spandsp: complex_filters.h Source File

spandsp 0.0.6

complex_filters.h
1/*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * complex_filters.h
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2003 Steve Underwood
9 *
10 * All rights reserved.
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Lesser General Public License version 2.1,
14 * as published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 */
25
26#if !defined(_SPANDSP_COMPLEX_FILTERS_H_)
27#define _SPANDSP_COMPLEX_FILTERS_H_
28
29typedef struct filter_s filter_t;
30
31typedef float (*filter_step_func_t)(filter_t *fi, float x);
32
33/*! Filter state */
34 typedef struct
35{
36 int nz;
37 int np;
38 filter_step_func_t fsf;
39} fspec_t;
40
41 struct filter_s
42{
43 fspec_t *fs;
44 float sum;
45 int ptr; /* Only for moving average filters */
46 float v[];
47};
48
49 typedef struct
50{
51 filter_t *ref;
52 filter_t *imf;
53} cfilter_t;
54
55#if defined(__cplusplus)
56extern "C"
57{
58#endif
59
60SPAN_DECLARE(filter_t *) filter_create(fspec_t *fs);
61SPAN_DECLARE(void) filter_delete(filter_t *fi);
62SPAN_DECLARE(float) filter_step(filter_t *fi, float x);
63
64SPAN_DECLARE(cfilter_t *) cfilter_create(fspec_t *fs);
65SPAN_DECLARE(void) cfilter_delete(cfilter_t *cfi);
66SPAN_DECLARE(complexf_t) cfilter_step(cfilter_t *cfi, const complexf_t *z);
67
68#if defined(__cplusplus)
69}
70#endif
71
72#endif
73/*- End of file ------------------------------------------------------------*/
cfilter_t
Definition complex_filters.h:50
complexf_t
Definition complex.h:43
filter_s
Definition complex_filters.h:42
fspec_t
Definition complex_filters.h:35