FreeCalypso > hg > gsm-codec-lib
view frtest/cvt-dlcap.c @ 95:f80a3202c8ff
libgsmefr: implement main decoder wrapper
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Sat, 26 Nov 2022 18:58:56 +0000 |
parents | 7960744ba19c |
children | b7ea278390eb |
line wrap: on
line source
/* * This program reads a TCH downlink capture produced with FreeCalypso tools * (fw version with TCH downlink sniffing feature and fc-shell tch record) * and converts it into our extended-libgsm binary format, to be further * fed to gsmfr-decode. */ #include <sys/types.h> #include <ctype.h> #include <stdio.h> #include <stdlib.h> static const char bfi_marker[2] = {0xBF, 0x00}; static decode_hex_digit(ch) { if (isdigit(ch)) return(ch - '0'); else if (isupper(ch)) return(ch - 'A' + 10); else return(ch - 'a' + 10); } main(argc, argv) char **argv; { FILE *inf, *outf; char linebuf[128]; int lineno; char *cp; int i; u_short status_words[3]; u_char tidsp_bytes[33], libgsm_bytes[33]; if (argc != 3) { fprintf(stderr, "usage: %s infile outfile\n", argv[0]); exit(1); } inf = fopen(argv[1], "r"); if (!inf) { perror(argv[1]); exit(1); } outf = fopen(argv[2], "w"); if (!outf) { perror(argv[2]); exit(1); } for (lineno = 1; fgets(linebuf, sizeof linebuf, inf); lineno++) { /* grok DSP status words */ cp = linebuf; for (i = 0; i < 3; i++) { if (!isxdigit(cp[0]) || !isxdigit(cp[1]) || !isxdigit(cp[2]) || !isxdigit(cp[3])) { invalid: fprintf(stderr, "error: %s is not in the expected format\n", argv[1]); exit(1); } status_words[i] = (decode_hex_digit(cp[0]) << 12) | (decode_hex_digit(cp[1]) << 8) | (decode_hex_digit(cp[2]) << 4) | decode_hex_digit(cp[3]); cp += 4; if (*cp++ != ' ') goto invalid; } /* read the frame bits */ for (i = 0; i < 33; i++) { if (!isxdigit(cp[0]) || !isxdigit(cp[1])) goto invalid; tidsp_bytes[i] = (decode_hex_digit(cp[0]) << 4) | decode_hex_digit(cp[1]); cp += 2; } /* bit 2 of status word 0 is BFI */ if (status_words[0] & 0x0004) fwrite(bfi_marker, 1, 2, outf); else { gsm0610_tidsp_to_libgsm(tidsp_bytes, libgsm_bytes); fwrite(libgsm_bytes, 1, 33, outf); } } exit(0); }