chromium/third_party/libc++/src/include/__iterator/aliasing_iterator.h

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___ITERATOR_ALIASING_ITERATOR_H
#define _LIBCPP___ITERATOR_ALIASING_ITERATOR_H

#include <__config>
#include <__iterator/iterator_traits.h>
#include <__memory/pointer_traits.h>
#include <__type_traits/is_trivial.h>
#include <cstddef>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

// This iterator wrapper is used to type-pun an iterator to return a different type. This is done without UB by not
// actually punning the type, but instead inspecting the object representation of the base type and copying that into
// an instance of the alias type. For that reason the alias type has to be trivial. The alias is returned as a prvalue
// when derferencing the iterator, since it is temporary storage. This wrapper is used to vectorize some algorithms.

_LIBCPP_BEGIN_NAMESPACE_STD

template <class _BaseIter, class _Alias>
struct __aliasing_iterator_wrapper { … };

// This is required to avoid ADL instantiations on _BaseT
__aliasing_iterator;

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___ITERATOR_ALIASING_ITERATOR_H