271 lines
9.5 KiB
C++
271 lines
9.5 KiB
C++
// Types used in iterator implementation -*- C++ -*-
|
|
|
|
// Copyright (C) 2001-2022 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
|
|
// terms of the GNU General Public License as published by the
|
|
// Free Software Foundation; either version 3, or (at your option)
|
|
// any later version.
|
|
|
|
// This library is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU General Public License for more details.
|
|
|
|
// Under Section 7 of GPL version 3, you are granted additional
|
|
// permissions described in the GCC Runtime Library Exception, version
|
|
// 3.1, as published by the Free Software Foundation.
|
|
|
|
// You should have received a copy of the GNU General Public License and
|
|
// a copy of the GCC Runtime Library Exception along with this program;
|
|
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
// <http://www.gnu.org/licenses/>.
|
|
|
|
/*
|
|
*
|
|
* Copyright (c) 1994
|
|
* Hewlett-Packard Company
|
|
*
|
|
* Permission to use, copy, modify, distribute and sell this software
|
|
* and its documentation for any purpose is hereby granted without fee,
|
|
* provided that the above copyright notice appear in all copies and
|
|
* that both that copyright notice and this permission notice appear
|
|
* in supporting documentation. Hewlett-Packard Company makes no
|
|
* representations about the suitability of this software for any
|
|
* purpose. It is provided "as is" without express or implied warranty.
|
|
*
|
|
*
|
|
* Copyright (c) 1996-1998
|
|
* Silicon Graphics Computer Systems, Inc.
|
|
*
|
|
* Permission to use, copy, modify, distribute and sell this software
|
|
* and its documentation for any purpose is hereby granted without fee,
|
|
* provided that the above copyright notice appear in all copies and
|
|
* that both that copyright notice and this permission notice appear
|
|
* in supporting documentation. Silicon Graphics makes no
|
|
* representations about the suitability of this software for any
|
|
* purpose. It is provided "as is" without express or implied warranty.
|
|
*/
|
|
|
|
/** @file bits/stl_iterator_base_types.h
|
|
* This is an internal header file, included by other library headers.
|
|
* 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.
|
|
*/
|
|
|
|
#ifndef _STL_ITERATOR_BASE_TYPES_H
|
|
#define _STL_ITERATOR_BASE_TYPES_H 1
|
|
|
|
#pragma GCC system_header
|
|
|
|
#include <bits/c++config.h>
|
|
|
|
#if __cplusplus >= 201103L
|
|
# include <type_traits> // For __void_t, is_convertible
|
|
#endif
|
|
|
|
#if __cplusplus > 201703L && __cpp_concepts >= 201907L
|
|
# include <bits/iterator_concepts.h>
|
|
#endif
|
|
|
|
namespace std _GLIBCXX_VISIBILITY(default)
|
|
{
|
|
_GLIBCXX_BEGIN_NAMESPACE_VERSION
|
|
|
|
/**
|
|
* @defgroup iterators Iterators
|
|
* Abstractions for uniform iterating through various underlying types.
|
|
*/
|
|
///@{
|
|
|
|
/**
|
|
* @defgroup iterator_tags Iterator Tags
|
|
* These are empty types, used to distinguish different iterators. The
|
|
* distinction is not made by what they contain, but simply by what they
|
|
* are. Different underlying algorithms can then be used based on the
|
|
* different operations supported by different iterator types.
|
|
*/
|
|
///@{
|
|
/// Marking input iterators.
|
|
struct input_iterator_tag { };
|
|
|
|
/// Marking output iterators.
|
|
struct output_iterator_tag { };
|
|
|
|
/// Forward iterators support a superset of input iterator operations.
|
|
struct forward_iterator_tag : public input_iterator_tag { };
|
|
|
|
/// Bidirectional iterators support a superset of forward iterator
|
|
/// operations.
|
|
struct bidirectional_iterator_tag : public forward_iterator_tag { };
|
|
|
|
/// 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
|
|
///@}
|
|
|
|
/**
|
|
* @brief Common %iterator class.
|
|
*
|
|
* This class does nothing but define nested typedefs. %Iterator classes
|
|
* can inherit from this class to save some work. The typedefs are then
|
|
* used in specializations and overloading.
|
|
*
|
|
* In particular, there are no default implementations of requirements
|
|
* such as @c operator++ and the like. (How could there be?)
|
|
*/
|
|
template<typename _Category, typename _Tp, typename _Distance = ptrdiff_t,
|
|
typename _Pointer = _Tp*, typename _Reference = _Tp&>
|
|
struct _GLIBCXX17_DEPRECATED iterator
|
|
{
|
|
/// One of the @link iterator_tags tag types@endlink.
|
|
typedef _Category iterator_category;
|
|
/// The type "pointed to" by the iterator.
|
|
typedef _Tp value_type;
|
|
/// Distance between iterators is represented as this type.
|
|
typedef _Distance difference_type;
|
|
/// This type represents a pointer-to-value_type.
|
|
typedef _Pointer pointer;
|
|
/// This type represents a reference-to-value_type.
|
|
typedef _Reference reference;
|
|
};
|
|
|
|
/**
|
|
* @brief Traits class for iterators.
|
|
*
|
|
* This class does nothing but define nested typedefs. The general
|
|
* version simply @a forwards the nested typedefs from the Iterator
|
|
* 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
|
|
{
|
|
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 // C++11
|
|
|
|
#if __cplusplus > 201703L
|
|
/// Partial specialization for object pointer types.
|
|
template<typename _Tp>
|
|
#if __cpp_concepts >= 201907L
|
|
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 random_access_iterator_tag iterator_category;
|
|
typedef _Tp value_type;
|
|
typedef ptrdiff_t difference_type;
|
|
typedef _Tp* pointer;
|
|
typedef _Tp& reference;
|
|
};
|
|
|
|
/// Partial specialization for const pointer types.
|
|
template<typename _Tp>
|
|
struct iterator_traits<const _Tp*>
|
|
{
|
|
typedef random_access_iterator_tag iterator_category;
|
|
typedef _Tp value_type;
|
|
typedef ptrdiff_t difference_type;
|
|
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 _GLIBCXX_CONSTEXPR
|
|
typename iterator_traits<_Iter>::iterator_category
|
|
__iterator_category(const _Iter&)
|
|
{ return typename iterator_traits<_Iter>::iterator_category(); }
|
|
|
|
///@}
|
|
|
|
#if __cplusplus >= 201103L
|
|
template<typename _Iter>
|
|
using __iterator_category_t
|
|
= typename iterator_traits<_Iter>::iterator_category;
|
|
|
|
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 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_VERSION
|
|
} // namespace
|
|
|
|
#endif /* _STL_ITERATOR_BASE_TYPES_H */
|