/* libSoX Biquad filter common definitions (c) 2006-7 robs@users.sourceforge.net * * This library is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or (at * your option) any later version. * * This library is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser * General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library; if not, write to the Free Software Foundation, * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA */ #ifndef biquad_included#define biquad_included #define LSX_EFF_ALIAS#include "sox_i.h" typedef enum {  filter_LPF,  filter_HPF,  filter_BPF_CSG,  filter_BPF,  filter_notch,  filter_APF,  filter_peakingEQ,  filter_lowShelf,  filter_highShelf,  filter_LPF_1,  filter_HPF_1,  filter_BPF_SPK,  filter_BPF_SPK_N,  filter_AP1,  filter_AP2,  filter_deemph,  filter_riaa} filter_t; typedef enum {  width_bw_Hz,  width_bw_kHz,  /* The old, non-RBJ, non-freq-warped band-pass/reject response;   * leaving here for now just in case anybody misses it: */  width_bw_old,  width_bw_oct,  width_Q,  width_slope} width_t; /* Private data for the biquad filter effects */typedef struct {  double gain;             /* For EQ filters */  double fc;               /* Centre/corner/cutoff frequency */  double width;            /* Filter width; interpreted as per width_type */  width_t width_type;   filter_t filter_type;   double b0, b1, b2;       /* Filter coefficients */  double a0, a1, a2;       /* Filter coefficients */   sox_sample_t i1, i2;     /* Filter memory */  double      o1, o2;      /* Filter memory */} biquad_t; int lsx_biquad_getopts(sox_effect_t * effp, int n, char **argv,    int min_args, int max_args, int fc_pos, int width_pos, int gain_pos,    char const * allowed_width_types, filter_t filter_type);int lsx_biquad_start(sox_effect_t * effp);int lsx_biquad_flow(sox_effect_t * effp, const sox_sample_t *ibuf, sox_sample_t *obuf,                        size_t *isamp, size_t *osamp); #endif