Simple sound playback using ALSA API and libasound

sound_playback.c

/*
 * Simple sound playback using ALSA API and libasound.
 *
 * Compile:
 * $ cc -o play sound_playback.c -lasound
 * 
 * Usage:
 * $ ./play <sample_rate> <channels> <seconds> < <file>
 * 
 * Examples:
 * $ ./play 44100 2 5 < /dev/urandom
 * $ ./play 22050 1 8 < /path/to/file.wav
 *
 * Copyright (C) 2009 Alessandro Ghedini <[email protected]>
 * --------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 42):
 * Alessandro Ghedini wrote this file. As long as you retain this
 * notice you can do whatever you want with this stuff. If we
 * meet some day, and you think this stuff is worth it, you can
 * buy me a beer in return.
 * --------------------------------------------------------------
 */

#include <alsa/asoundlib.h>
#include <stdio.h>

#define PCM_DEVICE "default"

int main(int argc, char **argv) {
	unsigned int pcm, tmp, dir;
	int rate, channels, seconds;
	snd_pcm_t *pcm_handle;
	snd_pcm_hw_params_t *params;
	snd_pcm_uframes_t frames;
	char *buff;
	int buff_size, loops;

	if (argc < 4) {
		printf("Usage: %s <sample_rate> <channels> <seconds>\n",
								argv[0]);
		return -1;
	}

	rate 	 = atoi(argv[1]);
	channels = atoi(argv[2]);
	seconds  = atoi(argv[3]);

	/* Open the PCM device in playback mode */
	if (pcm = snd_pcm_open(&pcm_handle, PCM_DEVICE,
					SND_PCM_STREAM_PLAYBACK, 0) < 0) 
		printf("ERROR: Can't open \"%s\" PCM device. %s\n",
					PCM_DEVICE, snd_strerror(pcm));

	/* Allocate parameters object and fill it with default values*/
	snd_pcm_hw_params_alloca(&params);

	snd_pcm_hw_params_any(pcm_handle, params);

	/* Set parameters */
	if (pcm = snd_pcm_hw_params_set_access(pcm_handle, params,
					SND_PCM_ACCESS_RW_INTERLEAVED) < 0) 
		printf("ERROR: Can't set interleaved mode. %s\n", snd_strerror(pcm));

	if (pcm = snd_pcm_hw_params_set_format(pcm_handle, params,
						SND_PCM_FORMAT_S16_LE) < 0) 
		printf("ERROR: Can't set format. %s\n", snd_strerror(pcm));

	if (pcm = snd_pcm_hw_params_set_channels(pcm_handle, params, channels) < 0) 
		printf("ERROR: Can't set channels number. %s\n", snd_strerror(pcm));

	if (pcm = snd_pcm_hw_params_set_rate_near(pcm_handle, params, &rate, 0) < 0) 
		printf("ERROR: Can't set rate. %s\n", snd_strerror(pcm));

	/* Write parameters */
	if (pcm = snd_pcm_hw_params(pcm_handle, params) < 0)
		printf("ERROR: Can't set harware parameters. %s\n", snd_strerror(pcm));

	/* Resume information */
	printf("PCM name: '%s'\n", snd_pcm_name(pcm_handle));

	printf("PCM state: %s\n", snd_pcm_state_name(snd_pcm_state(pcm_handle)));

	snd_pcm_hw_params_get_channels(params, &tmp);
	printf("channels: %i ", tmp);

	if (tmp == 1)
		printf("(mono)\n");
	else if (tmp == 2)
		printf("(stereo)\n");

	snd_pcm_hw_params_get_rate(params, &tmp, 0);
	printf("rate: %d bps\n", tmp);

	printf("seconds: %d\n", seconds);	

	/* Allocate buffer to hold single period */
	snd_pcm_hw_params_get_period_size(params, &frames, 0);

	buff_size = frames * channels * 2 /* 2 -> sample size */;
	buff = (char *) malloc(buff_size);

	snd_pcm_hw_params_get_period_time(params, &tmp, NULL);

	for (loops = (seconds * 1000000) / tmp; loops > 0; loops--) {

		if (pcm = read(0, buff, buff_size) == 0) {
			printf("Early end of file.\n");
			return 0;
		}

		if (pcm = snd_pcm_writei(pcm_handle, buff, frames) == -EPIPE) {
			printf("XRUN.\n");
			snd_pcm_prepare(pcm_handle);
		} else if (pcm < 0) {
			printf("ERROR. Can't write to PCM device. %s\n", snd_strerror(pcm));
		}

	}

	snd_pcm_drain(pcm_handle);
	snd_pcm_close(pcm_handle);
	free(buff);

	return 0;
}

Did an OSS snippet scan and this code got flagged.
Glad to have found the original source (it can be found in many places, including the typo(s)!) and glad to see the Beerware license on it :).