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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: ausys-sdl.c,v 1.2 2002/02/02 22:43:17 mdw Exp $ |
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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 $ |
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32 | * Revision 1.2 2002/02/02 22:43:17 mdw |
33 | * Remove bogus debugging. Reduce output buffer size for faster response. |
34 | * |
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35 | * Revision 1.1 2002/02/02 19:16:28 mdw |
36 | * New audio subsystem. |
37 | * |
38 | */ |
39 | |
40 | /*----- Header files ------------------------------------------------------*/ |
41 | |
42 | #ifdef HAVE_CONFIG_H |
43 | # include "config.h" |
44 | #endif |
45 | |
46 | #include <errno.h> |
47 | #include <stdio.h> |
48 | #include <string.h> |
49 | |
50 | #include <sys/types.h> |
51 | #include <sys/time.h> |
52 | #include <unistd.h> |
53 | #include <pthread.h> |
54 | |
55 | #include <SDL.h> |
56 | |
57 | #include <mLib/alloc.h> |
58 | #include <mLib/bits.h> |
59 | #include <mLib/sub.h> |
60 | #include <mLib/trace.h> |
61 | |
62 | #include "au.h" |
63 | #include "ausys.h" |
64 | #include "err.h" |
65 | #include "jog.h" |
66 | |
67 | /*----- Data structures ---------------------------------------------------*/ |
68 | |
69 | /* --- Queue of samples to play --- */ |
70 | |
71 | typedef struct qnode { |
72 | struct qnode *next; /* Next item in the queue */ |
73 | au_data *a; /* Pointer to sample data */ |
74 | } qnode; |
75 | |
76 | /*----- Global variables --------------------------------------------------*/ |
77 | |
78 | const char *const ausys_suffix = "wav"; |
79 | |
80 | /*----- Static data -------------------------------------------------------*/ |
81 | |
82 | static SDL_AudioSpec auspec; /* Driver's selected parameters */ |
83 | static qnode *qhead = 0, *qtail = 0; /* Queue of samples to play */ |
84 | static qnode *qfree = 0; /* Queue of samples to free */ |
85 | |
86 | static pthread_t tid_free; /* The sample-freeing thread */ |
87 | static pthread_mutex_t mx_free; /* Mutex for @qfree@ */ |
88 | static pthread_cond_t cv_free; /* More sample data to free */ |
89 | |
90 | static pthread_mutex_t mx_sub; /* Protects mLib @sub@ functions */ |
91 | |
92 | /*----- Thread structure --------------------------------------------------* |
93 | * |
94 | * SDL makes a buffer-stuffing thread that @fill@ is run from. This function |
95 | * reads samples to play from the queue at @qhead@. Hence @qhead@ must be |
96 | * locked when it's modified, using @SDL_LockAudio@. |
97 | * |
98 | * In order to keep latency down when new sample data is wanted, we don't do |
99 | * potentially tedious things like freeing sample data blocks in the @fill@ |
100 | * thread. Instead, there's a queue of sample blocks which need freeing, and |
101 | * a separate thread @dofree@ which processes the queue. The queue, @qfree@ |
102 | * is locked by @mx_free@. When new nodes are added to @qfree@, the |
103 | * condition @cv_free@ is signalled. |
104 | * |
105 | * Finally, the mLib `sub' module isn't thread-safe, so it's locked |
106 | * separately by @mx_sub@. |
107 | * |
108 | * There's an ordering on mutexes. If you want more than one mutex at a |
109 | * time, you must lock the greatest first. The ordering is: |
110 | * |
111 | * SDL_Audio > free > sub |
112 | */ |
113 | |
114 | /*----- Main code ---------------------------------------------------------*/ |
115 | |
116 | /* --- @fill@ --- * |
117 | * |
118 | * Arguments: @void *u@ = user data (ignored) |
119 | * @octet *q@ = pointer to buffer to fill in |
120 | * @int qsz@ = size of the buffer |
121 | * |
122 | * Returns: --- |
123 | * |
124 | * Use: Fills an audio buffer with precomputed stuff. |
125 | */ |
126 | |
127 | static void fill(void *u, octet *q, int qsz) |
128 | { |
129 | static const octet *p = 0; /* Current place in current sample */ |
130 | static size_t sz = 0; /* How far to go in current sample */ |
131 | qnode *qf = 0, **qft = &qf; /* Samples we've finished with */ |
132 | |
133 | /* --- If @p@ is null we need to get a new sample --- */ |
134 | |
135 | if (!p && qhead) { |
136 | T( trace(T_AUSYS, "ausys: begin playing `%s'", SYM_NAME(qhead->a->s)); ) |
137 | p = qhead->a->p; |
138 | sz = qhead->a->sz; |
139 | } |
140 | |
141 | /* --- Main queue-filling loop --- */ |
142 | |
143 | while (qsz) { |
144 | size_t n; |
145 | |
146 | /* --- If the queue is empty, play silence --- */ |
147 | |
148 | if (!p) { |
149 | memset(q, auspec.silence, qsz); |
150 | break; |
151 | } |
152 | |
153 | /* --- Fill the buffer with my sample --- */ |
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154 | |
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155 | n = qsz; |
156 | if (n > sz) |
157 | n = sz; |
158 | memcpy(q, p, n); |
159 | p += n; q += n; |
160 | sz -= n; qsz -= n; |
161 | |
162 | /* --- If the sample is used up, throw it away --- */ |
163 | |
164 | if (!sz) { |
165 | qnode *qq = qhead; |
166 | qhead = qq->next; |
167 | if (!qhead) |
168 | qtail = 0; |
169 | T( trace(T_AUSYS, "ausys: put `%s' on free list", |
170 | SYM_NAME(qq->a->s)); ) |
171 | *qft = qq; |
172 | qft = &qq->next; |
173 | if (qhead) { |
174 | T( trace(T_AUSYS, "ausys: begin playing `%s'", |
175 | SYM_NAME(qhead->a->s)); ) |
176 | p = qhead->a->p; |
177 | sz = qhead->a->sz; |
178 | } else { |
179 | T( trace(T_AUSYS, "ausys: sample queue is empty"); ) |
180 | p = 0; |
181 | sz = 0; |
182 | } |
183 | } |
184 | } |
185 | |
186 | /* --- Finally dump freed samples, all in one go --- */ |
187 | |
188 | if (qf) { |
189 | pthread_mutex_lock(&mx_free); |
190 | *qft = qfree; |
191 | qfree = qf; |
192 | pthread_mutex_unlock(&mx_free); |
193 | pthread_cond_signal(&cv_free); |
194 | } |
195 | } |
196 | |
197 | /* --- @dofree@ --- * |
198 | * |
199 | * Arguments: @void *u@ = unused pointer |
200 | * |
201 | * Returns: An unused pointer. |
202 | * |
203 | * Use: Frees unwanted sample queue nodes. |
204 | */ |
205 | |
206 | static void *dofree(void *u) |
207 | { |
208 | qnode *q, *qq; |
209 | |
210 | pthread_mutex_lock(&mx_free); |
211 | for (;;) { |
212 | T( trace(T_AUSYS, "ausys: dofree sleeping"); ) |
213 | pthread_cond_wait(&cv_free, &mx_free); |
214 | T( trace(T_AUSYS, "ausys: dofree woken: work to do"); ) |
215 | |
216 | while (qfree) { |
217 | q = qfree; |
218 | qfree = 0; |
219 | pthread_mutex_lock(&mx_sub); |
220 | while (q) { |
221 | qq = q->next; |
222 | T( trace(T_AUSYS, "ausys: freeing `%s'", SYM_NAME(q->a->s)); ) |
223 | au_free_unlocked(q->a); |
224 | DESTROY(q); |
225 | q = qq; |
226 | } |
227 | pthread_mutex_unlock(&mx_sub); |
228 | } |
229 | } |
230 | } |
231 | |
232 | /* --- @ausys_init@ --- * |
233 | * |
234 | * Arguments: --- |
235 | * |
236 | * Returns: --- |
237 | * |
238 | * Use: Does any initialization required by the system-specific audio |
239 | * handler. |
240 | */ |
241 | |
242 | void ausys_init(void) |
243 | { |
244 | SDL_AudioSpec want; |
245 | pthread_attr_t ta; |
246 | int e; |
247 | |
248 | /* --- Crank up the sample-freeing thread --- */ |
249 | |
250 | if ((e = pthread_mutex_init(&mx_free, 0)) != 0 || |
251 | (e = pthread_mutex_init(&mx_sub, 0)) != 0 || |
252 | (e = pthread_cond_init(&cv_free, 0)) != 0 || |
253 | (e = pthread_attr_init(&ta)) != 0 || |
254 | (e = pthread_attr_setdetachstate(&ta, PTHREAD_CREATE_DETACHED)) != 0 || |
255 | (e = pthread_create(&tid_free, &ta, dofree, 0)) != 0) { |
256 | err_report(ERR_AUDIO, ERRAU_INIT, e, |
257 | "couldn't create audio threads: %s", strerror(errno)); |
258 | exit(EXIT_FAILURE); |
259 | } |
260 | pthread_attr_destroy(&ta); |
261 | |
262 | /* --- Crank up the SDL audio subsystem --- */ |
263 | |
264 | if (SDL_Init(SDL_INIT_AUDIO | SDL_INIT_NOPARACHUTE)) { |
265 | err_report(ERR_AUDIO, ERRAU_INIT, 0, |
266 | "couldn't initialize SDL audio: %s", SDL_GetError()); |
267 | exit(EXIT_FAILURE); |
268 | } |
269 | |
270 | /* --- Open the audio device --- */ |
271 | |
272 | want.freq = 8000; |
273 | want.format = AUDIO_U8; |
274 | want.channels = 1; |
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275 | want.samples = 1024; |
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276 | want.callback = fill; |
277 | want.userdata = 0; |
278 | |
279 | if (SDL_OpenAudio(&want, &auspec)) { |
280 | err_report(ERR_AUDIO, ERRAU_INIT, 0, |
281 | "couldn't open audio device: %s", SDL_GetError()); |
282 | exit(EXIT_FAILURE); |
283 | } |
284 | |
285 | /* --- Prepare whatever needs to be done --- */ |
286 | |
287 | SDL_PauseAudio(0); |
288 | |
289 | T( trace(T_AUSYS, "ausys: initalized ok"); ) |
290 | } |
291 | |
292 | /* --- @ausys_shutdown@ --- * |
293 | * |
294 | * Arguments: --- |
295 | * |
296 | * Returns: --- |
297 | * |
298 | * Use: Does any tidying up required. |
299 | */ |
300 | |
301 | void ausys_shutdown(void) |
302 | { |
303 | /* --- Busy-wait until sound buffer empties --- */ |
304 | |
305 | while (qhead) { |
306 | struct timeval tv = { 0, 100000 }; |
307 | select(0, 0, 0, 0, &tv); |
308 | } |
309 | |
310 | /* --- Shut stuff down --- */ |
311 | |
312 | pthread_cancel(tid_free); |
313 | SDL_CloseAudio(); |
314 | SDL_Quit(); |
315 | |
316 | T( trace(T_AUSYS, "ausys: shut down ok"); ) |
317 | } |
318 | |
319 | /* --- @ausys_lock@, @ausys_unlock@ --- * |
320 | * |
321 | * Arguments: --- |
322 | * |
323 | * Returns: --- |
324 | * |
325 | * Use: Locks or unlocks the audio subsystem. This protects the |
326 | * audio queue from becoming corrupted during all the tedious |
327 | * asynchronous stuff. |
328 | */ |
329 | |
330 | void ausys_lock(void) |
331 | { |
332 | pthread_mutex_lock(&mx_free); |
333 | pthread_mutex_lock(&mx_sub); |
334 | T( trace(T_AUSYS, "ausys: acquired lock"); ) |
335 | } |
336 | |
337 | void ausys_unlock(void) |
338 | { |
339 | pthread_mutex_unlock(&mx_sub); |
340 | pthread_mutex_unlock(&mx_free); |
341 | T( trace(T_AUSYS, "ausys: released lock"); ) |
342 | } |
343 | |
344 | /* --- @ausys_decode@ --- * |
345 | * |
346 | * Arguments: @au_sample *s@ = pointer to sample block |
347 | * @const void *p@ = pointer to sample file contents |
348 | * @size_t sz@ = size of sample file contents |
349 | * |
350 | * Returns: Pointer to a sample data structure. |
351 | * |
352 | * Use: Decodes a WAV file into something the system-specific layer |
353 | * actually wants to deal with. |
354 | */ |
355 | |
356 | au_data *ausys_decode(au_sample *s, const void *p, size_t sz) |
357 | { |
358 | au_data *a; |
359 | SDL_AudioCVT cvt; |
360 | SDL_AudioSpec spec; |
361 | SDL_RWops *rw; |
362 | Uint8 *buf; |
363 | Uint32 len; |
364 | void *q; |
365 | |
366 | /* --- Firstly, extract the audio data from the WAV file --- */ |
367 | |
368 | rw = SDL_RWFromMem((void *)p, sz); |
369 | if (!SDL_LoadWAV_RW(rw, 1, &spec, &buf, &len)) { |
370 | err_report(ERR_AUDIO, ERRAU_OPEN, 0, |
371 | "can't read WAV file for `%s': %s", |
372 | SYM_NAME(s), SDL_GetError()); |
373 | goto fail_0; |
374 | } |
375 | |
376 | /* --- Now convert that to the driver's expected format --- */ |
377 | |
378 | if (SDL_BuildAudioCVT(&cvt, spec.format, spec.channels, spec.freq, |
379 | auspec.format, auspec.channels, auspec.freq) == -1) { |
380 | err_report(ERR_AUDIO, ERRAU_OPEN, 0, |
381 | "can't build conversion structure for `%s': %s", |
382 | SYM_NAME(s), SDL_GetError()); |
383 | goto fail_1; |
384 | } |
385 | |
386 | cvt.buf = xmalloc(len * cvt.len_mult); |
387 | cvt.len = len; |
388 | memcpy(cvt.buf, buf, len); |
389 | SDL_FreeWAV(buf); |
390 | |
391 | if (SDL_ConvertAudio(&cvt)) { |
392 | err_report(ERR_AUDIO, ERRAU_OPEN, 0, |
393 | "can't convert `%s': %s", SYM_NAME(s), SDL_GetError()); |
394 | goto fail_2; |
395 | } |
396 | |
397 | /* --- Now fiddle with buffers --- */ |
398 | |
399 | sz = len * cvt.len_ratio; |
400 | if (cvt.len_ratio >= 1) |
401 | q = cvt.buf; |
402 | else { |
403 | q = xmalloc(sz); |
404 | memcpy(q, cvt.buf, sz); |
405 | xfree(cvt.buf); |
406 | } |
407 | |
408 | /* --- Construct a new node --- */ |
409 | |
410 | pthread_mutex_lock(&mx_sub); |
411 | a = CREATE(au_data); |
412 | pthread_mutex_unlock(&mx_sub); |
413 | a->p = q; |
414 | a->sz = sz; |
415 | |
416 | T( trace(T_AUSYS, "ausys: decoded `%s' ok", SYM_NAME(s)); ) |
417 | return (a); |
418 | |
419 | /* --- Tidy up after errors --- */ |
420 | |
421 | fail_2: |
422 | xfree(cvt.buf); |
423 | goto fail_0; |
424 | fail_1: |
425 | SDL_FreeWAV(buf); |
426 | fail_0: |
427 | return (0); |
428 | } |
429 | |
430 | /* --- @ausys_queue@ --- * |
431 | * |
432 | * Arguments: @au_data *a@ = an audio thingy to play |
433 | * |
434 | * Returns: --- |
435 | * |
436 | * Use: Queues an audio sample to be played. The sample should be |
437 | * freed (with @au_free@) when it's no longer wanted. |
438 | */ |
439 | |
440 | void ausys_queue(au_data *a) |
441 | { |
442 | qnode *q; |
443 | |
444 | pthread_mutex_lock(&mx_sub); |
445 | q = CREATE(qnode); |
446 | pthread_mutex_unlock(&mx_sub); |
447 | q->next = 0; |
448 | q->a = a; |
449 | SDL_LockAudio(); |
450 | if (qtail) |
451 | qtail->next = q; |
452 | else |
453 | qhead = q; |
454 | qtail = q; |
455 | SDL_UnlockAudio(); |
456 | T( trace(T_AUSYS, "ausys: queuing `%s'", SYM_NAME(a->s)); ) |
457 | } |
458 | |
459 | /* --- @ausys_free@ --- * |
460 | * |
461 | * Arguments: @au_data *a@ = an audio thingy to free |
462 | * |
463 | * Returns: --- |
464 | * |
465 | * Use: Frees a decoded audio sample. |
466 | */ |
467 | |
468 | void ausys_free(au_data *a) |
469 | { |
470 | xfree(a->p); |
471 | DESTROY(a); |
472 | T( trace(T_AUSYS, "ausys: freeing data for `%s' ok", SYM_NAME(a->s)); ) |
473 | } |
474 | |
475 | /*----- That's all, folks -------------------------------------------------*/ |