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/* This file is part of the KDE libraries
* Copyright (C) 1999 Waldo Bastian <bastian@kde.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License version 2 as published by the Free Software Foundation;
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
**/
#ifndef __ksycocadict_h__
#define __ksycocadict_h__
#include <qstring.h>
#include <qvaluelist.h>
#include <qdatastream.h>
#include "kdelibs_export.h"
class KSycocaEntry;
class KSycocaDictStringList;
/**
* @internal
* Hash table implementation for the sycoca database file
*/
class KDECORE_EXPORT KSycocaDict
{
public:
/**
* Create an empty dict, for building the database
*/
KSycocaDict();
/**
* Create a dict from an existing database
*/
KSycocaDict(QDataStream *str, int offset);
~KSycocaDict();
/**
* Adds a 'payload' to the dictionary with key 'key'.
*
* 'payload' should have a valid offset by the time
* the dictionary gets saved.
**/
void add(const QString &key, KSycocaEntry *payload);
/**
* Removes the 'payload' from the dictionary with key 'key'.
*
* Not very fast, use with care O(N)
**/
void remove(const QString &key);
/**
* Looks up an entry identified by 'key'.
*
* If 0 is returned, no matching entry exists.
* Otherwise, the offset of the entry is returned.
*
* NOTE: It is not guaranteed that this entry is
* indeed the one you were looking for.
* After loading the entry you should check that it
* indeed matches the search key. If it doesn't
* then no matching entry exists.
*/
int find_string(const QString &key );
/**
* The number of entries in the dictionary.
*
* Only valid when building the database.
*/
uint count();
/**
* Reset the dictionary.
*
* Only valid when building the database.
*/
void clear();
/**
* Save the dictionary to the stream
* A reasonable fast hash algorithm will be created.
*
* Typically this will find 90% of the entries directly.
* Average hash table size: nrOfItems * 20 bytes.
* Average duplicate list size: nrOfItms * avgKeyLength / 5.
*
* Unknown keys have an average 20% chance to give a false hit.
* (That's why your program should check the result)
*
* Example:
* Assume 1000 items with an average key length of 60 bytes.
*
* Approx. 900 items will hash directly to the right entry.
* Approx. 100 items require a lookup in the duplicate list.
*
* The hash table size will be approx. 20Kb.
* The duplicate list size will be approx. 12Kb.
**/
void save(QDataStream &str);
protected:
Q_UINT32 hashKey( const QString &);
private:
KSycocaDictStringList *d;
QDataStream *mStr;
Q_INT32 mOffset;
Q_UINT32 mHashTableSize;
QValueList<Q_INT32> mHashList;
};
#endif
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