KUDr@5633: /* $Id$ */
KUDr@5633: 
belugas@6481: /** @file hashtable.hpp */
belugas@6481: 
KUDr@5633: #ifndef  HASHTABLE_HPP
KUDr@5633: #define  HASHTABLE_HPP
KUDr@5633: 
KUDr@5633: template <class Titem_>
KUDr@5633: struct CHashTableSlotT
KUDr@5633: {
KUDr@5633: 	typedef typename Titem_::Key Key;          // make Titem_::Key a property of HashTable
KUDr@5633: 
KUDr@5633: 	Titem_*    m_pFirst;
KUDr@5633: 
KUDr@5633: 	CHashTableSlotT() : m_pFirst(NULL) {}
KUDr@5633: 
KUDr@5633: 	/** hash table slot helper - clears the slot by simple forgetting its items */
KUDr@5633: 	FORCEINLINE void Clear() {m_pFirst = NULL;}
KUDr@5633: 
KUDr@5633: 	/** hash table slot helper - linear search for item with given key through the given blob - const version */
KUDr@5633: 	FORCEINLINE const Titem_* Find(const Key& key) const
KUDr@5633: 	{
KUDr@5633: 		for (const Titem_* pItem = m_pFirst; pItem != NULL; pItem = pItem->GetHashNext()) {
KUDr@5633: 			if (pItem->GetKey() == key) {
KUDr@5633: 				// we have found the item, return it
KUDr@5633: 				return pItem;
KUDr@5633: 			}
KUDr@5633: 		}
KUDr@5633: 		return NULL;
KUDr@5633: 	}
KUDr@5633: 
KUDr@5633: 	/** hash table slot helper - linear search for item with given key through the given blob - non-const version */
KUDr@5633: 	FORCEINLINE Titem_* Find(const Key& key)
KUDr@5633: 	{
KUDr@5633: 		for (Titem_* pItem = m_pFirst; pItem != NULL; pItem = pItem->GetHashNext()) {
KUDr@5633: 			if (pItem->GetKey() == key) {
KUDr@5633: 				// we have found the item, return it
KUDr@5633: 				return pItem;
KUDr@5633: 			}
KUDr@5633: 		}
KUDr@5633: 		return NULL;
KUDr@5633: 	}
KUDr@5633: 
KUDr@5633: 	/** hash table slot helper - add new item to the slot */
KUDr@5633: 	FORCEINLINE void Attach(Titem_& new_item)
KUDr@5633: 	{
KUDr@5633: 		assert(new_item.GetHashNext() == NULL);
KUDr@5633: 		new_item.SetHashNext(m_pFirst);
KUDr@5633: 		m_pFirst = &new_item;
KUDr@5633: 	}
KUDr@5633: 
KUDr@5633: 	/** hash table slot helper - remove item from a slot */
KUDr@5633: 	FORCEINLINE bool Detach(Titem_& item_to_remove)
KUDr@5633: 	{
KUDr@5633: 		if (m_pFirst == &item_to_remove) {
KUDr@5633: 			m_pFirst = item_to_remove.GetHashNext();
KUDr@5633: 			item_to_remove.SetHashNext(NULL);
KUDr@5633: 			return true;
KUDr@5633: 		}
KUDr@5633: 		Titem_* pItem = m_pFirst;
KUDr@5633: 		while (true) {
KUDr@5633: 			if (pItem == NULL) {
KUDr@5633: 				return false;
KUDr@5633: 			}
KUDr@5633: 			Titem_* pNextItem = pItem->GetHashNext();
KUDr@5633: 			if (pNextItem == &item_to_remove) break;
KUDr@5633: 			pItem = pNextItem;
KUDr@5633: 		}
KUDr@5633: 		pItem->SetHashNext(item_to_remove.GetHashNext());
KUDr@5633: 		item_to_remove.SetHashNext(NULL);
KUDr@5633: 		return true;
KUDr@5633: 	}
KUDr@5633: 
KUDr@5633: 	/** hash table slot helper - remove and return item from a slot */
KUDr@5633: 	FORCEINLINE Titem_* Detach(const Key& key)
KUDr@5633: 	{
KUDr@5633: 		// do we have any items?
KUDr@5633: 		if (m_pFirst == NULL) {
KUDr@5633: 			return NULL;
KUDr@5633: 		}
KUDr@5633: 		// is it our first item?
KUDr@5633: 		if (m_pFirst->GetKey() == key) {
KUDr@5633: 			Titem_& ret_item = *m_pFirst;
KUDr@5633: 			m_pFirst = m_pFirst->GetHashNext();
KUDr@5633: 			ret_item.SetHashNext(NULL);
KUDr@5633: 			return &ret_item;
KUDr@5633: 		}
KUDr@5633: 		// find it in the following items
KUDr@5633: 		Titem_* pPrev = m_pFirst;
KUDr@5633: 		for (Titem_* pItem = m_pFirst->GetHashNext(); pItem != NULL; pPrev = pItem, pItem = pItem->GetHashNext()) {
KUDr@5633: 			if (pItem->GetKey() == key) {
KUDr@5633: 				// we have found the item, unlink and return it
KUDr@5633: 				pPrev->SetHashNext(pItem->GetHashNext());
KUDr@5633: 				pItem->SetHashNext(NULL);
KUDr@5633: 				return pItem;
KUDr@5633: 			}
KUDr@5633: 		}
KUDr@5633: 		return NULL;
KUDr@5633: 	}
KUDr@5633: };
KUDr@5633: 
belugas@6481: /** class CHashTableT<Titem, Thash_bits> - simple hash table
KUDr@5633:  *  of pointers allocated elsewhere.
KUDr@5633:  *
KUDr@5633:  *  Supports: Add/Find/Remove of Titems.
KUDr@5633:  *
KUDr@5633:  *  Your Titem must meet some extra requirements to be CHashTableT
KUDr@5633:  *  compliant:
KUDr@5633:  *    - its constructor/destructor (if any) must be public
KUDr@5633:  *    - if the copying of item requires an extra resource management,
KUDr@5633:  *        you must define also copy constructor
KUDr@5633:  *    - must support nested type (struct, class or typedef) Titem::Key
KUDr@5633:  *        that defines the type of key class for that item
KUDr@5633:  *    - must support public method:
KUDr@5633:  *        const Key& GetKey() const; // return the item's key object
KUDr@5633:  *
KUDr@5633:  *  In addition, the Titem::Key class must support:
KUDr@5633:  *    - public method that calculates key's hash:
KUDr@5633:  *        int CalcHash() const;
KUDr@5633:  *    - public 'equality' operator to compare the key with another one
KUDr@5633:  *        bool operator == (const Key& other) const;
KUDr@5633:  */
KUDr@5633: template <class Titem_, int Thash_bits_>
KUDr@5633: class CHashTableT {
KUDr@5633: public:
KUDr@5633: 	typedef Titem_ Titem;                         // make Titem_ visible from outside of class
KUDr@5633: 	typedef typename Titem_::Key Tkey;            // make Titem_::Key a property of HashTable
KUDr@5633: 	static const int Thash_bits = Thash_bits_;    // publish num of hash bits
KUDr@5633: 	static const int Tcapacity = 1 << Thash_bits; // and num of slots 2^bits
KUDr@5633: 
KUDr@5633: protected:
KUDr@5633: 	/** each slot contains pointer to the first item in the list,
KUDr@5633: 	 *  Titem contains pointer to the next item - GetHashNext(), SetHashNext() */
KUDr@5633: 	typedef CHashTableSlotT<Titem_> Slot;
KUDr@5633: 
KUDr@5633: 	Slot*  m_slots;     // here we store our data (array of blobs)
KUDr@5633: 	int    m_num_items; // item counter
KUDr@5633: 
KUDr@5633: public:
KUDr@5633: 	// default constructor
KUDr@5633: 	FORCEINLINE CHashTableT()
KUDr@5633: 	{
KUDr@5633: 		// construct all slots
KUDr@5633: 		m_slots = new Slot[Tcapacity];
KUDr@5633: 		m_num_items = 0;
KUDr@5633: 	}
KUDr@5633: 
KUDr@5633: 	~CHashTableT() {delete [] m_slots; m_num_items = 0; m_slots = NULL;}
KUDr@5633: 
KUDr@5633: protected:
KUDr@5633: 	/** static helper - return hash for the given key modulo number of slots */
KUDr@5633: 	FORCEINLINE static int CalcHash(const Tkey& key)
KUDr@5633: 	{
KUDr@5633: 		int32 hash = key.CalcHash();
KUDr@5633: 		if ((8 * Thash_bits) < 32) hash ^= hash >> (min(8 * Thash_bits, 31));
KUDr@5633: 		if ((4 * Thash_bits) < 32) hash ^= hash >> (min(4 * Thash_bits, 31));
KUDr@5633: 		if ((2 * Thash_bits) < 32) hash ^= hash >> (min(2 * Thash_bits, 31));
KUDr@5633: 		if ((1 * Thash_bits) < 32) hash ^= hash >> (min(1 * Thash_bits, 31));
KUDr@5633: 		hash &= (1 << Thash_bits) - 1;
KUDr@5633: 		return hash;
KUDr@5633: 	}
KUDr@5633: 
KUDr@5633: 	/** static helper - return hash for the given item modulo number of slots */
KUDr@5633: 	FORCEINLINE static int CalcHash(const Titem_& item) {return CalcHash(item.GetKey());}
KUDr@5633: 
KUDr@5633: public:
KUDr@5633: 	/** item count */
KUDr@5633: 	FORCEINLINE int Count() const {return m_num_items;}
KUDr@5633: 
KUDr@5633: 	/** simple clear - forget all items - used by CSegmentCostCacheT.Flush() */
KUDr@5633: 	FORCEINLINE void Clear() const {for (int i = 0; i < Tcapacity; i++) m_slots[i].Clear();}
KUDr@5633: 
KUDr@5633: 	/** const item search */
KUDr@5633: 	const Titem_* Find(const Tkey& key) const
KUDr@5633: 	{
KUDr@5633: 		int hash = CalcHash(key);
KUDr@5633: 		const Slot& slot = m_slots[hash];
KUDr@5633: 		const Titem_* item = slot.Find(key);
KUDr@5633: 		return item;
KUDr@5633: 	}
KUDr@5633: 
KUDr@5633: 	/** non-const item search */
KUDr@5633: 	Titem_* Find(const Tkey& key)
KUDr@5633: 	{
KUDr@5633: 		int hash = CalcHash(key);
KUDr@5633: 		Slot& slot = m_slots[hash];
KUDr@5633: 		Titem_* item = slot.Find(key);
KUDr@5633: 		return item;
KUDr@5633: 	}
KUDr@5633: 
KUDr@5633: 	/** non-const item search & optional removal (if found) */
KUDr@5633: 	Titem_* TryPop(const Tkey& key)
KUDr@5633: 	{
KUDr@5633: 		int hash = CalcHash(key);
KUDr@5633: 		Slot& slot = m_slots[hash];
KUDr@5633: 		Titem_* item = slot.Detach(key);
KUDr@5633: 		if (item != NULL) {
KUDr@5633: 			m_num_items--;
KUDr@5633: 		}
KUDr@5633: 		return item;
KUDr@5633: 	}
KUDr@5633: 
KUDr@5633: 	/** non-const item search & removal */
KUDr@5633: 	Titem_& Pop(const Tkey& key)
KUDr@5633: 	{
KUDr@5633: 		Titem_* item = TryPop(key);
KUDr@5633: 		assert(item != NULL);
KUDr@5633: 		return *item;
KUDr@5633: 	}
KUDr@5633: 
KUDr@5633: 	/** non-const item search & optional removal (if found) */
KUDr@5633: 	bool TryPop(Titem_& item)
KUDr@5633: 	{
KUDr@5633: 		const Tkey& key = item.GetKey();
KUDr@5633: 		int hash = CalcHash(key);
KUDr@5633: 		Slot& slot = m_slots[hash];
KUDr@5633: 		bool ret = slot.Detach(item);
KUDr@5633: 		if (ret) {
KUDr@5633: 			m_num_items--;
KUDr@5633: 		}
KUDr@5633: 		return ret;
KUDr@5633: 	}
KUDr@5633: 
KUDr@5633: 	/** non-const item search & removal */
KUDr@5633: 	void Pop(Titem_& item)
KUDr@5633: 	{
KUDr@5633: 		bool ret = TryPop(item);
KUDr@5633: 		assert(ret);
KUDr@5633: 	}
KUDr@5633: 
KUDr@5633: 	/** add one item - copy it from the given item */
KUDr@5633: 	void Push(Titem_& new_item)
KUDr@5633: 	{
KUDr@5633: 		int hash = CalcHash(new_item);
KUDr@5633: 		Slot& slot = m_slots[hash];
KUDr@5633: 		assert(slot.Find(new_item.GetKey()) == NULL);
KUDr@5633: 		slot.Attach(new_item);
KUDr@5633: 		m_num_items++;
KUDr@5633: 	}
KUDr@5633: };
KUDr@5633: 
KUDr@5633: #endif /* HASHTABLE_HPP */