/* ======== SourceMM ========
* Copyright (C) 2004-2005 Metamod:Source Development Team
* No warranties of any kind
*
* License: zlib/libpng
*
* Author(s): David "BAILOPAN" Anderson
* ============================
*/

#ifndef _INCLUDE_SH_TINYHASH_H_
#define _INCLUDE_SH_TINYHASH_H_

#include <time.h>
#include "sh_list.h"

#define _T_INIT_HASH_SIZE	32

//namespace SourceHook
//{
template <class K>
int HashFunction(const K & k);

template <class K>
int Compare(const K & k1, const K & k2);

/**
* This is a tiny, growable hash class.
* Meant for quick and dirty dictionaries only!
*/
template <class K, class V> 
class THash
{
public:
	struct THashNode
	{
		THashNode(const K & k, const V & v) : 
	key(k), val(v)
	{
	};
	THashNode & operator =(const THashNode &other) 
	{ 
		key = other.key; 
		val = other.val; 
	} 
	K key;
	V val;
	time_t stamp;
	};
	typedef List<THashNode *> *	NodePtr;
public:
	class const_iterator;
	THash() : m_Buckets(NULL), m_numBuckets(0), m_percentUsed(0.0f), m_Items(0)
	{
		_Refactor();
	}
	THash(const THash &other) : m_Buckets(new NodePtr[other.numBuckets]),
		m_numBuckets(other.m_numBuckets),
		m_percentUsed(other.m_percentUsed)
	{
		for (size_t i=0; i<m_numBuckets; i++)
			m_Buckets[i] = NULL;
		for (const_iterator iter=other.begin(); iter != other.end(); ++iter)
			_FindOrInsert(iter->key)->val = iter->val;
	}
	void operator=(const THash &other)
	{
		Clear();
		for (const_iterator iter=other.begin(); iter!=other.end(); ++iter)
			_FindOrInsert(iter->key)->val = iter->val;
	}
	~THash()
	{
		_Clear();
	}
	void Clear()
	{
		_Clear();
		_Refactor();
	}
	void Insert(const K & key, const V & val)
	{
		Insert(key, val, time(NULL));
	}
	void Insert(const K & key, const V & val, time_t stamp)
	{
		THashNode *pNode = _FindOrInsert(key);
		pNode->val = val;
		pNode->stamp = stamp;
	}
	bool Exists(const K & key)
	{
		size_t place = HashFunction(key) % m_numBuckets;

		if (!m_Buckets[place])
			return false;

		typename List<THashNode *>::iterator iter;
		for (iter = m_Buckets[place]->begin(); iter != m_Buckets[place]->end(); iter++)
		{
			if (Compare(key, (*iter)->key) == 0)
				return true;
		}
		return false;
	}
	V & Retrieve(const K & k, time_t & stamp)
	{
		THashNode *pNode = _FindOrInsert(k);
		stamp = pNode->stamp;
		return pNode->val;
	}
	V & Retrieve(const K & k)
	{
		time_t stamp;
		return Retrieve(k, stamp);
	}
	void Remove(const K & key)
	{
		size_t place = HashFunction(key) % m_numBuckets;

		if (!m_Buckets[place])
			return;

		typename List<THashNode *>::iterator iter;
		for (iter = m_Buckets[place]->begin(); iter != m_Buckets[place]->end(); iter++)
		{
			if (Compare(key, (*iter)->key) == 0)
			{
				iter = m_Buckets[place]->erase(iter);
				m_Items--;
				return;
			}
		}
	}
	size_t Prune(time_t start=0, time_t end=0)
	{
		typename List<THashNode *>::iterator iter;
		time_t stamp;
		size_t removed = 0;
		for (size_t i=0; i<m_numBuckets; i++)
		{
			if (!m_Buckets[i])
				continue;
			iter = m_Buckets[i]->begin();
			bool remove;
			while (iter != m_Buckets[i]->end())
			{
				stamp = (*iter)->stamp;
				remove = false;
				if (stamp != 0)
				{
					if (start == 0 && end == 0)
						remove = true;
					else if (start == 0 && stamp < end)
						remove = true;
					else if (end == 0 && stamp > start)
						remove = true;
					else if (stamp > start && stamp < end)
						remove = true;
					if (remove)
					{
						iter = m_Buckets[i]->erase(iter);
						removed++;
					} else {
						iter++;
					}
				}
			}
		}
		m_Items -= removed;
		return removed;
	}
	size_t Size()
	{
		return m_Items;
	}
	size_t GetBuckets()
	{
		return m_numBuckets;
	}
	float PercentUsed()
	{
		return m_percentUsed;
	}
	V & operator [](const K & key)
	{
		THashNode *pNode = _FindOrInsert(key);
		return pNode->val;
	}
private:
	void _Clear()
	{
		typename List<THashNode *>::iterator iter, end;
		for (size_t i=0; i<m_numBuckets; i++)
		{
			if (m_Buckets[i])
			{
				end = m_Buckets[i]->end(); 
				iter = m_Buckets[i]->begin(); 
				while (iter != end) 
				{ 
					delete (*iter); 
					iter++; 
				} 
				m_Buckets[i]->clear();
				delete m_Buckets[i];
			}
		}
		if (m_Buckets)
			delete [] m_Buckets;
		m_numBuckets = 0;
		m_Items = 0;
		m_Buckets = NULL;
	}
	THashNode *_FindOrInsert(const K & key)
	{
		size_t place = HashFunction(key) % m_numBuckets;
		THashNode *pNode = NULL;
		if (!m_Buckets[place])
		{
			m_Buckets[place] = new List<THashNode *>;
			pNode = new THashNode(key, V());
			m_Buckets[place]->push_back(pNode);
			m_percentUsed += (1.0f / (float)m_numBuckets);
			m_Items++;
		} else {
			typename List<THashNode *>::iterator iter;
			for (iter=m_Buckets[place]->begin(); iter!=m_Buckets[place]->end(); iter++)
			{
				if (Compare((*iter)->key, key) == 0)
					return (*iter);
			}
			//node does not exist
			pNode = new THashNode(key, V());
			m_Buckets[place]->push_back(pNode);
			m_Items++;
		}
		if (PercentUsed() > 0.75f)
			_Refactor();
		return pNode;
	}
	void _Refactor()
	{
		m_percentUsed = 0.0f;
		if (!m_numBuckets)
		{
			m_numBuckets = _T_INIT_HASH_SIZE;
			m_Buckets = new NodePtr[m_numBuckets];
			for (size_t i=0; i<m_numBuckets; i++)
				m_Buckets[i] = NULL;
		} else {
			size_t oldSize = m_numBuckets;
			m_numBuckets *= 2;
			typename List<THashNode *>::iterator iter;
			size_t place;
			THashNode *pHashNode;
			NodePtr *temp = new NodePtr[m_numBuckets];
			for (size_t i=0; i<m_numBuckets; i++)
				temp[i] = NULL;
			//look in old hash table
			for (size_t i=0; i<oldSize; i++)
			{
				//does a bucket have anything?
				if (m_Buckets[i])
				{
					//go through the list of items
					for (iter = m_Buckets[i]->begin(); iter != m_Buckets[i]->end(); iter++)
					{
						pHashNode = (*iter);
						//rehash it with the new bucket filter
						place = HashFunction(pHashNode->key) % m_numBuckets;
						//add it to the new hash table
						if (!temp[place])
						{
							temp[place] = new List<THashNode *>;
							m_percentUsed += (1.0f / (float)m_numBuckets);
						}
						temp[place]->push_back(pHashNode);
					}
					//delete that bucket!
					delete m_Buckets[i];
					m_Buckets[i] = NULL;
				}
			}
			//reassign bucket table
			delete [] m_Buckets;
			m_Buckets = temp;
		}
	}
public:
	friend class iterator;
	friend class const_iterator;
	class iterator
	{
		friend class THash;
	public:
		iterator() : curbucket(-1), hash(NULL), end(true)
		{
		};
		iterator(THash *h) : curbucket(-1), hash(h), end(false)
		{
			if (!h->m_Buckets)
				end = true;
			else
				_Inc();
		};
		//pre increment
		iterator & operator++()
		{
			_Inc();
			return *this;
		}
		//post increment
		iterator operator++(int)
		{
			iterator old(*this);
			_Inc();
			return old;
		}
		const THashNode & operator * () const
		{
			return *(*iter);
		}
		THashNode & operator * ()
		{
			return *(*iter);
		}
		const THashNode * operator ->() const
		{
			return (*iter);
		}
		THashNode * operator ->()
		{
			return (*iter);
		}
		bool operator ==(const iterator &where) const
		{
			if (where.hash == this->hash
				&& where.end == this->end
				&& 
				(this->end || 
				((where.curbucket == this->curbucket) 
				&& (where.iter == iter))
				))
				return true;
			return false;
		}
		bool operator !=(const iterator &where) const
		{
			return !( (*this) == where );
		}
	private:
		void _Inc()
		{
			if (end || !hash || curbucket >= static_cast<int>(hash->m_numBuckets))
				return;
			if (curbucket < 0)
			{
				for (int i=0; i<(int)hash->m_numBuckets; i++)
				{
					if (hash->m_Buckets[i])
					{
						iter = hash->m_Buckets[i]->begin();
						if (iter == hash->m_Buckets[i]->end())
							continue;
						curbucket = i;
						break;
					}
				}
				if (curbucket < 0)
					end = true;
			} else {
				if (iter != hash->m_Buckets[curbucket]->end())
					iter++;
				if (iter == hash->m_Buckets[curbucket]->end())
				{
					int oldbucket = curbucket;
					for (int i=curbucket+1; i<(int)hash->m_numBuckets; i++)
					{
						if (hash->m_Buckets[i])
						{
							iter = hash->m_Buckets[i]->begin();
							if (iter == hash->m_Buckets[i]->end())
								continue;
							curbucket = i;
							break;
						}
					}
					if (curbucket == oldbucket)
						end = true;
				}
			}
		}
	private:
		int curbucket;
		typename List<THashNode *>::iterator iter;
		THash *hash;
		bool end;
	};
	class const_iterator
	{
		friend class THash;
	public:
		const_iterator() : curbucket(-1), hash(NULL), end(true)
		{
		};
		const_iterator(const THash *h) : curbucket(-1), hash(h), end(true)
		{
			if (!h->m_Buckets)
				end = true;
			else
				_Inc();
		};
		const_iterator & operator++()
		{
			_Inc();
			return *this;
		}
		const_iterator operator++(int)
		{
			iterator old(*this);
			_Inc();
			return old;
		}
		void erase()
		{
			if (end || !hash || curbucket < 0 || curbucket >= static_cast<int>(hash->m_numBuckets))
				return true;

			iterator tmp = *this;
			++tmp;
			delete (*iter);
			hash->m_Items--;
			hash->m_Buckets[curbucket]->erase(iter);
			*this = tmp;
		}
		const THashNode & operator *() const
		{
			return *(*iter);
		}
		const THashNode * operator ->() const
		{
			return (*iter);
		}
		bool operator ==(const const_iterator &where) const
		{
			if (where.hash == this->hash
				&& where.end == this->end
				&&
				(this->end ||
				((where.curbucket == this->curbucket)
				&& (where.iter == iter))
				))
				return true;
			return false;
		}
		bool operator !=(const const_iterator &where) const
		{
			return !((*this)==where);
		}
	private:
		void _Inc()
		{
			if (end || !hash || curbucket >= static_cast<int>(hash->m_numBuckets))
				return;
			if (curbucket < 0)
			{
				for (int i=0; i<(int)hash->m_numBuckets; i++)
				{
					if (hash->m_Buckets[i])
					{
						iter = hash->m_Buckets[i]->begin();
						if (iter == hash->m_Buckets[i]->end())
							continue;
						curbucket = i;
						break;
					}
				}
				if (curbucket < 0)
					end = true;
			} else {
				if (iter != hash->m_Buckets[curbucket]->end())
					iter++;
				if (iter == hash->m_Buckets[curbucket]->end())
				{
					int oldbucket = curbucket;
					for (int i=curbucket+1; i<(int)hash->m_numBuckets; i++)
					{
						if (hash->m_Buckets[i])
						{
							iter = hash->m_Buckets[i]->begin();
							if (iter == hash->m_Buckets[i]->end())
								continue;
							curbucket = i;
							break;
						}
					}
					if (curbucket == oldbucket)
						end = true;
				}
			}
		}
	private:
		int curbucket;
		typename List<THashNode *>::iterator iter;
		const THash *hash;
		bool end;
	};
public:
	iterator begin()
	{
		return iterator(this);
	}
	iterator end()
	{
		iterator iter;
		iter.hash = this;
		return iter;
	}
	const_iterator begin() const
	{
		return const_iterator(this);
	}
	const_iterator end() const
	{
		const_iterator iter;
		iter.hash = this;
		return iter;
	}
	iterator erase(iterator where)
	{
		where.erase();
		return where;
	}
	template <typename U>
		void erase(const U & u)
	{
		iterator iter = find(u);
		if (iter == end())
			return;
		iter.erase();
	}
	template <typename U>
		iterator find(const U & u) const
	{
		iterator b = begin();
		iterator e = end();
		for (iterator iter = b; iter != e; iter++)
		{
			if ( (*iter).key == u )
				return iter;
		}
		return end();
	}
	template <typename U>
		iterator find(const U & u)
	{
		iterator b = begin();
		iterator e = end();
		for (iterator iter = b; iter != e; iter++)
		{
			if ( (*iter).key == u )
				return iter;
		}
		return end();
	}
private:
	NodePtr	*m_Buckets;
	size_t m_numBuckets;
	float m_percentUsed;
	size_t m_Items;
};
//};

#endif //_INCLUDE_SH_TINYHASH_H_