generic_file.hpp

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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: generic_file.hpp,v 1.25.2.3 2009/04/07 08:45:29 edrusb Rel $
00022 //
00023 /*********************************************************************/
00024 
00039 
00040 
00042 // IMPORTANT : THIS FILE MUST ALWAYS BE INCLUDE AFTER infinint.hpp   //
00043 //             (and infinint.hpp must be included too, always)       //
00045 #include "infinint.hpp"
00047 
00048 
00049 
00050 #ifndef GENERIC_FILE_HPP
00051 #define GENERIC_FILE_HPP
00052 
00053 
00054 #include "../my_config.h"
00055 
00056 extern "C"
00057 {
00058 #if HAVE_UNISTD_H
00059 #include <unistd.h>
00060 #endif
00061 } // end extern "C"
00062 
00063 #include "path.hpp"
00064 #include "integers.hpp"
00065 #include "user_interaction.hpp"
00066 #include "thread_cancellation.hpp"
00067 
00068 #include <string>
00069 
00070 namespace libdar
00071 {
00072 
00075 
00076     const int CRC_SIZE = 2;
00077     typedef char crc[CRC_SIZE];
00078     extern void clear(crc & value);
00079     extern void copy_crc(crc & dst, const crc & src);
00080     extern bool same_crc(const crc &a, const crc &b);
00081     extern std::string crc2str(const crc &a);
00082 
00084     enum gf_mode
00085     {
00086         gf_read_only,  
00087         gf_write_only, 
00088         gf_read_write  
00089     };
00090 
00091 
00092     extern gf_mode generic_file_get_mode(S_I fd);
00093     extern const char * generic_file_get_name(gf_mode mode);
00094 
00096 
00108     class generic_file
00109     {
00110     public :
00112         generic_file(user_interaction & dialog, gf_mode m) { rw = m; clear(value); crc_offset = 0; enable_crc(false); gf_ui = dialog.clone(); };
00114         generic_file(const generic_file &ref) { copy_from(ref); };
00116         generic_file & operator = (const generic_file & ref) { detruire(); copy_from(ref); return *this; };
00118         virtual ~generic_file() { detruire(); };
00119 
00121         gf_mode get_mode() const { return rw; };
00122 
00124         S_I read(char *a, size_t size);
00126         S_I write(const char *a, size_t size);
00128         S_I write(const std::string & arg);
00130         S_I read_back(char &a);
00132         S_I read_forward(char &a) { return read(&a, 1); };
00134         virtual bool skip(const infinint & pos) = 0;
00136         virtual bool skip_to_eof() = 0;
00138         virtual bool skip_relative(S_I x) = 0;
00140         virtual infinint get_position() = 0;
00141 
00143         void copy_to(generic_file &ref);
00145         void copy_to(generic_file &ref, crc & value);
00147         U_32 copy_to(generic_file &ref, U_32 size); // returns the number of byte effectively copied
00149         infinint copy_to(generic_file &ref, infinint size); // returns the number of byte effectively copied
00151         bool diff(generic_file & f); // return true if arg differs from "this"
00152 
00154         void reset_crc();
00156         void get_crc(crc & val) { enable_crc(false); copy_crc(val, value); };
00157 
00159         user_interaction & get_gf_ui() const { return *gf_ui; };
00160 
00161     protected :
00162         void set_mode(gf_mode x) { rw = x; };
00163         virtual S_I inherited_read(char *a, size_t size) = 0;
00164             // must provide as much byte as requested up to end of file
00165             // stay blocked if not enough available
00166             // returning zero or less than requested means end of file
00167         virtual S_I inherited_write(const char *a, size_t size) = 0;
00168             // must write all data or block or throw exceptions
00169             // thus always returns the second argument
00170 
00171     private :
00172         gf_mode rw;
00173         crc value;
00174         S_I crc_offset;
00175         user_interaction *gf_ui;
00176         S_I (generic_file::* active_read)(char *a, size_t size);
00177         S_I (generic_file::* active_write)(const char *a, size_t size);
00178 
00179         void enable_crc(bool mode);
00180         void compute_crc(const char *a, S_I size);
00181         S_I read_crc(char *a, size_t size);
00182         S_I write_crc(const char *a, size_t size);
00183 
00184         void detruire() { if(gf_ui != NULL) delete gf_ui; };
00185         void copy_from(const generic_file & ref);
00186     };
00187 
00189     class fichier : public generic_file, public thread_cancellation
00190     {
00191     public :
00192         fichier(user_interaction & dialog, S_I fd);
00193         fichier(user_interaction & dialog, const char *name, gf_mode m);
00194         fichier(user_interaction & dialog, const path & chemin, gf_mode m);
00195         ~fichier() { close(filedesc); };
00196 
00197         infinint get_size() const;
00198 
00199             // herite de generic_file
00200         bool skip(const infinint & pos);
00201         bool skip_to_eof();
00202         bool skip_relative(S_I x);
00203         infinint get_position();
00204 
00205     protected :
00206         S_I inherited_read(char *a, size_t size);
00207         S_I inherited_write(const char *a, size_t size);
00208 
00209     private :
00210         S_I filedesc;
00211 
00212         void open(const char *name, gf_mode m);
00213     };
00214 
00215 #define CONTEXT_INIT "init"
00216 #define CONTEXT_OP   "operation"
00217 #define CONTEXT_LAST_SLICE  "last_slice"
00218 
00220 
00229     class contextual : public generic_file
00230     {
00231     public :
00232         contextual(user_interaction & dialog, gf_mode m) : generic_file(dialog, m) {};
00233 
00234         virtual void set_info_status(const std::string & s) = 0;
00235         virtual std::string get_info_status() const = 0;
00236     };
00237 
00239 
00240 } // end of namespace
00241 
00242 #endif
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