dbo_hash.h

Go to the documentation of this file.

/*MT*
    
    MediaTomb - http://www.mediatomb.cc/
    
    dbo_hash.h - this file is part of MediaTomb.
    
    Copyright (C) 2005 Gena Batyan <bgeradz@mediatomb.cc>,
                       Sergey 'Jin' Bostandzhyan <jin@mediatomb.cc>
    
    Copyright (C) 2006-2010 Gena Batyan <bgeradz@mediatomb.cc>,
                            Sergey 'Jin' Bostandzhyan <jin@mediatomb.cc>,
                            Leonhard Wimmer <leo@mediatomb.cc>
    
    MediaTomb is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License version 2
    as published by the Free Software Foundation.
    
    MediaTomb is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
    
    You should have received a copy of the GNU General Public License
    version 2 along with MediaTomb; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
    
    $Id: dbo_hash.h 2081 2010-03-23 20:18:00Z lww $
*/


#ifndef __HASH_DBO_HASH_H__
#define __HASH_DBO_HASH_H__

#include "direct_hash_base.h"
#include <assert.h>

template <typename KT, typename VT> struct dbo_hash_slot
{
    KT key;
    VT *value;
};

template <typename KT, typename VT>
class DBOHash : public DHashBase<KT, struct dbo_hash_slot<KT, VT> >
{
protected:
    KT emptyKey;
    KT deletedKey;
public:
    DBOHash(int capacity, KT emptyKey, KT deletedKey) : DHashBase<KT, struct dbo_hash_slot<KT, VT> >(capacity)
    {
        // emptyKey and deletedKey must not be the same!
        assert(emptyKey != deletedKey);
        this->emptyKey = emptyKey;
        this->deletedKey = deletedKey;
        init();
    }
    virtual ~DBOHash()
    {
        releaseData();
    }
protected:
    void init()
    {
        if (! emptyKey)
            this->zero();
        else
        {
            for (int i = 0; i < this->capacity; i++)
                this->data[i].key = emptyKey;
            this->count = 0;
        }
    }
    void releaseData()
    {
        dbo_hash_slot<KT, VT> *slot;
        for (int i = 0; i < this->capacity; i++)
        {
            slot = this->data + i;
            if (slot->key != emptyKey && slot->key != deletedKey)
                slot->value->release();
        }
    }
public:
    void clear()
    {
        dbo_hash_slot<KT, VT> *slot;
        for (int i = 0; i < this->capacity; i++)
        {
            slot = this->data + i;
            if (slot->key != emptyKey && slot->key != deletedKey)
            {
                slot->key = emptyKey;
                slot->value->release();
            }
            else if (slot->key == deletedKey)
            {
                slot->key = emptyKey;
            }
        }
        this->count = 0;
    }
    
    inline bool remove(KT key)
    {
        struct dbo_hash_slot<KT, VT> *slot;
        if (! search(key, &slot))
            return false;
        slot->key = deletedKey;
        slot->value->release();
        this->count--;
        return true;
    }
    
    /* virtual methods */
    virtual int hashCode(KT key)
    {
        return this->baseTypeHashCode((unsigned int)key);
    }
    virtual bool match(KT key, struct dbo_hash_slot<KT, VT> *slot)
    {
        return (key == slot->key);
    }
    virtual bool isEmptySlot(struct dbo_hash_slot<KT, VT> *slot)
    {
        return (slot->key == emptyKey);
    }
    
    virtual bool isDeletedSlot(struct dbo_hash_slot<KT, VT> *slot)
    {
        return (slot->key == deletedKey);
    }
    
    inline void put(KT key, zmm::Ref<VT> value)
    {
        struct dbo_hash_slot<KT, VT> *slot;
        search(key, &slot);
        put(key, (hash_slot_t)slot, value);
    }
    void put(KT key, hash_slot_t destSlot, zmm::Ref<VT> value)
    {
        struct dbo_hash_slot<KT, VT> *slot = (struct dbo_hash_slot<KT, VT> *)destSlot;
        if (slot->key != emptyKey && slot->key != deletedKey)
        {
            VT *valuePtr = value.getPtr();
            valuePtr->retain();
            slot->value->release();
            slot->value = valuePtr;
        }
        else
        {
            this->count++;
            slot->key = key;
            VT *valuePtr = value.getPtr();
            valuePtr->retain();
            slot->value = valuePtr;
        }    
    }

    inline zmm::Ref<VT> get(KT key)
    {
        struct dbo_hash_slot<KT, VT> *slot;
        bool found = search(key, &slot);
        if (found)
            return zmm::Ref<VT>(slot->value);
        else
            return nil;
        
        hash_slot_t destSlot;
        return get(key, &destSlot);
    }
    inline zmm::Ref<VT> get(KT key, hash_slot_t *destSlot)
    {
        struct dbo_hash_slot<KT, VT> **slot = (struct dbo_hash_slot<KT, VT> **)destSlot;
        bool found = search(key, slot);
        if (found)
            return zmm::Ref<VT>((*slot)->value);
        else
            return nil;
    }
};

#endif // __HASH_DBO_HASH_H__

---