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/*
This file is part of Konsole, an X terminal.
Copyright 1997,1998 by Lars Doelle <lars.doelle@on-line.de>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.
*/
#ifndef HISTORYFILE_H
#define HISTORYFILE_H
// Qt
#include <QTemporaryFile>
namespace Konsole
{
/*
An extendable tmpfile(1) based buffer.
*/
class HistoryFile
{
public:
HistoryFile();
virtual ~HistoryFile();
virtual void add(const char *buffer, qint64 count);
virtual void get(char *buffer, qint64 size, qint64 loc);
virtual void removeLast(qint64 loc);
virtual qint64 len() const;
//mmaps the file in read-only mode
void map();
//un-mmaps the file
void unmap();
private:
qint64 _length;
QTemporaryFile _tmpFile;
//pointer to start of mmap'ed file data, or 0 if the file is not mmap'ed
uchar *_fileMap;
//incremented whenever 'add' is called and decremented whenever
//'get' is called.
//this is used to detect when a large number of lines are being read and processed from the history
//and automatically mmap the file for better performance (saves the overhead of many lseek-read calls).
int _readWriteBalance;
//when _readWriteBalance goes below this threshold, the file will be mmap'ed automatically
static const int MAP_THRESHOLD = -1000;
};
}
#endif
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