FreeCalypso > hg > gsm-codec-lib
diff frtest/cvt-dlcap.c @ 19:7960744ba19c
frtest: gsmfr-cvt-dlcap program based on fc-tch2fr
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sun, 20 Nov 2022 06:11:16 +0000 |
parents | |
children | b7ea278390eb |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/frtest/cvt-dlcap.c Sun Nov 20 06:11:16 2022 +0000 @@ -0,0 +1,87 @@ +/* + * 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); +}