src/audio/sun/SDL_sunaudio.c

   1 /*
   2     SDL - Simple DirectMedia Layer
   3     Copyright (C) 1997-2006 Sam Lantinga
   4
   5     This library is free software; you can redistribute it and/or
   6     modify it under the terms of the GNU Lesser General Public
   7     License as published by the Free Software Foundation; either
   8     version 2.1 of the License, or (at your option) any later version.
   9
  10     This library is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13     Lesser General Public License for more details.
  14
  15     You should have received a copy of the GNU Lesser General Public
  16     License along with this library; if not, write to the Free Software
  17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  18
  19     Sam Lantinga
  20     slouken@libsdl.org
  21 */
  22 #include "SDL_config.h"
  23
  24 /* Allow access to a raw mixing buffer */
  25
  26 #include <fcntl.h>
  27 #include <errno.h>
  28 #ifdef __NETBSD__
  29 #include <sys/ioctl.h>
  30 #include <sys/audioio.h>
  31 #endif
  32 #ifdef __SVR4
  33 #include <sys/audioio.h>
  34 #else
  35 #include <sys/time.h>
  36 #include <sys/types.h>
  37 #endif
  38 #include <unistd.h>
  39
  40 #include "SDL_timer.h"
  41 #include "SDL_audio.h"
  42 #include "../SDL_audiomem.h"
  43 #include "../SDL_audio_c.h"
  44 #include "../SDL_audiodev_c.h"
  45 #include "SDL_sunaudio.h"
  46
  47 /* Open the audio device for playback, and don't block if busy */
  48 #define OPEN_FLAGS      (O_WRONLY|O_NONBLOCK)
  49
  50 /* Audio driver functions */
  51 static int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec);
  52 static void DSP_WaitAudio(_THIS);
  53 static void DSP_PlayAudio(_THIS);
  54 static Uint8 *DSP_GetAudioBuf(_THIS);
  55 static void DSP_CloseAudio(_THIS);
  56
  57 static Uint8 snd2au(int sample);
  58
  59 /* Audio driver bootstrap functions */
  60
  61 static int Audio_Available(void)
  62 {
  63         int fd;
  64         int available;
  65
  66         available = 0;
  67         fd = SDL_OpenAudioPath(NULL, 0, OPEN_FLAGS, 1);
  68         if ( fd >= 0 ) {
  69                 available = 1;
  70                 close(fd);
  71         }
  72         return(available);
  73 }
  74
  75 static void Audio_DeleteDevice(SDL_AudioDevice *device)
  76 {
  77         SDL_free(device->hidden);
  78         SDL_free(device);
  79 }
  80
  81 static SDL_AudioDevice *Audio_CreateDevice(int devindex)
  82 {
  83         SDL_AudioDevice *this;
  84
  85         /* Initialize all variables that we clean on shutdown */
  86         this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));
  87         if ( this ) {
  88                 SDL_memset(this, 0, (sizeof *this));
  89                 this->hidden = (struct SDL_PrivateAudioData *)
  90                                 SDL_malloc((sizeof *this->hidden));
  91         }
  92         if ( (this == NULL) || (this->hidden == NULL) ) {
  93                 SDL_OutOfMemory();
  94                 if ( this ) {
  95                         SDL_free(this);
  96                 }
  97                 return(0);
  98         }
  99         SDL_memset(this->hidden, 0, (sizeof *this->hidden));
 100         audio_fd = -1;
 101
 102         /* Set the function pointers */
 103         this->OpenAudio = DSP_OpenAudio;
 104         this->WaitAudio = DSP_WaitAudio;
 105         this->PlayAudio = DSP_PlayAudio;
 106         this->GetAudioBuf = DSP_GetAudioBuf;
 107         this->CloseAudio = DSP_CloseAudio;
 108
 109         this->free = Audio_DeleteDevice;
 110
 111         return this;
 112 }
 113
 114 AudioBootStrap SUNAUDIO_bootstrap = {
 115         "audio", "UNIX /dev/audio interface",
 116         Audio_Available, Audio_CreateDevice
 117 };
 118
 119 #ifdef DEBUG_AUDIO
 120 void CheckUnderflow(_THIS)
 121 {
 122 #ifdef AUDIO_GETINFO
 123         audio_info_t info;
 124         int left;
 125
 126         ioctl(audio_fd, AUDIO_GETINFO, &info);
 127         left = (written - info.play.samples);
 128         if ( written && (left == 0) ) {
 129                 fprintf(stderr, "audio underflow!\n");
 130         }
 131 #endif
 132 }
 133 #endif
 134
 135 void DSP_WaitAudio(_THIS)
 136 {
 137 #ifdef AUDIO_GETINFO
 138 #define SLEEP_FUDGE     10              /* 10 ms scheduling fudge factor */
 139         audio_info_t info;
 140         Sint32 left;
 141
 142         ioctl(audio_fd, AUDIO_GETINFO, &info);
 143         left = (written - info.play.samples);
 144         if ( left > fragsize ) {
 145                 Sint32 sleepy;
 146
 147                 sleepy = ((left - fragsize)/frequency);
 148                 sleepy -= SLEEP_FUDGE;
 149                 if ( sleepy > 0 ) {
 150                         SDL_Delay(sleepy);
 151                 }
 152         }
 153 #else
 154         fd_set fdset;
 155
 156         FD_ZERO(&fdset);
 157         FD_SET(audio_fd, &fdset);
 158         select(audio_fd+1, NULL, &fdset, NULL, NULL);
 159 #endif
 160 }
 161
 162 void DSP_PlayAudio(_THIS)
 163 {
 164         /* Write the audio data */
 165         if ( ulaw_only ) {
 166                 /* Assuming that this->spec.freq >= 8000 Hz */
 167                 int accum, incr, pos;
 168                 Uint8 *aubuf;
 169
 170                 accum = 0;
 171                 incr  = this->spec.freq/8;
 172                 aubuf = ulaw_buf;
 173                 switch (audio_fmt & 0xFF) {
 174                         case 8: {
 175                                 Uint8 *sndbuf;
 176
 177                                 sndbuf = mixbuf;
 178                                 for ( pos=0; pos < fragsize; ++pos ) {
 179                                         *aubuf = snd2au((0x80-*sndbuf)*64);
 180                                         accum += incr;
 181                                         while ( accum > 0 ) {
 182                                                 accum -= 1000;
 183                                                 sndbuf += 1;
 184                                         }
 185                                         aubuf += 1;
 186                                 }
 187                         }
 188                         break;
 189                         case 16: {
 190                                 Sint16 *sndbuf;
 191
 192                                 sndbuf = (Sint16 *)mixbuf;
 193                                 for ( pos=0; pos < fragsize; ++pos ) {
 194                                         *aubuf = snd2au(*sndbuf/4);
 195                                         accum += incr;
 196                                         while ( accum > 0 ) {
 197                                                 accum -= 1000;
 198                                                 sndbuf += 1;
 199                                         }
 200                                         aubuf += 1;
 201                                 }
 202                         }
 203                         break;
 204                 }
 205 #ifdef DEBUG_AUDIO
 206                 CheckUnderflow(this);
 207 #endif
 208                 if ( write(audio_fd, ulaw_buf, fragsize) < 0 ) {
 209                         /* Assume fatal error, for now */
 210                         this->enabled = 0;
 211                 }
 212                 written += fragsize;
 213         } else {
 214 #ifdef DEBUG_AUDIO
 215                 CheckUnderflow(this);
 216 #endif
 217                 if ( write(audio_fd, mixbuf, this->spec.size) < 0 ) {
 218                         /* Assume fatal error, for now */
 219                         this->enabled = 0;
 220                 }
 221                 written += fragsize;
 222         }
 223 }
 224
 225 Uint8 *DSP_GetAudioBuf(_THIS)
 226 {
 227         return(mixbuf);
 228 }
 229
 230 void DSP_CloseAudio(_THIS)
 231 {
 232         if ( mixbuf != NULL ) {
 233                 SDL_FreeAudioMem(mixbuf);
 234                 mixbuf = NULL;
 235         }
 236         if ( ulaw_buf != NULL ) {
 237                 SDL_free(ulaw_buf);
 238                 ulaw_buf = NULL;
 239         }
 240         close(audio_fd);
 241 }
 242
 243 int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec)
 244 {
 245         char audiodev[1024];
 246 #ifdef AUDIO_SETINFO
 247         int enc;
 248 #endif
 249         int desired_freq = spec->freq;
 250
 251         /* Initialize our freeable variables, in case we fail*/
 252         audio_fd = -1;
 253         mixbuf = NULL;
 254         ulaw_buf = NULL;
 255
 256         /* Determine the audio parameters from the AudioSpec */
 257         switch ( spec->format & 0xFF ) {
 258
 259                 case 8: { /* Unsigned 8 bit audio data */
 260                         spec->format = AUDIO_U8;
 261 #ifdef AUDIO_SETINFO
 262                         enc = AUDIO_ENCODING_LINEAR8;
 263 #endif
 264                 }
 265                 break;
 266
 267                 case 16: { /* Signed 16 bit audio data */
 268                         spec->format = AUDIO_S16SYS;
 269 #ifdef AUDIO_SETINFO
 270                         enc = AUDIO_ENCODING_LINEAR;
 271 #endif
 272                 }
 273                 break;
 274
 275                 default: {
 276                         SDL_SetError("Unsupported audio format");
 277                         return(-1);
 278                 }
 279         }
 280         audio_fmt = spec->format;
 281
 282         /* Open the audio device */
 283         audio_fd = SDL_OpenAudioPath(audiodev, sizeof(audiodev), OPEN_FLAGS, 1);
 284         if ( audio_fd < 0 ) {
 285                 SDL_SetError("Couldn't open %s: %s", audiodev,
 286                              strerror(errno));
 287                 return(-1);
 288         }
 289
 290         ulaw_only = 0;          /* modern Suns do support linear audio */
 291 #ifdef AUDIO_SETINFO
 292         for(;;) {
 293             audio_info_t info;
 294             AUDIO_INITINFO(&info); /* init all fields to "no change" */
 295
 296             /* Try to set the requested settings */
 297             info.play.sample_rate = spec->freq;
 298             info.play.channels = spec->channels;
 299             info.play.precision = (enc == AUDIO_ENCODING_ULAW)
 300                                   ? 8 : spec->format & 0xff;
 301             info.play.encoding = enc;
 302             if( ioctl(audio_fd, AUDIO_SETINFO, &info) == 0 ) {
 303
 304                 /* Check to be sure we got what we wanted */
 305                 if(ioctl(audio_fd, AUDIO_GETINFO, &info) < 0) {
 306                     SDL_SetError("Error getting audio parameters: %s",
 307                                  strerror(errno));
 308                     return -1;
 309                 }
 310                 if(info.play.encoding == enc
 311                    && info.play.precision == (spec->format & 0xff)
 312                    && info.play.channels == spec->channels) {
 313                     /* Yow! All seems to be well! */
 314                     spec->freq = info.play.sample_rate;
 315                     break;
 316                 }
 317             }
 318
 319             switch(enc) {
 320             case AUDIO_ENCODING_LINEAR8:
 321                 /* unsigned 8bit apparently not supported here */
 322                 enc = AUDIO_ENCODING_LINEAR;
 323                 spec->format = AUDIO_S16SYS;
 324                 break;  /* try again */
 325
 326             case AUDIO_ENCODING_LINEAR:
 327                 /* linear 16bit didn't work either, resort to µ-law */
 328                 enc = AUDIO_ENCODING_ULAW;
 329                 spec->channels = 1;
 330                 spec->freq = 8000;
 331                 spec->format = AUDIO_U8;
 332                 ulaw_only = 1;
 333                 break;
 334
 335             default:
 336                 /* oh well... */
 337                 SDL_SetError("Error setting audio parameters: %s",
 338                              strerror(errno));
 339                 return -1;
 340             }
 341         }
 342 #endif /* AUDIO_SETINFO */
 343         written = 0;
 344
 345         /* We can actually convert on-the-fly to U-Law */
 346         if ( ulaw_only ) {
 347                 spec->freq = desired_freq;
 348                 fragsize = (spec->samples*1000)/(spec->freq/8);
 349                 frequency = 8;
 350                 ulaw_buf = (Uint8 *)SDL_malloc(fragsize);
 351                 if ( ulaw_buf == NULL ) {
 352                         SDL_OutOfMemory();
 353                         return(-1);
 354                 }
 355                 spec->channels = 1;
 356         } else {
 357                 fragsize = spec->samples;
 358                 frequency = spec->freq/1000;
 359         }
 360 #ifdef DEBUG_AUDIO
 361         fprintf(stderr, "Audio device %s U-Law only\n",
 362                                 ulaw_only ? "is" : "is not");
 363         fprintf(stderr, "format=0x%x chan=%d freq=%d\n",
 364                 spec->format, spec->channels, spec->freq);
 365 #endif
 366
 367         /* Update the fragment size as size in bytes */
 368         SDL_CalculateAudioSpec(spec);
 369
 370         /* Allocate mixing buffer */
 371         mixbuf = (Uint8 *)SDL_AllocAudioMem(spec->size);
 372         if ( mixbuf == NULL ) {
 373                 SDL_OutOfMemory();
 374                 return(-1);
 375         }
 376         SDL_memset(mixbuf, spec->silence, spec->size);
 377
 378         /* We're ready to rock and roll. :-) */
 379         return(0);
 380 }
 381
 382 /************************************************************************/
 383 /* This function (snd2au()) copyrighted:                                */
 384 /************************************************************************/
 385 /*      Copyright 1989 by Rich Gopstein and Harris Corporation          */
 386 /*                                                                      */
 387 /*      Permission to use, copy, modify, and distribute this software   */
 388 /*      and its documentation for any purpose and without fee is        */
 389 /*      hereby granted, provided that the above copyright notice        */
 390 /*      appears in all copies and that both that copyright notice and   */
 391 /*      this permission notice appear in supporting documentation, and  */
 392 /*      that the name of Rich Gopstein and Harris Corporation not be    */
 393 /*      used in advertising or publicity pertaining to distribution     */
 394 /*      of the software without specific, written prior permission.     */
 395 /*      Rich Gopstein and Harris Corporation make no representations    */
 396 /*      about the suitability of this software for any purpose.  It     */
 397 /*      provided "as is" without express or implied warranty.           */
 398 /************************************************************************/
 399
 400 static Uint8 snd2au(int sample)
 401 {
 402
 403         int mask;
 404
 405         if (sample < 0) {
 406                 sample = -sample;
 407                 mask = 0x7f;
 408         } else {
 409                 mask = 0xff;
 410         }
 411
 412         if (sample < 32) {
 413                 sample = 0xF0 | (15 - sample / 2);
 414         } else if (sample < 96) {
 415                 sample = 0xE0 | (15 - (sample - 32) / 4);
 416         } else if (sample < 224) {
 417                 sample = 0xD0 | (15 - (sample - 96) / 8);
 418         } else if (sample < 480) {
 419                 sample = 0xC0 | (15 - (sample - 224) / 16);
 420         } else if (sample < 992) {
 421                 sample = 0xB0 | (15 - (sample - 480) / 32);
 422         } else if (sample < 2016) {
 423                 sample = 0xA0 | (15 - (sample - 992) / 64);
 424         } else if (sample < 4064) {
 425                 sample = 0x90 | (15 - (sample - 2016) / 128);
 426         } else if (sample < 8160) {
 427                 sample = 0x80 | (15 - (sample - 4064) /  256);
 428         } else {
 429                 sample = 0x80;
 430         }
 431         return (mask & sample);
 432 }