ref: 2c1b8ba27e95fcd918b5fc2bbbc0720c7b0ec6e6
dir: /src/crop.c/
/* libSoX effect: Crop ends of audio (c) 2009 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
*/
/* This is W.I.P. hence marked SOX_EFF_ALPHA for now.
* Need to change size_t/INT32_MAX to uint64_t/INT64_MAX (for LFS) and do
* proper length change tracking through the effects chain.
*/
#include "sox_i.h"
#include <string.h>
typedef struct {
int argc;
struct {int flag; char * str; size_t at;} pos[2];
} priv_t;
static int parse(sox_effect_t * effp, char * * argv, sox_rate_t rate)
{
priv_t * p = (priv_t *)effp->priv;
char const * s, * q;
int i;
for (i = p->argc - 1; i == 0 || i == 1; --i) {
if (argv) /* 1st parse only */
p->pos[i].str = lsx_strdup(argv[i]);
s = p->pos[i].str;
if (strchr("+-" + 1 - i, *s))
p->pos[i].flag = *s++;
if (!(q = lsx_parsesamples(rate, s, &p->pos[i].at, 't')) || *q)
break;
}
return i >= 0 ? lsx_usage(effp) : SOX_SUCCESS;
}
static int create(sox_effect_t * effp, int argc, char * * argv)
{
priv_t * p = (priv_t *)effp->priv;
--argc, ++argv;
p->argc = argc;
return parse(effp, argv, 1e5); /* No rate yet; parse with dummy */
}
static int start(sox_effect_t * effp)
{
priv_t * p = (priv_t *)effp->priv;
int i;
p->pos[1].at = SIZE_MAX / 2 / effp->in_signal.channels;
parse(effp, 0, effp->in_signal.rate); /* Re-parse now rate is known */
for (i = 0; i < 2; ++i) {
p->pos[i].at *= effp->in_signal.channels;
if (p->pos[i].flag == '-') {
if (effp->in_signal.length == SOX_UNSPEC) {
lsx_fail("cannot crop from end: audio length is not known");
return SOX_EOF;
}
if (p->pos[i].at > effp->in_signal.length) {
lsx_fail("cannot crop that much from end: audio is too short");
return SOX_EOF;
}
p->pos[i].at = effp->in_signal.length - p->pos[i].at;
}
}
if (p->pos[1].flag != '+') {
if (p->pos[0].at > p->pos[1].at) {
lsx_fail("start position must be less than stop position");
return SOX_EOF;
}
if (!(p->pos[1].at -= p->pos[0].at))
p->pos[0].at = 0;
}
if (effp->in_signal.length) {
if (!p->pos[0].at && p->pos[1].at == effp->in_signal.length)
return SOX_EFF_NULL;
if (p->pos[0].at > effp->in_signal.length ||
(p->argc > 1 && p->pos[0].at + p->pos[1].at > effp->in_signal.length)) {
lsx_fail("audio is too short");
return SOX_EOF;
}
effp->out_signal.length = p->argc == 2 ?
p->pos[1].at : effp->in_signal.length - p->pos[0].at;
}
return SOX_SUCCESS;
}
static int flow(sox_effect_t * effp, sox_sample_t const * ibuf,
sox_sample_t * obuf, size_t * isamp, size_t * osamp)
{
priv_t * p = (priv_t *)effp->priv;
size_t skipped;
p->pos[0].at -= skipped = min(p->pos[0].at, *isamp);
*osamp = !p->pos[0].at * min(p->pos[1].at, min(*isamp - skipped, *osamp));
memcpy(obuf, ibuf + skipped, *osamp * sizeof(*obuf));
*isamp = skipped + *osamp;
return (p->pos[1].at -= *osamp) ? SOX_SUCCESS : SOX_EOF;
}
static int stop(sox_effect_t * effp)
{
priv_t * p = (priv_t *)effp->priv;
if (p->pos[0].at || (p->pos[1].at && p->argc == 2))
lsx_warn("input audio was too short to crop as requested");
return SOX_SUCCESS;
}
static int lsx_kill(sox_effect_t * effp)
{
priv_t * p = (priv_t *)effp->priv;
free(p->pos[0].str);
free(p->pos[1].str);
return SOX_SUCCESS;
}
sox_effect_handler_t const * lsx_crop_effect_fn(void)
{
static sox_effect_handler_t handler = {
"crop", "[-]before [[+|-]from]\n"
" n\tposition relative to start\n"
" -n\tposition relative to end\n"
" +n\tposition relative to previous",
SOX_EFF_MCHAN | /* SOX_EFF_LENGTH | */ SOX_EFF_MODIFY | SOX_EFF_ALPHA,
create, start, flow, NULL, stop, lsx_kill, sizeof(priv_t)
};
return &handler;
}
size_t sox_crop_get_start(sox_effect_t * effp)
{
return ((priv_t *)effp->priv)->pos[0].at;
}
void sox_crop_clear_start(sox_effect_t * effp)
{
((priv_t *)effp->priv)->pos[0].at = 0;
}
#if 0
/*---------------------- emulation of the `trim' effect ----------------------*/
static int trim_getopts(sox_effect_t * effp, int argc, char * * argv)
{
priv_t * p = (priv_t *)effp->priv;
p->pos[1].flag = '+';
return lsx_crop_effect_fn()->getopts(effp, argc, argv);
}
sox_effect_handler_t const * lsx_trim_effect_fn(void)
{
static sox_effect_handler_t handler;
handler = *lsx_crop_effect_fn();
handler.name = "trim";
handler.usage = "start [length]";
handler.getopts = trim_getopts;
return &handler;
}
#endif