#ifndef _STL_STACK_H
#define _STL_STACK_H 1

#include <bits/concept_check.h>
#include <debug/debug.h>

namespace std _GLIBCXX_VISIBILITY(default) {
	_GLIBCXX_BEGIN_NAMESPACE_VERSION

	/**
	 *  @brief  A standard container giving FILO behavior.
	 *
	 *  @ingroup sequences
	 *
	 *  @tparam _Tp  Type of element.
	 *  @tparam _Sequence  Type of underlying sequence, defaults to deque<_Tp>.
	 *
	 *  Meets many of the requirements of a
	 *  <a href="tables.html#65">container</a>,
	 *  but does not define anything to do with iterators.  Very few of the
	 *  other standard container interfaces are defined.
	 *
	 *  This is not a true container, but an @e adaptor.  It holds
	 *  another container, and provides a wrapper interface to that
	 *  container.  The wrapper is what enforces strict
	 *  first-in-last-out %stack behavior.
	 *
	 *  The second template parameter defines the type of the underlying
	 *  sequence/container.  It defaults to std::deque, but it can be
	 *  any type that supports @c back, @c push_back, and @c pop_front,
	 *  such as std::list, std::vector, or an appropriate user-defined
	 *  type.
	 *
	 *  Members not found in @a normal containers are @c container_type,
	 *  which is a typedef for the second Sequence parameter, and @c
	 *  push, @c pop, and @c top, which are standard %stack/FILO
	 *  operations.
	*/
	template<typename _Tp, typename _Sequence = deque<_Tp> >
	class stack {
			// concept requirements
			typedef typename _Sequence::value_type _Sequence_value_type;
			__glibcxx_class_requires(_Tp, _SGIAssignableConcept)
			__glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
			__glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)

			template<typename _Tp1, typename _Seq1>
			friend bool
			operator==(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&);

			template<typename _Tp1, typename _Seq1>
			friend bool
			operator<(const stack<_Tp1, _Seq1>&, const stack<_Tp1, _Seq1>&);

		public:
			typedef typename _Sequence::value_type                value_type;
			typedef typename _Sequence::reference                 reference;
			typedef typename _Sequence::const_reference           const_reference;
			typedef typename _Sequence::size_type                 size_type;
			typedef          _Sequence                            container_type;

		protected:
			//  See queue::c for notes on this name.
			_Sequence c;

		public:
			// XXX removed old def ctor, added def arg to this one to match 14882
			/**
			 *  @brief  Default constructor creates no elements.
			 */
#if __cplusplus < 201103L
			explicit
			stack(const _Sequence& __c = _Sequence())
				: c(__c) { }
#else
			explicit
			stack(const _Sequence& __c)
				: c(__c) { }

			explicit
			stack(_Sequence&& __c = _Sequence())
				: c(std::move(__c)) { }
#endif

			/**
			 *  Returns true if the %stack is empty.
			 */
			bool
			empty() const {
				return c.empty();
			}

			/**  Returns the number of elements in the %stack.  */
			size_type
			size() const {
				return c.size();
			}

			/**
			 *  Returns a read/write reference to the data at the first
			 *  element of the %stack.
			 */
			reference
			top() {
				__glibcxx_requires_nonempty();
				return c.back();
			}

			/**
			 *  Returns a read-only (constant) reference to the data at the first
			 *  element of the %stack.
			 */
			const_reference
			top() const {
				__glibcxx_requires_nonempty();
				return c.back();
			}

			/**
			 *  @brief  Add data to the top of the %stack.
			 *  @param  __x  Data to be added.
			 *
			 *  This is a typical %stack operation.  The function creates an
			 *  element at the top of the %stack and assigns the given data
			 *  to it.  The time complexity of the operation depends on the
			 *  underlying sequence.
			 */
			void
			push(const value_type& __x) {
				c.push_back(__x);
			}

#if __cplusplus >= 201103L
			void
			push(value_type&& __x) {
				c.push_back(std::move(__x));
			}

			template<typename... _Args>
			void
			emplace(_Args&&... __args) {
				c.emplace_back(std::forward<_Args>(__args)...);
			}
#endif

			/**
			 *  @brief  Removes first element.
			 *
			 *  This is a typical %stack operation.  It shrinks the %stack
			 *  by one.  The time complexity of the operation depends on the
			 *  underlying sequence.
			 *
			 *  Note that no data is returned, and if the first element's
			 *  data is needed, it should be retrieved before pop() is
			 *  called.
			 */
			void
			pop() {
				__glibcxx_requires_nonempty();
				c.pop_back();
			}

#if __cplusplus >= 201103L
			void
			swap(stack& __s)
			noexcept(noexcept(swap(c, __s.c))) {
				using std::swap;
				swap(c, __s.c);
			}
#endif
	};

	/**
	 *  @brief  Stack equality comparison.
	 *  @param  __x  A %stack.
	 *  @param  __y  A %stack of the same type as @a __x.
	 *  @return  True iff the size and elements of the stacks are equal.
	 *
	 *  This is an equivalence relation.  Complexity and semantics
	 *  depend on the underlying sequence type, but the expected rules
	 *  are: this relation is linear in the size of the sequences, and
	 *  stacks are considered equivalent if their sequences compare
	 *  equal.
	*/
	template<typename _Tp, typename _Seq>
	inline bool
	operator==(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) {
		return __x.c == __y.c;
	}

	/**
	 *  @brief  Stack ordering relation.
	 *  @param  __x  A %stack.
	 *  @param  __y  A %stack of the same type as @a x.
	 *  @return  True iff @a x is lexicographically less than @a __y.
	 *
	 *  This is an total ordering relation.  Complexity and semantics
	 *  depend on the underlying sequence type, but the expected rules
	 *  are: this relation is linear in the size of the sequences, the
	 *  elements must be comparable with @c <, and
	 *  std::lexicographical_compare() is usually used to make the
	 *  determination.
	*/
	template<typename _Tp, typename _Seq>
	inline bool
	operator<(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) {
		return __x.c < __y.c;
	}

	/// Based on operator==
	template<typename _Tp, typename _Seq>
	inline bool
	operator!=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) {
		return !(__x == __y);
	}

	/// Based on operator<
	template<typename _Tp, typename _Seq>
	inline bool
	operator>(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) {
		return __y < __x;
	}

	/// Based on operator<
	template<typename _Tp, typename _Seq>
	inline bool
	operator<=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) {
		return !(__y < __x);
	}

	/// Based on operator<
	template<typename _Tp, typename _Seq>
	inline bool
	operator>=(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y) {
		return !(__x < __y);
	}

#if __cplusplus >= 201103L
	template<typename _Tp, typename _Seq>
	inline void
	swap(stack<_Tp, _Seq>& __x, stack<_Tp, _Seq>& __y)
	noexcept(noexcept(__x.swap(__y))) {
		__x.swap(__y);
	}

	template<typename _Tp, typename _Seq, typename _Alloc>
	struct uses_allocator<stack<_Tp, _Seq>, _Alloc>
			: public uses_allocator<_Seq, _Alloc>::type { };
#endif

	_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif /* _STL_STACK_H */