1 //===----------------------------------------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #ifndef STACK_ALLOCATOR_H
11 #define STACK_ALLOCATOR_H
12
13 #include <cstddef>
14 #include <new>
15
16 template <class T, std::size_t N>
17 class stack_allocator
18 {
19 char buf_[sizeof(T)*N];
20 char* ptr_;
21 public:
22 typedef T value_type;
23 typedef value_type* pointer;
24 typedef const value_type* const_pointer;
25 typedef value_type& reference;
26 typedef const value_type& const_reference;
27 typedef std::size_t size_type;
28 typedef std::ptrdiff_t difference_type;
29
30 template <class U> struct rebind {typedef stack_allocator<U, N> other;};
31
stack_allocator()32 stack_allocator() : ptr_(buf_) {}
33
34 private:
35 stack_allocator(const stack_allocator&);// = delete;
36 stack_allocator& operator=(const stack_allocator&);// = delete;
37
38 public:
39 pointer allocate(size_type n, const void* = 0)
40 {
41 if (n > N - (ptr_ - buf_) / sizeof(value_type)) {
42 #ifndef _LIBCPP_NO_EXCEPTIONS
43 throw std::bad_alloc();
44 #else
45 std::terminate();
46 #endif
47 }
48 pointer r = (T*)ptr_;
49 ptr_ += n * sizeof(T);
50 return r;
51 }
deallocate(pointer p,size_type n)52 void deallocate(pointer p, size_type n)
53 {
54 if ((char*)(p + n) == ptr_)
55 ptr_ = (char*)p;
56 }
57
max_size()58 size_type max_size() const {return N;}
59 };
60
61 template <class T, std::size_t N>
62 inline
63 void
swap(stack_allocator<T,N> & x,stack_allocator<T,N> & y)64 swap(stack_allocator<T, N>& x, stack_allocator<T, N>& y) {}
65
66 #endif // STACK_ALLOCATOR_H
67