//---------------------------------------------------------------
// Synapse Gaming - Hash Map
// Copyright © Synapse Gaming 2004 - 2005
// Written by John Kabus
//---------------------------------------------------------------

#ifndef HASHMAP_H_
#define HASHMAP_H_

#include "platform/types.h"
#include "core/tVector.h"


template<class T, class Tinfo> class hash_multimap
{
public:
	U32 hashCode;
	// entry level info or single object per-entry...
	Tinfo info;
	// for storing multiple objects per-entry...
	Vector<T> object;
	hash_multimap *mapHigh;
	hash_multimap *mapLow;
	hash_multimap *linkHigh;
	hash_multimap *linkLow;
	hash_multimap()
	{
		// theoretical mean for hash code (balance the tree)...
		hashCode = 0x7fffffff;
		// this unfortunately clears objects after the constructor
		// setups up values, but is necessary for clearing pointers...
		dMemset(&info, 0, sizeof(Tinfo));
		mapHigh = mapLow = linkHigh = linkLow = NULL;
	}
	hash_multimap(U32 hashcode)
	{
		hashCode = hashcode;
		// this unfortunately clears objects after the constructor
		// setups up values, but is necessary for clearing pointers...
		dMemset(&info, 0, sizeof(Tinfo));
		mapHigh = mapLow = linkHigh = linkLow = NULL;
	}
	virtual ~hash_multimap()
	{
		clear();
	}
	void clear()
	{
		if(mapHigh)
			delete mapHigh;
		if(mapLow)
			delete mapLow;
		mapHigh = mapLow = linkHigh = linkLow = NULL;
	}
	void relink(hash_multimap *high, hash_multimap *low, hash_multimap *insert)
	{
		if(high)
			high->linkLow = insert;
		if(low)
			low->linkHigh = insert;
		insert->linkHigh = high;
		insert->linkLow = low;
	}
	hash_multimap *find(U32 hashcode)
	{
		if(hashcode == hashCode)
			return this;
		else if(hashcode < hashCode)
		{
			if(!mapLow)
			{
				mapLow = new hash_multimap(hashcode);
				relink(this, this->linkLow, mapLow);
				return mapLow;
			}
			return mapLow->find(hashcode);
		}
		else
		{
			if(!mapHigh)
			{
				mapHigh = new hash_multimap(hashcode);
				relink(this->linkHigh, this, mapHigh);
				return mapHigh;
			}
			return mapHigh->find(hashcode);
		}
	}
};


#endif//HASHMAP_H_