1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
|
/*
* Copyright (C) 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <cmath>
#include <ostream>
#include <string>
#include <android-base/stringprintf.h>
#include <utils/Timers.h>
namespace android {
// Value which represents "frames per second". This class is a wrapper around
// float, providing some useful utilities, such as comparisons with tolerance
// and converting between period duration and frequency.
class Fps {
public:
static constexpr Fps fromPeriodNsecs(nsecs_t period) { return Fps(1e9f / period, period); }
Fps() = default;
explicit constexpr Fps(float fps)
: fps(fps), period(fps == 0.0f ? 0 : static_cast<nsecs_t>(1e9f / fps)) {}
constexpr float getValue() const { return fps; }
constexpr nsecs_t getPeriodNsecs() const { return period; }
bool equalsWithMargin(const Fps& other) const { return std::abs(fps - other.fps) < kMargin; }
// DO NOT use for std::sort. Instead use comparesLess().
bool lessThanWithMargin(const Fps& other) const { return fps + kMargin < other.fps; }
bool greaterThanWithMargin(const Fps& other) const { return fps > other.fps + kMargin; }
bool lessThanOrEqualWithMargin(const Fps& other) const { return !greaterThanWithMargin(other); }
bool greaterThanOrEqualWithMargin(const Fps& other) const { return !lessThanWithMargin(other); }
bool isValid() const { return fps > 0.0f; }
int getIntValue() const { return static_cast<int>(std::round(fps)); }
// Use this comparator for sorting. Using a comparator with margins can
// cause std::sort to crash.
inline static bool comparesLess(const Fps& left, const Fps& right) {
return left.fps < right.fps;
}
// Compares two FPS with margin.
// Transitivity is not guaranteed, i.e. a==b and b==c doesn't imply a==c.
// DO NOT use with hash maps. Instead use EqualsInBuckets.
struct EqualsWithMargin {
bool operator()(const Fps& left, const Fps& right) const {
return left.equalsWithMargin(right);
}
};
// Equals comparator which can be used with hash maps.
// It's guaranteed that if two elements are equal, then their hashes are equal.
struct EqualsInBuckets {
bool operator()(const Fps& left, const Fps& right) const {
return left.getBucket() == right.getBucket();
}
};
inline friend std::string to_string(const Fps& fps) {
return base::StringPrintf("%.2ffps", fps.fps);
}
inline friend std::ostream& operator<<(std::ostream& os, const Fps& fps) {
return os << to_string(fps);
}
private:
friend std::hash<android::Fps>;
constexpr Fps(float fps, nsecs_t period) : fps(fps), period(period) {}
float getBucket() const { return std::round(fps / kMargin); }
static constexpr float kMargin = 0.001f;
float fps = 0;
nsecs_t period = 0;
};
static_assert(std::is_trivially_copyable_v<Fps>);
} // namespace android
namespace std {
template <>
struct hash<android::Fps> {
std::size_t operator()(const android::Fps& fps) const {
return std::hash<float>()(fps.getBucket());
}
};
} // namespace std
|
