/**
 * Module Name: gen_fir
 * Description:
 * Files: gen_fir.c
 *
 * Author: ismael
 * Created: Tue Feb 15 15:45:52 2011
 * Revision: 0.1
 *
 * Comments: Filter type is selected with the type variable in .params configuration file.
 * It can be changed only during the initialization (stats modification is ignored). Possible types are:
 * 		- 0: rectangular filter
 * 		- 1: raised cosine
 * 		- 2: root-raised cosine
 * 		- 3: MATLAB coefficients readed from fdacoefs.h file
 *
 * For raised and root raised filters, 'rate' and 'alpha' variables need to be selected.
 *
 */

#include <phal_sw_api.h>
#include <math.h>
#include <swapi_utils.h>

#include "typetools.h"
#include "stats.h"

#include "moduleConfig.h"

/** This file must be included AFTER moduleConfig.h */
#include <skeletonExt.h>

#include "rcos.h"

#include "fdacoefs.h"

float taps[MAX_COEFFS];
int mem[MAX_COEFFS];

int norm;

/** Generates filter coefficients
 */
int myinit()
{
	int i;

	if (Ntaps>MAX_COEFFS) {
		xprintf("Error number of coefficients too large (%d>%d)\n",Ntaps,MAX_COEFFS);
		return 1;
	}

	memset(taps,0,sizeof(float)*Ntaps);

	/* compute filter coeficients */
	switch(FilterType) {
		/* rect */
		case 0:
			memset(taps,1,sizeof(float)*Ntaps);
			for (i=0;i<Ntaps;i++) {
				filter[i]=(int) (taps[i]*scale);
			}
			break;
		case 1:
			/* raised cosine */
			rcos(taps,Ntaps,alpha,rate);
			for (i=0;i<Ntaps;i++) {
				filter[i]=(int) (taps[i]*scale);
			}
			break;
		case 2:
			/* root raised cosine */
			rrcos(taps,Ntaps,alpha,rate);
			for (i=0;i<Ntaps;i++) {
				filter[i]=(int) (taps[i]*scale);
			}
			break;
		case 3:
			Ntaps=IFFL;
			memcpy(filter,IFF,Ntaps*sizeof(int));
			break;
		default:
			printf("Error unknown filter type %d\n",FilterType);
	}
	norm=0;
	for (i=0;i<Ntaps;i++) {
		norm+=filter[i]*filter[i];
	}
	memset(mem,0,sizeof(int)*Ntaps);
	return 1;
}

/* perform linear filtering */
int execute()
{
	int i;
	int nsamples;
	float g;
	int *x = IN(0);				/** pointer to input interface 0 */
	int *y = OUT(0);			/** pointer to output interface 0 */


	nsamples=getLength(0);
	g=(float) gain/norm;

	for (i=0;i<nsamples;i++) {
		y[i]=(int) (convii(filter,mem,Ntaps,x[i])*g);
	}

	return nsamples;
}