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author | Matthias P. Braendli <matthias.braendli@mpb.li> | 2014-01-02 21:55:13 +0100 |
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committer | Matthias P. Braendli <matthias.braendli@mpb.li> | 2014-01-02 21:55:13 +0100 |
commit | a31630e0d5b9880c716d9004ef4154396ba41ebc (patch) | |
tree | aebbd3b132e5f2dd31bc34750ccded2378fc687a /encode_rs.c | |
parent | 9aaac5be9db5e1537badc65242412ef14c5096e3 (diff) | |
download | ka9q-fec-a31630e0d5b9880c716d9004ef4154396ba41ebc.tar.gz ka9q-fec-a31630e0d5b9880c716d9004ef4154396ba41ebc.tar.bz2 ka9q-fec-a31630e0d5b9880c716d9004ef4154396ba41ebc.zip |
Extract fec-3.0.1
Diffstat (limited to 'encode_rs.c')
-rw-r--r-- | encode_rs.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/encode_rs.c b/encode_rs.c new file mode 100644 index 0000000..0649094 --- /dev/null +++ b/encode_rs.c @@ -0,0 +1,52 @@ +/* Reed-Solomon encoder + * Copyright 2002, Phil Karn, KA9Q + * May be used under the terms of the GNU Lesser General Public License (LGPL) + */ +#include <string.h> + +#ifdef FIXED +#include "fixed.h" +#elif defined(BIGSYM) +#include "int.h" +#else +#include "char.h" +#endif + +void ENCODE_RS( +#ifdef FIXED +data_t *data, data_t *bb,int pad){ +#else +void *p,data_t *data, data_t *bb){ + struct rs *rs = (struct rs *)p; +#endif + int i, j; + data_t feedback; + +#ifdef FIXED + /* Check pad parameter for validity */ + if(pad < 0 || pad >= NN) + return; +#endif + + memset(bb,0,NROOTS*sizeof(data_t)); + + for(i=0;i<NN-NROOTS-PAD;i++){ + feedback = INDEX_OF[data[i] ^ bb[0]]; + if(feedback != A0){ /* feedback term is non-zero */ +#ifdef UNNORMALIZED + /* This line is unnecessary when GENPOLY[NROOTS] is unity, as it must + * always be for the polynomials constructed by init_rs() + */ + feedback = MODNN(NN - GENPOLY[NROOTS] + feedback); +#endif + for(j=1;j<NROOTS;j++) + bb[j] ^= ALPHA_TO[MODNN(feedback + GENPOLY[NROOTS-j])]; + } + /* Shift */ + memmove(&bb[0],&bb[1],sizeof(data_t)*(NROOTS-1)); + if(feedback != A0) + bb[NROOTS-1] = ALPHA_TO[MODNN(feedback + GENPOLY[0])]; + else + bb[NROOTS-1] = 0; + } +} |