Zipios++
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00001 #ifndef VIRTUALSEEKER_H 00002 #define VIRTUALSEEKER_H 00003 00004 #include "zipios++/zipios-config.h" 00005 00006 #include "zipios++/meta-iostreams.h" 00007 00008 00009 namespace zipios { 00010 00011 using std::ios ; 00012 using std::cerr ; 00013 using std::endl ; 00014 00020 class VirtualSeeker { 00021 public: 00022 inline VirtualSeeker( int start_offset = 0, int end_offset = 0) ; 00023 inline void setOffsets( int start_offset, int end_offset ) ; 00024 inline void getOffsets( int &start_offset, int &end_offset ) const ; 00025 inline int startOffset() const ; 00026 inline int endOffset() const ; 00027 inline void vseekg( istream &is, int offset, ios::seekdir sd ) const ; 00028 inline int vtellg( istream &is ) const ; 00029 private: 00030 // start and end offsets 00031 int _s_off, _e_off ; 00032 }; 00033 00034 00035 00036 VirtualSeeker::VirtualSeeker( int start_offset, int end_offset ) 00037 : _s_off( start_offset ), 00038 _e_off( end_offset ) 00039 {} 00040 00041 00042 void VirtualSeeker::setOffsets( int start_offset, int end_offset ) { 00043 _s_off = start_offset ; 00044 _e_off = end_offset ; 00045 } 00046 00047 00048 void VirtualSeeker::getOffsets( int &start_offset, int &end_offset ) const { 00049 start_offset = _s_off ; 00050 end_offset = _e_off ; 00051 } 00052 00053 00054 int VirtualSeeker::startOffset() const { 00055 return _s_off ; 00056 } 00057 00058 00059 int VirtualSeeker::endOffset() const { 00060 return _e_off ; 00061 } 00062 00063 void VirtualSeeker::vseekg( istream &is, int offset, ios::seekdir sd ) const { 00064 if ( sd == ios::cur ) 00065 is.seekg( offset, sd ) ; 00066 else if ( sd == ios::beg ) 00067 is.seekg( offset + _s_off, sd ) ; 00068 else if ( sd == ios::end ) 00069 is.seekg( offset - _e_off, sd ) ; 00070 else 00071 cerr << "VirtualSeekManager::seekg: error - not supposed to happen!" << endl ; 00072 } 00073 00074 00075 int VirtualSeeker::vtellg( istream &is ) const { 00076 return static_cast< int >( is.tellg() ) - _s_off ; 00077 } 00078 00079 00080 } // namespace 00081 00082 #endif 00083 00088 /* 00089 Zipios++ - a small C++ library that provides easy access to .zip files. 00090 Copyright (C) 2000 Thomas Søndergaard 00091 00092 This library is free software; you can redistribute it and/or 00093 modify it under the terms of the GNU Lesser General Public 00094 License as published by the Free Software Foundation; either 00095 version 2 of the License, or (at your option) any later version. 00096 00097 This library is distributed in the hope that it will be useful, 00098 but WITHOUT ANY WARRANTY; without even the implied warranty of 00099 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00100 Lesser General Public License for more details. 00101 00102 You should have received a copy of the GNU Lesser General Public 00103 License along with this library; if not, write to the Free Software 00104 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 00105 */