1 /* libSoX effect: divide 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 /* This is W.I.P. hence marked SOX_EFF_ALPHA for now.
19 * Needs better handling of when the divisor approaches or is zero; some
20 * sort of interpolation of the output values perhaps.
21 */
22
23 #include "sox_i.h"
24 #include <string.h>
25
26 typedef struct {
27 sox_sample_t * last;
28 } priv_t;
29
start(sox_effect_t * effp)30 static int start(sox_effect_t * effp)
31 {
32 priv_t * p = (priv_t *)effp->priv;
33 p->last = lsx_calloc(effp->in_signal.channels, sizeof(*p->last));
34 return SOX_SUCCESS;
35 }
36
flow(sox_effect_t * effp,const sox_sample_t * ibuf,sox_sample_t * obuf,size_t * isamp,size_t * osamp)37 static int flow(sox_effect_t * effp, const sox_sample_t * ibuf,
38 sox_sample_t * obuf, size_t * isamp, size_t * osamp)
39 {
40 priv_t * p = (priv_t *)effp->priv;
41 size_t i, len = min(*isamp, *osamp) / effp->in_signal.channels;
42 *osamp = *isamp = len * effp->in_signal.channels;
43
44 while (len--) {
45 double divisor = *obuf++ = *ibuf++;
46 if (divisor) {
47 double out, mult = 1. / SOX_SAMPLE_TO_FLOAT_64BIT(divisor,);
48 for (i = 1; i < effp->in_signal.channels; ++i) {
49 out = *ibuf++ * mult;
50 p->last[i] = *obuf++ = SOX_ROUND_CLIP_COUNT(out, effp->clips);
51 }
52 }
53 else for (i = 1; i < effp->in_signal.channels; ++i, ++ibuf)
54 *obuf++ = p->last[i];
55 }
56 return SOX_SUCCESS;
57 }
58
stop(sox_effect_t * effp)59 static int stop(sox_effect_t * effp)
60 {
61 priv_t * p = (priv_t *)effp->priv;
62 free(p->last);
63 return SOX_SUCCESS;
64 }
65
lsx_divide_effect_fn(void)66 sox_effect_handler_t const * lsx_divide_effect_fn(void)
67 {
68 static sox_effect_handler_t handler = {
69 "divide", NULL, SOX_EFF_MCHAN | SOX_EFF_GAIN | SOX_EFF_ALPHA,
70 NULL, start, flow, NULL, stop, NULL, sizeof(priv_t)
71 };
72 return &handler;
73 }
74