in preparation for de-pluginising h223, move golay code support into libwireshark

svn path=/trunk/; revision=22603

1 files changed, 49 insertions, 0 deletions

diff --git a/epan/golay.h b/epan/golay.h
new file mode 100644
index 0000000000..1a6e7994a8
--- /dev/null
+++ b/epan/golay.h
@@ -0,0 +1,49 @@
+/* $Id$
+ *
+ * Provides routines for encoding and decoding the extended Golay
+ * (24,12,8) code.
+ *
+ * This implementation will detect up to 4 errors in a codeword (without
+ * being able to correct them); it will correct up to 3 errors.
+ *
+ * We use guint32s to hold the 24-bit codewords, with the data part in
+ * the bottom 12 bits and the parity in bits 12-23.
+ *
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+#ifndef __GOLAY_H__
+#define __GOLAY_H__
+
+/* encodes a 12-bit word to a 24-bit codeword
+ */
+guint32 golay_encode(guint w);
+
+/* return a mask showing the bits which are in error in a received
+ * 24-bit codeword, or -1 if 4 errors were detected.
+ */
+gint32 golay_errors(guint32 codeword);
+
+/* decode a received codeword. Up to 3 errors are corrected for; 4
+   errors are detected as uncorrectable (return -1); 5 or more errors
+   cause an incorrect correction.
+*/
+gint golay_decode(guint32 w);
+
+#endif