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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_SSO_ALLOCATOR_H
#define _LIBCPP_SSO_ALLOCATOR_H
#include <__config>
#include <memory>
#include <new>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _Tp, size_t _Np> class _LIBCPP_HIDDEN __sso_allocator;
template <size_t _Np>
class _LIBCPP_HIDDEN __sso_allocator<void, _Np>
{
public:
typedef const void* const_pointer;
typedef void value_type;
};
template <class _Tp, size_t _Np>
class _LIBCPP_HIDDEN __sso_allocator
{
typename aligned_storage<sizeof(_Tp) * _Np>::type buf_;
bool __allocated_;
public:
typedef size_t size_type;
typedef _Tp* pointer;
typedef _Tp value_type;
template <class U>
struct rebind {
using other = __sso_allocator<U, _Np>;
};
_LIBCPP_INLINE_VISIBILITY __sso_allocator() throw() : __allocated_(false) {}
_LIBCPP_INLINE_VISIBILITY __sso_allocator(const __sso_allocator&) throw() : __allocated_(false) {}
template <class _Up> _LIBCPP_INLINE_VISIBILITY __sso_allocator(const __sso_allocator<_Up, _Np>&) throw()
: __allocated_(false) {}
private:
__sso_allocator& operator=(const __sso_allocator&);
public:
_LIBCPP_INLINE_VISIBILITY pointer allocate(size_type __n, typename __sso_allocator<void, _Np>::const_pointer = nullptr)
{
if (!__allocated_ && __n <= _Np)
{
__allocated_ = true;
return (pointer)&buf_;
}
return allocator<_Tp>().allocate(__n);
}
_LIBCPP_INLINE_VISIBILITY void deallocate(pointer __p, size_type __n)
{
if (__p == (pointer)&buf_)
__allocated_ = false;
else
allocator<_Tp>().deallocate(__p, __n);
}
_LIBCPP_INLINE_VISIBILITY size_type max_size() const throw() {return size_type(~0) / sizeof(_Tp);}
_LIBCPP_INLINE_VISIBILITY
bool operator==(const __sso_allocator& __a) const {return &buf_ == &__a.buf_;}
_LIBCPP_INLINE_VISIBILITY
bool operator!=(const __sso_allocator& __a) const {return &buf_ != &__a.buf_;}
};
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_SSO_ALLOCATOR_H
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