333f50d30c
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@114470 91177308-0d34-0410-b5e6-96231b3b80d8
76 lines
2.3 KiB
C++
76 lines
2.3 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___SSO_ALLOCATOR
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#define _LIBCPP___SSO_ALLOCATOR
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#include <__config>
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#include <type_traits>
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#include <new>
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#pragma GCC system_header
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _Tp, size_t _N> class _LIBCPP_HIDDEN __sso_allocator;
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template <size_t _N>
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class _LIBCPP_HIDDEN __sso_allocator<void, _N>
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{
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public:
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typedef const void* const_pointer;
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typedef void value_type;
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};
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template <class _Tp, size_t _N>
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class _LIBCPP_HIDDEN __sso_allocator
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{
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typename aligned_storage<sizeof(_Tp) * _N>::type buf_;
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bool __allocated_;
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public:
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typedef size_t size_type;
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typedef _Tp* pointer;
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typedef _Tp value_type;
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_LIBCPP_INLINE_VISIBILITY __sso_allocator() throw() : __allocated_(false) {}
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_LIBCPP_INLINE_VISIBILITY __sso_allocator(const __sso_allocator&) throw() : __allocated_(false) {}
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template <class _Up> _LIBCPP_INLINE_VISIBILITY __sso_allocator(const __sso_allocator<_Up, _N>&) throw()
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: __allocated_(false) {}
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private:
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__sso_allocator& operator=(const __sso_allocator&);
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public:
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_LIBCPP_INLINE_VISIBILITY pointer allocate(size_type __n, typename __sso_allocator<void, _N>::const_pointer = 0)
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{
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if (!__allocated_ && __n <= _N)
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{
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__allocated_ = true;
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return (pointer)&buf_;
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}
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return static_cast<pointer>(::operator new(__n * sizeof(_Tp)));
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}
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_LIBCPP_INLINE_VISIBILITY void deallocate(pointer __p, size_type)
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{
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if (__p == (pointer)&buf_)
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__allocated_ = false;
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else
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::operator delete(__p);
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}
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_LIBCPP_INLINE_VISIBILITY size_type max_size() const throw() {return size_type(~0) / sizeof(_Tp);}
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_LIBCPP_INLINE_VISIBILITY
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bool operator==(__sso_allocator& __a) const {return &buf_ == &__a.buf_;}
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_LIBCPP_INLINE_VISIBILITY
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bool operator!=(__sso_allocator& __a) const {return &buf_ != &__a.buf_;}
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};
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___SSO_ALLOCATOR
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