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/***************************************************************************
alsa.c - description
-------------------
begin : Sat Mar 01 2003
copyright : (C) 2002 by Pete Bernert
email : BlackDove@addcom.de
***************************************************************************/
/***************************************************************************
* *
* 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 of the License, or *
* (at your option) any later version. See also the license.txt file for *
* additional informations. *
* *
***************************************************************************/
#include <stdio.h>
#define ALSA_PCM_NEW_HW_PARAMS_API
#define ALSA_PCM_NEW_SW_PARAMS_API
#include <alsa/asoundlib.h>
#include "out.h"
static snd_pcm_t *handle = NULL;
static snd_pcm_uframes_t buffer_size;
// SETUP SOUND
static int alsa_init(void)
{
snd_pcm_hw_params_t *hwparams;
snd_pcm_status_t *status;
unsigned int pspeed;
int pchannels;
int format;
unsigned int buffer_time = 100000;
unsigned int period_time = buffer_time / 4;
int err;
pchannels=2;
pspeed = 44100;
format = SND_PCM_FORMAT_S16;
if ((err = snd_pcm_open(&handle, "default",
SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK)) < 0)
{
printf("Audio open error: %s\n", snd_strerror(err));
return -1;
}
if((err = snd_pcm_nonblock(handle, 0))<0)
{
printf("Can't set blocking moded: %s\n", snd_strerror(err));
return -1;
}
snd_pcm_hw_params_alloca(&hwparams);
if((err=snd_pcm_hw_params_any(handle, hwparams))<0)
{
printf("Broken configuration for this PCM: %s\n", snd_strerror(err));
return -1;
}
if((err=snd_pcm_hw_params_set_access(handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED))<0)
{
printf("Access type not available: %s\n", snd_strerror(err));
return -1;
}
if((err=snd_pcm_hw_params_set_format(handle, hwparams, format))<0)
{
printf("Sample format not available: %s\n", snd_strerror(err));
return -1;
}
if((err=snd_pcm_hw_params_set_channels(handle, hwparams, pchannels))<0)
{
printf("Channels count not available: %s\n", snd_strerror(err));
return -1;
}
if((err=snd_pcm_hw_params_set_rate_near(handle, hwparams, &pspeed, 0))<0)
{
printf("Rate not available: %s\n", snd_strerror(err));
return -1;
}
if((err=snd_pcm_hw_params_set_buffer_time_near(handle, hwparams, &buffer_time, 0))<0)
{
printf("Buffer time error: %s\n", snd_strerror(err));
return -1;
}
if((err=snd_pcm_hw_params_set_period_time_near(handle, hwparams, &period_time, 0))<0)
{
printf("Period time error: %s\n", snd_strerror(err));
return -1;
}
if((err=snd_pcm_hw_params(handle, hwparams))<0)
{
printf("Unable to install hw params: %s\n", snd_strerror(err));
return -1;
}
snd_pcm_status_alloca(&status);
if((err=snd_pcm_status(handle, status))<0)
{
printf("Unable to get status: %s\n", snd_strerror(err));
return -1;
}
buffer_size = snd_pcm_status_get_avail(status);
return 0;
}
// REMOVE SOUND
static void alsa_finish(void)
{
if(handle != NULL)
{
snd_pcm_drop(handle);
snd_pcm_close(handle);
handle = NULL;
}
}
// GET BYTES BUFFERED
static int alsa_busy(void)
{
int l;
if (handle == NULL) // failed to open?
return 1;
l = snd_pcm_avail(handle);
if (l < 0) return 0;
if (l < buffer_size / 2) // can we write in at least the half of fragments?
l = 1; // -> no? wait
else l = 0; // -> else go on
return l;
}
// FEED SOUND DATA
static void alsa_feed(void *pSound, int lBytes)
{
if (handle == NULL) return;
if (snd_pcm_state(handle) == SND_PCM_STATE_XRUN)
snd_pcm_prepare(handle);
snd_pcm_writei(handle,pSound, lBytes / 4);
}
void out_register_alsa(struct out_driver *drv)
{
drv->name = "alsa";
drv->init = alsa_init;
drv->finish = alsa_finish;
drv->busy = alsa_busy;
drv->feed = alsa_feed;
}
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