libcxx initial import

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@103490 91177308-0d34-0410-b5e6-96231b3b80d8

test/strings/basic.string/input_iterator.h

@@ -0,0 +1,32 @@
+#ifndef INPUT_ITERATOR_H
+#define INPUT_ITERATOR_H
+
+#include <iterator>
+
+template <class It>
+class input_iterator
+{
+    It it_;
+public:
+    typedef typename std::input_iterator_tag                   iterator_category;
+    typedef typename std::iterator_traits<It>::value_type      value_type;
+    typedef typename std::iterator_traits<It>::difference_type difference_type;
+    typedef It                                                 pointer;
+    typedef typename std::iterator_traits<It>::reference       reference;
+
+    input_iterator() : it_() {}
+    explicit input_iterator(It it) : it_(it) {}
+
+    reference operator*() const {return *it_;}
+    pointer operator->() const {return it_;}
+
+    input_iterator& operator++() {++it_; return *this;}
+    input_iterator operator++(int) {input_iterator tmp(*this); ++(*this); return tmp;}
+
+    friend bool operator==(const input_iterator& x, const input_iterator& y)
+        {return x.it_ == y.it_;}
+    friend bool operator!=(const input_iterator& x, const input_iterator& y)
+        {return !(x == y);}
+};
+
+#endif