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

#define GET_BIT(X,N) ( ( (X) >> (N) ) & 1 )

void ad7771_data_to_voltage(double ref, uint32_t *raw_code, double *voltage) {
	if((*raw_code <= 0x7FFFFF) && (*raw_code >= 0x00)) {
		*voltage = (double)(*raw_code * (ref/16777216.0));
	}
	else {
		*voltage = (double)((*raw_code * (ref/16777216.0))-ref);
	}
}

timespec diff(timespec start, timespec end){
    timespec temp;
    if ((end.tv_nsec-start.tv_nsec)<0) {
        temp.tv_sec = end.tv_sec-start.tv_sec-1;
        temp.tv_nsec = 1000000000+end.tv_nsec-start.tv_nsec;
    } else {
        temp.tv_sec = end.tv_sec-start.tv_sec;
        temp.tv_nsec = end.tv_nsec-start.tv_nsec;
    }
    return temp;
}

int	main (int argc, char *argv[])	{
	double ref = 2.5;
	uint32_t raw_code = 0;
	double voltage = -1;

	int i;
	int err;

	snd_pcm_t *capture_handle;
	snd_pcm_hw_params_t *hw_params;
	//const int datarate=128000;
	if ((err = snd_pcm_open (&capture_handle, "hw", SND_PCM_STREAM_CAPTURE, 0)) < 0) {
		fprintf (stderr, "cannot open audio device %s (%s)\n", argv[1], snd_strerror (err));
		exit (1);
	}

	if ((err = snd_pcm_hw_params_malloc (&hw_params)) < 0) {
		fprintf (stderr, "cannot allocate hardware parameter structure (%s)\n", snd_strerror (err));
		exit (1);
	}
	fprintf (stderr,"1	\n");
	if ((err = snd_pcm_hw_params_any (capture_handle, hw_params)) < 0) {
		fprintf (stderr, "cannot initialize hardware parameter structure (%s)\n", snd_strerror (err));
		exit (1);
	}
	fprintf (stderr,"2	\n");
	if ((err = snd_pcm_hw_params_set_access (capture_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
		fprintf (stderr, "cannot set access type (%s)\n", snd_strerror (err));
		exit (1);
	}
	fprintf (stderr,"3	\n");
	if ((err = snd_pcm_hw_params_set_format (capture_handle, hw_params, SND_PCM_FORMAT_S32)) < 0) {
		fprintf (stderr, "cannot set sample format (%s)\n", snd_strerror (err));
		exit (1);
	}
	fprintf (stderr,"4	\n");
	unsigned int rate = 192000;
	if ((err = snd_pcm_hw_params_set_rate_near (capture_handle, hw_params, &rate, 0)) < 0) {
		fprintf (stderr, "cannot set sample rate (%s)\n", snd_strerror (err));
		exit (1);
	}
	fprintf (stderr,"5	\n"); fprintf (stderr,"Rate: %d\n",rate);
	if ((err = snd_pcm_hw_params_set_channels (capture_handle, hw_params, 8)) < 0) {
		fprintf (stderr, "cannot set channel count (%s)\n", snd_strerror (err));
		exit (1);
	}
	fprintf (stderr,"6	\n");
	if ((err = snd_pcm_hw_params (capture_handle, hw_params)) < 0) {
		fprintf (stderr, "cannot set parameters (%s)\n", snd_strerror (err));
		exit (1);
	}
	fprintf (stderr,"7	\n");
	snd_pcm_hw_params_free (hw_params);
	fprintf (stderr,"8	\n");
	if ((err = snd_pcm_prepare (capture_handle)) < 0) {
		fprintf (stderr, "cannot prepare audio interface for use (%s)\n", snd_strerror (err));
		exit (1);
	}
	fprintf (stderr,"9	\n");

	timespec time1_, time2_;

	uint32_t ad7771_butch_size=32*32;
	uint8_t buf[32*1024];
	uint32_t counbter=0;

	for (int i1 = 0; i1 < 10; ++i1) {

		clock_gettime(CLOCK_REALTIME, &time1_);
		std::cout<< "loop ns: " << diff(time2_,time1_).tv_nsec << std::endl;
		clock_gettime(CLOCK_REALTIME, &time2_);

		if ((err = snd_pcm_readi (capture_handle, &buf, ad7771_butch_size)) != ad7771_butch_size) {
			fprintf (stderr, "read from audio interface failed (%s)\n", snd_strerror (err));
			exit (1);
		}
		//counbter+=ad7771_butch_size;
	}

	fprintf (stderr,"10	\n");
	snd_pcm_close (capture_handle);
	exit (0);
}

root@BeagleBone:/home/debian# g++ -oalsatut1 alsatut1.cpp -lasound && ./alsatut1
1
2
3
4
5
Rate: 192000
6
7
8
9
loop ns: 2113288995
loop ns: 9338154
loop ns: 6528263
loop ns: 7033311
loop ns: 6846199
loop ns: 7037977
loop ns: 6838533
loop ns: 7022313
loop ns: 6833200
loop ns: 6833283
10
root@BeagleBone:/home/debian#