mirror of
https://github.com/RaySollium99/libpicofe.git
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154 lines
3.3 KiB
C
154 lines
3.3 KiB
C
/*
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* (C) notaz, 2013
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*
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* This work is licensed under the terms of any of these licenses
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* (at your option):
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* - GNU GPL, version 2 or later.
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* - GNU LGPL, version 2.1 or later.
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* - MAME license.
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* See the COPYING file in the top-level directory.
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*/
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#include <stdio.h>
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#include <alsa/asoundlib.h>
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#include <unistd.h>
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#include "sndout_alsa.h"
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#define PFX "sndout_alsa: "
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static snd_pcm_t *handle;
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static snd_pcm_uframes_t buffer_size, period_size;
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static void *silent_period;
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static unsigned int channels;
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static int failure_counter;
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int sndout_alsa_init(void)
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{
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int ret;
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ret = snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0);
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if (ret != 0)
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return -1;
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return 0;
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}
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int sndout_alsa_start(int rate_, int stereo)
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{
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snd_pcm_hw_params_t *hwparams = NULL;
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unsigned int rate = rate_;
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int samples, shift;
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int ret;
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samples = rate * 40 / 1000;
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for (shift = 8; (1 << shift) < samples; shift++)
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;
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period_size = 1 << shift;
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buffer_size = 8 * period_size;
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snd_pcm_hw_params_alloca(&hwparams);
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ret = snd_pcm_hw_params_any(handle, hwparams);
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ret |= snd_pcm_hw_params_set_access(handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED);
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ret |= snd_pcm_hw_params_set_format(handle, hwparams, SND_PCM_FORMAT_S16_LE);
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ret |= snd_pcm_hw_params_set_channels(handle, hwparams, stereo ? 2 : 1);
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ret |= snd_pcm_hw_params_set_rate_near(handle, hwparams, &rate, 0);
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ret |= snd_pcm_hw_params_set_buffer_size_near(handle, hwparams, &buffer_size);
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ret |= snd_pcm_hw_params_set_period_size_near(handle, hwparams, &period_size, NULL);
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if (ret != 0) {
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fprintf(stderr, PFX "failed to set hwparams\n");
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goto fail;
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}
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ret = snd_pcm_hw_params(handle, hwparams);
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if (ret != 0) {
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fprintf(stderr, PFX "failed to apply hwparams: %d\n", ret);
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goto fail;
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}
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snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
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snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
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snd_pcm_hw_params_get_channels(hwparams, &channels);
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silent_period = realloc(silent_period, period_size * 2 * channels);
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if (silent_period != NULL)
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memset(silent_period, 0, period_size * 2 * channels);
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ret = snd_pcm_prepare(handle);
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if (ret != 0) {
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fprintf(stderr, PFX "snd_pcm_prepare failed: %d\n", ret);
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goto fail;
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}
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ret = snd_pcm_start(handle);
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if (ret != 0) {
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fprintf(stderr, PFX "snd_pcm_start failed: %d\n", ret);
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goto fail;
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}
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failure_counter = 0;
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return 0;
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fail:
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// to flush out redirected logs
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fflush(stdout);
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fflush(stderr);
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return -1;
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}
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void sndout_alsa_stop(void)
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{
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int ret = snd_pcm_drop(handle);
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if (ret != 0)
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fprintf(stderr, PFX "snd_pcm_drop failed: %d\n", ret);
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}
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void sndout_alsa_wait(void)
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{
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snd_pcm_sframes_t left;
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while (1)
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{
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left = snd_pcm_avail(handle);
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if (left < 0 || left >= buffer_size / 2)
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break;
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usleep(4000);
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}
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}
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int sndout_alsa_write_nb(const void *samples, int len)
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{
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snd_pcm_sframes_t left;
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int ret;
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len /= 2;
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if (channels == 2)
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len /= 2;
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left = snd_pcm_avail(handle);
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if (left >= 0 && left < len)
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return 0;
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ret = snd_pcm_writei(handle, samples, len);
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if (ret < 0) {
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ret = snd_pcm_recover(handle, ret, 1);
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if (ret != 0 && failure_counter++ < 5)
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fprintf(stderr, PFX "snd_pcm_recover: %d\n", ret);
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if (silent_period)
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snd_pcm_writei(handle, silent_period, period_size);
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snd_pcm_writei(handle, samples, len);
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}
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return len;
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}
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void sndout_alsa_exit(void)
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{
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snd_pcm_close(handle);
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handle = NULL;
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}
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