Update copyright years.

[thirdparty/gcc.git] / libstdc++-v3 / include / bits / stl_iterator_base_types.h

diff --git a/libstdc++-v3/include/bits/stl_iterator_base_types.h b/libstdc++-v3/include/bits/stl_iterator_base_types.h
index 1a852591345b8d8fe0f6205753031ad136241bb6..431bf8a62d6bc934731cf6b4bfc04bb3ae167f8a 100644 (file)
--- a/libstdc++-v3/include/bits/stl_iterator_base_types.h
+++ b/libstdc++-v3/include/bits/stl_iterator_base_types.h
@@ -1,7 +1,6 @@
 // Types used in iterator implementation -*- C++ -*-
 
-// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
-// Free Software Foundation, Inc.
+// Copyright (C) 2001-2020 Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
 // software; you can redistribute it and/or modify it under the
@@ -49,9 +48,9 @@
  * purpose.  It is provided "as is" without express or implied warranty.
  */
 
-/** @file stl_iterator_base_types.h
+/** @file bits/stl_iterator_base_types.h
  *  This is an internal header file, included by other library headers.
- *  You should not attempt to use it directly.
+ *  Do not attempt to use it directly. @headername{iterator}
  *
  *  This file contains all of the general iterator-related utility types,
  *  such as iterator_traits and struct iterator.
@@ -64,7 +63,17 @@
 
 #include <bits/c++config.h>
 
-_GLIBCXX_BEGIN_NAMESPACE(std)
+#if __cplusplus >= 201103L
+# include <type_traits>  // For __void_t, is_convertible
+#endif
+
+#if __cplusplus > 201703L && __cpp_concepts
+# include <bits/iterator_concepts.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   /**
    *  @defgroup iterators Iterators
@@ -96,6 +105,11 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
   /// Random-access iterators support a superset of bidirectional
   /// iterator operations.
   struct random_access_iterator_tag : public bidirectional_iterator_tag { };
+
+#if __cplusplus > 201703L
+  /// Contiguous iterators point to objects stored contiguously in memory.
+  struct contiguous_iterator_tag : public random_access_iterator_tag { };
+#endif
   //@}
 
   /**
@@ -132,6 +146,38 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
    *  argument.  Specialized versions for pointers and pointers-to-const
    *  provide tighter, more correct semantics.
   */
+  template<typename _Iterator>
+    struct iterator_traits;
+
+#if __cplusplus >= 201103L
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 2408. SFINAE-friendly common_type/iterator_traits is missing in C++14
+  template<typename _Iterator, typename = __void_t<>>
+    struct __iterator_traits { };
+
+#if ! __cpp_lib_concepts
+
+  template<typename _Iterator>
+    struct __iterator_traits<_Iterator,
+                            __void_t<typename _Iterator::iterator_category,
+                                     typename _Iterator::value_type,
+                                     typename _Iterator::difference_type,
+                                     typename _Iterator::pointer,
+                                     typename _Iterator::reference>>
+    {
+      typedef typename _Iterator::iterator_category iterator_category;
+      typedef typename _Iterator::value_type        value_type;
+      typedef typename _Iterator::difference_type   difference_type;
+      typedef typename _Iterator::pointer           pointer;
+      typedef typename _Iterator::reference         reference;
+    };
+#endif // ! concepts
+
+  template<typename _Iterator>
+    struct iterator_traits
+    : public __iterator_traits<_Iterator> { };
+
+#else // ! C++11
   template<typename _Iterator>
     struct iterator_traits
     {
@@ -141,7 +187,24 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
       typedef typename _Iterator::pointer           pointer;
       typedef typename _Iterator::reference         reference;
     };
+#endif // C++11
 
+#if __cplusplus > 201703L
+  /// Partial specialization for object pointer types.
+  template<typename _Tp>
+#if __cpp_concepts
+    requires is_object_v<_Tp>
+#endif
+    struct iterator_traits<_Tp*>
+    {
+      using iterator_concept  = contiguous_iterator_tag;
+      using iterator_category = random_access_iterator_tag;
+      using value_type       = remove_cv_t<_Tp>;
+      using difference_type   = ptrdiff_t;
+      using pointer          = _Tp*;
+      using reference        = _Tp&;
+    };
+#else
   /// Partial specialization for pointer types.
   template<typename _Tp>
     struct iterator_traits<_Tp*>
@@ -163,37 +226,46 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
       typedef const _Tp*                  pointer;
       typedef const _Tp&                  reference;
     };
+#endif
 
   /**
    *  This function is not a part of the C++ standard but is syntactic
    *  sugar for internal library use only.
   */
   template<typename _Iter>
-    inline typename iterator_traits<_Iter>::iterator_category
+    inline _GLIBCXX_CONSTEXPR
+    typename iterator_traits<_Iter>::iterator_category
     __iterator_category(const _Iter&)
     { return typename iterator_traits<_Iter>::iterator_category(); }
 
   //@}
 
-  // If _Iterator has a base returns it otherwise _Iterator is returned
-  // untouched
-  template<typename _Iterator, bool _HasBase>
-    struct _Iter_base
-    {
-      typedef _Iterator iterator_type;
-      static iterator_type _S_base(_Iterator __it)
-      { return __it; }
-    };
+#if __cplusplus >= 201103L
+  template<typename _Iter>
+    using __iterator_category_t
+      = typename iterator_traits<_Iter>::iterator_category;
 
-  template<typename _Iterator>
-    struct _Iter_base<_Iterator, true>
+  template<typename _InIter>
+    using _RequireInputIter =
+      __enable_if_t<is_convertible<__iterator_category_t<_InIter>,
+                                  input_iterator_tag>::value>;
+
+  template<typename _It,
+          typename _Cat = __iterator_category_t<_It>>
+    struct __is_random_access_iter
+      : is_base_of<random_access_iterator_tag, _Cat>
     {
-      typedef typename _Iterator::iterator_type iterator_type;
-      static iterator_type _S_base(_Iterator __it)
-      { return __it.base(); }
+      typedef is_base_of<random_access_iterator_tag, _Cat> _Base;
+      enum { __value = _Base::value };
     };
+#else
+  template<typename _It, typename _Traits = iterator_traits<_It>,
+          typename _Cat = typename _Traits::iterator_category>
+    struct __is_random_access_iter
+    { enum { __value = __is_base_of(random_access_iterator_tag, _Cat) }; };
+#endif
 
-_GLIBCXX_END_NAMESPACE
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
 
 #endif /* _STL_ITERATOR_BASE_TYPES_H */
-