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

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