git ssb

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#define _DEFAULT_SOURCE
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#include <alsa/asoundlib.h>
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#include <dlfcn.h>
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#include <err.h>
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#include <math.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include "tune.h"
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#include "ccdl.h"
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#define max(a,b) ((a) > (b) ? (a) : (b))
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#define min(a,b) ((a) < (b) ? (a) : (b))
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static unsigned int rate = 48000;
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static unsigned int channels_out = 1;
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static unsigned int channels_in = 1;
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static unsigned int latency = 10000; // us
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static int resample = 1; // allow resampling
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static snd_pcm_format_t format = SND_PCM_FORMAT_FLOAT;
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int main(int argc, char *argv[])
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{
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	struct ccdl ccdl;
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	void *tune_obj = NULL;
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	int err;
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	snd_pcm_t *pcm_out, *pcm_in;
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	const char *src_fname = "tune.c";
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	const char *device_out = "default";
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	const char *device_in = "default";
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	if (argc > 1) src_fname = argv[1];
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	if (argc > 2) device_out = argv[2];
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	if (argc > 3) device_in = argv[3];
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	ccdl_init(&ccdl, src_fname, "play");
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	if (ccdl_watch(&ccdl)) {
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		errx(1, "ccdl_watch");
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	}
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	err = snd_pcm_open(&pcm_out, device_out, SND_PCM_STREAM_PLAYBACK, 0);
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	if (err < 0) {
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		warnx("Playback open error: %s", snd_strerror(err));
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		return 1;
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	}
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	err = snd_pcm_open(&pcm_in, device_in,
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			SND_PCM_STREAM_CAPTURE,
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			SND_PCM_NONBLOCK);
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	if (err < 0) {
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		warnx("Capture open error: %s", snd_strerror(err));
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		return 1;
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	}
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	if ((err = snd_pcm_set_params(pcm_out, format,
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	                              SND_PCM_ACCESS_RW_INTERLEAVED,
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	                              channels_out, rate, resample, latency)) < 0) {
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		warnx("Playback open error: %s", snd_strerror(err));
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		return 1;
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	}
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	if ((err = snd_pcm_set_params(pcm_in, format,
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	                              SND_PCM_ACCESS_RW_INTERLEAVED,
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	                              channels_in, rate, resample, latency)) < 0) {
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		warnx("Capture open error: %s", snd_strerror(err));
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		return 1;
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	}
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	double time = 0;
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	double step = 1/(double)rate;
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	while (1) {
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		snd_pcm_sframes_t frames, frames_in, frames_out;
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		frames = snd_pcm_avail_update(pcm_out);
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		if (frames < 0) {
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			err = snd_pcm_recover(pcm_out, frames, 0);
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			if (err) err = snd_pcm_wait(pcm_out, 1000);
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			if (err) warnx("snd_pcm_wait(%s)", snd_strerror(err));
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			continue;
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		}
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		float buffer[frames];
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		frames_in = snd_pcm_readi(pcm_in, buffer, frames);
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		if (frames_in < 0) snd_pcm_recover(pcm_in, frames_in, 0);
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		play_fn *play;
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		*(void **)(&play) = ccdl_get(&ccdl);
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		if (play) {
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			for (size_t i = 0; i < (size_t)frames; i++) {
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				time += step;
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				float frame_in = (ssize_t)i < frames_in ? buffer[i] : 0;
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				buffer[i] = play(&tune_obj, time, frame_in);
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			}
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		} else {
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			time += step * frames;
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		}
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		frames_out = snd_pcm_writei(pcm_out, buffer, frames);
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		if (frames_out < 0) snd_pcm_recover(pcm_out, frames_out, 0);
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	}
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	snd_pcm_close(pcm_out);
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	snd_pcm_close(pcm_in);
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	return ccdl_deinit(&ccdl);
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}
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