//
// mp::short_queue
//
// Copyright (C) 2008 FURUHASHI Sadayuki
//
//    Licensed under the Apache License, Version 2.0 (the "License");
//    you may not use this file except in compliance with the License.
//    You may obtain a copy of the License at
//
//        http://www.apache.org/licenses/LICENSE-2.0
//
//    Unless required by applicable law or agreed to in writing, software
//    distributed under the License is distributed on an "AS IS" BASIS,
//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//    See the License for the specific language governing permissions and
//    limitations under the License.
//

#ifndef MP_SHORT_QUEUE_H__
#define MP_SHORT_QUEUE_H__

namespace mp {


template <typename T>
struct short_queue_item {
	char object[sizeof(T)];
	short_queue_item<T>* next;
};

template <typename T, typename Allocator = std::allocator<short_queue_item<T> > >
class short_queue {
public:
	short_queue();
	~short_queue();

public:
	typedef T value_type;
	typedef T* pointer;
	typedef const T* const_pointer;
	typedef T& reference;
	typedef const T& const_reference;
	typedef size_t size_type;
	typedef ptrdiff_t difference_type;
	typedef Allocator allocator_type;

public:
	typedef short_queue_item<T> item_t;

	class iterator {
	public:
		iterator() : node(NULL) {}
		iterator(item_t* n) : node(n) {}

	public:
		typedef ptrdiff_t difference_type;
		typedef std::forward_iterator_tag iterator_category;
		typedef T value_type;
		typedef T* pointer;
		typedef T& reference;

	public:
		reference operator* () const
		{ return *reinterpret_cast<pointer>(node->object); }

		pointer   operator-> () const
		{ return reinterpret_cast<pointer>(node->object);  }

		iterator& operator++ ()
		{ node = node->next;
		  return *this; }

		iterator  operator++ (int)
		{ iterator tmp = *this;
		  node = node->next;
		  return tmp; }

		bool      operator== (const iterator& x) const
		{ return node == x.node; }

		bool      operator!= (const iterator& x) const
		{ return node != x.node; }

	private:
		item_t* node;
	};

	class const_iterator {
	public:
		const_iterator() : node(NULL) {}
		const_iterator(const item_t* n) : node(n) {}

	public:
		typedef ptrdiff_t difference_type;
		typedef std::forward_iterator_tag iterator_category;
		typedef T value_type;
		typedef const T* pointer;
		typedef const T& reference;

	public:
		reference operator* () const
		{ return *reinterpret_cast<pointer>(node->object); }

		pointer   operator-> () const
		{ return reinterpret_cast<pointer>(node->object);  }

		iterator& operator++ ()
		{ node = node->next;
		  return *this; }

		iterator  operator++ (int)
		{ iterator tmp = *this;
		  node = node->next;
		  return tmp; }

		bool      operator== (const iterator& x) const
		{ return node == x.node; }

		bool      operator!= (const iterator& x) const
		{ return node != x.node; }

	private:
		const item_t* node;
	};

public:
	void push();
MP_ARGS_BEGIN
	template <MP_ARGS_TEMPLATE>
	void push(MP_ARGS_PARAMS);
MP_ARGS_END

	void pop();

	void clear();

	iterator begin();
	iterator end();

	reference top();
	const_reference top() const;

	bool empty() const;

private:
	item_t* start;

private:
	allocator_type get_allocator() const;
};


}  // namespace mp

#include "mp/short_queue_impl.h"

#endif /* mp/short_queue.h */