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- // -*- C++ -*-
- //===----------------------------------------------------------------------===//
- //
- // The LLVM Compiler Infrastructure
- //
- // This file is dual licensed under the MIT and the University of Illinois Open
- // Source Licenses. See LICENSE.TXT for details.
- //
- //===----------------------------------------------------------------------===//
- #ifndef _LIBCPP___SSO_ALLOCATOR
- #define _LIBCPP___SSO_ALLOCATOR
- #include <__config>
- #include <type_traits>
- #include <new>
- #include <__undef___deallocate>
- #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;
- _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 = 0)
- {
- if (!__allocated_ && __n <= _Np)
- {
- __allocated_ = true;
- return (pointer)&buf_;
- }
- return static_cast<pointer>(_VSTD::__allocate(__n * sizeof(_Tp)));
- }
- _LIBCPP_INLINE_VISIBILITY void deallocate(pointer __p, size_type)
- {
- if (__p == (pointer)&buf_)
- __allocated_ = false;
- else
- _VSTD::__deallocate(__p);
- }
- _LIBCPP_INLINE_VISIBILITY size_type max_size() const throw() {return size_type(~0) / sizeof(_Tp);}
- _LIBCPP_INLINE_VISIBILITY
- bool operator==(__sso_allocator& __a) const {return &buf_ == &__a.buf_;}
- _LIBCPP_INLINE_VISIBILITY
- bool operator!=(__sso_allocator& __a) const {return &buf_ != &__a.buf_;}
- };
- _LIBCPP_END_NAMESPACE_STD
- #endif // _LIBCPP___SSO_ALLOCATOR
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