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Diffstat (limited to 'libtransport/src/core/fec.h')
| -rw-r--r-- | libtransport/src/core/fec.h | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/libtransport/src/core/fec.h b/libtransport/src/core/fec.h new file mode 100644 index 000000000..8234057a7 --- /dev/null +++ b/libtransport/src/core/fec.h @@ -0,0 +1,65 @@ +/* + * 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 */ |