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
|
/*
* 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
|