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//===----------------------------------------------------------------------===//
//
// 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_ALIGNED_ALLOC_H
#define _LIBCPP___MEMORY_ALIGNED_ALLOC_H
#include <__config>
#include <cstddef>
#include <cstdlib>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#ifndef _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
// Low-level helpers to call the aligned allocation and deallocation functions
// on the target platform. This is used to implement libc++'s own memory
// allocation routines -- if you need to allocate memory inside the library,
// chances are that you want to use `__libcpp_allocate` instead.
//
// Returns the allocated memory, or `nullptr` on failure.
inline _LIBCPP_HIDE_FROM_ABI
void* __libcpp_aligned_alloc(std::size_t __alignment, std::size_t __size) {
# if defined(_LIBCPP_MSVCRT_LIKE)
return ::_aligned_malloc(__size, __alignment);
# elif _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_C11_ALIGNED_ALLOC)
// aligned_alloc() requires that __size is a multiple of __alignment,
// but for C++ [new.delete.general], only states "if the value of an
// alignment argument passed to any of these functions is not a valid
// alignment value, the behavior is undefined".
// To handle calls such as ::operator new(1, std::align_val_t(128)), we
// round __size up to the next multiple of __alignment.
size_t __rounded_size = (__size + __alignment - 1) & ~(__alignment - 1);
// Rounding up could have wrapped around to zero, so we have to add another
// max() ternary to the actual call site to avoid succeeded in that case.
return ::aligned_alloc(__alignment, __size > __rounded_size ? __size : __rounded_size);
# else
void* __result = nullptr;
(void)::posix_memalign(&__result, __alignment, __size);
// If posix_memalign fails, __result is unmodified so we still return `nullptr`.
return __result;
# endif
}
inline _LIBCPP_HIDE_FROM_ABI
void __libcpp_aligned_free(void* __ptr) {
#if defined(_LIBCPP_MSVCRT_LIKE)
::_aligned_free(__ptr);
#else
::free(__ptr);
#endif
}
#endif // !_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___MEMORY_ALIGNED_ALLOC_H
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