uisimulator/x11/oss_sound.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  *
   9  * Copyright (C) 2002 Dave Chapman
  10  *
  11  * oss_sound - a sound driver for Linux (and others?) OSS audio
  12  *
  13  * All files in this archive are subject to the GNU General Public License.
  14  * See the file COPYING in the source tree root for full license agreement.
  15  *
  16  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  17  * KIND, either express or implied.
  18  *
  19  ****************************************************************************/
  20
  21 #include <stdio.h>
  22 #include <fcntl.h>
  23
  24 #include <linux/soundcard.h>
  25 #include "../common/sound.h"
  26
  27 /* We want to use the "real" open in this file */
  28 #undef open
  29
  30 int init_sound(sound_t* sound) {
  31   sound->fd=open("/dev/dsp", O_WRONLY);
  32   sound->freq=-1;
  33   sound->channels=-1;
  34
  35   if (sound->fd <= 0) {
  36     fprintf(stderr,"Can not open /dev/dsp - simulating sound output\n");
  37     sound->fd=0;
  38   }
  39 }
  40
  41 int config_sound(sound_t* sound, int sound_freq, int channels) {
  42   int format=AFMT_U16_LE;
  43   int setting=0x000C000D;  // 12 fragments size 8kb ? WHAT IS THIS?
  44
  45   sound->freq=sound_freq;
  46   sound->channels=channels;
  47
  48   if (sound->fd) {
  49     if (ioctl(sound->fd,SNDCTL_DSP_SETFRAGMENT,&setting)==-1) {
  50       perror("SNDCTL_DSP_SETFRAGMENT");
  51     }
  52
  53     if (ioctl(sound->fd,SNDCTL_DSP_CHANNELS,&channels)==-1) {
  54       perror("SNDCTL_DSP_STEREO");
  55     }
  56     if (channels==0) { fprintf(stderr,"Warning, only mono supported\n"); }
  57
  58     if (ioctl(sound->fd,SNDCTL_DSP_SETFMT,&format)==-1) {
  59       perror("SNDCTL_DSP_SETFMT");
  60     }
  61
  62     if (ioctl(sound->fd,SNDCTL_DSP_SPEED,&sound_freq)==-1) {
  63       perror("SNDCTL_DSP_SPEED");
  64     }
  65   }
  66 }
  67
  68 int output_sound(sound_t* sound,const void* buf, int count) {
  69   unsigned long long t;
  70
  71   if (sound->fd) {
  72     return(write(sound->fd,buf,count));
  73   } else {
  74     t=(unsigned int)(((unsigned int)(1000000/sound->channels)*count)/sound->freq);
  75 //    fprintf(stderr,"writing %d bytes at %d frequency - sleeping for %u microseconds\n",count,sound->freq,t);
  76     usleep(t);
  77     return(count);
  78   }
  79 }
  80
  81 void close_sound(sound_t* sound) {
  82   if (sound->fd) close(sound->fd);
  83   sound->fd=-1;
  84 }