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1 // Copyright 2014 The Chromium Authors. All rights reserved. | 1 // Copyright 2014 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef BASE_CONTAINERS_ADAPTERS_H_ | 5 #ifndef BASE_CONTAINERS_ADAPTERS_H_ |
6 #define BASE_CONTAINERS_ADAPTERS_H_ | 6 #define BASE_CONTAINERS_ADAPTERS_H_ |
7 | 7 |
| 8 #include <stddef.h> |
| 9 |
| 10 #include <iterator> |
| 11 |
8 #include "base/macros.h" | 12 #include "base/macros.h" |
9 | 13 |
10 namespace base { | 14 namespace base { |
11 | 15 |
12 namespace internal { | 16 namespace internal { |
13 | 17 |
14 // Internal adapter class for implementing base::Reversed. | 18 // Internal adapter class for implementing base::Reversed. |
15 template <typename T> | 19 template <typename T> |
16 class ReversedAdapter { | 20 class ReversedAdapter { |
17 public: | 21 public: |
18 typedef decltype(static_cast<T*>(nullptr)->rbegin()) Iterator; | 22 using Iterator = decltype(static_cast<T*>(nullptr)->rbegin()); |
19 | 23 |
20 explicit ReversedAdapter(T& t) : t_(t) {} | 24 explicit ReversedAdapter(T& t) : t_(t) {} |
21 ReversedAdapter(const ReversedAdapter& ra) : t_(ra.t_) {} | 25 ReversedAdapter(const ReversedAdapter& ra) : t_(ra.t_) {} |
22 | 26 |
| 27 // TODO(mdempsky): Once we can use C++14 library features, use std::rbegin |
| 28 // and std::rend instead, so we can remove the specialization below. |
23 Iterator begin() const { return t_.rbegin(); } | 29 Iterator begin() const { return t_.rbegin(); } |
24 Iterator end() const { return t_.rend(); } | 30 Iterator end() const { return t_.rend(); } |
25 | 31 |
26 private: | 32 private: |
27 T& t_; | 33 T& t_; |
28 | 34 |
29 DISALLOW_ASSIGN(ReversedAdapter); | 35 DISALLOW_ASSIGN(ReversedAdapter); |
30 }; | 36 }; |
31 | 37 |
| 38 template <typename T, size_t N> |
| 39 class ReversedAdapter<T[N]> { |
| 40 public: |
| 41 using Iterator = std::reverse_iterator<T*>; |
| 42 |
| 43 explicit ReversedAdapter(T (&t)[N]) : t_(t) {} |
| 44 ReversedAdapter(const ReversedAdapter& ra) : t_(ra.t_) {} |
| 45 |
| 46 Iterator begin() const { return Iterator(&t_[N]); } |
| 47 Iterator end() const { return Iterator(&t_[0]); } |
| 48 |
| 49 private: |
| 50 T (&t_)[N]; |
| 51 |
| 52 DISALLOW_ASSIGN(ReversedAdapter); |
| 53 }; |
| 54 |
32 } // namespace internal | 55 } // namespace internal |
33 | 56 |
34 // Reversed returns a container adapter usable in a range-based "for" statement | 57 // Reversed returns a container adapter usable in a range-based "for" statement |
35 // for iterating a reversible container in reverse order. | 58 // for iterating a reversible container in reverse order. |
36 // | 59 // |
37 // Example: | 60 // Example: |
38 // | 61 // |
39 // std::vector<int> v = ...; | 62 // std::vector<int> v = ...; |
40 // for (int i : base::Reversed(v)) { | 63 // for (int i : base::Reversed(v)) { |
41 // // iterates through v from back to front | 64 // // iterates through v from back to front |
42 // } | 65 // } |
43 template <typename T> | 66 template <typename T> |
44 internal::ReversedAdapter<T> Reversed(T& t) { | 67 internal::ReversedAdapter<T> Reversed(T& t) { |
45 return internal::ReversedAdapter<T>(t); | 68 return internal::ReversedAdapter<T>(t); |
46 } | 69 } |
47 | 70 |
48 } // namespace base | 71 } // namespace base |
49 | 72 |
50 #endif // BASE_CONTAINERS_ADAPTERS_H_ | 73 #endif // BASE_CONTAINERS_ADAPTERS_H_ |
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