// The vector base class serves two purposes. First, its constructor// and destructor allocate (but don't initialize) storage. This makes// exception safety easier. Second, the base class encapsulates all of// the differences between SGI-style allocators and standard-conforming// allocators.#ifdef __STL_USE_STD_ALLOCATORS// Base class for ordinary allocators.template <class _Tp, class _Allocator, bool _IsStatic>class _Vector_alloc_base {public: typedef typename _Alloc_traits<_Tp, _Allocator>::allocator_type allocator_type; allocator_type get_allocator() const { return _M_data_allocator; } _Vector_alloc_base(const allocator_type& __a) : _M_data_allocator(__a), _M_start(0), _M_finish(0), _M_end_of_storage(0) {} protected: allocator_type _M_data_allocator; _Tp* _M_start; _Tp* _M_finish; _Tp* _M_end_of_storage; _Tp* _M_allocate(size_t __n) { return _M_data_allocator.allocate(__n); } void _M_deallocate(_Tp* __p, size_t __n) { if (__p) _M_data_allocator.deallocate(__p, __n); }};
// Specialization for allocators that have the property that we don't// actually have to store an allocator object. template <class _Tp, class _Allocator>class _Vector_alloc_base<_Tp, _Allocator, true> {public: typedef typename _Alloc_traits<_Tp, _Allocator>::allocator_type allocator_type; allocator_type get_allocator() const { return allocator_type(); } _Vector_alloc_base(const allocator_type&) : _M_start(0), _M_finish(0), _M_end_of_storage(0) {} protected: _Tp* _M_start; _Tp* _M_finish; _Tp* _M_end_of_storage; typedef typename _Alloc_traits<_Tp, _Allocator>::_Alloc_type _Alloc_type; _Tp* _M_allocate(size_t __n) { return _Alloc_type::allocate(__n); } void _M_deallocate(_Tp* __p, size_t __n) { _Alloc_type::deallocate(__p, __n);}};template <class _Tp, class _Alloc>struct _Vector_base : public _Vector_alloc_base<_Tp, _Alloc, _Alloc_traits<_Tp, _Alloc>::_S_instanceless>{ typedef _Vector_alloc_base<_Tp, _Alloc, _Alloc_traits<_Tp, _Alloc>::_S_instanceless> _Base; typedef typename _Base::allocator_type allocator_type; _Vector_base(const allocator_type& __a) : _Base(__a) {} _Vector_base(size_t __n, const allocator_type& __a) : _Base(__a) { _M_start = _M_allocate(__n); _M_finish = _M_start; _M_end_of_storage = _M_start + __n; } ~_Vector_base() { _M_deallocate(_M_start, _M_end_of_storage - _M_start); }};
template <class _Tp, class _Alloc> class _Vector_base {public: typedef _Alloc allocator_type; allocator_type get_allocator() const { return allocator_type(); } _Vector_base(const _Alloc&) : _M_start(0), _M_finish(0), _M_end_of_storage(0) {} _Vector_base(size_t __n, const _Alloc&) : _M_start(0), _M_finish(0), _M_end_of_storage(0) { _M_start = _M_allocate(__n); _M_finish = _M_start; _M_end_of_storage = _M_start + __n; } ~_Vector_base() { _M_deallocate(_M_start, _M_end_of_storage - _M_start); }protected: _Tp* _M_start; _Tp* _M_finish; _Tp* _M_end_of_storage; typedef simple_alloc<_Tp, _Alloc> _M_data_allocator; _Tp* _M_allocate(size_t __n) { return _M_data_allocator::allocate(__n); } void _M_deallocate(_Tp* __p, size_t __n) { _M_data_allocator::deallocate(__p, __n); }};
