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authorBill Yi <byi@google.com>2015-06-23 13:53:11 -0700
committerBill Yi <byi@google.com>2015-06-23 13:53:11 -0700
commit4e213d510f437769f8a28578dd4f786fb7d16c44 (patch)
tree0d5cbd5a7eee87b3dca5820d282ef618a7e25991 /fec.c
downloadfec-4e213d510f437769f8a28578dd4f786fb7d16c44.tar.gz
Initial codenougat-mr1-arc
Diffstat (limited to 'fec.c')
-rw-r--r--fec.c66
1 files changed, 66 insertions, 0 deletions
diff --git a/fec.c b/fec.c
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+++ b/fec.c
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+/* Utility routines for FEC support
+ * Copyright 2004, Phil Karn, KA9Q
+ */
+
+#include <stdio.h>
+#include "fec.h"
+
+unsigned char Partab[256];
+int P_init;
+
+/* Create 256-entry odd-parity lookup table
+ * Needed only on non-ia32 machines
+ */
+void partab_init(void){
+ int i,cnt,ti;
+
+ /* Initialize parity lookup table */
+ for(i=0;i<256;i++){
+ cnt = 0;
+ ti = i;
+ while(ti){
+ if(ti & 1)
+ cnt++;
+ ti >>= 1;
+ }
+ Partab[i] = cnt & 1;
+ }
+ P_init=1;
+}
+
+/* Lookup table giving count of 1 bits for integers 0-255 */
+int Bitcnt[] = {
+ 0, 1, 1, 2, 1, 2, 2, 3,
+ 1, 2, 2, 3, 2, 3, 3, 4,
+ 1, 2, 2, 3, 2, 3, 3, 4,
+ 2, 3, 3, 4, 3, 4, 4, 5,
+ 1, 2, 2, 3, 2, 3, 3, 4,
+ 2, 3, 3, 4, 3, 4, 4, 5,
+ 2, 3, 3, 4, 3, 4, 4, 5,
+ 3, 4, 4, 5, 4, 5, 5, 6,
+ 1, 2, 2, 3, 2, 3, 3, 4,
+ 2, 3, 3, 4, 3, 4, 4, 5,
+ 2, 3, 3, 4, 3, 4, 4, 5,
+ 3, 4, 4, 5, 4, 5, 5, 6,
+ 2, 3, 3, 4, 3, 4, 4, 5,
+ 3, 4, 4, 5, 4, 5, 5, 6,
+ 3, 4, 4, 5, 4, 5, 5, 6,
+ 4, 5, 5, 6, 5, 6, 6, 7,
+ 1, 2, 2, 3, 2, 3, 3, 4,
+ 2, 3, 3, 4, 3, 4, 4, 5,
+ 2, 3, 3, 4, 3, 4, 4, 5,
+ 3, 4, 4, 5, 4, 5, 5, 6,
+ 2, 3, 3, 4, 3, 4, 4, 5,
+ 3, 4, 4, 5, 4, 5, 5, 6,
+ 3, 4, 4, 5, 4, 5, 5, 6,
+ 4, 5, 5, 6, 5, 6, 6, 7,
+ 2, 3, 3, 4, 3, 4, 4, 5,
+ 3, 4, 4, 5, 4, 5, 5, 6,
+ 3, 4, 4, 5, 4, 5, 5, 6,
+ 4, 5, 5, 6, 5, 6, 6, 7,
+ 3, 4, 4, 5, 4, 5, 5, 6,
+ 4, 5, 5, 6, 5, 6, 6, 7,
+ 4, 5, 5, 6, 5, 6, 6, 7,
+ 5, 6, 6, 7, 6, 7, 7, 8,
+};
+