2 * The copyright in this software is being made available under the 2-clauses
3 * BSD License, included below. This software may be subject to other third
4 * party and contributor rights, including patent rights, and no such rights
5 * are granted under this license.
7 * Copyright (c) 2001-2003, David Janssens
8 * Copyright (c) 2002-2003, Yannick Verschueren
9 * Copyright (c) 2003-2005, Francois Devaux and Antonin Descampe
10 * Copyright (c) 2005, Herve Drolon, FreeImage Team
11 * Copyright (c) 2002-2005, Communications and remote sensing Laboratory, Universite catholique de Louvain, Belgium
12 * Copyright (c) 2005-2006, Dept. of Electronic and Information Engineering, Universita' degli Studi di Perugia, Italy
13 * All rights reserved.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34 * POSSIBILITY OF SUCH DAMAGE.
41 @brief Functions used to compute Reed-Solomon parity and check of byte arrays
48 /** Global definitions for Reed-Solomon encoder/decoder
49 * Phil Karn KA9Q, September 1996
51 * The parameters MM and KK specify the Reed-Solomon code parameters.
53 * Set MM to be the size of each code symbol in bits. The Reed-Solomon
54 * block size will then be NN = 2**M - 1 symbols. Supported values are
57 * Set KK to be the number of data symbols in each block, which must be
58 * less than the block size. The code will then be able to correct up
59 * to NN-KK erasures or (NN-KK)/2 errors, or combinations thereof with
60 * each error counting as two erasures.
62 #define MM 8 /* RS code over GF(2**MM) - change to suit */
64 /* KK defined in rs.c */
66 #define NN ((1 << MM) - 1)
69 typedef unsigned char dtype;
71 typedef unsigned int dtype;
74 /** Initialization function */
77 /** These two functions *must* be called in this order (e.g.,
78 * by init_rs()) before any encoding/decoding
80 void generate_gf(void); /* Generate Galois Field */
81 void gen_poly(void); /* Generate generator polynomial */
83 /** Reed-Solomon encoding
84 * data[] is the input block, parity symbols are placed in bb[]
85 * bb[] may lie past the end of the data, e.g., for (255,223):
86 * encode_rs(&data[0],&data[223]);
88 int encode_rs(dtype data[], dtype bb[]);
90 /** Reed-Solomon erasures-and-errors decoding
91 * The received block goes into data[], and a list of zero-origin
92 * erasure positions, if any, goes in eras_pos[] with a count in no_eras.
94 * The decoder corrects the symbols in place, if possible and returns
95 * the number of corrected symbols. If the codeword is illegal or
96 * uncorrectible, the data array is unchanged and -1 is returned
98 int eras_dec_rs(dtype data[], int eras_pos[], int no_eras);
101 Computes the minimum between two integers
102 @param a first integer to compare
103 @param b second integer to compare
104 @return returns the minimum integer between a and b
107 #define min(a,b) (((a) < (b)) ? (a) : (b))
110 #endif /* __RS_HEADER__ */
113 #endif /* USE_JPWL */