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/*
* fec.c -- forward error correction based on Vandermonde matrices
* 980614
* (C) 1997-98 Luigi Rizzo (luigi@iet.unipi.it)
*
* Portions derived from code by Phil Karn (karn@ka9q.ampr.org),
* Robert Morelos-Zaragoza (robert@spectra.eng.hawaii.edu) and Hari
* Thirumoorthy (harit@spectra.eng.hawaii.edu), Aug 1995
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
* TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*/
/*
* The following parameter defines how many bits are used for
* field elements. The code supports any value from 2 to 16
* but fastest operation is achieved with 8 bit elements
* This is the only parameter you may want to change.
*/
#ifndef GF_BITS
#define GF_BITS 8 /* code over GF(2**GF_BITS) - change to suit */
#endif
#if (GF_BITS <= 8)
typedef unsigned char gf;
#else
typedef unsigned short gf;
#endif
#define GF_SIZE ((1 << GF_BITS) - 1) /* powers of \alpha */
struct fec_parms {
unsigned long magic ;
int k, n ; /* parameters of the code */
gf *enc_matrix ;
};
void fec_free(struct fec_parms *p) ;
struct fec_parms *fec_new(int k, int n) ;
void fec_encode(struct fec_parms *code, gf *src[], gf *fec, int index, int sz);
int fec_decode(struct fec_parms *code, gf *pkt[], int index[], int sz);
/* end of file */
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