| // -*- 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 |
| #define _LIBCPP___SSO_ALLOCATOR |
| |
| #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; |
| |
| _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==(__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 |