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/*
* Copyright (C) 2019 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 <utility>
namespace android {
namespace base {
// Helpers for converting a variadic template parameter pack to a homogeneous collection.
// Parameters must be implictly convertible to the contained type (including via move/copy ctors).
//
// Use as follows:
//
// template <typename... Args>
// std::vector<int> CreateVector(Args&&... args) {
// std::vector<int> result;
// Append(result, std::forward<Args>(args)...);
// return result;
// }
template <typename CollectionType, typename T>
void Append(CollectionType& collection, T&& arg) {
collection.push_back(std::forward<T>(arg));
}
template <typename CollectionType, typename T, typename... Args>
void Append(CollectionType& collection, T&& arg, Args&&... args) {
collection.push_back(std::forward<T>(arg));
return Append(collection, std::forward<Args>(args)...);
}
// Assert that all of the arguments in a variadic template parameter pack are of a given type
// after std::decay.
template <typename T, typename Arg, typename... Args>
void AssertType(Arg&&) {
static_assert(std::is_same<T, typename std::decay<Arg>::type>::value);
}
template <typename T, typename Arg, typename... Args>
void AssertType(Arg&&, Args&&... args) {
static_assert(std::is_same<T, typename std::decay<Arg>::type>::value);
AssertType<T>(std::forward<Args>(args)...);
}
} // namespace base
} // namespace android
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