58 lines
1.6 KiB
C
58 lines
1.6 KiB
C
/* Include file to configure the RS codec for character symbols
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*
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* Copyright 2002, Phil Karn, KA9Q
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* May be used under the terms of the GNU General Public License (GPL)
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*/
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#define DTYPE unsigned char
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/* Reed-Solomon codec control block */
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struct rs {
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int mm; /* Bits per symbol */
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int nn; /* Symbols per block (= (1<<mm)-1) */
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DTYPE *alpha_to; /* log lookup table */
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DTYPE *index_of; /* Antilog lookup table */
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DTYPE *genpoly; /* Generator polynomial */
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int nroots; /* Number of generator roots = number of parity symbols */
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int fcr; /* First consecutive root, index form */
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int prim; /* Primitive element, index form */
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int iprim; /* prim-th root of 1, index form */
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int pad; /* Padding bytes in shortened block */
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};
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static inline int modnn(struct rs *rs,int x){
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while (x >= rs->nn) {
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x -= rs->nn;
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x = (x >> rs->mm) + (x & rs->nn);
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}
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return x;
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}
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#define MODNN(x) modnn(rs,x)
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#define MM (rs->mm)
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#define NN (rs->nn)
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#define ALPHA_TO (rs->alpha_to)
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#define INDEX_OF (rs->index_of)
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#define GENPOLY (rs->genpoly)
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#define NROOTS (rs->nroots)
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#define FCR (rs->fcr)
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#define PRIM (rs->prim)
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#define IPRIM (rs->iprim)
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#define PAD (rs->pad)
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#define A0 (NN)
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#define ENCODE_RS encode_rs_char
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#define DECODE_RS decode_rs_char
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#define INIT_RS init_rs_char
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#define FREE_RS free_rs_char
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void ENCODE_RS(void *p,DTYPE *data,DTYPE *parity);
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int DECODE_RS(void *p,DTYPE *data,int *eras_pos,int no_eras);
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void *INIT_RS(int symsize,int gfpoly,int fcr,
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int prim,int nroots,int pad);
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void FREE_RS(void *p);
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