1*638691a0SAndroid Build Coastguard Worker /* Utility routines for FEC support
2*638691a0SAndroid Build Coastguard Worker * Copyright 2004, Phil Karn, KA9Q
3*638691a0SAndroid Build Coastguard Worker */
4*638691a0SAndroid Build Coastguard Worker
5*638691a0SAndroid Build Coastguard Worker #include <stdio.h>
6*638691a0SAndroid Build Coastguard Worker #include "fec.h"
7*638691a0SAndroid Build Coastguard Worker
8*638691a0SAndroid Build Coastguard Worker unsigned char Partab[256];
9*638691a0SAndroid Build Coastguard Worker int P_init;
10*638691a0SAndroid Build Coastguard Worker
11*638691a0SAndroid Build Coastguard Worker /* Create 256-entry odd-parity lookup table
12*638691a0SAndroid Build Coastguard Worker * Needed only on non-ia32 machines
13*638691a0SAndroid Build Coastguard Worker */
partab_init(void)14*638691a0SAndroid Build Coastguard Worker void partab_init(void){
15*638691a0SAndroid Build Coastguard Worker int i,cnt,ti;
16*638691a0SAndroid Build Coastguard Worker
17*638691a0SAndroid Build Coastguard Worker /* Initialize parity lookup table */
18*638691a0SAndroid Build Coastguard Worker for(i=0;i<256;i++){
19*638691a0SAndroid Build Coastguard Worker cnt = 0;
20*638691a0SAndroid Build Coastguard Worker ti = i;
21*638691a0SAndroid Build Coastguard Worker while(ti){
22*638691a0SAndroid Build Coastguard Worker if(ti & 1)
23*638691a0SAndroid Build Coastguard Worker cnt++;
24*638691a0SAndroid Build Coastguard Worker ti >>= 1;
25*638691a0SAndroid Build Coastguard Worker }
26*638691a0SAndroid Build Coastguard Worker Partab[i] = cnt & 1;
27*638691a0SAndroid Build Coastguard Worker }
28*638691a0SAndroid Build Coastguard Worker P_init=1;
29*638691a0SAndroid Build Coastguard Worker }
30*638691a0SAndroid Build Coastguard Worker
31*638691a0SAndroid Build Coastguard Worker /* Lookup table giving count of 1 bits for integers 0-255 */
32*638691a0SAndroid Build Coastguard Worker int Bitcnt[] = {
33*638691a0SAndroid Build Coastguard Worker 0, 1, 1, 2, 1, 2, 2, 3,
34*638691a0SAndroid Build Coastguard Worker 1, 2, 2, 3, 2, 3, 3, 4,
35*638691a0SAndroid Build Coastguard Worker 1, 2, 2, 3, 2, 3, 3, 4,
36*638691a0SAndroid Build Coastguard Worker 2, 3, 3, 4, 3, 4, 4, 5,
37*638691a0SAndroid Build Coastguard Worker 1, 2, 2, 3, 2, 3, 3, 4,
38*638691a0SAndroid Build Coastguard Worker 2, 3, 3, 4, 3, 4, 4, 5,
39*638691a0SAndroid Build Coastguard Worker 2, 3, 3, 4, 3, 4, 4, 5,
40*638691a0SAndroid Build Coastguard Worker 3, 4, 4, 5, 4, 5, 5, 6,
41*638691a0SAndroid Build Coastguard Worker 1, 2, 2, 3, 2, 3, 3, 4,
42*638691a0SAndroid Build Coastguard Worker 2, 3, 3, 4, 3, 4, 4, 5,
43*638691a0SAndroid Build Coastguard Worker 2, 3, 3, 4, 3, 4, 4, 5,
44*638691a0SAndroid Build Coastguard Worker 3, 4, 4, 5, 4, 5, 5, 6,
45*638691a0SAndroid Build Coastguard Worker 2, 3, 3, 4, 3, 4, 4, 5,
46*638691a0SAndroid Build Coastguard Worker 3, 4, 4, 5, 4, 5, 5, 6,
47*638691a0SAndroid Build Coastguard Worker 3, 4, 4, 5, 4, 5, 5, 6,
48*638691a0SAndroid Build Coastguard Worker 4, 5, 5, 6, 5, 6, 6, 7,
49*638691a0SAndroid Build Coastguard Worker 1, 2, 2, 3, 2, 3, 3, 4,
50*638691a0SAndroid Build Coastguard Worker 2, 3, 3, 4, 3, 4, 4, 5,
51*638691a0SAndroid Build Coastguard Worker 2, 3, 3, 4, 3, 4, 4, 5,
52*638691a0SAndroid Build Coastguard Worker 3, 4, 4, 5, 4, 5, 5, 6,
53*638691a0SAndroid Build Coastguard Worker 2, 3, 3, 4, 3, 4, 4, 5,
54*638691a0SAndroid Build Coastguard Worker 3, 4, 4, 5, 4, 5, 5, 6,
55*638691a0SAndroid Build Coastguard Worker 3, 4, 4, 5, 4, 5, 5, 6,
56*638691a0SAndroid Build Coastguard Worker 4, 5, 5, 6, 5, 6, 6, 7,
57*638691a0SAndroid Build Coastguard Worker 2, 3, 3, 4, 3, 4, 4, 5,
58*638691a0SAndroid Build Coastguard Worker 3, 4, 4, 5, 4, 5, 5, 6,
59*638691a0SAndroid Build Coastguard Worker 3, 4, 4, 5, 4, 5, 5, 6,
60*638691a0SAndroid Build Coastguard Worker 4, 5, 5, 6, 5, 6, 6, 7,
61*638691a0SAndroid Build Coastguard Worker 3, 4, 4, 5, 4, 5, 5, 6,
62*638691a0SAndroid Build Coastguard Worker 4, 5, 5, 6, 5, 6, 6, 7,
63*638691a0SAndroid Build Coastguard Worker 4, 5, 5, 6, 5, 6, 6, 7,
64*638691a0SAndroid Build Coastguard Worker 5, 6, 6, 7, 6, 7, 7, 8,
65*638691a0SAndroid Build Coastguard Worker };
66*638691a0SAndroid Build Coastguard Worker
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