1 // Copyright 2014 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef V8_BASE_ITERATOR_H_
6 #define V8_BASE_ITERATOR_H_
7 
8 #include <iterator>
9 
10 namespace v8 {
11 namespace base {
12 
13 template <class Category, class Type, class Diff = std::ptrdiff_t,
14           class Pointer = Type*, class Reference = Type&>
15 struct iterator {
16   typedef Category iterator_category;
17   typedef Type value_type;
18   typedef Diff difference_type;
19   typedef Pointer pointer;
20   typedef Reference reference;
21 };
22 
23 // The intention of the base::iterator_range class is to encapsulate two
24 // iterators so that the range defined by the iterators can be used like
25 // a regular STL container (actually only a subset of the full container
26 // functionality is available usually).
27 template <typename ForwardIterator>
28 class iterator_range {
29  public:
30   typedef ForwardIterator iterator;
31   typedef ForwardIterator const_iterator;
32   typedef typename std::iterator_traits<iterator>::pointer pointer;
33   typedef typename std::iterator_traits<iterator>::reference reference;
34   typedef typename std::iterator_traits<iterator>::value_type value_type;
35   typedef
36       typename std::iterator_traits<iterator>::difference_type difference_type;
37 
iterator_range()38   iterator_range() : begin_(), end_() {}
39   template <typename ForwardIterator1, typename ForwardIterator2>
iterator_range(ForwardIterator1 && begin,ForwardIterator2 && end)40   iterator_range(ForwardIterator1&& begin, ForwardIterator2&& end)
41       : begin_(std::forward<ForwardIterator1>(begin)),
42         end_(std::forward<ForwardIterator2>(end)) {}
43 
begin()44   iterator begin() { return begin_; }
end()45   iterator end() { return end_; }
begin()46   const_iterator begin() const { return begin_; }
end()47   const_iterator end() const { return end_; }
cbegin()48   const_iterator cbegin() const { return begin_; }
cend()49   const_iterator cend() const { return end_; }
50 
empty()51   bool empty() const { return cbegin() == cend(); }
52 
53   // Random Access iterators only.
54   reference operator[](difference_type n) { return begin()[n]; }
size()55   difference_type size() const { return cend() - cbegin(); }
56 
57  private:
58   const_iterator const begin_;
59   const_iterator const end_;
60 };
61 
62 }  // namespace base
63 }  // namespace v8
64 
65 #endif  // V8_BASE_ITERATOR_H_
66