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92abb22c64
This reverts commit ef9e7b1a1365c07ab0df2e2016c4442c3963c2c7 with the following changes to accommodate an embedder for whom the original optimizations caused issues: * Ensure stable order in the backing stores presented to the embedder. This is a pessimization that will be reverted when the embedder migrates. Tracked in https://github.com/flutter/flutter/issues/51228 * Forego the optimization where the unused layers would be collected before allocation of new layers needs to happen. This is a pessimization that will be reverted when the embedder migrates. Tracked in https://github.com/flutter/flutter/issues/51229 More context in b/146142979.
39 lines
979 B
C++
39 lines
979 B
C++
// Copyright 2013 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef FLUTTER_FML_HASH_COMBINE_H_
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#define FLUTTER_FML_HASH_COMBINE_H_
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#include <functional>
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namespace fml {
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template <class Type>
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constexpr void HashCombineSeed(std::size_t& seed, Type arg) {
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seed ^= std::hash<Type>{}(arg) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
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}
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template <class Type, class... Rest>
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constexpr void HashCombineSeed(std::size_t& seed,
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Type arg,
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Rest... other_args) {
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HashCombineSeed(seed, arg);
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HashCombineSeed(seed, other_args...);
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}
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constexpr std::size_t HashCombine() {
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return 0xdabbad00;
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}
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template <class... Type>
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constexpr std::size_t HashCombine(Type... args) {
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std::size_t seed = HashCombine();
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HashCombineSeed(seed, args...);
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return seed;
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}
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} // namespace fml
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#endif // FLUTTER_FML_HASH_COMBINE_H_
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