src/sounder.c

   1 /* libSoX Sounder format handler          (c) 2008 robs@users.sourceforge.net
   2  * See description in soundr3b.zip on the 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 static int start_read(sox_format_t * ft)
  22 {
  23   uint16_t type, rate;
  24
  25   if (lsx_readw(ft, &type) || lsx_readw(ft, &rate) || lsx_skipbytes(ft, (size_t) 4))
  26     return SOX_EOF;
  27   if (type) {
  28     lsx_fail_errno(ft, SOX_EHDR, "invalid Sounder header");
  29     return SOX_EOF;
  30   }
  31   return lsx_check_read_params(ft, 1, (sox_rate_t)rate, SOX_ENCODING_UNSIGNED, 8, (uint64_t)0, sox_true);
  32 }
  33
  34 static int write_header(sox_format_t * ft)
  35 {
  36   return lsx_writew(ft, 0)   /* sample type */
  37       || lsx_writew(ft, min(65535, (unsigned)(ft->signal.rate + .5)))
  38       || lsx_writew(ft, 10)  /* speaker driver volume */
  39       || lsx_writew(ft, 4)?  /* speaker driver DC shift */
  40       SOX_EOF : SOX_SUCCESS;
  41 }
  42
  43 LSX_FORMAT_HANDLER(sounder)
  44 {
  45   static char const * const names[] = {"sndr", NULL};
  46   static unsigned const write_encodings[] = {SOX_ENCODING_UNSIGNED, 8, 0, 0};
  47   static sox_format_handler_t const handler = {SOX_LIB_VERSION_CODE,
  48     "8-bit linear audio as used by Aaron Wallace's `Sounder' of 1991",
  49     names, SOX_FILE_LIT_END | SOX_FILE_MONO,
  50     start_read, lsx_rawread, NULL,
  51     write_header, lsx_rawwrite, NULL,
  52     lsx_rawseek, write_encodings, NULL, 0
  53   };
  54   return &handler;
  55 }