mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2025-10-25 01:50:30 -04:00
48 lines
1.1 KiB
C
48 lines
1.1 KiB
C
|
/* Reed-Solomon encoder
|
||
|
|
* Copyright 2002, Phil Karn, KA9Q
|
||
|
|
* May be used under the terms of the GNU General Public License (GPL)
|
||
|
|
*/
|
||
|
|
#include <string.h>
|
||
|
|
|
||
|
|
#ifdef FIXED
|
||
|
|
#include "fixed.h"
|
||
|
|
#elif defined(BIGSYM)
|
||
|
|
#include "int.h"
|
||
|
|
#else
|
||
|
|
#include "char.h"
|
||
|
|
#endif
|
||
|
|
|
||
|
|
void ENCODE_RS(
|
||
|
|
#ifndef FIXED
|
||
|
|
void *p,
|
||
|
|
#endif
|
||
|
|
DTYPE *data, DTYPE *bb){
|
||
|
|
#ifndef FIXED
|
||
|
|
struct rs *rs = (struct rs *)p;
|
||
|
|
#endif
|
||
|
|
int i, j;
|
||
|
|
DTYPE feedback;
|
||
|
|
|
||
|
|
memset(bb,0,NROOTS*sizeof(DTYPE));
|
||
|
|
|
||
|
|
for(i=0;i<NN-NROOTS;i++){
|
||
|
|
feedback = INDEX_OF[data[i] ^ bb[0]];
|
||
|
|
if(feedback != A0){ /* feedback term is non-zero */
|
||
|
|
#ifdef UNNORMALIZED
|
||
|
|
/* This line is unnecessary when GENPOLY[NROOTS] is unity, as it must
|
||
|
|
* always be for the polynomials constructed by init_rs()
|
||
|
|
*/
|
||
|
|
feedback = MODNN(NN - GENPOLY[NROOTS] + feedback);
|
||
|
|
#endif
|
||
|
|
for(j=1;j<NROOTS;j++)
|
||
|
|
bb[j] ^= ALPHA_TO[MODNN(feedback + GENPOLY[NROOTS-j])];
|
||
|
|
}
|
||
|
|
/* Shift */
|
||
|
|
memmove(&bb[0],&bb[1],sizeof(DTYPE)*(NROOTS-1));
|
||
|
|
if(feedback != A0)
|
||
|
|
bb[NROOTS-1] = ALPHA_TO[MODNN(feedback + GENPOLY[0])];
|
||
|
|
else
|
||
|
|
bb[NROOTS-1] = 0;
|
||
|
|
}
|
||
|
|
}
|