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99 lines
2.9 KiB
C
99 lines
2.9 KiB
C
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/* Reed Solomon Coding for glyphs
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* Copyright Henry Minsky (hqm@alum.mit.edu) 1991-2009
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*
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* This software library is licensed under terms of the GNU GENERAL
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* PUBLIC LICENSE
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*
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* RSCODE is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* RSCODE is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Rscode. If not, see <http://www.gnu.org/licenses/>.
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*
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* Source code is available at http://rscode.sourceforge.net
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*
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* Commercial licensing is available under a separate license, please
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* contact author for details.
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*
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*/
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/****************************************************************
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Below is NPAR, the only compile-time parameter you should have to
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modify.
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It is the number of parity bytes which will be appended to
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your data to create a codeword.
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Note that the maximum codeword size is 255, so the
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sum of your message length plus parity should be less than
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or equal to this maximum limit.
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In practice, you will get slooow error correction and decoding
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if you use more than a reasonably small number of parity bytes.
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(say, 10 or 20)
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****************************************************************/
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/****************************************************************/
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#include <openpilot.h>
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#define TRUE 1
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#define FALSE 0
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typedef unsigned long BIT32;
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typedef unsigned short BIT16;
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/* **************************************************************** */
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/* Maximum degree of various polynomials. */
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#define MAXDEG (RS_ECC_NPARITY*2)
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/*************************************/
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/* Encoder parity bytes */
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extern int pBytes[MAXDEG];
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/* Decoder syndrome bytes */
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extern int synBytes[MAXDEG];
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/* print debugging info */
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extern int DEBUG;
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/* Reed Solomon encode/decode routines */
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void initialize_ecc (void);
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int check_syndrome (void);
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void decode_data (unsigned char data[], int nbytes);
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void encode_data (unsigned char msg[], int nbytes, unsigned char dst[]);
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/* CRC-CCITT checksum generator */
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BIT16 crc_ccitt(unsigned char *msg, int len);
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/* galois arithmetic tables */
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extern const int gexp[];
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extern const int glog[];
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void init_galois_tables (void);
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int ginv(int elt);
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int gmult(int a, int b);
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/* Error location routines */
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int correct_errors_erasures (unsigned char codeword[], int csize,int nerasures, int erasures[]);
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/* polynomial arithmetic */
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void add_polys(int dst[], int src[]) ;
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void scale_poly(int k, int poly[]);
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void mult_polys(int dst[], int p1[], int p2[]);
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void copy_poly(int dst[], int src[]);
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void zero_poly(int poly[]);
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