| /* |
| * 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 |