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27 lines
935 B
C
27 lines
935 B
C
/* Stuff common to all the general-purpose Reed-Solomon codecs
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* Copyright 2004 Phil Karn, KA9Q
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* May be used under the terms of the GNU Lesser General Public License (LGPL)
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*/
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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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data_t *alpha_to; /* log lookup table */
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data_t *index_of; /* Antilog lookup table */
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data_t *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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