//i<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<USING MMAP>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>.

#include<stdio.h>

#include<alsa/asoundlib.h>

#include<fcntl.h>

#include<unistd.h>

#include<sys/time.h>

int main()

{

const snd_pcm_channel_area_t *areas;

int size;

unsigned char *buffer;

char *pcm_name;

unsigned int rate = 8000;

int chan;

int rc;

unsigned int val;

char check;

int pcmreturn;

//Set PCM stream and handle

snd_pcm_t *pcm_handle;

snd_pcm_stream_t stream = SND_PCM_STREAM_PLAYBACK;

//Set HARDWARE parameters

snd_pcm_hw_params_t *hwparams;

//pcm_name = (char *)malloc(10);

pcm_name = "plughw:0,0";

//allocate memory for hardware

if(snd_pcm_hw_params_malloc(&hwparams)<0)

{

fprintf(stderr,"No memory allocated for hardware");

return(-1);

}

if (snd_pcm_open(&pcm_handle, pcm_name, stream, 0) < 0) {

fprintf(stderr, "Error opening PCM device %s\n", pcm_name);

return(-1);

}

//INITIALIZE HARDWARE WITH CONFIGURATION OF THE SOUNDCARD

if(snd_pcm_hw_params_any(pcm_handle,hwparams)<0)

{

fprintf(stderr,"The hardware device cannot be configured\n");

}

//SET FORMAT TO 16 BIT LITTLE ENDIAN

snd_pcm_hw_params_set_format(pcm_handle,hwparams,SND_PCM_FORMAT_S16_LE);

/* Two channels (stereo) */

snd_pcm_hw_params_set_channels(pcm_handle,hwparams,2);

/* 44100 bits/second sampling rate (CD quality) */

if (snd_pcm_hw_params_set_access(pcm_handle, hwparams, SND_PCM_ACCESS_MMAP_INTERLEAVED) < 0) {

fprintf(stderr, "Error setting access.\n");

return(-1);

}

//SETTING RATE ie SAMPLING FREQUENCY

snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams, &rate, 0);

//SETTING HARDWARE PARAMETERS

if(rc=(snd_pcm_hw_params(pcm_handle,hwparams))<0)

{

fprintf(stderr,"\nCannot set hardware parameters\n");

return -1;

}

//snd_pcm_uframes_t periodsize = 8192;

snd_pcm_uframes_t frames,offset ;//OF TYPE UNSIGNED LONG

snd_pcm_sframes_t commitres;

//frames =32;

//SETTING SOME MORE PARAMETERS

//size = frames*4;

//SETTING BUFFER SIZE

/*if (snd_pcm_hw_params_set_buffer_size(pcm_handle, hwparams, (periodsize*2)>>2) < 0) {

fprintf(stderr, "Error setting buffersize.\n");

return(-1);

}

*/

int first=0;;

int err;

snd_pcm_sframes_t avail = snd_pcm_avail_update(pcm_handle);

printf("\nNumber of frames available is : %d \n",(int)avail);

//-------------------------------------------------------------------------------------------------------

//<<<<<<<<<<<<<<<<<<<<<<DISPLAYING INFORMATION>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

//Buffer size

snd_pcm_hw_params_get_buffer_size(hwparams, (snd_pcm_uframes_t*)&val);

printf("\nThe buffer size is %d \n",val);

//Buffer time

snd_pcm_hw_params_get_buffer_time(hwparams, &val,0);

printf("\nBuffer time is : %d \n",val);

//Period size

snd_pcm_hw_params_get_period_size(hwparams,&frames,0);

printf("\nperiod size : %d \n",(int)frames);

////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////

//<<<<<<<<<<<<<mmap_begin>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

err=snd_pcm_mmap_begin(pcm_handle,&areas,&offset,&frames);

//Periods between buffer

snd_pcm_hw_params_get_periods(hwparams,&val,0);

printf("\n Periods between buffer is : %d \n",val);

//<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>.

if(err<0)

{

printf("\nMMAP error\n");

return -1;

}

else printf("\n%d\n",err);

/*

commitres = snd_pcm_mmap_commit(pcm_handle,offset,frames);

if(commitres<0)

{

printf("\nFrames not committed to memory\n");

}

*/

//<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

//<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<,OPENING FILE>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>....

int dest = open("sample3.wav",O_RDONLY);

if(dest<0)

{

perror("\nFile could not be opened\n");

return -1;

}

//buffer = (unsigned char *)malloc(1000);

/*

unsigned long buf = offset;

if(read(dest,&offset,1)<0)

{

perror("\nNo destination for read\n");

return -1;

}

*/

/*

avail=snd_pcm_avail_update(pcm_handle);

printf("\nAvailable frames = %d \n\n",(int)avail);

struct timeval tvbefore,tvafter;

gettimeofday(&tvbefore,NULL);

*/

unsigned char *ptr[2];

int i;

//unsigned int steps=0;

for(i=0;i<2;i++)

ptr[i] = (unsigned char*)areas[i].addr + (areas[i].first/8) + offset*(areas[i].step/8);

printf("\nOffset of the first sample : %u \n",areas[0].first);

printf("\n\nOffset of the memory map is : %u \n",areas[0].step/8);

printf("\nAreas start address is : %u \n",areas[0].addr);

printf("\nNumber of frames ; %u \n",frames);

printf("\n\nPointer before ; %u \n",ptr[0]);

long pl;

for(pl=0;pl<100000;pl++);

if(ptr[1]==NULL)

printf("\nNull pointer 1 allocated\n");

if(ptr[0]==NULL)

printf("\nNull pointer 0 allocated \n");

int check2=1;

snd_pcm_sframes_t size2 =30;

while(1)

{

for(i=0;i<2;i++)

{

//ptr[i] = (unsigned char*)areas[i].addr + (areas[i].first/8) + offset*(areas[i].step/8);

if(read(dest,ptr[i],120)!=0)

{

if(ptr[i]!=NULL)

{

if(pcmreturn = snd_pcm_mmap_writei(pcm_handle,ptr[i],size2)<0)

{

snd_pcm_prepare(pcm_handle);

printf("\n<<<<<<<Buffer Underrun>>>>>>>>\n");

break;

}

// printf("\n%d\n",pcmreturn);

ptr[i]+=0;

printf("\n%lu\n",ptr[i]);

}

}

else {

check2=0;

break;

}

}

if(check2==0)

break;

// l:break;

}

commitres = snd_pcm_mmap_commit(pcm_handle,offset,frames);

if(commitres<0)

{

printf("\nFrames not committed to memory\n");

}

}