz@ = size of the buffer |
118 | * |
119 | * Returns: --- |
120 | * |
121 | * Use: Fills an audio buffer with precomputed stuff. |
122 | */ |
123 | |
124 | static void fill(void *u, octet *q, int qsz) |
125 | { |
126 | static const octet *p = 0; /* Current place in current sample */ |
127 | static size_t sz = 0; /* How far to go in current sample */ |
128 | qnode *qf = 0, **qft = &qf; /* Samples we've finished with */ |
129 | |
130 | /* --- If @p@ is null we need to get a new sample --- */ |
131 | |
132 | if (!p && qhead) { |
133 | T( trace(T_AUSYS, "ausys: begin playing `%s'", SYM_NAME(qhead->a->s)); ) |
134 | p = qhead->a->p; |
135 | sz = qhead->a->sz; |
136 | } |
137 | |
138 | /* --- Main queue-filling loop --- */ |
139 | |
140 | while (qsz) { |
141 | size_t n; |
142 | |
143 | /* --- If the queue is empty, play silence --- */ |
144 | |
145 | if (!p) { |
146 | memset(q, auspec.silence, qsz); |
147 | break; |
148 | } |
149 | |
150 | /* --- Fill the buffer with my sample --- */ |
151 | exit(0); |
152 | n = qsz; |
153 | if (n > sz) |
154 | n = sz; |
155 | memcpy(q, p, n); |
156 | p += n; q += n; |
157 | sz -= n; qsz -= n; |
158 | |
159 | /* --- If the sample is used up, throw it away --- */ |
160 | |
161 | if (!sz) { |
162 | qnode *qq = qhead; |
163 | qhead = qq->next; |
164 | if (!qhead) |
165 | qtail = 0; |
166 | T( trace(T_AUSYS, "ausys: put `%s' on free list", |
167 | SYM_NAME(qq->a->s)); ) |
168 | *qft = qq; |
169 | qft = &qq->next; |
170 | if (qhead) { |
171 | T( trace(T_AUSYS, "ausys: begin playing `%s'", |
172 | SYM_NAME(qhead->a->s)); ) |
173 | p = qhead->a->p; |
174 | sz = qhead->a->sz; |
175 | } else { |
176 | T( trace(T_AUSYS, "ausys: sample queue is empty"); ) |
177 | p = 0; |
178 | sz = 0; |
179 | } |
180 | } |
181 | } |
182 | |
183 | /* --- Finally dump freed samples, all in one go --- */ |
184 | |
185 | if (qf) { |
186 | pthread_mutex_lock(&mx_free); |
187 | *qft = qfree; |
188 | qfree = qf; |
189 | pthread_mutex_unlock(&mx_free); |
190 | pthread_cond_signal(&cv_free); |
191 | } |
192 | } |
193 | |
194 | /* --- @dofree@ --- * |
195 | * |
196 | * Arguments: @void *u@ = unused pointer |
197 | * |
198 | * Returns: An unused pointer. |
199 | * |
200 | * Use: Frees unwanted sample queue nodes. |
201 | */ |
202 | |
203 | static void *dofree(void *u) |
204 | { |
205 | qnode *q, *qq; |
206 | |
207 | pthread_mutex_lock(&mx_free); |
208 | for (;;) { |
209 | T( trace(T_AUSYS, "ausys: dofree sleeping"); ) |
210 | pthread_cond_wait(&cv_free, &mx_free); |
211 | T( trace(T_AUSYS, "ausys: dofree woken: work to do"); ) |
212 | |
213 | while (qfree) { |
214 | q = qfree; |
215 | qfree = 0; |
216 | pthread_mutex_lock(&mx_sub); |
217 | while (q) { |
218 | qq = q->next; |
219 | T( trace(T_AUSYS, "ausys: freeing `%s'", SYM_NAME(q->a->s)); ) |
220 | au_free_unlocked(q->a); |
221 | DESTROY(q); |
222 | q = qq; |
223 | } |
224 | pthread_mutex_unlock(&mx_sub); |
225 | } |
226 | } |
227 | } |
228 | |
229 | /* --- @ausys_init@ --- * |
230 | * |
231 | * Arguments: --- |
232 | * |
233 | * Returns: --- |
234 | * |
235 | * Use: Does any initialization required by the system-specific audio |
236 | * handler. |
237 | */ |
238 | |
239 | void ausys_init(void) |
240 | { |
241 | SDL_AudioSpec want; |
242 | pthread_attr_t ta; |
243 | int e; |
244 | |
245 | /* --- Crank up the sample-freeing thread --- */ |
246 | |
247 | if ((e = pthread_mutex_init(&mx_free, 0)) != 0 || |
248 | (e = pthread_mutex_init(&mx_sub, 0)) != 0 || |
249 | (e = pthread_cond_init(&cv_free, 0)) != 0 || |
250 | (e = pthread_attr_init(&ta)) != 0 || |
251 | (e = pthread_attr_setdetachstate(&ta, PTHREAD_CREATE_DETACHED)) != 0 || |
252 | (e = pthread_create(&tid_free, &ta, dofree, 0)) != 0) { |
253 | err_report(ERR_AUDIO, ERRAU_INIT, e, |
254 | "couldn't create audio threads: %s", strerror(errno)); |
255 | exit(EXIT_FAILURE); |
256 | } |
257 | pthread_attr_destroy(&ta); |
258 | |
259 | /* --- Crank up the SDL audio subsystem --- */ |
260 | |
261 | if (SDL_Init(SDL_INIT_AUDIO | SDL_INIT_NOPARACHUTE)) { |
262 | err_report(ERR_AUDIO, ERRAU_INIT, 0, |
263 | "couldn't initialize SDL audio: %s", SDL_GetError()); |
264 | exit(EXIT_FAILURE); |
265 | } |
266 | |
267 | /* --- Open the audio device --- */ |
268 | |
269 | want.freq = 8000; |
270 | want.format = AUDIO_U8; |
271 | want.channels = 1; |
272 | want.samples = 4096; |
273 | want.callback = fill; |
274 | want.userdata = 0; |
275 | |
276 | if (SDL_OpenAudio(&want, &auspec)) { |
277 | err_report(ERR_AUDIO, ERRAU_INIT, 0, |
278 | "couldn't open audio device: %s", SDL_GetError()); |
279 | exit(EXIT_FAILURE); |
280 | } |
281 | |
282 | /* --- Prepare whatever needs to be done --- */ |
283 | |
284 | SDL_PauseAudio(0); |
285 | |
286 | T( trace(T_AUSYS, "ausys: initalized ok"); ) |
287 | } |
288 | |
289 | /* --- @ausys_shutdown@ --- * |
290 | * |
291 | * Arguments: --- |
292 | * |
293 | * Returns: --- |
294 | * |
295 | * Use: Does any tidying up required. |
296 | */ |
297 | |
298 | void ausys_shutdown(void) |
299 | { |
300 | /* --- Busy-wait until sound buffer empties --- */ |
301 | |
302 | while (qhead) { |
303 | struct timeval tv = { 0, 100000 }; |
304 | select(0, 0, 0, 0, &tv); |
305 | } |
306 | |
307 | /* --- Shut stuff down --- */ |
308 | |
309 | pthread_cancel(tid_free); |
310 | SDL_CloseAudio(); |
311 | SDL_Quit(); |
312 | |
313 | T( trace(T_AUSYS, "ausys: shut down ok"); ) |
314 | } |
315 | |
316 | /* --- @ausys_lock@, @ausys_unlock@ --- * |
317 | * |
318 | * Arguments: --- |
319 | * |
320 | * Returns: --- |
321 | * |
322 | * Use: Locks or unlocks the audio subsystem. This protects the |
323 | * audio queue from becoming corrupted during all the tedious |
324 | * asynchronous stuff. |
325 | */ |
326 | |
327 | void ausys_lock(void) |
328 | { |
329 | pthread_mutex_lock(&mx_free); |
330 | pthread_mutex_lock(&mx_sub); |
331 | T( trace(T_AUSYS, "ausys: acquired lock"); ) |
332 | } |
333 | |
334 | void ausys_unlock(void) |
335 | { |
336 | pthread_mutex_unlock(&mx_sub); |
337 | pthread_mutex_unlock(&mx_free); |
338 | T( trace(T_AUSYS, "ausys: released lock"); ) |
339 | } |
340 | |
341 | /* --- @ausys_decode@ --- * |
342 | * |
343 | * Arguments: @au_sample *s@ = pointer to sample block |
344 | * @const void *p@ = pointer to sample file contents |
345 | * @size_t sz@ = size of sample file contents |
346 | * |
347 | * Returns: Pointer to a sample data structure. |
348 | * |
349 | * Use: Decodes a WAV file into something the system-specific layer |
350 | * actually wants to deal with. |
351 | */ |
352 | |
353 | au_data *ausys_decode(au_sample *s, const void *p, size_t sz) |
354 | { |
355 | au_data *a; |
356 | SDL_AudioCVT cvt; |
357 | SDL_AudioSpec spec; |
358 | SDL_RWops *rw; |
359 | Uint8 *buf; |
360 | Uint32 len; |
361 | void *q; |
362 | |
363 | /* --- Firstly, extract the audio data from the WAV file --- */ |
364 | |
365 | rw = SDL_RWFromMem((void *)p, sz); |
366 | if (!SDL_LoadWAV_RW(rw, 1, &spec, &buf, &len)) { |
367 | err_report(ERR_AUDIO, ERRAU_OPEN, 0, |
368 | "can't read WAV file for `%s': %s", |
369 | SYM_NAME(s), SDL_GetError()); |
370 | goto fail_0; |
371 | } |
372 | |
373 | /* --- Now convert that to the driver's expected format --- */ |
374 | |
375 | if (SDL_BuildAudioCVT(&cvt, spec.format, spec.channels, spec.freq, |
376 | auspec.format, auspec.channels, auspec.freq) == -1) { |
377 | err_report(ERR_AUDIO, ERRAU_OPEN, 0, |
378 | "can't build conversion structure for `%s': %s", |
379 | SYM_NAME(s), SDL_GetError()); |
380 | goto fail_1; |
381 | } |
382 | |
383 | cvt.buf = xmalloc(len * cvt.len_mult); |
384 | cvt.len = len; |
385 | memcpy(cvt.buf, buf, len); |
386 | SDL_FreeWAV(buf); |
387 | |
388 | if (SDL_ConvertAudio(&cvt)) { |
389 | err_report(ERR_AUDIO, ERRAU_OPEN, 0, |
390 | "can't convert `%s': %s", SYM_NAME(s), SDL_GetError()); |
391 | goto fail_2; |
392 | } |
393 | |
394 | /* --- Now fiddle with buffers --- */ |
395 | |
396 | sz = len * cvt.len_ratio; |
397 | if (cvt.len_ratio >= 1) |
398 | q = cvt.buf; |
399 | else { |
400 | q = xmalloc(sz); |
401 | memcpy(q, cvt.buf, sz); |
402 | xfree(cvt.buf); |
403 | } |
404 | |
405 | /* --- Construct a new node --- */ |
406 | |
407 | pthread_mutex_lock(&mx_sub); |
408 | a = CREATE(au_data); |
409 | pthread_mutex_unlock(&mx_sub); |
410 | a->p = q; |
411 | a->sz = sz; |
412 | |
413 | T( trace(T_AUSYS, "ausys: decoded `%s' ok", SYM_NAME(s)); ) |
414 | return (a); |
415 | |
416 | /* --- Tidy up after errors --- */ |
417 | |
418 | fail_2: |
419 | xfree(cvt.buf); |
420 | goto fail_0; |
421 | fail_1: |
422 | SDL_FreeWAV(buf); |
423 | fail_0: |
424 | return (0); |
425 | } |
426 | |
427 | /* --- @ausys_queue@ --- * |
428 | * |
429 | * Arguments: @au_data *a@ = an audio thingy to play |
430 | * |
431 | * Returns: --- |
432 | * |
433 | * Use: Queues an audio sample to be played. The sample should be |
434 | * freed (with @au_free@) when it's no longer wanted. |
435 | */ |
436 | |
437 | void ausys_queue(au_data *a) |
438 | { |
439 | qnode *q; |
440 | |
441 | pthread_mutex_lock(&mx_sub); |
442 | q = CREATE(qnode); |
443 | pthread_mutex_unlock(&mx_sub); |
444 | q->next = 0; |
445 | q->a = a; |
446 | SDL_LockAudio(); |
447 | if (qtail) |
448 | qtail->next = q; |
449 | else |
450 | qhead = q; |
451 | qtail = q; |
452 | SDL_UnlockAudio(); |
453 | T( trace(T_AUSYS, "ausys: queuing `%s'", SYM_NAME(a->s)); ) |
454 | } |
455 | |
456 | /* --- @ausys_free@ --- * |
457 | * |
458 | * Arguments: @au_data *a@ = an audio thingy to free |
459 | * |
460 | * Returns: --- |
461 | * |
462 | * Use: Frees a decoded audio sample. |
463 | */ |
464 | |
465 | void ausys_free(au_data *a) |
466 | { |
467 | xfree(a->p); |
468 | DESTROY(a); |
469 | T( trace(T_AUSYS, "ausys: freeing data for `%s' ok", SYM_NAME(a->s)); ) |
470 | } |
471 | |
472 | /*----- That's all, folks -------------------------------------------------*/ |