libspandsp 0.0.4
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00001 /* 00002 * SpanDSP - a series of DSP components for telephony 00003 * 00004 * complex_filters.h 00005 * 00006 * Written by Steve Underwood <steveu@coppice.org> 00007 * 00008 * Copyright (C) 2003 Steve Underwood 00009 * 00010 * All rights reserved. 00011 * 00012 * This program is free software; you can redistribute it and/or modify 00013 * it under the terms of the GNU Lesser General Public License version 2.1, 00014 * as published by the Free Software Foundation. 00015 * 00016 * This program is distributed in the hope that it will be useful, 00017 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00018 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00019 * GNU Lesser General Public License for more details. 00020 * 00021 * You should have received a copy of the GNU Lesser General Public 00022 * License along with this program; if not, write to the Free Software 00023 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 00024 * 00025 * $Id: complex_filters.h,v 1.12 2008/04/17 14:27:00 steveu Exp $ 00026 */ 00027 00028 #if !defined(_SPANDSP_COMPLEX_FILTERS_H_) 00029 #define _SPANDSP_COMPLEX_FILTERS_H_ 00030 00031 typedef struct filter_s filter_t; 00032 00033 typedef float (*filter_step_func_t)(filter_t *fi, float x); 00034 00035 /*! Filter state */ 00036 typedef struct 00037 { 00038 int nz; 00039 int np; 00040 filter_step_func_t fsf; 00041 } fspec_t; 00042 00043 struct filter_s 00044 { 00045 fspec_t *fs; 00046 float sum; 00047 int ptr; /* for moving average filters only */ 00048 float v[]; 00049 }; 00050 00051 typedef struct 00052 { 00053 filter_t *ref; 00054 filter_t *imf; 00055 } cfilter_t; 00056 00057 #if defined(__cplusplus) 00058 extern "C" 00059 { 00060 #endif 00061 00062 filter_t *filter_create(fspec_t *fs); 00063 void filter_delete(filter_t *fi); 00064 float filter_step(filter_t *fi, float x); 00065 00066 cfilter_t *cfilter_create(fspec_t *fs); 00067 void cfilter_delete(cfilter_t *cfi); 00068 complexf_t cfilter_step(cfilter_t *cfi, const complexf_t *z); 00069 00070 #if defined(__cplusplus) 00071 } 00072 #endif 00073 00074 #endif 00075 /*- End of file ------------------------------------------------------------*/