forked from osmocom/wireshark
97 lines
2.8 KiB
C
97 lines
2.8 KiB
C
/** @file
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*
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* Global definitions for Reed-Solomon encoder/decoder,
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* by Phil Karn (karn@ka9q.ampr.org) September 1996
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* Copyright 1999 Phil Karn, KA9Q
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Set one of these to enable encoder/decoder debugging and error checking,
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* at the expense of speed */
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/* #undef DEBUG 1*/
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/* #undef DEBUG 2*/
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#undef DEBUG
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/* To select the CCSDS standard (255,223) code, define CCSDS. This
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* implies standard values for MM, KK, B0 and PRIM.
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*/
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/* #undef CCSDS 1*/
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#undef CCSDS
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#ifndef CCSDS
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/* Otherwise, leave CCSDS undefined and set the parameters below:
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*
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* Set MM to be the size of each code symbol in bits. The Reed-Solomon
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* block size will then be NN = 2**M - 1 symbols. Supported values are
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* defined in rs.c.
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*/
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#define MM 8 /* Symbol size in bits */
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/*
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* Set KK to be the number of data symbols in each block, which must be
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* less than the block size. The code will then be able to correct up
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* to NN-KK erasures or (NN-KK)/2 errors, or combinations thereof with
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* each error counting as two erasures.
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*/
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#define KK 207 /* Number of data symbols per block */
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/* Set B0 to the first root of the generator polynomial, in alpha form, and
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* set PRIM to the power of alpha used to generate the roots of the
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* generator polynomial. The generator polynomial will then be
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* @**PRIM*B0, @**PRIM*(B0+1), @**PRIM*(B0+2)...@**PRIM*(B0+NN-KK)
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* where "@" represents a lower case alpha.
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*/
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#define B0 1 /* First root of generator polynomial, alpha form */
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#define PRIM 1 /* power of alpha used to generate roots of generator poly */
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#define STANDARD_ORDER
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/* If you want to select your own field generator polynomial, you'll have
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* to edit that in rs.c.
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*/
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#else /* CCSDS */
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/* Don't change these, they're CCSDS standard */
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#define MM 8
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#define KK 223
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#define B0 112
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#define PRIM 11
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#endif
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#define NN ((1 << MM) - 1)
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#if MM <= 8
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typedef unsigned char dtype;
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#else
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typedef unsigned int dtype;
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#endif
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/* Reed-Solomon encoding
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* data[] is the input block, parity symbols are placed in bb[]
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* bb[] may lie past the end of the data, e.g., for (255,223):
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* encode_rs(&data[0],&data[223]);
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*/
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int encode_rs(dtype data[], dtype bb[]);
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/* Reed-Solomon erasures-and-errors decoding
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* The received block goes into data[], and a list of zero-origin
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* erasure positions, if any, goes in eras_pos[] with a count in no_eras.
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*
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* The decoder corrects the symbols in place, if possible and returns
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* the number of corrected symbols. If the codeword is illegal or
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* uncorrectible, the data array is unchanged and -1 is returned
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*/
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int eras_dec_rs(dtype data[], int eras_pos[], int no_eras);
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#ifdef __cplusplus
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}
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#endif
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