src/input.c

   1 /* libSoX effect: Input audio from a file   (c) 2008 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 #include "sox_i.h"
  19
  20 typedef struct {sox_format_t * file;} priv_t;
  21
  22 static int getopts(sox_effect_t * effp, int argc, char * * argv)
  23 {
  24   priv_t * p = (priv_t *)effp->priv;
  25   if (argc != 2 || !(p->file = (sox_format_t *)argv[1]) || p->file->mode != 'r')
  26     return SOX_EOF;
  27   return SOX_SUCCESS;
  28 }
  29
  30 static int drain(
  31     sox_effect_t * effp, sox_sample_t * obuf, size_t * osamp)
  32 {
  33   priv_t * p = (priv_t *)effp->priv;
  34
  35   /* ensure that *osamp is a multiple of the number of channels. */
  36   *osamp -= *osamp % effp->out_signal.channels;
  37
  38   /* Read up to *osamp samples into obuf; store the actual number read
  39    * back to *osamp */
  40   *osamp = sox_read(p->file, obuf, *osamp);
  41
  42   /* sox_read may return a number that is less than was requested; only if
  43    * 0 samples is returned does it indicate that end-of-file has been reached
  44    * or an error has occurred */
  45   if (!*osamp && p->file->sox_errno)
  46     lsx_fail("%s: %s", p->file->filename, p->file->sox_errstr);
  47   return *osamp? SOX_SUCCESS : SOX_EOF;
  48 }
  49
  50 sox_effect_handler_t const * lsx_input_effect_fn(void)
  51 {
  52   static sox_effect_handler_t handler = {
  53     "input", NULL, SOX_EFF_MCHAN | SOX_EFF_LENGTH | SOX_EFF_INTERNAL,
  54     getopts, NULL, NULL, drain, NULL, NULL, sizeof(priv_t)
  55   };
  56   return &handler;
  57 }
  58