mdw@git.distorted.org.uk Git - jog/blob - au.c

   1 /* -*-c-*-
   2  *
   3  * $Id: au.c,v 1.2 2002/02/02 22:43:50 mdw Exp $
   4  *
   5  * High-level audio subsystem
   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: au.c,v $
  32  * Revision 1.2  2002/02/02 22:43:50  mdw
  33  * Provide a decent interface for finding out about the audio cache and
  34  * configuring its capacity.
  35  *
  36  * Revision 1.1  2002/02/02 19:16:28  mdw
  37  * New audio subsystem.
  38  *
  39  */
  40
  41 /*----- Header files ------------------------------------------------------*/
  42
  43 #ifdef HAVE_CONFIG_H
  44 #  include "config.h"
  45 #endif
  46
  47 #include <assert.h>
  48 #include <errno.h>
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <string.h>
  52
  53 #include <sys/types.h>
  54 #include <unistd.h>
  55 #include <sys/stat.h>
  56 #include <fcntl.h>
  57
  58 #include <mLib/alloc.h>
  59 #include <mLib/dstr.h>
  60 #include <mLib/sub.h>
  61 #include <mLib/sym.h>
  62 #include <mLib/trace.h>
  63
  64 #include "au.h"
  65 #include "ausys.h"
  66 #include "err.h"
  67 #include "jog.h"
  68
  69 /*----- Static variables --------------------------------------------------*/
  70
  71 static unsigned au_flags = 0;
  72 static sym_table au_tab;                /* Sample cache, by name */
  73 static const char *au_dir = AUDIODIR;   /* Directory containing samples */
  74 static struct { au_data *next, *prev; } au_spare; /* Lists for sample data */
  75 static au_cacheinfo cache;              /* Cache usage information */
  76
  77 #define AU_SPARE ((au_data*)&au_spare)
  78 #define f_init 1u
  79
  80 /*----- Utility functions -------------------------------------------------*/
  81
  82 /* --- @filename@ --- *
  83  *
  84  * Arguments:   @const char *tag@ = sample tag string
  85  *
  86  * Returns:     A pointer to a filename for the sample.
  87  *
  88  * Use:         Converts tag strings to filenames.
  89  */
  90
  91 static const char *filename(const char *tag)
  92 {
  93   static dstr d = DSTR_INIT;
  94
  95   DRESET(&d);
  96   dstr_putf(&d, "%s/%s.%s", au_dir, tag, ausys_suffix);
  97   T( trace(T_AU, "au: map tag `%s' -> `%s'", tag, d.buf); )
  98   return (d.buf);
  99 }
 100
 101 /* --- @prune@ --- *
 102  *
 103  * Arguments:   ---
 104  *
 105  * Returns:     ---
 106  *
 107  * Use:         Prunes the cache of old sample data.
 108  */
 109
 110 static void prune(void)
 111 {
 112   T( trace(T_AU, "au: pruning cache (%lu/%lu)",
 113            (unsigned long)cache.sz_total, (unsigned long)cache.sz_max); )
 114   while (cache.sz_total > cache.sz_max && AU_SPARE->next != AU_SPARE) {
 115     au_data *a = AU_SPARE->next;
 116     au_sample *s = a->s;
 117     assert(!a->ref);
 118     AU_SPARE->next = a->next;
 119     a->next->prev = AU_SPARE;
 120     s->a = 0;
 121     cache.sz_spare -= a->sz;
 122     cache.sz_total -= a->sz;
 123     cache.n_spare--;
 124     cache.n_total--;
 125     ausys_free(a);
 126     T( trace(T_AU, "au: ... discarded `%s' (%lu/%lu)", SYM_NAME(s),
 127              (unsigned long)cache.sz_total, (unsigned long)cache.sz_max); )
 128   }
 129 }
 130
 131 /*----- Main code ---------------------------------------------------------*/
 132
 133 /* --- @au_init@ --- *
 134  *
 135  * Arguments:   @const char *dir@ = samples directory, or null
 136  *              @size_t max@ = maximum cache size
 137  *
 138  * Returns:     ---
 139  *
 140  * Use:         Initializes the audio subsystem.
 141  */
 142
 143 void au_init(const char *dir, size_t max)
 144 {
 145   if (au_flags & f_init)
 146     return;
 147
 148   /* --- Set up the sound directory --- */
 149
 150   if (!dir)
 151     dir = getenv("JOG_AUDIR");
 152   if (dir)
 153     au_dir = dir;
 154
 155   /* --- Initialize the sample cache --- */
 156
 157   sym_create(&au_tab);
 158   AU_SPARE->next = AU_SPARE->prev = AU_SPARE;
 159   cache.sz_max = max;
 160
 161   /* --- Initialize the system-specific subsystem --- */
 162
 163   ausys_init();
 164   T( trace(T_AU, "au: initialized ok (dir = `%s')", au_dir); )
 165
 166   /* --- Done --- */
 167
 168   au_flags |= f_init;
 169 }
 170
 171 /* --- @au_shutdown@ --- *
 172  *
 173  * Arguments:   ---
 174  *
 175  * Returns:     ---
 176  *
 177  * Use:         Shuts down the audio subsystem.
 178  */
 179
 180 void au_shutdown(void)
 181 {
 182   if (!(au_flags & f_init))
 183     return;
 184   ausys_shutdown();
 185   T( trace(T_AU, "au: shutdown ok"); )
 186 }
 187
 188 /* --- @au_getcacheinfo@ --- *
 189  *
 190  * Arguments:   @au_cacheinfo *c@ = where to put the information
 191  *
 192  * Returns:     ---
 193  *
 194  * Use:         Extracts audio cache information.
 195  */
 196
 197 void au_getcacheinfo(au_cacheinfo *c)
 198 {
 199   ausys_lock();
 200   *c = cache;
 201   ausys_unlock();
 202   assert(c->sz_spare + c->sz_queue == c->sz_total);
 203   assert(c->n_spare + c->n_queue == c->n_total);
 204 }
 205
 206 /* --- @au_setcachelimit@ --- *
 207  *
 208  * Arguments:   @size_t max@ = new cache limit
 209  *
 210  * Returns:     ---
 211  *
 212  * Use:         Reconfigures the maximum cache size.  This probably isn't
 213  *              very useful, but it was easy...
 214  */
 215
 216 void au_setcachelimit(size_t max)
 217 {
 218   ausys_lock();
 219   cache.sz_max = max;
 220   prune();
 221   ausys_unlock();
 222 }
 223
 224 /* --- @au_find@ --- *
 225  *
 226  * Arguments:   @const char *tag@ = sample tag string
 227  *
 228  * Returns:     A pointer to the sample corresponding to the tag, or null if
 229  *              the sample wasn't found.
 230  *
 231  * Use:         Looks up a sample by its name.
 232  */
 233
 234 au_sample *au_find(const char *tag)
 235 {
 236   unsigned f;
 237   au_sample *s = sym_find(&au_tab, tag, -1, sizeof(*s), &f);
 238
 239   if (!f) {
 240     struct stat st;
 241
 242     s->f = 0;
 243     s->a = 0;
 244     if (stat(filename(tag), &st))
 245       s->f |= AUF_NOMATCH;
 246   }
 247   if (s->f & AUF_NOMATCH) {
 248     T( trace(T_AU, "au: sample `%s' not found%s", tag, f ? " (hit)": ""); )
 249     return (0);
 250   }
 251   T( trace(T_AU, "au: sample `%s' found%s", tag, f ? " (hit)" : ""); )
 252   return (s);
 253 }
 254
 255 /* --- @au_fetch@ --- *
 256  *
 257  * Arguments:   @au_sample *s@ = sample pointer
 258  *
 259  * Returns:     A pointer to the audio data for the sample.
 260  *
 261  * Use:         Fetches a sample, and decodes it, if necessary.  The decoded
 262  *              sample data is left with an outstanding reference to it, so
 263  *              it won't be freed.  This is used internally by @au_queue@,
 264  *              before passing the fetched sample data to the system-specific
 265  *              layer for playback.  It can also be used to lock sample data
 266  *              in memory (e.g., for the `abort' error message), or (by
 267  *              freeing it immediately afterwards) to prefetch a sample which
 268  *              will be used soon, to reduce the latency before the sample is
 269  *              heard.
 270  */
 271
 272 au_data *au_fetch(au_sample *s)
 273 {
 274   dstr d = DSTR_INIT;
 275   struct stat st;
 276   const char *fn;
 277   size_t n;
 278   ssize_t r;
 279   au_data *a;
 280   int fd;
 281
 282   /* --- If we already have the sample data --- *
 283    *
 284    * If it's currently languishing in the spare bin, rescue it.  If this
 285    * doesn't work, we can release the audio lock, because nothing else messes
 286    * with the spare list.
 287    */
 288
 289   ausys_lock();
 290   a = s->a;
 291   if (a) {
 292     if (!a->ref) {
 293       assert(a->next);
 294       a->prev->next = a->next;
 295       a->next->prev = a->prev;
 296       a->next = a->prev = 0;
 297       cache.sz_spare -= a->sz;
 298       cache.sz_queue += a->sz;
 299       cache.n_spare--;
 300       cache.n_queue++;
 301       cache.hits++;
 302     }
 303     a->ref++;
 304     T( trace(T_AU, "au: reusing sample `%s'", SYM_NAME(s)); )
 305     ausys_unlock();
 306     return (a);
 307   }
 308   ausys_unlock();
 309
 310   /* --- Read the file --- *
 311    *
 312    * Buffered I/O will just involve more copying.
 313    */
 314
 315   T( trace(T_AU, "au: fetching sample `%s'", SYM_NAME(s)); )
 316   fn = filename(SYM_NAME(s));
 317   if ((fd = open(fn, O_RDONLY)) < 0) {
 318     err_report(ERR_AUDIO, ERRAU_OPEN, errno,
 319                "couldn't open sample `%s': %s", fn, strerror(errno));
 320     goto fail_0;
 321   }
 322   if (fstat(fd, &st)) {
 323     err_report(ERR_AUDIO, ERRAU_OPEN, errno,
 324                "couldn't fstat `%s': %s", fn, strerror(errno));
 325     goto fail_1;
 326   }
 327   n = st.st_size + 1;
 328   if (n < 4096)
 329     n = 4096;
 330   for (;;) {
 331     dstr_ensure(&d, n);
 332   again:
 333     if ((r = read(fd, d.buf + d.len, n)) < 0) {
 334       if (errno == EWOULDBLOCK || errno == EAGAIN || errno == EINTR)
 335         goto again;
 336       err_report(ERR_AUDIO, ERRAU_OPEN, errno,
 337                  "couldn't read `%s': %s", fn, strerror(errno));
 338       goto fail_1;
 339     }
 340     if (!r)
 341       break;
 342     d.len += r;
 343     n -= r;
 344     if (!n)
 345       n = d.len;
 346   }
 347   close(fd);
 348
 349   /* --- Convert it into internal form --- */
 350
 351   if ((a = ausys_decode(s, d.buf, d.len)) == 0)
 352     goto fail_0;
 353   a->ref = 1;
 354   a->next = a->prev = 0;
 355   a->s = s;
 356   s->a = a;
 357
 358   /* --- Done --- */
 359
 360   ausys_lock();
 361   cache.sz_queue += a->sz;
 362   cache.sz_total += a->sz;
 363   cache.n_queue++;
 364   cache.n_total++;
 365   cache.misses++;
 366   prune();
 367   ausys_unlock();
 368   goto done;
 369 done:
 370   dstr_destroy(&d);
 371   return (a);
 372
 373   /* --- Tidy up after botched file I/O --- */
 374
 375 fail_1:
 376   close(fd);
 377 fail_0:
 378   dstr_destroy(&d);
 379   return (0);
 380 }
 381
 382 /* --- @au_queue@ --- *
 383  *
 384  * Arguments:   @au_sample *s@ = sample pointer
 385  *
 386  * Returns:     Zero on success, nonzero on failure.
 387  *
 388  * Use:         Queues a sample to be played.
 389  */
 390
 391 int au_queue(au_sample *s)
 392 {
 393   au_data *a;
 394
 395   assert(s);
 396   if ((a = au_fetch(s)) == 0)
 397     return (-1);
 398   T( trace(T_AU, "au: queuing sample `%s'", SYM_NAME(s)); )
 399   ausys_queue(s->a);
 400   return (0);
 401 }
 402
 403 /* --- @au_free@, @au_free_unlocked@ --- *
 404  *
 405  * Arguments:   @au_data *a@ = pointer to audio data block
 406  *
 407  * Returns:     ---
 408  *
 409  * Use:         Frees a sample data block when it's no longer required.
 410  */
 411
 412 void au_free(au_data *a)
 413 {
 414   ausys_lock();
 415   au_free_unlocked(a);
 416   ausys_unlock();
 417 }
 418
 419 void au_free_unlocked(au_data *a)
 420 {
 421   /* --- If the sample is unreferenced, throw it in the spare bin --- *
 422    *
 423    * This can be called from a background audio processing thread, so we need
 424    * to acquire the lock.
 425    */
 426
 427   assert(a->ref);
 428   assert(!a->next);
 429   assert(!a->prev);
 430   a->ref--;
 431   if (a->ref) {
 432     T( trace(T_AU, "au: drop ref to `%s' (other refs remain)",
 433              SYM_NAME(a->s)); )
 434     ;
 435   } else {
 436     a->next = AU_SPARE;
 437     a->prev = AU_SPARE->prev;
 438     AU_SPARE->prev->next = a;
 439     AU_SPARE->prev = a;
 440     cache.sz_queue -= a->sz;
 441     cache.sz_spare += a->sz;
 442     cache.n_queue--;
 443     cache.n_spare++;
 444     T( trace(T_AU, "au: drop last ref to `%s'", SYM_NAME(a->s)); )
 445     prune();
 446   }
 447 }
 448
 449 /* --- @au_play@, @au_tryplay@ --- *
 450  *
 451  * Arguments:   @const char *tag@ = sample tag string
 452  *
 453  * Returns:     Zero on success, nonzero on failure.
 454  *
 455  * Use:         Convenience functions for queueing samples by tag.
 456  *              If @au_tryplay@ cannot find the requested sample, it returns
 457  *              a zero value; if @au_play@ cannot find the sample, it reports
 458  *              an error.
 459  */
 460
 461 int au_tryplay(const char *tag)
 462 {
 463   au_sample *s;
 464
 465   if (!(au_flags & f_init))
 466     return (0);
 467   if ((s = au_find(tag)) == 0 || au_queue(s))
 468     return (-1);
 469   return (0);
 470 }
 471
 472 int au_play(const char *tag)
 473 {
 474   int rc;
 475
 476   if ((rc = au_tryplay(tag)) != 0)
 477     err_report(ERR_AUDIO, ERRAU_NOTFOUND, 0, "sample `%s' not found", tag);
 478   return (rc);
 479 }
 480
 481 /*----- That's all, folks -------------------------------------------------*/