Merge pull request #161 from winner245/input_iterator

Add basic  input iterator support

MyTinySTL/iterator.h

@@ -103,6 +103,10 @@ struct has_iterator_cat_of
 template <class T, class U>
 struct has_iterator_cat_of<T, U, false> : public m_false_type {};
 
+template <class Iter>
+struct is_exactly_input_iterator : public m_bool_constant<has_iterator_cat_of<Iter, input_iterator_tag>::value && 
+    !has_iterator_cat_of<Iter, forward_iterator_tag>::value> {};
+
 template <class Iter>
 struct is_input_iterator : public has_iterator_cat_of<Iter, input_iterator_tag> {};
 

MyTinySTL/stream_iterator.h

@@ -0,0 +1,81 @@
+#ifndef MYTINYSTL_STREAM_ITERATOR_H_
+#define MYTINYSTL_STREAM_ITERATOR_H_
+
+#include "basic_string.h"
+
+namespace mystl
+{
+
+template<typename T, typename CharT = char,
+        typename Traits = std::char_traits<CharT>, typename Dist = ptrdiff_t>
+class istream_iterator
+: public iterator<input_iterator_tag, T, Dist, const T*, const T&>
+{
+public:
+    using char_type = CharT;
+    using traits_type = Traits;
+    using istream_type = std::basic_istream<CharT, Traits>;  
+
+    istream_iterator() /* noexcept(std::is_nothrow_default_constructible<T>::value) */
+        : m_stream{nullptr}, m_value{} {}
+
+    istream_iterator(istream_type& is)
+        : m_stream{std::addressof(is)}
+    { read(); }
+
+    istream_iterator(const istream_iterator& other) /* noexcept(std::is_nothrow_copy_constructible<T>::value) */
+        = default;   // memberwise copy
+
+    istream_iterator& operator=(const istream_iterator&) = default;   // memberwise copy-asgn
+
+    ~istream_iterator() = default;
+
+    const T& operator*() const noexcept {
+        MYSTL_DEBUG(m_stream != nullptr);
+        return m_value;
+    }
+
+    const T* operator->() const noexcept {
+        return std::addressof(*this);
+    }
+
+    istream_iterator& operator++() {
+        MYSTL_DEBUG(m_stream != nullptr);
+        read();
+        return *this;
+    }
+
+     istream_iterator operator++(int) {
+        auto tmp = *this;
+        ++*this;
+        return tmp;
+    }
+
+private:
+    istream_type* m_stream;
+    T m_value; 
+
+    void read() {
+        if (m_stream && !(*m_stream >> m_value)) {  // m_stream 有效且读到 EOS
+            m_stream = nullptr;  
+        }
+    }  
+
+    friend bool operator==(const istream_iterator& lhs, const istream_iterator& rhs) {
+        return lhs.m_stream == rhs.m_stream;
+    }  
+
+    friend bool operator!=(const istream_iterator& lhs, const istream_iterator& rhs) {
+        return lhs.m_stream != rhs.m_stream;
+    }  
+};
+
+
+// TODO 
+// template<typename T, typename CharT = char,
+//          typename Traits = char_traits<CharT> >
+// class ostream_iterator : public iterator<output_iterator_tag, void, void, void, void> {};
+}
+
+
+#endif

Test/iterator_test.h

@@ -0,0 +1,42 @@
+#ifndef MYTINYSTL_ITERATOR_TEST_H_
+#define MYTINYSTL_ITERATOR_TEST_H_
+
+#include "test.h"
+#include "../MyTinySTL/iterator.h"
+#include "../MyTinySTL/stream_iterator.h"
+
+namespace mystl
+{
+namespace test
+{
+namespace iterator_test
+{
+
+void stream_iterator_test()
+{
+  std::cout << "[===============================================================]\n";
+  std::cout << "[------------- Run iterator test : stream_iterator--------------]\n";
+  std::cout << "[-------------------------- API test ---------------------------]\n";
+
+  static_assert(mystl::is_exactly_input_iterator<mystl::istream_iterator<int>>::value, 
+                "istream_iterator must have input_iterator_tag)");
+
+  std::istringstream is("1 2 3");  
+  mystl::istream_iterator<int> first{is}, last;   
+  std::cout << mystl::distance(first, last) << '\n';
+
+  std::istringstream istream("1 2 3 4 5 6");  
+  mystl::istream_iterator<int> beg{istream}, end;  
+  for (; beg != end; ++beg) {
+    std::cout << *beg << " ";
+  }
+  std::cout << '\n';
+
+  PASSED;
+}
+
+} // namespace stream_iterator_test
+} // namespace test
+} // namespace mystl
+#endif // !MYTINYSTL_STREAM_ITERATOR_TEST_H_
+

Test/test.cpp

@@ -20,6 +20,7 @@
 #include "unordered_map_test.h"
 #include "unordered_set_test.h"
 #include "string_test.h"
+#include "iterator_test.h"
 
 int main()
 {
@@ -29,6 +30,7 @@ int main()
 
   RUN_ALL_TESTS();
   algorithm_performance_test::algorithm_performance_test();
+  iterator_test::stream_iterator_test();
   vector_test::vector_test();
   list_test::list_test();
   deque_test::deque_test();