FreeCalypso > hg > gsm-codec-lib
view libgsmhr1/sid_detect.c @ 556:18aca50d68df default tip
doc/Calypso-TCH-downlink: update for FR1 BFI-with-data
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Fri, 11 Oct 2024 01:54:00 +0000 |
parents | aaf4dec8bee0 |
children |
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/* * The function in this module implements detection of perfect, error-free * HRv1 SID frames in TS 101 318 raw packed format. If SID is detected, * the return value is 2: the code for valid SID per GSM 06.41. */ #include <stdint.h> #include <string.h> #include "tw_gsmhr.h" int gsmhr_ts101318_is_perfect_sid(const uint8_t *payload) { static const uint8_t all_ff_bytes[9] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}; if ((payload[4] & 0x7F) != 0x7F) return 0; if (memcmp(payload + 5, all_ff_bytes, 9) == 0) return 2; else return 0; }