Bill Yi | 4e213d5 | 2015-06-23 13:53:11 -0700 | [diff] [blame] | 1 | /* Stuff common to all the general-purpose Reed-Solomon codecs |
| 2 | * Copyright 2004 Phil Karn, KA9Q |
| 3 | * May be used under the terms of the GNU Lesser General Public License (LGPL) |
| 4 | */ |
| 5 | |
| 6 | /* Reed-Solomon codec control block */ |
| 7 | struct rs { |
| 8 | int mm; /* Bits per symbol */ |
| 9 | int nn; /* Symbols per block (= (1<<mm)-1) */ |
| 10 | data_t *alpha_to; /* log lookup table */ |
| 11 | data_t *index_of; /* Antilog lookup table */ |
| 12 | data_t *genpoly; /* Generator polynomial */ |
| 13 | int nroots; /* Number of generator roots = number of parity symbols */ |
| 14 | int fcr; /* First consecutive root, index form */ |
| 15 | int prim; /* Primitive element, index form */ |
| 16 | int iprim; /* prim-th root of 1, index form */ |
| 17 | int pad; /* Padding bytes in shortened block */ |
| 18 | }; |
| 19 | |
| 20 | static inline int modnn(struct rs *rs,int x){ |
| 21 | while (x >= rs->nn) { |
| 22 | x -= rs->nn; |
| 23 | x = (x >> rs->mm) + (x & rs->nn); |
| 24 | } |
| 25 | return x; |
| 26 | } |