FreeCalypso > hg > gsm-codec-lib

annotate libgsmfrp/sidclass.c @ 237:e4a4bf11f37c

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
doc/PCM8-conversions: document command line utilities
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 08 May 2023 04:29:05 +0000
parents 2b5770c715ee
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
2
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
1 /*
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
2 * gsmfr_preproc_sid_classify() utility function classifies
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
3 * a GSM 06.10 frame in RTP encoding according to the rules
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
4 * of GSM 06.31 (or 3GPP TS 46.031) section 6.1.1, judging it
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
5 * as SID=0, SID=1 or SID=2.
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
6 */
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
7
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
8 #include "gsm_fr_preproc.h"
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
9
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
10 static const unsigned short sid_field_bits[95] = {
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
11 57, 58, 60, 61, 63, 64, 66, 67, 69, 70, 72, 73,
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
12 75, 76, 78, 79, 81, 82, 84, 85, 87, 88, 90, 91,
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
13 93, 94, 113, 114, 116, 117, 119, 120, 122, 123,
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
14 125, 126, 128, 129, 131, 132, 134, 135, 137,
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
15 138, 140, 141, 143, 144, 146, 147, 149, 150,
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
16 169, 170, 172, 173, 175, 176, 178, 179, 181,
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
17 182, 184, 185, 187, 188, 190, 191, 193, 194,
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
18 196, 197, 199, 200, 202, 203, 205, 206, 225,
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
19 226, 228, 229, 231, 232, 234, 235, 237, 240,
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
20 243, 246, 249, 252, 255, 258, 261
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
21 };
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
22
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
23 static inline int get_bit(const gsm_byte *frame, unsigned bitnum)
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
24 {
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
25 unsigned bytenum = bitnum >> 3;
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
26 unsigned bit_in_byte = 7 - (bitnum & 7);
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
27 unsigned bitmask = 1 << bit_in_byte;
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
28
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
29 if (frame[bytenum] & bitmask)
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
30 return 1;
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
31 else
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
32 return 0;
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
33 }
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
34
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
35 int gsmfr_preproc_sid_classify(const gsm_byte *frame)
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
36 {
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
37 unsigned idx, n;
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
38
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
39 n = 0;
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
40 for (idx = 0; idx < 95; idx++) {
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
41 if (get_bit(frame, sid_field_bits[idx]))
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
42 n++;
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
43 if (n >= 16)
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
44 return 0;
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
45 }
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
46 if (n < 2)
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
47 return 2;
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
48 else
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
49 return 1;
2b5770c715ee libgsmfrp: compiling utility functions
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
50 }