FreeCalypso > hg > gsm-net-reveng
comparison trau-decode/trau-sync8.c @ 27:f508dacf2cf9
trau-decode: new programs dump-1bit and trau-sync8
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sun, 18 Aug 2024 06:26:23 +0000 |
parents | trau-decode/parse-main.c@4d1732e4a143 |
children |
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26:f80e64139670 | 27:f508dacf2cf9 |
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1 /* | |
2 * This program reads a 64 kbit/s timeslot recording file, examines one | |
3 * of the eight 8 kbit/s subslots (selected), looks for the sync pattern of | |
4 * GSM 08.61 (HRv1 speech or HR data), and dumps each synced frame | |
5 * as a hex line. | |
6 */ | |
7 | |
8 #include <sys/types.h> | |
9 #include <sys/file.h> | |
10 #include <sys/stat.h> | |
11 #include <stdio.h> | |
12 #include <stdint.h> | |
13 #include <stdlib.h> | |
14 #include <string.h> | |
15 #include <strings.h> | |
16 #include <unistd.h> | |
17 | |
18 static uint8_t *filebuf; | |
19 static unsigned total_size; | |
20 | |
21 static void | |
22 read_ts_file(filename, subslot_arg) | |
23 char *filename, *subslot_arg; | |
24 { | |
25 FILE *inf; | |
26 struct stat st; | |
27 int subslot, right_shift; | |
28 unsigned n; | |
29 uint8_t *dp; | |
30 int b; | |
31 | |
32 inf = fopen(filename, "r"); | |
33 if (!inf) { | |
34 perror(filename); | |
35 exit(1); | |
36 } | |
37 fstat(fileno(inf), &st); | |
38 if (!S_ISREG(st.st_mode)) { | |
39 fprintf(stderr, "error: %s is not a regular file\n", filename); | |
40 exit(1); | |
41 } | |
42 total_size = st.st_size; | |
43 if (total_size < 160) { | |
44 fprintf(stderr, "error: %s is too short\n", filename); | |
45 exit(1); | |
46 } | |
47 filebuf = malloc(total_size); | |
48 if (!filebuf) { | |
49 perror("malloc of file size"); | |
50 exit(1); | |
51 } | |
52 subslot = atoi(subslot_arg); | |
53 if (subslot < 0 || subslot > 7) { | |
54 fprintf(stderr, "error: invalid subslot argument\n"); | |
55 exit(1); | |
56 } | |
57 right_shift = 7 - subslot; | |
58 dp = filebuf; | |
59 for (n = 0; n < total_size; n++) { | |
60 b = getc(inf); | |
61 if (b < 0) { | |
62 fprintf(stderr, | |
63 "error: getc() returned EOF contrary to st_size\n"); | |
64 exit(1); | |
65 } | |
66 *dp++ = (b >> right_shift) & 1; | |
67 } | |
68 fclose(inf); | |
69 } | |
70 | |
71 static int | |
72 check_sync(pos) | |
73 unsigned pos; | |
74 { | |
75 uint8_t *cand = filebuf + pos; | |
76 unsigned n; | |
77 | |
78 for (n = 0; n < 8; n++) { | |
79 if (cand[n]) | |
80 return 0; | |
81 } | |
82 if (!cand[8]) | |
83 return 0; | |
84 if (cand[16]) | |
85 return 0; | |
86 if (!cand[17]) | |
87 return 0; | |
88 for (n = 3; n < 20; n++) { | |
89 if (!cand[n * 8]) | |
90 return 0; | |
91 } | |
92 return 1; | |
93 } | |
94 | |
95 static void | |
96 process_frame(pos) | |
97 unsigned pos; | |
98 { | |
99 uint8_t *sp = filebuf + pos; | |
100 unsigned n, m, d; | |
101 | |
102 for (n = 0; n < 40; n++) { | |
103 d = 0; | |
104 for (m = 0; m < 4; m++) { | |
105 d <<= 1; | |
106 d |= *sp++; | |
107 } | |
108 printf("%x", d); | |
109 } | |
110 putchar('\n'); | |
111 } | |
112 | |
113 static void | |
114 process_filebuf() | |
115 { | |
116 unsigned p, endp; | |
117 int sync = 0, match; | |
118 | |
119 endp = total_size - 160; | |
120 for (p = 0; p < endp; ) { | |
121 match = check_sync(p); | |
122 if (match != sync) { | |
123 printf("# %s frame sync at file offset 0x%x\n", | |
124 match ? "Acquired" : "Lost", p); | |
125 } | |
126 if (match) { | |
127 process_frame(p); | |
128 if (!filebuf[p+158] && !filebuf[p+159]) { | |
129 printf( | |
130 "# both T bits equal 0, shifting frame alignment\n"); | |
131 p += 158; | |
132 } else | |
133 p += 160; | |
134 } else | |
135 p++; | |
136 sync = match; | |
137 } | |
138 } | |
139 | |
140 main(argc, argv) | |
141 char **argv; | |
142 { | |
143 if (argc != 3) { | |
144 fprintf(stderr, "usage: %s binfile subslot\n", argv[0]); | |
145 exit(1); | |
146 } | |
147 read_ts_file(argv[1], argv[2]); | |
148 process_filebuf(); | |
149 exit(0); | |
150 } |