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   off_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   do {NUMERIC_PARAMETER(num_repeats, 0, UINT_MAX - 1)} while (0);
  33   return argc? lsx_usage(effp) : SOX_SUCCESS;
  34 }
  35
  36 static int start(sox_effect_t * effp)
  37 {
  38   priv_t * p = (priv_t *)effp->priv;
  39   if (!p->num_repeats)
  40     return SOX_EFF_NULL;
  41
  42   if (!(p->tmp_file = lsx_tmpfile())) {
  43     lsx_fail("can't create temporary file: %s", strerror(errno));
  44     return SOX_EOF;
  45   }
  46   p->num_samples = p->remaining_samples = 0;
  47   p->remaining_repeats = p->num_repeats + 1;
  48   return SOX_SUCCESS;
  49 }
  50
  51 static int flow(sox_effect_t * effp, const sox_sample_t * ibuf,
  52     sox_sample_t * obuf, size_t * isamp, size_t * osamp)
  53 {
  54   priv_t * p = (priv_t *)effp->priv;
  55   if (fwrite(ibuf, sizeof(*ibuf), *isamp, p->tmp_file) != *isamp) {
  56     lsx_fail("error writing temporary file: %s", strerror(errno));
  57     return SOX_EOF;
  58   }
  59   p->num_samples += *isamp;
  60   (void)obuf, *osamp = 0; /* samples not output until drain */
  61   return SOX_SUCCESS;
  62 }
  63
  64 static int drain(sox_effect_t * effp, sox_sample_t * obuf, size_t * osamp)
  65 {
  66   priv_t * p = (priv_t *)effp->priv;
  67   size_t odone = 0, n;
  68
  69   while ((p->remaining_samples || p->remaining_repeats) && odone < *osamp) {
  70     if (!p->remaining_samples) {
  71       p->remaining_samples = p->num_samples;
  72       --p->remaining_repeats;
  73       rewind(p->tmp_file);
  74     }
  75     n = min(p->remaining_samples, (off_t)(*osamp - odone));
  76     if ((fread(obuf + odone, sizeof(*obuf), n, p->tmp_file)) != n) {
  77       lsx_fail("error reading temporary file: %s", strerror(errno));
  78       return SOX_EOF;
  79     }
  80     p->remaining_samples -= n;
  81     odone += n;
  82   }
  83   *osamp = odone;
  84   return p->remaining_samples || p->remaining_repeats? SOX_SUCCESS : SOX_EOF;
  85 }
  86
  87 static int stop(sox_effect_t * effp)
  88 {
  89   priv_t * p = (priv_t *)effp->priv;
  90   fclose(p->tmp_file); /* auto-deleted by lsx_tmpfile */
  91   return SOX_SUCCESS;
  92 }
  93
  94 sox_effect_handler_t const * lsx_repeat_effect_fn(void)
  95 {
  96   static sox_effect_handler_t effect = {"repeat", "[count]",
  97     SOX_EFF_MCHAN | SOX_EFF_LENGTH | SOX_EFF_MODIFY,
  98     create, start, flow, drain, stop, NULL, sizeof(priv_t)};
  99   return &effect;
 100 }