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1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include <inttypes.h>
18 #include <errno.h>
19 #include <sys/types.h>
20 #include <sys/stat.h>
21 #include <fcntl.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <unistd.h>
25 #include <string.h>
26 #include <fec.h>
27 
28 #define FEC_RSM 255
29 #define FEC_ROOTS 16
30 #define FEC_RSN (FEC_RSM - FEC_ROOTS)
31 #define FEC_PARAMS(roots) \
32     8, 0x11d, 0, 1, (roots), 0
33 
main()34 int main()
35 {
36     uint8_t data[FEC_RSM];
37     uint8_t dupl[FEC_RSM];
38     uint8_t corr[FEC_RSM];
39     int i, rc, neras, errors;
40     int erasures[FEC_RSM];
41     void *rs;
42 
43     memset(data, 0x00, sizeof(data));
44     memset(corr, 0x00, sizeof(corr));
45 
46     rs = init_rs_char(FEC_PARAMS(FEC_ROOTS));
47 
48     if (!rs) {
49         perror("init_rs_char");
50         exit(1);
51     }
52 
53     encode_rs_char(rs, data, &corr[FEC_RSN]);
54 
55     for (neras = 1; neras <= FEC_ROOTS; ++neras) {
56         printf("%d errors\n", neras);
57 
58         for (i = 0; i < neras; ++i) {
59             corr[i] = 0xFD;
60             erasures[i] = i;
61         }
62 
63         memcpy(dupl, corr, sizeof(corr));
64 
65         rc = decode_rs_char(rs, corr, NULL, 0);
66 
67         printf("\tno erasures: %d\n", rc);
68 
69         errors = 0;
70         for (i = 0; i < FEC_RSN; ++i) {
71             if (corr[i] != 0x00) {
72                 printf("\t\terror at %d (%02x)\n", i, corr[i]);
73                 ++errors;
74             }
75         }
76         printf("\t\t%d errors in output\n", errors);
77 
78         rc = decode_rs_char(rs, dupl, erasures, neras);
79 
80         printf("\terasures: %d\n", rc);
81 
82         errors = 0;
83         for (i = 0; i < FEC_RSN; ++i) {
84             if (dupl[i] != 0x00) {
85                 printf("\t\terror at %d (%02x)\n", i, dupl[i]);
86                 ++errors;
87             }
88         }
89         printf("\t\t%d errors in output\n", errors);
90     }
91 
92     exit(0);
93 }
94