Disk ARchive 2.4.2
storage.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 : http://dar.linux.free.fr/email.html
00020 /*********************************************************************/
00021 // $Id: storage.hpp,v 1.20 2011/01/22 22:39:10 edrusb Rel $
00022 //
00023 /*********************************************************************/
00024 
00028 
00029 #include "../my_config.h"
00030 #include "erreurs.hpp"
00031 #include "integers.hpp"
00032 
00033 #ifdef LIBDAR_MODE
00034 #include "infinint.hpp"
00035 #endif
00036 
00037     // it is necessary to not protect the previous inclusion inside
00038     // the STORAGE_HPP protection to avoid cyclic dependancies.
00039 
00040 #ifndef STORAGE_HPP
00041 #define STORAGE_HPP
00042 
00043 #ifndef LIBDAR_MODE
00044 namespace libdar
00045 {
00046     class infinint;
00047 }
00048 #endif
00049 
00050 namespace libdar
00051 {
00052     class generic_file;
00053 
00055 
00058 
00059     class storage
00060     {
00061     private:
00062         struct cellule
00063         {
00064             cellule() : next(NULL), prev(NULL), data(NULL), size(0) {};
00065             struct cellule *next, *prev;
00066             unsigned char *data;
00067             U_32 size;
00068         };
00069 
00070     public:
00071         storage(U_32 size)
00072             { E_BEGIN; make_alloc(size, first, last); E_END("storage::storage","U_32"); };
00073         storage(const infinint & size);
00074         storage(const storage & ref)
00075             { E_BEGIN; copy_from(ref); E_END("storage::storage", "storage &"); };
00076         storage(generic_file & f, const infinint &size);
00077         ~storage()
00078             { E_BEGIN; detruit(first); E_END("storage::~storage", ""); };
00079 
00080         const storage & operator = (const storage & val)
00081             { E_BEGIN; detruit(first); copy_from(val); return *this; E_END("storage::operator=",""); };
00082 
00083         bool operator < (const storage & ref) const
00084             { E_BEGIN; return difference(ref) < 0; E_END("storage::operator <",""); }; // true if arg uses more space than this
00085         bool operator == (const storage & ref) const
00086             { E_BEGIN; return difference(ref) == 0; E_END("storage::operator ==",""); }; //true if arg have same space than this
00087         bool operator > (const storage & ref) const
00088             { E_BEGIN; return difference(ref) > 0; E_END("storage::operator >", ""); };
00089         bool operator <= (const storage & ref) const
00090             { E_BEGIN; return difference(ref) <= 0; E_END("storage::operator <=", ""); };
00091         bool operator >= (const storage & ref) const
00092             { E_BEGIN; return difference(ref) >= 0; E_END("storage::operator >=", ""); };
00093         bool operator != (const storage & ref) const
00094             { E_BEGIN; return difference(ref) != 0; E_END("storage::operator !=", ""); };
00095         unsigned char & operator [](infinint position);
00096         unsigned char operator [](const infinint & position) const;
00097         infinint size() const;
00098         void clear(unsigned char val = 0);
00099         void dump(generic_file & f) const;
00100 
00101         class iterator
00102         {
00103         public :
00104             iterator() : ref(NULL), cell(NULL), offset(0) {};
00105                 // default constructor by reference is OK
00106                 // default destructor is OK
00107                 // default operator = is OK
00108 
00109             iterator operator ++ (S_I x)
00110                 { E_BEGIN; iterator ret = *this; skip_plus_one(); return ret;  E_END("storage::iterator::operator++", "(S_I)"); };
00111             iterator operator -- (S_I x)
00112                 { E_BEGIN; iterator ret = *this; skip_less_one(); return ret; E_END("storage::iterator::operator--", "(S_I)");};
00113             iterator & operator ++ ()
00114                 { E_BEGIN; skip_plus_one(); return *this; E_END("storage::iterator::operator++", "()"); };
00115             iterator & operator -- ()
00116                 { E_BEGIN; skip_less_one(); return *this; E_END("storage::iterator::operator--", "()"); };
00117             iterator operator + (U_32 s) const
00118                 { E_BEGIN; iterator ret = *this; ret += s; return ret; E_END("storage::iterator::operator +", ""); };
00119             iterator operator - (U_32 s) const
00120                 { E_BEGIN; iterator ret = *this; ret -= s; return ret; E_END("storage::iterator::operator -", ""); };
00121             iterator & operator += (U_32 s);
00122             iterator & operator -= (U_32 s);
00123             unsigned char &operator *() const;
00124 
00125             void skip_to(const storage & st, infinint val); // absolute position in st
00126             infinint get_position() const;
00127 
00128             bool operator == (const iterator & cmp) const
00129                 { E_BEGIN; return ref == cmp.ref && cell == cmp.cell && offset == cmp.offset; E_END("storage::iterator::operator ==", ""); };
00130             bool operator != (const iterator & cmp) const
00131                 { E_BEGIN; return ! (*this == cmp); E_END("storage::iterator::operator !=", ""); };
00132 
00133         private:
00134             static const U_32 OFF_BEGIN = 1;
00135             static const U_32 OFF_END = 2;
00136 
00137             const storage *ref;
00138             struct cellule *cell;
00139             U_32 offset;
00140 
00141             void relative_skip_to(S_32 val);
00142             bool points_on_data() const
00143                 { E_BEGIN; return ref != NULL && cell != NULL && offset < cell->size; E_END("storage::iterator::point_on_data", "");};
00144 
00145             inline void skip_plus_one();
00146             inline void skip_less_one();
00147 
00148             friend class storage;
00149         };
00150 
00151             // public storage methode using iterator
00152 
00153         iterator begin() const
00154             { E_BEGIN; iterator ret; ret.cell = first; if(ret.cell != NULL) ret.offset = 0; else ret.offset = iterator::OFF_END; ret.ref = this; return ret; E_END("storage::begin", ""); };
00155         iterator end() const
00156             { E_BEGIN; iterator ret; ret.cell = NULL; ret.offset = iterator::OFF_END; ret.ref = this; return ret; E_END("storage::end", ""); };
00157 
00158             // WARNING for the two following methods :
00159             // there is no "reverse_iterator" type, unlike the standart lib,
00160             // thus when going from rbegin() to rend(), you must use the -- operator
00161             // unlike the stdlib, that uses the ++ operator. this is the only difference in use with stdlib.
00162         iterator rbegin() const
00163             { E_BEGIN; iterator ret; ret.cell = last; ret.offset = last != NULL ? last->size-1 : 0; ret.ref = this; return ret; E_END("storage::rbegin", ""); };
00164         iterator rend() const
00165             { E_BEGIN; iterator ret; ret.cell = NULL, ret.offset = iterator::OFF_BEGIN; ret.ref = this; return ret; E_END("storage::rend", ""); };
00166 
00168 
00172         U_I write(iterator & it, unsigned char *a, U_I size);
00173         U_I read(iterator & it, unsigned char *a, U_I size) const;
00174         bool write(iterator & it, unsigned char a)
00175             { E_BEGIN; return write(it, &a, 1) == 1; E_END("storage::write", "unsigned char"); };
00176         bool read(iterator & it, unsigned char &a) const
00177             { E_BEGIN; return read(it, &a, 1) == 1; E_END("storage::read", "unsigned char"); };
00178 
00179             // after one of these 3 calls, the iterator given in argument are undefined (they may point nowhere)
00180         void insert_null_bytes_at_iterator(iterator it, U_I size);
00181         void insert_const_bytes_at_iterator(iterator it, unsigned char a, U_I size);
00182         void insert_bytes_at_iterator(iterator it, unsigned char *a, U_I size);
00183         void insert_as_much_as_necessary_const_byte_to_be_as_wider_as(const storage & ref, const iterator & it, unsigned char value);
00184         void remove_bytes_at_iterator(iterator it, U_I number);
00185         void remove_bytes_at_iterator(iterator it, infinint number);
00186 
00187 
00188     private:
00189         struct cellule *first, *last;
00190 
00191         void copy_from(const storage & ref);
00192         S_32 difference(const storage & ref) const;
00193         void reduce(); // heuristic that tries to free some memory;
00194         void insert_bytes_at_iterator_cmn(iterator it, bool constant, unsigned char *a, U_I size);
00195         void fusionne(struct cellule *a_first, struct cellule *a_last, struct cellule *b_first, struct cellule *b_last,
00196                       struct cellule *&res_first, struct cellule * & res_last);
00197 
00199             // STATIC statments :
00200             //
00201 
00202         static void detruit(struct cellule *c);
00203         static void make_alloc(U_32 size, struct cellule * & begin, struct cellule * & end);
00204         static void make_alloc(infinint size, cellule * & begin, struct cellule * & end);
00205 
00206         friend class storage::iterator;
00207     };
00208 
00209     inline void storage::iterator::skip_plus_one()
00210     {
00211         E_BEGIN;
00212         if(cell != NULL)
00213             if(++offset >= cell->size)
00214             {
00215                 cell = cell->next;
00216                 if(cell != NULL)
00217                     offset = 0;
00218                 else
00219                     offset = OFF_END;
00220             }
00221         E_END("storage::iterator::slik_plus_one", "");
00222     }
00223 
00224     inline void storage::iterator::skip_less_one()
00225     {
00226         E_BEGIN;
00227         if(cell != NULL)
00228         {
00229             if(offset > 0)
00230                 --offset;
00231             else
00232             {
00233                 cell = cell->prev;
00234                 if(cell != NULL)
00235                     offset = cell->size - 1;
00236                 else
00237                     offset = OFF_BEGIN;
00238             }
00239         }
00240         E_END("storage::iterator::slik_plus_one", "");
00241     }
00242 
00243 } // end of namespace
00244 
00245 #endif
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