FreeCalypso > hg > gsm-codec-lib
annotate libgsmhr1/sid_detect.c @ 503:3654df24451f
libgsmhr1/mathdp31.[ch]: import original
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Wed, 19 Jun 2024 01:16:47 +0000 |
parents | aaf4dec8bee0 |
children |
rev | line source |
---|---|
494
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
1 /* |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
2 * The function in this module implements detection of perfect, error-free |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
3 * HRv1 SID frames in TS 101 318 raw packed format. If SID is detected, |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
4 * the return value is 2: the code for valid SID per GSM 06.41. |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
5 */ |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
6 |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
7 #include <stdint.h> |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
8 #include <string.h> |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
9 #include "tw_gsmhr.h" |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
10 |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
11 int gsmhr_ts101318_is_perfect_sid(const uint8_t *payload) |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
12 { |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
13 static const uint8_t all_ff_bytes[9] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
14 0xFF, 0xFF, 0xFF, 0xFF}; |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
15 |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
16 if ((payload[4] & 0x7F) != 0x7F) |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
17 return 0; |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
18 if (memcmp(payload + 5, all_ff_bytes, 9) == 0) |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
19 return 2; |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
20 else |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
21 return 0; |
aaf4dec8bee0
libgsmhr1: implement perfect SID detection
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
22 } |