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comparison frtest/cvt-dlcap.c @ 19:7960744ba19c

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frtest: gsmfr-cvt-dlcap program based on fc-tch2fr
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 20 Nov 2022 06:11:16 +0000
parents
children b7ea278390eb
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18:39dbaccc349d 19:7960744ba19c
1 /*
2 * This program reads a TCH downlink capture produced with FreeCalypso tools
3 * (fw version with TCH downlink sniffing feature and fc-shell tch record)
4 * and converts it into our extended-libgsm binary format, to be further
5 * fed to gsmfr-decode.
6 */
7
8 #include <sys/types.h>
9 #include <ctype.h>
10 #include <stdio.h>
11 #include <stdlib.h>
12
13 static const char bfi_marker[2] = {0xBF, 0x00};
14
15 static
16 decode_hex_digit(ch)
17 {
18 if (isdigit(ch))
19 return(ch - '0');
20 else if (isupper(ch))
21 return(ch - 'A' + 10);
22 else
23 return(ch - 'a' + 10);
24 }
25
26 main(argc, argv)
27 char **argv;
28 {
29 FILE *inf, *outf;
30 char linebuf[128];
31 int lineno;
32 char *cp;
33 int i;
34 u_short status_words[3];
35 u_char tidsp_bytes[33], libgsm_bytes[33];
36
37 if (argc != 3) {
38 fprintf(stderr, "usage: %s infile outfile\n", argv[0]);
39 exit(1);
40 }
41 inf = fopen(argv[1], "r");
42 if (!inf) {
43 perror(argv[1]);
44 exit(1);
45 }
46 outf = fopen(argv[2], "w");
47 if (!outf) {
48 perror(argv[2]);
49 exit(1);
50 }
51 for (lineno = 1; fgets(linebuf, sizeof linebuf, inf); lineno++) {
52 /* grok DSP status words */
53 cp = linebuf;
54 for (i = 0; i < 3; i++) {
55 if (!isxdigit(cp[0]) || !isxdigit(cp[1]) ||
56 !isxdigit(cp[2]) || !isxdigit(cp[3])) {
57 invalid: fprintf(stderr,
58 "error: %s is not in the expected format\n",
59 argv[1]);
60 exit(1);
61 }
62 status_words[i] = (decode_hex_digit(cp[0]) << 12) |
63 (decode_hex_digit(cp[1]) << 8) |
64 (decode_hex_digit(cp[2]) << 4) |
65 decode_hex_digit(cp[3]);
66 cp += 4;
67 if (*cp++ != ' ')
68 goto invalid;
69 }
70 /* read the frame bits */
71 for (i = 0; i < 33; i++) {
72 if (!isxdigit(cp[0]) || !isxdigit(cp[1]))
73 goto invalid;
74 tidsp_bytes[i] = (decode_hex_digit(cp[0]) << 4) |
75 decode_hex_digit(cp[1]);
76 cp += 2;
77 }
78 /* bit 2 of status word 0 is BFI */
79 if (status_words[0] & 0x0004)
80 fwrite(bfi_marker, 1, 2, outf);
81 else {
82 gsm0610_tidsp_to_libgsm(tidsp_bytes, libgsm_bytes);
83 fwrite(libgsm_bytes, 1, 33, outf);
84 }
85 }
86 exit(0);
87 }