epan/golay.h

   1 /* $Id$
   2  *
   3  * Provides routines for encoding and decoding the extended Golay
   4  * (24,12,8) code.
   5  *
   6  * This implementation will detect up to 4 errors in a codeword (without
   7  * being able to correct them); it will correct up to 3 errors.
   8  *
   9  * We use guint32s to hold the 24-bit codewords, with the data part in
  10  * the bottom 12 bits and the parity in bits 12-23.
  11  *
  12  *
  13  * Wireshark - Network traffic analyzer
  14  * By Gerald Combs <gerald@wireshark.org>
  15  * Copyright 1998 Gerald Combs
  16  *
  17  * This program is free software; you can redistribute it and/or
  18  * modify it under the terms of the GNU General Public License
  19  * as published by the Free Software Foundation; either version 2
  20  * of the License, or (at your option) any later version.
  21  *
  22  * This program is distributed in the hope that it will be useful,
  23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  * GNU General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License
  28  * along with this program; if not, write to the Free Software
  29  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  30  */
  31 #ifndef __GOLAY_H__
  32 #define __GOLAY_H__
  33
  34 #include "ws_symbol_export.h"
  35
  36 /* encodes a 12-bit word to a 24-bit codeword
  37  */
  38 WS_DLL_PUBLIC
  39 guint32 golay_encode(guint w);
  40
  41 /* return a mask showing the bits which are in error in a received
  42  * 24-bit codeword, or -1 if 4 errors were detected.
  43  */
  44 WS_DLL_PUBLIC
  45 gint32 golay_errors(guint32 codeword);
  46
  47 /* decode a received codeword. Up to 3 errors are corrected for; 4
  48    errors are detected as uncorrectable (return -1); 5 or more errors
  49    cause an incorrect correction.
  50 */
  51 WS_DLL_PUBLIC
  52 gint golay_decode(guint32 w);
  53
  54 #endif