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/* $Id: cursor.hpp,v 1.4 2006/11/05 04:42:43 ganzhorn Exp $
* This file is part of lfhex.
* Copyright (C) 2006 Salem Ganzhorn <eyekode@yahoo.com>
*
* 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 version 2.
*
* 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 _CURSOR_HPP_
#define _CURSOR_HPP_
#include <sys/types.h>
#include <limits.h>
#include <stdexcept>
#ifdef _LARGEFILE_SOURCE
#define MAX_OFFSET LONG_LONG_MAX
#else
#define MAX_OFFSET LONG_MAX
#endif
class Cursor {
public:
Cursor( off_t byteOffset = 0,
off_t charOffset = 0,
off_t low = 0,
off_t high = 1,
off_t charsPerByte = 2 ); // defaults to hex
Cursor( const Cursor& c);
off_t incrByChar( off_t n );
off_t incrByByte( off_t n );
off_t decrByChar( off_t n );
off_t decrByByte( off_t n );
off_t byteOffset() const; //returns the current byte offset
off_t charOffset() const; //returns the current char offset. (relative)
off_t charOffsetAbsolute() const; //returns the current absolute offset.
bool setRange( off_t low, off_t high );
// setCharsPerByte:
// sideEffect: sets charOffset to min(_charsPerByte-1,_charOffset)
off_t setCharsPerByte( off_t charsPerByte );
void setOffset( off_t byteOffset, off_t charOffset );
protected:
// performs: dst = src; and clamps the value to [low,high)
void assignClamped(off_t& dst,off_t src,off_t low,off_t high);
enum {
OutOfRange = -1,
};
protected:
off_t _byteOffset;
off_t _charOffset;
off_t _low;
off_t _high;
off_t _charsPerByte;
};
#endif
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