1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef INPUT_ITERATOR_H
11 #define INPUT_ITERATOR_H
12 
13 #include <iterator>
14 
15 template <class It>
16 class input_iterator
17 {
18     It it_;
19 public:
20     typedef typename std::input_iterator_tag                   iterator_category;
21     typedef typename std::iterator_traits<It>::value_type      value_type;
22     typedef typename std::iterator_traits<It>::difference_type difference_type;
23     typedef It                                                 pointer;
24     typedef typename std::iterator_traits<It>::reference       reference;
25 
input_iterator()26     input_iterator() : it_() {}
input_iterator(It it)27     explicit input_iterator(It it) : it_(it) {}
28 
29     reference operator*() const {return *it_;}
30     pointer operator->() const {return it_;}
31 
32     input_iterator& operator++() {++it_; return *this;}
33     input_iterator operator++(int) {input_iterator tmp(*this); ++(*this); return tmp;}
34 
35     friend bool operator==(const input_iterator& x, const input_iterator& y)
36         {return x.it_ == y.it_;}
37     friend bool operator!=(const input_iterator& x, const input_iterator& y)
38         {return !(x == y);}
39 };
40 
41 #endif  // INPUT_ITERATOR_H
42