// Copyright 2014 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef BASE_CONTAINERS_ADAPTERS_H_ #define BASE_CONTAINERS_ADAPTERS_H_ #include #include #include namespace base { namespace internal { // Internal adapter class for implementing base::Reversed. template class ReversedAdapter { public: using Iterator = decltype(std::rbegin(std::declval())); explicit ReversedAdapter(T& t) : t_(t) {} ReversedAdapter(const ReversedAdapter& ra) : t_(ra.t_) {} ReversedAdapter& operator=(const ReversedAdapter&) = delete; Iterator begin() const { return std::rbegin(t_); } Iterator end() const { return std::rend(t_); } private: T& t_; }; } // namespace internal // Reversed returns a container adapter usable in a range-based "for" statement // for iterating a reversible container in reverse order. // // Example: // // std::vector v = ...; // for (int i : base::Reversed(v)) { // // iterates through v from back to front // } template internal::ReversedAdapter Reversed(T& t) { return internal::ReversedAdapter(t); } } // namespace base #endif // BASE_CONTAINERS_ADAPTERS_H_