53 lines
1.2 KiB
C
53 lines
1.2 KiB
C
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#ifndef STACK_ALLOCATOR_H
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#define STACK_ALLOCATOR_H
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#include <cstddef>
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#include <new>
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template <class T, std::size_t N>
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class stack_allocator
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{
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char buf_[sizeof(T)*N];
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char* ptr_;
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public:
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typedef T value_type;
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typedef value_type* pointer;
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typedef const value_type* const_pointer;
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typedef value_type& reference;
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typedef const value_type& const_reference;
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typedef std::size_t size_type;
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typedef std::ptrdiff_t difference_type;
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template <class U> struct rebind {typedef stack_allocator<U, N> other;};
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stack_allocator() : ptr_(buf_) {}
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private:
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stack_allocator(const stack_allocator&);// = delete;
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stack_allocator& operator=(const stack_allocator&);// = delete;
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public:
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pointer allocate(size_type n, const void* = 0)
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{
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if (n > N - (ptr_ - buf_) / sizeof(value_type))
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throw std::bad_alloc();
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pointer r = (T*)ptr_;
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ptr_ += n * sizeof(T);
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return r;
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}
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void deallocate(pointer p, size_type n)
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{
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if ((char*)(p + n) == ptr_)
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ptr_ = (char*)p;
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}
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size_type max_size() const {return N;}
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};
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template <class T, std::size_t N>
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inline
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void
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swap(stack_allocator<T, N>& x, stack_allocator<T, N>& y) {}
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#endif
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