101 lines
3.8 KiB
C
101 lines
3.8 KiB
C
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/*
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* Copyright (c) 2001-2003, David Janssens
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* Copyright (c) 2002-2003, Yannick Verschueren
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* Copyright (c) 2003-2005, Francois Devaux and Antonin Descampe
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* Copyright (c) 2005, Herv<EFBFBD> Drolon, FreeImage Team
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* Copyright (c) 2002-2005, Communications and remote sensing Laboratory, Universite catholique de Louvain, Belgium
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* Copyright (c) 2005-2006, Dept. of Electronic and Information Engineering, Universita' degli Studi di Perugia, Italy
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifdef USE_JPWL
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/**
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@file rs.h
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@brief Functions used to compute Reed-Solomon parity and check of byte arrays
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*/
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#ifndef __RS_HEADER__
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#define __RS_HEADER__
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/** Global definitions for Reed-Solomon encoder/decoder
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* Phil Karn KA9Q, September 1996
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*
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* The parameters MM and KK specify the Reed-Solomon code parameters.
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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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* 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 MM 8 /* RS code over GF(2**MM) - change to suit */
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static int KK;
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/* Original code */
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/*#define KK 239*/ /* KK = number of information symbols */
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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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/** Initialization function */
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void init_rs(int);
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/** These two functions *must* be called in this order (e.g.,
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* by init_rs()) before any encoding/decoding
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*/
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void generate_gf(void); /* Generate Galois Field */
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void gen_poly(void); /* Generate generator polynomial */
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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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#endif /* __CRC32_HEADER__ */
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#endif /* USE_JPWL */
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