1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___ITERATOR_FRONT_INSERT_ITERATOR_H
11 #define _LIBCPP___ITERATOR_FRONT_INSERT_ITERATOR_H
12 
13 #include <__config>
14 #include <__iterator/iterator.h>
15 #include <__iterator/iterator_traits.h>
16 #include <__memory/addressof.h>
17 #include <__utility/move.h>
18 #include <cstddef>
19 
20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
21 #  pragma GCC system_header
22 #endif
23 
24 _LIBCPP_PUSH_MACROS
25 #include <__undef_macros>
26 
27 _LIBCPP_BEGIN_NAMESPACE_STD
28 
29 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
30 template <class _Container>
31 class _LIBCPP_TEMPLATE_VIS front_insert_iterator
32 #if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
33     : public iterator<output_iterator_tag, void, void, void, void>
34 #endif
35 {
36 _LIBCPP_SUPPRESS_DEPRECATED_POP
37 protected:
38     _Container* container;
39 public:
40     typedef output_iterator_tag iterator_category;
41     typedef void value_type;
42 #if _LIBCPP_STD_VER >= 20
43     typedef ptrdiff_t difference_type;
44 #else
45     typedef void difference_type;
46 #endif
47     typedef void pointer;
48     typedef void reference;
49     typedef _Container container_type;
50 
51     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit front_insert_iterator(_Container& __x) : container(_VSTD::addressof(__x)) {}
52     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 front_insert_iterator& operator=(const typename _Container::value_type& __value)
53         {container->push_front(__value); return *this;}
54 #ifndef _LIBCPP_CXX03_LANG
55     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 front_insert_iterator& operator=(typename _Container::value_type&& __value)
56         {container->push_front(_VSTD::move(__value)); return *this;}
57 #endif // _LIBCPP_CXX03_LANG
58     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 front_insert_iterator& operator*()     {return *this;}
59     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 front_insert_iterator& operator++()    {return *this;}
60     _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 front_insert_iterator  operator++(int) {return *this;}
61 };
62 _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(front_insert_iterator);
63 
64 template <class _Container>
65 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
66 front_insert_iterator<_Container>
67 front_inserter(_Container& __x)
68 {
69     return front_insert_iterator<_Container>(__x);
70 }
71 
72 _LIBCPP_END_NAMESPACE_STD
73 
74 _LIBCPP_POP_MACROS
75 
76 #endif // _LIBCPP___ITERATOR_FRONT_INSERT_ITERATOR_H
77