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alsa.cc

/*
 * AdPlay/UNIX - OPL2 audio player
 * Copyright (C) 2001 - 2004 Simon Peter <dn.tlp@gmx.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  
 */

#include "defines.h"
#include "alsa.h"

#define DEFAULT_DEVICE  "plughw:0,0"      // Default ALSA output device

ALSAPlayer::ALSAPlayer(Copl *nopl, const char *device, unsigned char bits,
                   int channels, int freq, unsigned long bufsize)
  : EmuPlayer(nopl, bits, channels, freq, bufsize)
{
  snd_pcm_hw_params_t   *hwparams;
  unsigned int          nfreq = freq;

  if(!device) device = DEFAULT_DEVICE;

  snd_pcm_hw_params_malloc(&hwparams);

  // Try to open audio device
  if(snd_pcm_open(&pcm_handle, device, SND_PCM_STREAM_PLAYBACK, 0) < 0) {
    message(MSG_ERROR, "error opening PCM device -- %s", device);
    exit(EXIT_FAILURE);
  }

  // Init hwparams with full configuration space
  if(snd_pcm_hw_params_any(pcm_handle, hwparams) < 0) {
    message(MSG_ERROR, "cannot configure this PCM device -- %s", device);
    exit(EXIT_FAILURE);
  }

  // Set access type
  if(snd_pcm_hw_params_set_access(pcm_handle, hwparams,
                          SND_PCM_ACCESS_RW_INTERLEAVED) < 0) {
    message(MSG_ERROR, "error setting access type");
    exit(EXIT_FAILURE);
  }

  // Set sample format
  if (snd_pcm_hw_params_set_format(pcm_handle, hwparams, bits == 16 ?
                           SND_PCM_FORMAT_S16 : SND_PCM_FORMAT_U8) < 0) {
    message(MSG_ERROR, "error setting format");
    exit(EXIT_FAILURE);
  }

  // Set sample rate (nearest possible)
  if(snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams, &nfreq, 0) < 0) {
    message(MSG_ERROR, "error setting sample rate");
    exit(EXIT_FAILURE);
  }

  if(nfreq != (unsigned int)freq)
    message(MSG_NOTE, "%d Hz sample rate not supported by your hardware, using "
          "%d Hz instead", freq, nfreq);

  // Set number of channels
  if(snd_pcm_hw_params_set_channels(pcm_handle, hwparams, channels) < 0) {
    message(MSG_ERROR, "error setting channels");
    exit(EXIT_FAILURE);
  }

  // Set number of periods
  if(snd_pcm_hw_params_set_periods(pcm_handle, hwparams, 2, 0) < 0) {
    message(MSG_ERROR, "error setting periods");
    exit(EXIT_FAILURE);
  }

  // Set buffer size (in samples)
  if(snd_pcm_hw_params_set_buffer_size(pcm_handle, hwparams, bufsize / getsampsize()) < 0) {
    message(MSG_ERROR, "error setting buffersize");
    exit(EXIT_FAILURE);
  }

  // Apply HW parameter settings to PCM device and prepare device
  if(snd_pcm_hw_params(pcm_handle, hwparams) < 0) {
    message(MSG_ERROR, "error setting HW params");
    exit(EXIT_FAILURE);
  }

  snd_pcm_hw_params_free(hwparams);
}

ALSAPlayer::~ALSAPlayer()
{
  // stop playback immediately
  snd_pcm_drop(pcm_handle);
  snd_pcm_close(pcm_handle);
}

void ALSAPlayer::output(const void *buf, unsigned long size)
{
  if(snd_pcm_writei(pcm_handle, buf, size / getsampsize()) < 0)
    snd_pcm_prepare(pcm_handle);
}

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