// Types used in iterator implementation -*- C++ -*-
-// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
-// 2010, 2011, 2012
-// 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
#include <bits/c++config.h>
#if __cplusplus >= 201103L
-# include <type_traits> // For _GLIBCXX_HAS_NESTED_TYPE, is_convertible
+# 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)
/// 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
//@}
/**
* argument. Specialized versions for pointers and pointers-to-const
* provide tighter, more correct semantics.
*/
-#if __cplusplus >= 201103L
-
-_GLIBCXX_HAS_NESTED_TYPE(iterator_category)
+ template<typename _Iterator>
+ struct iterator_traits;
- template<typename _Iterator,
- bool = __has_iterator_category<_Iterator>::value>
+#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, true>
+ 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::pointer pointer;
typedef typename _Iterator::reference reference;
};
+#endif // ! concepts
template<typename _Iterator>
struct iterator_traits
: public __iterator_traits<_Iterator> { };
-#else
+
+#else // ! C++11
template<typename _Iterator>
struct iterator_traits
{
typedef typename _Iterator::pointer pointer;
typedef typename _Iterator::reference reference;
};
-#endif
+#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*>
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 };
};
-
-#if __cplusplus >= 201103L
- template<typename _InIter>
- using _RequireInputIter = typename
- enable_if<is_convertible<typename
- iterator_traits<_InIter>::iterator_category,
- input_iterator_tag>::value>::type;
+#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_VERSION
} // namespace
#endif /* _STL_ITERATOR_BASE_TYPES_H */
-