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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// 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___MEMORY_TEMPORARY_BUFFER_H
#define _LIBCPP___MEMORY_TEMPORARY_BUFFER_H
#include <__config>
#include <__type_traits/alignment_of.h>
#include <__utility/pair.h>
#include <cstddef>
#include <new>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _Tp>
_LIBCPP_NODISCARD_EXT _LIBCPP_NO_CFI _LIBCPP_DEPRECATED_IN_CXX17
pair<_Tp*, ptrdiff_t>
get_temporary_buffer(ptrdiff_t __n) _NOEXCEPT
{
pair<_Tp*, ptrdiff_t> __r(0, 0);
const ptrdiff_t __m = (~ptrdiff_t(0) ^
ptrdiff_t(ptrdiff_t(1) << (sizeof(ptrdiff_t) * __CHAR_BIT__ - 1)))
/ sizeof(_Tp);
if (__n > __m)
__n = __m;
while (__n > 0)
{
#if !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION)
if (__is_overaligned_for_new(_LIBCPP_ALIGNOF(_Tp)))
{
align_val_t __al =
align_val_t(alignment_of<_Tp>::value);
__r.first = static_cast<_Tp*>(::operator new(
__n * sizeof(_Tp), __al, nothrow));
} else {
__r.first = static_cast<_Tp*>(::operator new(
__n * sizeof(_Tp), nothrow));
}
#else
if (__is_overaligned_for_new(_LIBCPP_ALIGNOF(_Tp)))
{
// Since aligned operator new is unavailable, return an empty
// buffer rather than one with invalid alignment.
return __r;
}
__r.first = static_cast<_Tp*>(::operator new(__n * sizeof(_Tp), nothrow));
#endif
if (__r.first)
{
__r.second = __n;
break;
}
__n /= 2;
}
return __r;
}
template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_IN_CXX17
void return_temporary_buffer(_Tp* __p) _NOEXCEPT
{
_VSTD::__libcpp_deallocate_unsized((void*)__p, _LIBCPP_ALIGNOF(_Tp));
}
struct __return_temporary_buffer
{
_LIBCPP_SUPPRESS_DEPRECATED_PUSH
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY void operator()(_Tp* __p) const {_VSTD::return_temporary_buffer(__p);}
_LIBCPP_SUPPRESS_DEPRECATED_POP
};
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___MEMORY_TEMPORARY_BUFFER_H
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