source: ntrip/branches/BNC_2.12/src/RTCM3/bits.h@ 10298

Last change on this file since 10298 was 9036, checked in by stuerze, 4 years ago

some modification to allow encoding and decoding of SSR corrections in RTCM-SSR and IGS-SSR formats

File size: 3.1 KB
Line 
1// Part of BNC, a utility for retrieving decoding and
2// converting GNSS data streams from NTRIP broadcasters.
3//
4// Copyright (C) 2015
5// German Federal Agency for Cartography and Geodesy (BKG)
6// http://www.bkg.bund.de
7// Alberding GmbH
8// http://www.alberding.eu
9//
10// Email: euref-ip@bkg.bund.de
11//
12// This program is free software; you can redistribute it and/or
13// modify it under the terms of the GNU General Public License
14// as published by the Free Software Foundation, version 2.
15//
16// This program is distributed in the hope that it will be useful,
17// but WITHOUT ANY WARRANTY; without even the implied warranty of
18// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19// GNU General Public License for more details.
20//
21// You should have received a copy of the GNU General Public License
22// along with this program; if not, write to the Free Software
23// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
24
25#ifndef BITS_H
26#define BITS_H
27
28#define LOADBITS(a) { \
29 while((a) > numbits) { \
30 if(!size--) return false; \
31 bitfield = (bitfield<<8)|*(data++); \
32 numbits += 8; \
33 } \
34}
35
36/* extract bits from data stream
37 b = variable to store result, a = number of bits */
38#define GETBITS64(b, a) { \
39 if(((a) > 56) && ((a)-56) > numbits) { \
40 uint64_t x; \
41 GETBITS(x, 56) \
42 LOADBITS((a)-56) \
43 b = ((x<<((a)-56)) | (bitfield<<(sizeof(bitfield)*8-numbits)) \
44 >>(sizeof(bitfield)*8-((a)-56))); \
45 numbits -= ((a)-56); \
46 } \
47 else { \
48 GETBITS(b, a) \
49 } \
50}
51
52/* extract bits from data stream
53 b = variable to store result, a = number of bits */
54#define GETBITS(b, a) { \
55 LOADBITS(a) \
56 b = (bitfield<<(64-numbits))>>(64-(a)); \
57 numbits -= (a); \
58}
59
60/* extract bits from data stream
61 b = variable to store result, a = number of bits */
62#define GETBITSFACTOR(b, a, c) { \
63 LOADBITS(a) \
64 b = ((bitfield<<(sizeof(bitfield)*8-numbits))>>(sizeof(bitfield)*8-(a)))*(c); \
65 numbits -= (a); \
66}
67
68/* extract floating value from data stream
69 b = variable to store result, a = number of bits */
70#define GETFLOAT(b, a, c) { \
71 LOADBITS(a) \
72 b = ((double)((bitfield<<(64-numbits))>>(64-(a))))*(c); \
73 numbits -= (a); \
74}
75
76/* extract signed floating value from data stream
77 b = variable to store result, a = number of bits */
78#define GETFLOATSIGN(b, a, c) { \
79 LOADBITS(a) \
80 b = ((double)(((int64_t)(bitfield<<(64-numbits)))>>(64-(a))))*(c); \
81 numbits -= (a); \
82}
83
84/* extract bits from data stream
85 b = variable to store result, a = number of bits */
86#define GETBITSSIGN(b, a) { \
87 LOADBITS(a) \
88 b = ((int64_t)(bitfield<<(64-numbits)))>>(64-(a)); \
89 numbits -= (a); \
90}
91
92#define GETFLOATSIGNM(b, a, c) { \
93 int l; \
94 LOADBITS(a) \
95 l = (bitfield<<(64-numbits))>>(64-1); \
96 b = ((double)(((bitfield<<(64-(numbits-1))))>>(64-(a-1))))*(c); \
97 numbits -= (a); \
98 if(l) b *= -1.0; \
99}
100
101#define SKIPBITS(b) { LOADBITS(b) numbits -= (b); }
102
103/* extract byte-aligned byte from data stream,
104 b = variable to store size, s = variable to store string pointer */
105#define GETSTRING(b, s) { \
106 b = *(data++); \
107 s = (char *) data; \
108 data += b; \
109 size -= b+1; \
110}
111
112#endif /* BITS_H */
Note: See TracBrowser for help on using the repository browser.