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Disk ARchive
2.5.2
Full featured and portable backup and archiving tool
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00001 /*********************************************************************/ 00002 // dar - disk archive - a backup/restoration program 00003 // Copyright (C) 2002-2052 Denis Corbin 00004 // 00005 // This program is free software; you can redistribute it and/or 00006 // modify it under the terms of the GNU General Public License 00007 // as published by the Free Software Foundation; either version 2 00008 // of the License, or (at your option) any later version. 00009 // 00010 // This program is distributed in the hope that it will be useful, 00011 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00012 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00013 // GNU General Public License for more details. 00014 // 00015 // You should have received a copy of the GNU General Public License 00016 // along with this program; if not, write to the Free Software 00017 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 00018 // 00019 // to contact the author : http://dar.linux.free.fr/email.html 00020 /*********************************************************************/ 00021 00027 00028 #ifndef NULL_FILE_HPP 00029 #define NULL_FILE_HPP 00030 00031 #include "../my_config.h" 00032 #include "generic_file.hpp" 00033 #include "thread_cancellation.hpp" 00034 00035 namespace libdar 00036 { 00037 00040 00042 00049 00050 class null_file : public generic_file, public thread_cancellation 00051 { 00052 public : 00053 null_file(gf_mode m) : generic_file(m) {}; 00054 bool skippable(skippability direction, const infinint & amount) { return true; }; 00055 bool skip(const infinint &pos) { return true; }; 00056 bool skip_to_eof() { return true; }; 00057 bool skip_relative(signed int x) { return false; }; 00058 infinint get_position() const { return 0; }; 00059 00060 protected : 00061 void inherited_read_ahead(const infinint & amount) {}; 00062 00063 U_I inherited_read(char *a, U_I size) 00064 { 00065 #ifdef MUTEX_WORKS 00066 check_self_cancellation(); 00067 #endif 00068 return 0; 00069 }; 00070 00071 void inherited_write(const char *a, U_I size) 00072 { 00073 #ifdef MUTEX_WORKS 00074 check_self_cancellation(); 00075 #endif 00076 }; 00077 00078 void inherited_sync_write() {}; 00079 void inherited_flush_read() {}; 00080 void inherited_terminate() {}; 00081 }; 00082 00084 00085 } // end of namespace 00086 00087 #endif