ref: 7793ebb29dc92e5ec10a4dc0deb51d6aa56eb9eb
parent: 1f8700d449e910419120189b496b5f1ed9b19341
author: robs <robs>
date: Thu Feb 12 15:30:20 EST 2009
crop effect; WIP
--- /dev/null
+++ b/src/crop.c
@@ -1,0 +1,140 @@
+/* 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_DEPRECATED for now.
+ * Need to change uint32_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 {sox_bool from_end; char * str; uint32_t at;} pos[2];+} priv_t;
+
+#if 0
+uint64_t sox_crop_get_start(sox_effect_t * effp)
+{+ priv_t * p = (priv_t *)effp->priv;
+ return p->pos[0].at;
+}
+
+void sox_crop_clear_start(sox_effect_t * effp)
+{+ priv_t * p = (priv_t *)effp->priv;
+ p->pos[0].at = 0;
+}
+#endif
+
+static int parse(sox_effect_t * effp, char * * argv, sox_rate_t rate)
+{+ priv_t * p = (priv_t *)effp->priv;
+ char const * s;
+ 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 (*s == '-') {+ p->pos[i].from_end = sox_true;
+ ++s;
+ }
+ if (!lsx_parsesamples(rate, s, &p->pos[i].at, 't'))
+ 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 = INT32_MAX;
+ 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].from_end) {+ 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[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;
+ return p->pos[0].at || p->pos[1].at != effp->in_signal.length ? SOX_SUCCESS : SOX_EFF_NULL;
+}
+
+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 too short to crop as requested");+ return SOX_SUCCESS;
+}
+
+static int 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]",
+ SOX_EFF_MCHAN | /* SOX_EFF_LENGTH | */ SOX_EFF_MODIFY | SOX_EFF_DEPRECATED,
+ create, start, flow, NULL, stop, kill, sizeof(priv_t)
+ };
+ return &handler;
+}
--- a/src/effects.h
+++ b/src/effects.h
@@ -24,6 +24,7 @@
EFFECT(chorus)
EFFECT(compand)
EFFECT(contrast)
+ EFFECT(crop)
EFFECT(dcshift)
EFFECT(deemph)
EFFECT(delay)