/*************************************************************************/
/* fir.c
/*************************************************************************/
#include <stdio.h>
#include <malloc.h>
#include "math.h"
#include "fir.h"
#include "firinterp.h"

/*************************************************************************/
/* Global Variables
/*************************************************************************/
int FIfilter(struct _sFIRIP *pObj, float *pX, float *pY, int len)
{
	int n, len2, k, i, j, nIp, firLen, kL;
	float *pSxt, *pBt, sum;
	kL = pObj->kL;
	nIp = pObj->nCoefPerPhase;
	firLen = pObj->firLen;

	pBt  = &pObj->pB[0];
	pSxt = &pObj->pX[0];
	len2 = 0;
	for (n=0; n < len; n++)
	{
		for (i=nIp; i > 0; i--)
			pSxt[i] = pSxt[i-1];

		pSxt[0] = pX[n];
		for (k=0; k < kL; k++)
		{
			sum = 0.0;
			i=0;
			for (j=k; j < firLen; j += kL) 
			{
				sum += pSxt[i] * pBt[j];
				i++;
			} 
			*(pY++) = sum;
			len2++;
		}
	
	}
	return len2;
}

void FIinit(struct _sFIRIP *pObj, int kL, int nCoefPerPhase)
{
	int n;
	pObj->kL = kL;

	pObj->firLen = kL*nCoefPerPhase;
	pObj->nCoefPerPhase = nCoefPerPhase;

	if ((pObj->firLen%2) == 0)
		pObj->firLen++;

	pObj->pB = (float*)malloc(pObj->firLen*sizeof(float));
	pObj->pX = (float*)malloc((pObj->nCoefPerPhase+1)*sizeof(float));


	for(n=0; n <= pObj->nCoefPerPhase; n++)
	{
		pObj->pX[n] = 0;
	}

	Sinc(pObj->pB, kL, 1.f, 1.f/kL, pObj->firLen);

}

void FIfree(struct _sFIRIP *pObj)
{
	free(pObj->pB);
	free(pObj->pX);
}