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LINUXaudio.c

/*  
    LINUXaudio.c:

    Copyright (C) 1995 Jonathan Mohr, John ffitch

    This file is part of Csound.

    The Csound Library is free software; you can redistribute it
    and/or modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    Csound is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with Csound; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA
*/

/*
 *  Linux code based on examples in the "Hacker's Guide to VoxWare 2.4"
 *  and the file "experimental.txt" accompanying the source code
 *  for VoxWare 2.9 and later (provided with the Linux kernel source),
 *  both by Hannu Savolainen (hannu@voxware.pp.fi).
 *
 *  The code not only initializes the sound board and driver for the correct
 *  sample size, rate, and channels, but customizes the DMA buffers to
 *  match Csound's input or output buffer size.
 *
 *  A new option ('-V') was added to Csound to allow the user to set the
 *  master output volume on the soundcard.
 *
 *  Jonathan Mohr
 *  Augustana University College
 *  Camrose, Alberta, Canada  T4V 2R3
 *  mohrj@augustana.ab.ca
 *
 *  1995 Oct 17
 */

#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/soundcard.h>
#include "cs.h"
#include "soundio.h"

#define MIXER_NAME  "/dev/mixer"


void setsndparms( int dspfd, int format, int nchanls, float sr,
                  unsigned bufsiz )
{
  int parm, original;
  unsigned frag_size;

  /* set sample size/format */
  switch ( format ) {
  case AE_UNCH:  /* unsigned char - standard Linux 8-bit format */
    parm = AFMT_U8;
    break;
  case AE_CHAR:  /* signed char. - probably not supported by Linux */
    parm = AFMT_S8;
    break;
  case AE_ULAW:
    parm = AFMT_MU_LAW;
    break;
  case AE_ALAW:
    parm = AFMT_A_LAW;
    break;
  case AE_SHORT:
#ifdef LINUX_BE
    parm = AFMT_S16_BE; /* Linux on SPARC is big-endian */
#else
    parm = AFMT_S16_LE; /* Linux on Intel x86 is little-endian */
#endif
    break;
  case AE_LONG:
    die(Str(X_327,"Linux sound driver does not support long integer samples"));
  case AE_FLOAT:
    die(Str(X_326,"Linux sound driver does not support floating-point samples"));
  default:
    /* Linux sound driver provides these names for modes not used by Csound */
    /* parm = AFMT_IMA_ADPCM; */
    /* parm = AFMT_U16_LE;    */
    /* parm = AFMT_U16_BE;    */
    die(Str(X_1342,"unknown sample format"));
  }
  original = parm;
  if (ioctl(dspfd, SOUND_PCM_WRITE_BITS, &parm) == -1)
    die(Str(X_1312,"unable to set requested sample format on soundcard"));
  if (parm != original)
    die(Str(X_1199,"soundcard does not support the requested sample format"));

  /* set number of channels (mono or stereo) */
  parm = nchanls;
  if (ioctl(dspfd, SOUND_PCM_WRITE_CHANNELS, &parm) == -1)
    die(Str(X_1310,"unable to set mode (mono/stereo) on soundcard"));
  if (parm != nchanls)
    die(Str(X_239,"DSP device does not support the requested mode (mono/stereo)"));

  /* set the sample rate */
  parm = (int) sr;
  if (ioctl(dspfd, SOUND_PCM_WRITE_RATE, &parm) == -1)
    die(Str(X_1313,"unable to set sample rate on soundcard"));
  if (parm != (int) sr) {
    sprintf(errmsg,Str(X_455,"Sample rate set to %d (instead of %d)"),
            parm, (int) sr);
    warning(errmsg);
  }

#ifndef __FreeBSD__
  /* set DMA buffer fragment size to Csound's output buffer size */
  parm = 0; frag_size = 1;
  /* find least power of 2 >= bufsiz */
  while ( frag_size < bufsiz ) {
    frag_size <<= 1;
    parm++;
  }
  parm |= 0x00020000;   /* Larry Troxler's idea */
  /*  parm |= 0x00ff0000; */    /* use max. number of buffer fragments */
  if (ioctl(dspfd, SNDCTL_DSP_SETFRAGMENT, &parm) == -1)
    die(Str(X_755,"failed while trying to set soundcard DMA buffer size"));

  /* find out what buffer size the driver allocated */
  if (ioctl(dspfd, SNDCTL_DSP_GETBLKSIZE, &parm) == -1)
    die(Str(X_754,"failed while querying soundcard about buffer size"));
  if (parm != (int)frag_size) {
    sprintf(errmsg,
            Str(X_466,"Soundcard DMA buffer size set to %d bytes (instead of %d)"),
            parm, frag_size);
    warning(errmsg);
  }
  else
    printf(Str(X_823,"hardware buffers set to %d bytes\n"), parm);
#endif
}


void setvolume( unsigned volume )
{
  int mixfd, parm;

  /* open mixer device for writing */
  if ( (mixfd = open(MIXER_NAME, O_WRONLY)) == -1 )
    die(Str(X_1309,"unable to open soundcard mixer for setting volume"));

  /* set volume (left and right channels the same) */
  parm = (volume & 0xff) | ((volume & 0xff) << 8);
  if (ioctl(mixfd, SOUND_MIXER_WRITE_VOLUME, &parm) == -1)
    die(Str(X_1311,"unable to set output volume on soundcard"));

  /* close mixer device */
  if ( close(mixfd) == -1 )
    die(Str(X_734,"error while closing sound mixer device"));
}



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