/* reedsolomon.h
*
* Global definitions for Reed-Solomon encoder/decoder,
* by Phil Karn (karn@ka9q.ampr.org) September 1996
* Copyright 1999 Phil Karn, KA9Q
*
* Wireshark - Network traffic analyzer
* By Gerald Combs
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifdef __cplusplus
extern "C" {
#endif
/* Set one of these to enable encoder/decoder debugging and error checking,
* at the expense of speed */
/* #undef DEBUG 1*/
/* #undef DEBUG 2*/
#undef DEBUG
/* To select the CCSDS standard (255,223) code, define CCSDS. This
* implies standard values for MM, KK, B0 and PRIM.
*/
/* #undef CCSDS 1*/
#undef CCSDS
#ifndef CCSDS
/* Otherwise, leave CCSDS undefined and set the parameters below:
*
* Set MM to be the size of each code symbol in bits. The Reed-Solomon
* block size will then be NN = 2**M - 1 symbols. Supported values are
* defined in rs.c.
*/
#define MM 8 /* Symbol size in bits */
/*
* Set KK to be the number of data symbols in each block, which must be
* less than the block size. The code will then be able to correct up
* to NN-KK erasures or (NN-KK)/2 errors, or combinations thereof with
* each error counting as two erasures.
*/
#define KK 207 /* Number of data symbols per block */
/* Set B0 to the first root of the generator polynomial, in alpha form, and
* set PRIM to the power of alpha used to generate the roots of the
* generator polynomial. The generator polynomial will then be
* @**PRIM*B0, @**PRIM*(B0+1), @**PRIM*(B0+2)...@**PRIM*(B0+NN-KK)
* where "@" represents a lower case alpha.
*/
#define B0 1 /* First root of generator polynomial, alpha form */
#define PRIM 1 /* power of alpha used to generate roots of generator poly */
#define STANDARD_ORDER
/* If you want to select your own field generator polynomial, you'll have
* to edit that in rs.c.
*/
#else /* CCSDS */
/* Don't change these, they're CCSDS standard */
#define MM 8
#define KK 223
#define B0 112
#define PRIM 11
#endif
#define NN ((1 << MM) - 1)
#if MM <= 8
typedef unsigned char dtype;
#else
typedef unsigned int dtype;
#endif
/* Reed-Solomon encoding
* data[] is the input block, parity symbols are placed in bb[]
* bb[] may lie past the end of the data, e.g., for (255,223):
* encode_rs(&data[0],&data[223]);
*/
int encode_rs(dtype data[], dtype bb[]);
/* Reed-Solomon erasures-and-errors decoding
* The received block goes into data[], and a list of zero-origin
* erasure positions, if any, goes in eras_pos[] with a count in no_eras.
*
* The decoder corrects the symbols in place, if possible and returns
* the number of corrected symbols. If the codeword is illegal or
* uncorrectible, the data array is unchanged and -1 is returned
*/
int eras_dec_rs(dtype data[], int eras_pos[], int no_eras);
#ifdef __cplusplus
}
#endif