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#ifndef VIRTUALSEEKER_H
#define VIRTUALSEEKER_H
#include "zipios++/zipios-config.h"
#include "zipios++/meta-iostreams.h"
namespace zipios {
using std::ios ;
using std::cerr ;
using std::endl ;
/** VirtualSeeker is a simple class that keeps track of a set of
specified 'virtual' file endings that mark a subset of a real
file. An example of its use (and its reason for existence) is to
keep track of the file endings of a Zip file embedded in another
file. */
class VirtualSeeker {
public:
inline VirtualSeeker( int start_offset = 0, int end_offset = 0) ;
inline void setOffsets( int start_offset, int end_offset ) ;
inline void getOffsets( int &start_offset, int &end_offset ) const ;
inline int startOffset() const ;
inline int endOffset() const ;
inline void vseekg( istream &is, int offset, ios::seekdir sd ) const ;
inline int vtellg( istream &is ) const ;
private:
// start and end offsets
int _s_off, _e_off ;
};
VirtualSeeker::VirtualSeeker( int start_offset, int end_offset )
: _s_off( start_offset ),
_e_off( end_offset )
{}
void VirtualSeeker::setOffsets( int start_offset, int end_offset ) {
_s_off = start_offset ;
_e_off = end_offset ;
}
void VirtualSeeker::getOffsets( int &start_offset, int &end_offset ) const {
start_offset = _s_off ;
end_offset = _e_off ;
}
int VirtualSeeker::startOffset() const {
return _s_off ;
}
int VirtualSeeker::endOffset() const {
return _e_off ;
}
void VirtualSeeker::vseekg( istream &is, int offset, ios::seekdir sd ) const {
if ( sd == ios::cur )
is.seekg( offset, sd ) ;
else if ( sd == ios::beg )
is.seekg( offset + _s_off, sd ) ;
else if ( sd == ios::end )
is.seekg( offset - _e_off, sd ) ;
else
cerr << "VirtualSeekManager::seekg: error - not supposed to happen!" << endl ;
}
int VirtualSeeker::vtellg( istream &is ) const {
return static_cast< int >( is.tellg() ) - _s_off ;
}
} // namespace
#endif
/** \file
Header file that defines VirtualSeeker.
*/
/*
Zipios++ - a small C++ library that provides easy access to .zip files.
Copyright (C) 2000 Thomas Søndergaard
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
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