1 /*
2 * Copyright (c) 2016, The OpenThread Authors.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. Neither the name of the copyright holder nor the
13 * names of its contributors may be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 /**
30 * @file
31 * This file implements common MeshCoP timestamp processing.
32 */
33
34 #include "timestamp.hpp"
35
36 #include "common/code_utils.hpp"
37
38 namespace ot {
39 namespace MeshCoP {
40
ConvertTo(otTimestamp & aTimestamp) const41 void Timestamp::ConvertTo(otTimestamp &aTimestamp) const
42 {
43 aTimestamp.mSeconds = GetSeconds();
44 aTimestamp.mTicks = GetTicks();
45 aTimestamp.mAuthoritative = GetAuthoritative();
46 }
47
SetFromTimestamp(const otTimestamp & aTimestamp)48 void Timestamp::SetFromTimestamp(const otTimestamp &aTimestamp)
49 {
50 SetSeconds(aTimestamp.mSeconds);
51 SetTicks(aTimestamp.mTicks);
52 SetAuthoritative(aTimestamp.mAuthoritative);
53 }
54
Compare(const Timestamp * aFirst,const Timestamp * aSecond)55 int Timestamp::Compare(const Timestamp *aFirst, const Timestamp *aSecond)
56 {
57 int rval;
58
59 if (aFirst == nullptr)
60 {
61 // When `aFirst` is null but `aSecond is not, we return -1,
62 // (indicate `aFirst (null) < aSecond (non-null)`).
63 ExitNow(rval = (aSecond == nullptr) ? 0 : -1);
64 }
65
66 if (aSecond == nullptr)
67 {
68 // When `aFirst` is not null, but `aSecond` is, we return +1,
69 // (indicate `aFirst (non-null) > aSecond (null)`).
70 ExitNow(rval = 1);
71 }
72
73 // Both are non-null.
74
75 rval = Compare(*aFirst, *aSecond);
76
77 exit:
78 return rval;
79 }
80
Compare(const Timestamp & aFirst,const Timestamp & aSecond)81 int Timestamp::Compare(const Timestamp &aFirst, const Timestamp &aSecond)
82 {
83 int rval;
84 uint64_t firstSeconds;
85 uint64_t secondSeconds;
86 uint16_t firstTicks;
87 uint16_t secondTicks;
88 bool firstAuthoritative;
89 bool secondAuthoritative;
90
91 firstSeconds = aFirst.GetSeconds();
92 secondSeconds = aSecond.GetSeconds();
93
94 if (firstSeconds != secondSeconds)
95 {
96 ExitNow(rval = (firstSeconds > secondSeconds) ? 1 : -1);
97 }
98
99 firstTicks = aFirst.GetTicks();
100 secondTicks = aSecond.GetTicks();
101
102 if (firstTicks != secondTicks)
103 {
104 ExitNow(rval = (firstTicks > secondTicks) ? 1 : -1);
105 }
106
107 firstAuthoritative = aFirst.GetAuthoritative();
108 secondAuthoritative = aSecond.GetAuthoritative();
109
110 if (firstAuthoritative != secondAuthoritative)
111 {
112 ExitNow(rval = firstAuthoritative ? 1 : -1);
113 }
114
115 rval = 0;
116
117 exit:
118 return rval;
119 }
120
AdvanceRandomTicks(void)121 void Timestamp::AdvanceRandomTicks(void)
122 {
123 uint16_t ticks = GetTicks();
124
125 ticks += Random::NonCrypto::GetUint32InRange(1, kMaxRandomTicks);
126
127 if (ticks & (kTicksMask >> kTicksOffset))
128 {
129 SetSeconds(GetSeconds() + 1);
130 }
131
132 SetTicks(ticks);
133 }
134
135 } // namespace MeshCoP
136 } // namespace ot
137