1 /** \file fec.h  \brief Forward error correction based on Vandermonde matrices
2  *  <br>980624<br> (C) 1997-98 Luigi Rizzo (luigi@iet.unipi.it)
3  *
4  *  $Author: peltotal $ $Date: 2006/11/07 19:36:19 $ $Revision: 1.11 $
5  *
6  *  Portions derived from code by Phil Karn (karn@ka9q.ampr.org),
7  *  Robert Morelos-Zaragoza (robert@spectra.eng.hawaii.edu) and Hari
8  *  Thirumoorthy (harit@spectra.eng.hawaii.edu), Aug 1995
9  *
10  *  Redistribution and use in source and binary forms, with or without
11  *  modification, are permitted provided that the following conditions
12  *  are met:
13  *
14  *  1. Redistributions of source code must retain the above copyright
15  *     notice, this list of conditions and the following disclaimer.
16  *  2. Redistributions in binary form must reproduce the above
17  *     copyright notice, this list of conditions and the following
18  *     disclaimer in the documentation and/or other materials
19  *     provided with the distribution.
20  *
21  *  THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND
22  *  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
23  *  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
24  *  PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS
25  *  BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
26  *  OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
27  *  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
28  *  OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
30  *  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  *  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
32  *  OF SUCH DAMAGE.
33  */
34 
35 /*
36  * The following parameter defines how many bits are used for
37  * field elements. The code supports any value from 2 to 16
38  * but fastest operation is achieved with 8 bit elements.
39  */
40 
41 #define GF_BITS  8      /* code over GF(2^^GF_BITS) - change to suit */
42 #define GF_SIZE ((1 << GF_BITS) - 1)    /* powers of \alpha */
43 
44 extern void fec_free(void *p) ;
45 extern void* fec_new(int k, int n) ;
46 
47 extern void init_fec(void) ;
48 extern void fec_encode(void *code, void **src, void *dst, int index, int sz) ;
49 extern int  fec_decode(void *code, void **pkt, int index[], int sz) ;
50