#define _ISOC9X_SOURCE  1
#define _ISOC99_SOURCE  1

#define __USE_ISOC9X    1
#define __USE_ISOC99    1

#include        <math.h>

#define BUFF_LENGTH 8192
#define BUFF_MIX 2048 //somewhat regular audio chunk size?


volatile float src_buff[BUFF_LENGTH]; //src float buffer
volatile float dst_buff[BUFF_LENGTH]; //dst float buffer


void resample() {

    int todo=BUFF_MIX;

	
    float advance_f=0.3;
    float volume_f=0.2; // 1/5 of max volume


    volatile float *src_ptr=src_buff;
    volatile float *dst_ptr=dst_buff;
	
	
    float res,res_next;
    float counter=0.0f;
    int pos;
	
    while (todo--) {

	pos=lrintf(counter);
	//pos=todo>>2;
	res=src_ptr[pos];
	res_next=src_ptr[pos+1];
        counter+=advance_f;

            //this line works perfect, since res and res_next contain 16 bits values
	res+= (res_next-res) * (counter-(float)pos);
	res*=volume_f; //thanks to the volume, now the value goes into the higher 16 bits

        *dst_ptr++ +=res;
    }

}


#define TEST_REPEAT 100000

int main() {


    //fill it with some data
    int i;
    for (i=0;i<BUFF_LENGTH;i++) {

	src_buff[i]=i;
        dst_buff[i]=i;

    }

    for (i=0;i<TEST_REPEAT;i++) {

        resample();

    }

}