//
//	Description
//		Record and play sound
//
//	Copyright (C) 2004  Hyesco Technology Co.,Ltd
//
//	Author: Zheng Geng <gzheng@hyesco.com>
//
//	History:
//
//	2004.8   Zheng Geng  <gzheng@hyesco.com>
//               Original version
//

#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <stdlib.h>
#include <stdio.h>
#include <linux/soundcard.h>

#define LENGTH 5    /* 存儲秒數(shù) */
#define RATE 44100   /* 采樣頻率 */
#define SIZE 16      /* 量化位數(shù) */
#define CHANNELS 1  /* 聲道數(shù)目 */

/* 用于保存數(shù)字音頻數(shù)據(jù)的內(nèi)存緩沖區(qū) */
unsigned char buf[LENGTH*RATE*SIZE*CHANNELS/8];
unsigned char tempbuf[LENGTH*RATE*SIZE*CHANNELS/8];

int main()
{
	int fd;
	int arg,i,n;	/* 用于ioctl調(diào)用的參數(shù) */
	int status;   /* 系統(tǒng)調(diào)用的返回值 */

	// 打開聲音設(shè)備 
	fd = open("/dev/sound/dsp", O_RDWR);
	if (fd < 0) 
	{
		perror("open of /dev/dsp failed");
		exit(1);
	}
	
	// 設(shè)置采樣時(shí)的量化位數(shù)
	arg = SIZE;
	status = ioctl(fd, SOUND_PCM_WRITE_BITS, &arg);
	if (status == -1)
		perror("SOUND_PCM_WRITE_BITS ioctl failed");
	if (arg != SIZE)
		perror("unable to set sample size");

	// 設(shè)置采樣時(shí)的聲道數(shù)目
	arg = CHANNELS; 
	status = ioctl(fd, SOUND_PCM_WRITE_CHANNELS, &arg);
	if (status == -1)
		perror("SOUND_PCM_WRITE_CHANNELS ioctl failed");
	if (arg != CHANNELS)
		perror("unable to set number of channels");

	//設(shè)置采樣時(shí)的采樣頻率
	arg = RATE;
	status = ioctl(fd, SOUND_PCM_WRITE_RATE, &arg);
	if (status == -1)
		perror("SOUND_PCM_WRITE_WRITE ioctl failed");
	
	//循環(huán)，直到按下Control-C
	n=RATE*SIZE*CHANNELS/8;
	while (1) 
	{
		memset(buf, 0, sizeof(buf));
		printf("Say something:\n");
		for (i=0;i<LENGTH;i++)
		{
			status = read(fd, tempbuf, n); // 錄音1秒
			if (status != n)
				perror("read wrong number of bytes");
			memcpy(buf+i*n,tempbuf,n);
		}

		printf("You said:\n");
			status = write(fd, buf, sizeof(buf)); // 回放
		if (status != sizeof(buf))
			perror("wrote wrong number of bytes");

		// 在繼續(xù)錄音前等待回放結(jié)束
		status = ioctl(fd, SOUND_PCM_SYNC, 0); 
		if (status == -1)
			perror("SOUND_PCM_SYNC ioctl failed");
		getchar();
	}
	close(fd); 
	return 0;
	
}