// lasp_sosfilterbank.h
//
// Author: J.A. de Jong - ASCEE
//
// Description: Implemententation of a discrete parallel filterbank using 
// cascaded second order sections (sos) for each filter in the filterbank. In
// parallel mode, the filters are allocated over a set of Worker threads that
// actually perform the computation. In serial mode, all filters in the bank
// are computed in series.
//////////////////////////////////////////////////////////////////////
#pragma once
#ifndef LASP_FILTERBANK_H
#define LASP_FILTERBANK_H
#include "lasp_config.h"
#include "lasp_types.h"
#include "lasp_mat.h"

#define MAX_SOS_FILTER_BANK_SIZE 40
#define MAX_SOS_FILTER_BANK_NSECTIONS 10

typedef struct Sosfilterbank Sosfilterbank;

/** 
 * Initializes a Sosfilterbank. Sets all coefficients in such a way that the
 * filter effectively does nothing (unit impulse response).
 * @param[in] nthreads: The number of threads used in computation should be 1
 * <= nthreads <= LASP_MAX_NUM_THREADS. If set to 0, a sensible value is
 * computed based on the number of filterbanks.
 * @param[in] filterbank_size: The number of parallel filters in the bank
 *
 * @return Sosfilterbank handle
 */
Sosfilterbank* Sosfilterbank_create(const us nthreads,
    const us filterbank_size,
    const us nsections);

/**
 * Returns the number of channels in the filterbank (the filberbank size).
 *
 * @param[in] fb: Filterbank handle
 * @return The number of filters in the bank
 * */
us Sosfilterbank_getFilterbankSize(const Sosfilterbank* fb);

/**
 * Initialize the filter coeficients in the filterbank
 *
 * @param fb: Filterbank handle
 * @param filter_no: Filter number in the bank
 * @param coefss: Array of filter coefficients. Should have a length of 
 * nsections x 6, for each of the sections, it contains (b0, b1, b2, a0, 
 * a1, a2), where b are the numerator coefficients and a are the denominator 
 * coefficients. 
 *
 */
void Sosfilterbank_setFilter(Sosfilterbank* fb,const us filter_no,
    const vd coefs);

/** 
 * Filters x using h, returns y
 *
 * @param x Input time sequence block. Should have at least one sample.

 * @return Filtered output in an allocated array. The number of
 * columns in this array equals the number of filters in the
 * filterbank. The number of output samples is equal to the number of
 * input samples in x (and is equal to the number of rows in the output).
 */
dmat Sosfilterbank_filter(Sosfilterbank* fb,
    const vd* x);

/** 
 * Cleans up an existing filter bank.
 *
 * @param f Filterbank handle
 */
void Sosfilterbank_free(Sosfilterbank* f);


#endif // LASP_FILTERBANK_H
//////////////////////////////////////////////////////////////////////