61 lines
2.0 KiB
C++
61 lines
2.0 KiB
C++
/*
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* Copyright (C) 2019 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <utility>
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namespace android {
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namespace base {
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// Helpers for converting a variadic template parameter pack to a homogeneous collection.
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// Parameters must be implictly convertible to the contained type (including via move/copy ctors).
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//
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// Use as follows:
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//
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// template <typename... Args>
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// std::vector<int> CreateVector(Args&&... args) {
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// std::vector<int> result;
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// Append(result, std::forward<Args>(args)...);
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// return result;
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// }
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template <typename CollectionType, typename T>
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void Append(CollectionType& collection, T&& arg) {
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collection.push_back(std::forward<T>(arg));
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}
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template <typename CollectionType, typename T, typename... Args>
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void Append(CollectionType& collection, T&& arg, Args&&... args) {
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collection.push_back(std::forward<T>(arg));
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return Append(collection, std::forward<Args>(args)...);
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}
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// Assert that all of the arguments in a variadic template parameter pack are of a given type
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// after std::decay.
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template <typename T, typename Arg, typename... Args>
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void AssertType(Arg&&) {
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static_assert(std::is_same<T, typename std::decay<Arg>::type>::value);
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}
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template <typename T, typename Arg, typename... Args>
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void AssertType(Arg&&, Args&&... args) {
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static_assert(std::is_same<T, typename std::decay<Arg>::type>::value);
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AssertType<T>(std::forward<Args>(args)...);
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}
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} // namespace base
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} // namespace android
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