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// 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 <iterator>
#include "base/macros.h"
#include "starboard/types.h"
namespace base {
namespace internal {
// Internal adapter class for implementing base::Reversed.
template <typename T>
class ReversedAdapter {
public:
using Iterator = decltype(static_cast<T*>(nullptr)->rbegin());
explicit ReversedAdapter(T& t) : t_(t) {}
ReversedAdapter(const ReversedAdapter& ra) : t_(ra.t_) {}
// TODO(mdempsky): Once we can use C++14 library features, use std::rbegin
// and std::rend instead, so we can remove the specialization below.
Iterator begin() const { return t_.rbegin(); }
Iterator end() const { return t_.rend(); }
private:
T& t_;
DISALLOW_ASSIGN(ReversedAdapter);
};
template <typename T, size_t N>
class ReversedAdapter<T[N]> {
public:
using Iterator = std::reverse_iterator<T*>;
explicit ReversedAdapter(T (&t)[N]) : t_(t) {}
ReversedAdapter(const ReversedAdapter& ra) : t_(ra.t_) {}
Iterator begin() const { return Iterator(&t_[N]); }
Iterator end() const { return Iterator(&t_[0]); }
private:
T (&t_)[N];
DISALLOW_ASSIGN(ReversedAdapter);
};
} // 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<int> v = ...;
// for (int i : base::Reversed(v)) {
// // iterates through v from back to front
// }
template <typename T>
internal::ReversedAdapter<T> Reversed(T& t) {
return internal::ReversedAdapter<T>(t);
}
} // namespace base
#endif // BASE_CONTAINERS_ADAPTERS_H_