OpenTTD/src/yapf/nodelist.hpp

/* $Id$ */

#ifndef  NODELIST_HPP
#define  NODELIST_HPP

#include "../misc/array.hpp"
#include "../misc/hashtable.hpp"
#include "../misc/binaryheap.hpp"

/** Hash table based node list multi-container class.
 *  Implements open list, closed list and priority queue for A-star
 *  path finder. */
template <class Titem_, int Thash_bits_open_, int Thash_bits_closed_>
class CNodeList_HashTableT {
public:
	/** make Titem_ visible from outside of class */
	typedef Titem_ Titem;
	/** make Titem_::Key a property of HashTable */
	typedef typename Titem_::Key Key;
	/** type that we will use as item container */
	typedef CArrayT<Titem_, 65536, 256> CItemArray;
	/** how pointers to open nodes will be stored */
	typedef CHashTableT<Titem_, Thash_bits_open_  > COpenList;
	/** how pointers to closed nodes will be stored */
	typedef CHashTableT<Titem_, Thash_bits_closed_> CClosedList;
	/** how the priority queue will be managed */
	typedef CBinaryHeapT<Titem_> CPriorityQueue;

protected:
	/** here we store full item data (Titem_) */
	CItemArray            m_arr;
	/** hash table of pointers to open item data */
	COpenList             m_open;
	/** hash table of pointers to closed item data */
	CClosedList           m_closed;
	/** priority queue of pointers to open item data */
	CPriorityQueue        m_open_queue;
	/** new open node under construction */
	Titem                *m_new_node;
public:
	/** default constructor */
	CNodeList_HashTableT()
		: m_open_queue(204800)
	{
		m_new_node = NULL;
	}
	/** destructor */
	~CNodeList_HashTableT()
	{
	}
	/** return number of open nodes */
	FORCEINLINE int OpenCount() {return m_open.Count();}
	/** return number of closed nodes */
	FORCEINLINE int ClosedCount() {return m_closed.Count();}
	/** allocate new data item from m_arr */
	FORCEINLINE Titem_* CreateNewNode()
	{
		if (m_new_node == NULL) m_new_node = &m_arr.Add();
		return m_new_node;
	}
	/** notify the nodelist, that we don't want to discard the given node */
	FORCEINLINE void FoundBestNode(Titem_& item)
	{
		// for now it is enough to invalidate m_new_node if it is our given node
		if (&item == m_new_node)
			m_new_node = NULL;
		// TODO: do we need to store best nodes found in some extra list/array? Probably not now.
	}
	/** insert given item as open node (into m_open and m_open_queue) */
	FORCEINLINE void InsertOpenNode(Titem_& item)
	{
		assert(m_closed.Find(item.GetKey()) == NULL);
		m_open.Push(item);
		// TODO: check if m_open_queue is not full
		assert(!m_open_queue.IsFull());
		m_open_queue.Push(item);
		if (&item == m_new_node)
			m_new_node = NULL;
	}
	/** return the best open node */
	FORCEINLINE Titem_* GetBestOpenNode()
	{
		if (!m_open_queue.IsEmpty()) {
			Titem_& item = m_open_queue.GetHead();
			return &item;
		}
		return NULL;
	}
	/** remove and return the best open node */
	FORCEINLINE Titem_* PopBestOpenNode()
	{
		if (!m_open_queue.IsEmpty()) {
			Titem_& item = m_open_queue.PopHead();
			m_open.Pop(item);
			return &item;
		}
		return NULL;
	}
	/** return the open node specified by a key or NULL if not found */
	FORCEINLINE Titem_* FindOpenNode(const Key& key)
	{
		Titem_* item = m_open.Find(key);
		return item;
	}
	/** remove and return the open node specified by a key */
	FORCEINLINE Titem_& PopOpenNode(const Key& key)
	{
		Titem_& item = m_open.Pop(key);
		int idxPop = m_open_queue.FindLinear(item);
		m_open_queue.RemoveByIdx(idxPop);
		return item;
	}
	/** close node */
	FORCEINLINE void InsertClosedNode(Titem_& item)
	{
		assert(m_open.Find(item.GetKey()) == NULL);
		m_closed.Push(item);
	}
	/** return the closed node specified by a key or NULL if not found */
	FORCEINLINE Titem_* FindClosedNode(const Key& key)
	{
		Titem_* item = m_closed.Find(key);
		return item;
	}

	FORCEINLINE int TotalCount() {return m_arr.Size();}
	FORCEINLINE Titem_& ItemAt(int idx) {return m_arr[idx];}
};

#endif /* NODELIST_HPP */