lsst.sphgeom ga1cf026fa3+ac198e9f13
codec.h
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1/*
2 * LSST Data Management System
3 * Copyright 2016 AURA/LSST.
4 *
5 * This product includes software developed by the
6 * LSST Project (http://www.lsst.org/).
7 *
8 * This program is free software: you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, either version 3 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the LSST License Statement and
19 * the GNU General Public License along with this program. If not,
20 * see <https://www.lsstcorp.org/LegalNotices/>.
21 */
22
23#ifndef LSST_SPHGEOM_CODEC_H_
24#define LSST_SPHGEOM_CODEC_H_
25
26// Optimized path requires little endian arch and support for unaligned loads.
27#if defined(__x86_64__) or (defined(__aarch64__) and defined(__LITTLE_ENDIAN__))
28#define OPTIMIZED_LITTLE_ENDIAN
29#endif
30
31#ifdef NO_OPTIMIZED_PATHS
32#undef OPTIMIZED_LITTLE_ENDIAN
33#endif
34
38
39#include <vector>
40
41namespace lsst {
42namespace sphgeom {
43
46inline void encodeDouble(double item, std::vector<uint8_t> & buffer) {
47#ifdef OPTIMIZED_LITTLE_ENDIAN
48 auto ptr = reinterpret_cast<uint8_t const *>(&item);
49 buffer.insert(buffer.end(), ptr, ptr + 8);
50#else
51 union { uint64_t u; double d; };
52 d = item;
53 buffer.push_back(static_cast<uint8_t>(u));
54 buffer.push_back(static_cast<uint8_t>(u >> 8));
55 buffer.push_back(static_cast<uint8_t>(u >> 16));
56 buffer.push_back(static_cast<uint8_t>(u >> 24));
57 buffer.push_back(static_cast<uint8_t>(u >> 32));
58 buffer.push_back(static_cast<uint8_t>(u >> 40));
59 buffer.push_back(static_cast<uint8_t>(u >> 48));
60 buffer.push_back(static_cast<uint8_t>(u >> 56));
61#endif
62}
63
66inline double decodeDouble(uint8_t const * buffer) {
67#ifdef OPTIMIZED_LITTLE_ENDIAN
68 return *reinterpret_cast<double const *>(buffer);
69#else
70 union { uint64_t u; double d; };
71 u = static_cast<uint64_t>(buffer[0]) +
72 (static_cast<uint64_t>(buffer[1]) << 8) +
73 (static_cast<uint64_t>(buffer[2]) << 16) +
74 (static_cast<uint64_t>(buffer[3]) << 24) +
75 (static_cast<uint64_t>(buffer[4]) << 32) +
76 (static_cast<uint64_t>(buffer[5]) << 40) +
77 (static_cast<uint64_t>(buffer[6]) << 48) +
78 (static_cast<uint64_t>(buffer[7]) << 56);
79 return d;
80#endif
81}
82
85inline void encodeU64(std::uint64_t item, std::vector<uint8_t> & buffer) {
86#ifdef OPTIMIZED_LITTLE_ENDIAN
87 auto ptr = reinterpret_cast<uint8_t const *>(&item);
88 buffer.insert(buffer.end(), ptr, ptr + 8);
89#else
90 union { uint64_t u; double d; };
91 d = item;
92 buffer.push_back(static_cast<uint8_t>(u));
93 buffer.push_back(static_cast<uint8_t>(u >> 8));
94 buffer.push_back(static_cast<uint8_t>(u >> 16));
95 buffer.push_back(static_cast<uint8_t>(u >> 24));
96 buffer.push_back(static_cast<uint8_t>(u >> 32));
97 buffer.push_back(static_cast<uint8_t>(u >> 40));
98 buffer.push_back(static_cast<uint8_t>(u >> 48));
99 buffer.push_back(static_cast<uint8_t>(u >> 56));
100#endif
101}
102
105inline std::uint64_t decodeU64(uint8_t const * buffer) {
106#ifdef OPTIMIZED_LITTLE_ENDIAN
107 return *reinterpret_cast<uint64_t const *>(buffer);
108#else
109 std::uint64_t u = static_cast<uint64_t>(buffer[0]) +
110 (static_cast<uint64_t>(buffer[1]) << 8) +
111 (static_cast<uint64_t>(buffer[2]) << 16) +
112 (static_cast<uint64_t>(buffer[3]) << 24) +
113 (static_cast<uint64_t>(buffer[4]) << 32) +
114 (static_cast<uint64_t>(buffer[5]) << 40) +
115 (static_cast<uint64_t>(buffer[6]) << 48) +
116 (static_cast<uint64_t>(buffer[7]) << 56);
117 return d;
118#endif
119}
120
121}} // namespace lsst::sphgeom
122
123#endif // LSST_SPHGEOM_CODEC_H_
void encodeDouble(double item, std::vector< uint8_t > &buffer)
Definition: codec.h:46
void encodeU64(std::uint64_t item, std::vector< uint8_t > &buffer)
Definition: codec.h:85
double decodeDouble(uint8_t const *buffer)
Definition: codec.h:66
std::uint64_t decodeU64(uint8_t const *buffer)
Definition: codec.h:105