| 1 | // <cast.h> -*- C++ -*-
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| 2 |
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| 3 | // Copyright (C) 2008-2021 Free Software Foundation, Inc.
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| 4 | //
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| 5 | // This file is part of the GNU ISO C++ Library. This library is free
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| 6 | // software; you can redistribute it and/or modify it under the
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| 7 | // terms of the GNU General Public License as published by the
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| 8 | // Free Software Foundation; either version 3, or (at your option)
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| 9 | // any later version.
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| 10 |
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| 11 | // This library is distributed in the hope that it will be useful,
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| 12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 14 | // GNU General Public License for more details.
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| 15 |
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| 16 | // Under Section 7 of GPL version 3, you are granted additional
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| 17 | // permissions described in the GCC Runtime Library Exception, version
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| 18 | // 3.1, as published by the Free Software Foundation.
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| 19 |
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| 20 | // You should have received a copy of the GNU General Public License and
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| 21 | // a copy of the GCC Runtime Library Exception along with this program;
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| 22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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| 23 | // <http://www.gnu.org/licenses/>.
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| 24 |
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| 25 | /** @file ext/cast.h
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| 26 | * This is an internal header file, included by other library headers.
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| 27 | * Do not attempt to use it directly. @headername{ext/pointer.h}
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| 28 | */
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| 29 |
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| 30 | #ifndef _GLIBCXX_CAST_H
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| 31 | #define _GLIBCXX_CAST_H 1
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| 32 |
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| 33 | namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
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| 34 | {
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| 35 | _GLIBCXX_BEGIN_NAMESPACE_VERSION
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| 36 |
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| 37 | /**
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| 38 | * These functions are here to allow containers to support non standard
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| 39 | * pointer types. For normal pointers, these resolve to the use of the
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| 40 | * standard cast operation. For other types the functions will perform
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| 41 | * the appropriate cast to/from the custom pointer class so long as that
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| 42 | * class meets the following conditions:
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| 43 | * 1) has a typedef element_type which names tehe type it points to.
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| 44 | * 2) has a get() const method which returns element_type*.
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| 45 | * 3) has a constructor which can take one element_type* argument.
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| 46 | */
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| 47 |
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| 48 | /**
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| 49 | * This type supports the semantics of the pointer cast operators (below.)
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| 50 | */
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| 51 | template<typename _ToType>
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| 52 | struct _Caster
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| 53 | { typedef typename _ToType::element_type* type; };
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| 54 |
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| 55 | template<typename _ToType>
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| 56 | struct _Caster<_ToType*>
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| 57 | { typedef _ToType* type; };
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| 58 |
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| 59 | /**
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| 60 | * Casting operations for cases where _FromType is not a standard pointer.
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| 61 | * _ToType can be a standard or non-standard pointer. Given that _FromType
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| 62 | * is not a pointer, it must have a get() method that returns the standard
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| 63 | * pointer equivalent of the address it points to, and must have an
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| 64 | * element_type typedef which names the type it points to.
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| 65 | */
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| 66 | template<typename _ToType, typename _FromType>
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| 67 | inline _ToType
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| 68 | __static_pointer_cast(const _FromType& __arg)
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| 69 | { return _ToType(static_cast<typename _Caster<_ToType>::
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| 70 | type>(__arg.get())); }
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| 71 |
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| 72 | template<typename _ToType, typename _FromType>
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| 73 | inline _ToType
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| 74 | __dynamic_pointer_cast(const _FromType& __arg)
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| 75 | { return _ToType(dynamic_cast<typename _Caster<_ToType>::
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| 76 | type>(__arg.get())); }
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| 77 |
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| 78 | template<typename _ToType, typename _FromType>
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| 79 | inline _ToType
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| 80 | __const_pointer_cast(const _FromType& __arg)
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| 81 | { return _ToType(const_cast<typename _Caster<_ToType>::
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| 82 | type>(__arg.get())); }
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| 83 |
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| 84 | template<typename _ToType, typename _FromType>
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| 85 | inline _ToType
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| 86 | __reinterpret_pointer_cast(const _FromType& __arg)
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| 87 | { return _ToType(reinterpret_cast<typename _Caster<_ToType>::
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| 88 | type>(__arg.get())); }
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| 89 |
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| 90 | /**
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| 91 | * Casting operations for cases where _FromType is a standard pointer.
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| 92 | * _ToType can be a standard or non-standard pointer.
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| 93 | */
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| 94 | template<typename _ToType, typename _FromType>
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| 95 | inline _ToType
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| 96 | __static_pointer_cast(_FromType* __arg)
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| 97 | { return _ToType(static_cast<typename _Caster<_ToType>::
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| 98 | type>(__arg)); }
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| 99 |
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| 100 | template<typename _ToType, typename _FromType>
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| 101 | inline _ToType
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| 102 | __dynamic_pointer_cast(_FromType* __arg)
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| 103 | { return _ToType(dynamic_cast<typename _Caster<_ToType>::
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| 104 | type>(__arg)); }
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| 105 |
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| 106 | template<typename _ToType, typename _FromType>
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| 107 | inline _ToType
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| 108 | __const_pointer_cast(_FromType* __arg)
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| 109 | { return _ToType(const_cast<typename _Caster<_ToType>::
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| 110 | type>(__arg)); }
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| 111 |
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| 112 | template<typename _ToType, typename _FromType>
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| 113 | inline _ToType
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| 114 | __reinterpret_pointer_cast(_FromType* __arg)
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| 115 | { return _ToType(reinterpret_cast<typename _Caster<_ToType>::
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| 116 | type>(__arg)); }
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| 117 |
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| 118 | _GLIBCXX_END_NAMESPACE_VERSION
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| 119 | } // namespace
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| 120 |
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| 121 | #endif // _GLIBCXX_CAST_H
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