1 /* Effect: fir filter from coefs Copyright (c) 2009 robs@users.sourceforge.net
2 *
3 * This library is free software; you can redistribute it and/or modify it
4 * under the terms of the GNU Lesser General Public License as published by
5 * the Free Software Foundation; either version 2.1 of the License, or (at
6 * your option) any later version.
7 *
8 * This library is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU Lesser General Public License
14 * along with this library; if not, write to the Free Software Foundation,
15 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
16 */
17
18 #include "sox_i.h"
19 #include "dft_filter.h"
20
21 typedef struct {
22 dft_filter_priv_t base;
23 char const * filename;
24 double * h;
25 int n;
26 } priv_t;
27
create(sox_effect_t * effp,int argc,char ** argv)28 static int create(sox_effect_t * effp, int argc, char * * argv)
29 {
30 priv_t * p = (priv_t *)effp->priv;
31 dft_filter_priv_t * b = &p->base;
32 double d;
33 char c;
34
35 b->filter_ptr = &b->filter;
36 --argc, ++argv;
37 if (!argc)
38 p->filename = "-"; /* default to stdin */
39 else if (argc == 1)
40 p->filename = argv[0], --argc;
41 else for (; argc && sscanf(*argv, "%lf%c", &d, &c) == 1; --argc, ++argv) {
42 p->n++;
43 p->h = lsx_realloc(p->h, p->n * sizeof(*p->h));
44 p->h[p->n - 1] = d;
45 }
46 return argc? lsx_usage(effp) : SOX_SUCCESS;
47 }
48
start(sox_effect_t * effp)49 static int start(sox_effect_t * effp)
50 {
51 priv_t * p = (priv_t *)effp->priv;
52 dft_filter_t * f = p->base.filter_ptr;
53 double d;
54 char c;
55 int i;
56
57 if (!f->num_taps) {
58 if (!p->n && p->filename) {
59 FILE * file = lsx_open_input_file(effp, p->filename, sox_true);
60 if (!file)
61 return SOX_EOF;
62 while ((i = fscanf(file, " #%*[^\n]%c", &c)) >= 0) {
63 if (i >= 1) continue; /* found and skipped a comment */
64 if ((i = fscanf(file, "%lf", &d)) > 0) {
65 /* found a coefficient value */
66 p->n++;
67 p->h = lsx_realloc(p->h, p->n * sizeof(*p->h));
68 p->h[p->n - 1] = d;
69 } else break; /* either EOF, or something went wrong
70 (read or syntax error) */
71 }
72 if (!feof(file)) {
73 lsx_fail("error reading coefficient file");
74 if (file != stdin) fclose(file);
75 return SOX_EOF;
76 }
77 if (file != stdin) fclose(file);
78 }
79 lsx_report("%i coefficients", p->n);
80 if (!p->n)
81 return SOX_EFF_NULL;
82 if (effp->global_info->plot != sox_plot_off) {
83 char title[100];
84 sprintf(title, "SoX effect: fir (%d coefficients)", p->n);
85 lsx_plot_fir(p->h, p->n, effp->in_signal.rate,
86 effp->global_info->plot, title, -30., 30.);
87 free(p->h);
88 return SOX_EOF;
89 }
90 lsx_set_dft_filter(f, p->h, p->n, p->n >> 1);
91 }
92 return lsx_dft_filter_effect_fn()->start(effp);
93 }
94
lsx_fir_effect_fn(void)95 sox_effect_handler_t const * lsx_fir_effect_fn(void)
96 {
97 static sox_effect_handler_t handler;
98 handler = *lsx_dft_filter_effect_fn();
99 handler.name = "fir";
100 handler.usage = "[coef-file|coefs]";
101 handler.getopts = create;
102 handler.start = start;
103 handler.priv_size = sizeof(priv_t);
104 return &handler;
105 }
106