src/repeat.c

   1 /* libSoX repeat effect  Copyright (c) 2004 Jan Paul Schmidt <jps@fundament.org>
   2  * Re-write (c) 2008 robs@users.sourceforge.net
   3  *
   4  * This library is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU Lesser General Public License as published by
   6  * the Free Software Foundation; either version 2.1 of the License, or (at
   7  * your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public License
  15  * along with this library; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18
  19 #include "sox_i.h"
  20
  21 typedef struct {
  22   unsigned      num_repeats, remaining_repeats;
  23   uint64_t      num_samples, remaining_samples;
  24   FILE          * tmp_file;
  25 } priv_t;
  26
  27 static int create(sox_effect_t * effp, int argc, char * * argv)
  28 {
  29   priv_t * p = (priv_t *)effp->priv;
  30   p->num_repeats = 1;
  31   --argc, ++argv;
  32   if (argc == 1 && !strcmp(*argv, "-")) {
  33     p->num_repeats = UINT_MAX;
  34     return SOX_SUCCESS;
  35   }
  36   do {NUMERIC_PARAMETER(num_repeats, 0, UINT_MAX - 1)} while (0);
  37   return argc? lsx_usage(effp) : SOX_SUCCESS;
  38 }
  39
  40 static int start(sox_effect_t * effp)
  41 {
  42   priv_t * p = (priv_t *)effp->priv;
  43   if (!p->num_repeats)
  44     return SOX_EFF_NULL;
  45
  46   if (!(p->tmp_file = lsx_tmpfile())) {
  47     lsx_fail("can't create temporary file: %s", strerror(errno));
  48     return SOX_EOF;
  49   }
  50   p->num_samples = p->remaining_samples = 0;
  51   p->remaining_repeats = p->num_repeats;
  52   if (effp->in_signal.length != SOX_UNKNOWN_LEN && p->num_repeats != UINT_MAX)
  53     effp->out_signal.length = effp->in_signal.length * (p->num_repeats + 1);
  54   else
  55     effp->out_signal.length = SOX_UNKNOWN_LEN;
  56
  57   return SOX_SUCCESS;
  58 }
  59
  60 static int flow(sox_effect_t * effp, const sox_sample_t * ibuf,
  61     sox_sample_t * obuf, size_t * isamp, size_t * osamp)
  62 {
  63   priv_t * p = (priv_t *)effp->priv;
  64   size_t len = min(*isamp, *osamp);
  65   memcpy(obuf, ibuf, len * sizeof(*obuf));
  66   if (fwrite(ibuf, sizeof(*ibuf), len, p->tmp_file) != len) {
  67     lsx_fail("error writing temporary file: %s", strerror(errno));
  68     return SOX_EOF;
  69   }
  70   p->num_samples += len;
  71   *isamp = *osamp = len;
  72   return SOX_SUCCESS;
  73 }
  74
  75 static int drain(sox_effect_t * effp, sox_sample_t * obuf, size_t * osamp)
  76 {
  77   priv_t * p = (priv_t *)effp->priv;
  78   size_t odone = 0, n;
  79
  80   *osamp -= *osamp % effp->in_signal.channels;
  81
  82   while ((p->remaining_samples || p->remaining_repeats) && odone < *osamp) {
  83     if (!p->remaining_samples) {
  84       p->remaining_samples = p->num_samples;
  85       if (p->remaining_repeats != UINT_MAX)
  86         --p->remaining_repeats;
  87       rewind(p->tmp_file);
  88     }
  89     n = min(p->remaining_samples, *osamp - odone);
  90     if ((fread(obuf + odone, sizeof(*obuf), n, p->tmp_file)) != n) {
  91       lsx_fail("error reading temporary file: %s", strerror(errno));
  92       return SOX_EOF;
  93     }
  94     p->remaining_samples -= n;
  95     odone += n;
  96   }
  97   *osamp = odone;
  98   return p->remaining_samples || p->remaining_repeats? SOX_SUCCESS : SOX_EOF;
  99 }
 100
 101 static int stop(sox_effect_t * effp)
 102 {
 103   priv_t * p = (priv_t *)effp->priv;
 104   fclose(p->tmp_file); /* auto-deleted by lsx_tmpfile */
 105   return SOX_SUCCESS;
 106 }
 107
 108 sox_effect_handler_t const * lsx_repeat_effect_fn(void)
 109 {
 110   static sox_effect_handler_t effect = {"repeat", "[count (1)]",
 111     SOX_EFF_MCHAN | SOX_EFF_LENGTH | SOX_EFF_MODIFY,
 112     create, start, flow, drain, stop, NULL, sizeof(priv_t)};
 113   return &effect;
 114 }