Disk ARchive 2.3.12
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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 : dar.linux@free.fr 00020 /*********************************************************************/ 00021 // $Id: null_file.hpp,v 1.11.4.1 2007/07/22 16:35:00 edrusb Rel $ 00022 // 00023 /*********************************************************************/ 00024 00029 00030 #ifndef NULL_FILE_HPP 00031 #define NULL_FILE_HPP 00032 00033 #include "../my_config.h" 00034 #include "generic_file.hpp" 00035 #include "thread_cancellation.hpp" 00036 00037 namespace libdar 00038 { 00039 00041 00048 00049 class null_file : public generic_file, public thread_cancellation 00050 { 00051 public : 00052 null_file(user_interaction & dialog, gf_mode m) : generic_file(dialog, m) {}; 00053 bool skip(const infinint &pos) { return pos == 0; }; 00054 bool skip_to_eof() { return true; }; 00055 bool skip_relative(signed int x) { return false; }; 00056 infinint get_position() { return 0; }; 00057 00058 protected : 00059 int inherited_read(char *a, size_t size) 00060 { 00061 #ifdef MUTEX_WORKS 00062 check_self_cancellation(); 00063 #endif 00064 return 0; 00065 }; 00066 00067 int inherited_write(const char *a, size_t size) 00068 { 00069 #ifdef MUTEX_WORKS 00070 check_self_cancellation(); 00071 #endif 00072 return size; 00073 }; 00074 }; 00075 00076 } // end of namespace 00077 00078 #endif