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authorMatthias P. Braendli <matthias.braendli@mpb.li>2014-01-02 21:55:13 +0100
committerMatthias P. Braendli <matthias.braendli@mpb.li>2014-01-02 21:55:13 +0100
commita31630e0d5b9880c716d9004ef4154396ba41ebc (patch)
treeaebbd3b132e5f2dd31bc34750ccded2378fc687a /encode_rs.c
parent9aaac5be9db5e1537badc65242412ef14c5096e3 (diff)
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Extract fec-3.0.1
Diffstat (limited to 'encode_rs.c')
-rw-r--r--encode_rs.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/encode_rs.c b/encode_rs.c
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--- /dev/null
+++ b/encode_rs.c
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+/* 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;
+ }
+}