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26 lines
935 B
26 lines
935 B
/* 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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