1 /* Include file to configure the RS codec for integer symbols
2 *
3 * Copyright 2002, Phil Karn, KA9Q
4 * May be used under the terms of the GNU General Public License (GPL)
5 */
6 #define DTYPE int
7
8 /* Reed-Solomon codec control block */
9 struct rs {
10 int mm; /* Bits per symbol */
11 int nn; /* Symbols per block (= (1<<mm)-1) */
12 DTYPE *alpha_to; /* log lookup table */
13 DTYPE *index_of; /* Antilog lookup table */
14 DTYPE *genpoly; /* Generator polynomial */
15 int nroots; /* Number of generator roots = number of parity symbols */
16 int fcr; /* First consecutive root, index form */
17 int prim; /* Primitive element, index form */
18 int iprim; /* prim-th root of 1, index form */
19 int pad; /* Padding bytes in shortened block */
20 };
21
modnn(struct rs * rs,int x)22 static inline int modnn(struct rs *rs,int x){
23 while (x >= rs->nn) {
24 x -= rs->nn;
25 x = (x >> rs->mm) + (x & rs->nn);
26 }
27 return x;
28 }
29 #define MODNN(x) modnn(rs,x)
30
31 #define MM (rs->mm)
32 #define NN (rs->nn)
33 #define ALPHA_TO (rs->alpha_to)
34 #define INDEX_OF (rs->index_of)
35 #define GENPOLY (rs->genpoly)
36 #define NROOTS (rs->nroots)
37 #define FCR (rs->fcr)
38 #define PRIM (rs->prim)
39 #define IPRIM (rs->iprim)
40 #define PAD (rs->pad)
41 #define A0 (NN)
42
43 #define ENCODE_RS encode_rs_int
44 #define DECODE_RS decode_rs_int
45 #define INIT_RS init_rs_int
46 #define FREE_RS free_rs_int
47
48 void ENCODE_RS(void *p,DTYPE *data,DTYPE *parity);
49 int DECODE_RS(void *p,DTYPE *data,int *eras_pos,int no_eras);
50 void *INIT_RS(int symsize,int gfpoly,int fcr,
51 int prim,int nroots,int pad);
52 void FREE_RS(void *p);
53
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57