summaryrefslogtreecommitdiffstats
path: root/kviewshell/plugins/djvu/libdjvu/DjVuFileCache.cpp
blob: 13220a96e9bb7699a35fe77da17b63f14769c77e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
//C-  -*- C++ -*-
//C- -------------------------------------------------------------------
//C- DjVuLibre-3.5
//C- Copyright (c) 2002  Leon Bottou and Yann Le Cun.
//C- Copyright (c) 2001  AT&T
//C-
//C- This software is subject to, and may be distributed under, the
//C- GNU General Public License, Version 2. The license should have
//C- accompanied the software or you may obtain a copy of the license
//C- from the Free Software Foundation at http://www.fsf.org .
//C-
//C- This program is distributed in the hope that it will be useful,
//C- but WITHOUT ANY WARRANTY; without even the implied warranty of
//C- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//C- GNU General Public License for more details.
//C- 
//C- DjVuLibre-3.5 is derived from the DjVu(r) Reference Library
//C- distributed by Lizardtech Software.  On July 19th 2002, Lizardtech 
//C- Software authorized us to replace the original DjVu(r) Reference 
//C- Library notice by the following text (see doc/lizard2002.djvu):
//C-
//C-  ------------------------------------------------------------------
//C- | DjVu (r) Reference Library (v. 3.5)
//C- | Copyright (c) 1999-2001 LizardTech, Inc. All Rights Reserved.
//C- | The DjVu Reference Library is protected by U.S. Pat. No.
//C- | 6,058,214 and patents pending.
//C- |
//C- | This software is subject to, and may be distributed under, the
//C- | GNU General Public License, Version 2. The license should have
//C- | accompanied the software or you may obtain a copy of the license
//C- | from the Free Software Foundation at http://www.fsf.org .
//C- |
//C- | The computer code originally released by LizardTech under this
//C- | license and unmodified by other parties is deemed "the LIZARDTECH
//C- | ORIGINAL CODE."  Subject to any third party intellectual property
//C- | claims, LizardTech grants recipient a worldwide, royalty-free, 
//C- | non-exclusive license to make, use, sell, or otherwise dispose of 
//C- | the LIZARDTECH ORIGINAL CODE or of programs derived from the 
//C- | LIZARDTECH ORIGINAL CODE in compliance with the terms of the GNU 
//C- | General Public License.   This grant only confers the right to 
//C- | infringe patent claims underlying the LIZARDTECH ORIGINAL CODE to 
//C- | the extent such infringement is reasonably necessary to enable 
//C- | recipient to make, have made, practice, sell, or otherwise dispose 
//C- | of the LIZARDTECH ORIGINAL CODE (or portions thereof) and not to 
//C- | any greater extent that may be necessary to utilize further 
//C- | modifications or combinations.
//C- |
//C- | The LIZARDTECH ORIGINAL CODE is provided "AS IS" WITHOUT WARRANTY
//C- | OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
//C- | TO ANY WARRANTY OF NON-INFRINGEMENT, OR ANY IMPLIED WARRANTY OF
//C- | MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
//C- +------------------------------------------------------------------
// 
// $Id: DjVuFileCache.cpp,v 1.9 2004/08/06 15:11:29 leonb Exp $
// $Name: release_3_5_15 $

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#if NEED_GNUG_PRAGMAS
# pragma implementation
#endif

#include "DjVuFileCache.h"
#include "debug.h"

#include <stdlib.h>


#ifdef HAVE_NAMESPACES
namespace DJVU {
# ifdef NOT_DEFINED // Just to fool emacs c++ mode
}
#endif
#endif


DjVuFileCache::~DjVuFileCache(void) {}

int
DjVuFileCache::Item::qsort_func(const void * el1, const void * el2)
{
   const Item * item1=*(Item **) el1;
   const Item * item2=*(Item **) el2;
   time_t time1=item1->get_time();
   time_t time2=item2->get_time();
   return time1<time2 ? -1 : time1>time2 ? 1 : 0;
}

void
DjVuFileCache::set_max_size(int xmax_size)
{
   DEBUG_MSG("DjVuFileCache::set_max_size(): resizing to " << xmax_size << "\n");
   DEBUG_MAKE_INDENT(3);

   GCriticalSectionLock lock(&class_lock);
   
   max_size=xmax_size;
   cur_size=calculate_size();

   if (max_size>=0) clear_to_size(enabled ? max_size : 0);
}

void
DjVuFileCache::enable(bool en)
{
   enabled=en;
   set_max_size(max_size);
}

void
DjVuFileCache::add_file(const GP<DjVuFile> & file)
{
   DEBUG_MSG("DjVuFileCache::add_file(): trying to add a new item\n");
   DEBUG_MAKE_INDENT(3);

   GCriticalSectionLock lock(&class_lock);

      // See if the file is already cached
   GPosition pos;
   for(pos=list;pos;++pos)
      if (list[pos]->get_file()==file) break;
   
   if (pos) list[pos]->refresh();	// Refresh the timestamp
   else
   {
	 // Doesn't exist in the list yet
      int _max_size=enabled ? max_size : 0;
      if (max_size<0) _max_size=max_size;

      int add_size=file->get_memory_usage();
   
      if (_max_size>=0 && add_size>_max_size)
      {
	 DEBUG_MSG("but this item is way too large => doing nothing\n");
	 return;
      }

      if (_max_size>=0) clear_to_size(_max_size-add_size);

      list.append(new Item(file));
      cur_size+=add_size;
      file_added(file);
   }
}

void
DjVuFileCache::clear_to_size(int size)
{
   DEBUG_MSG("DjVuFileCache::clear_to_size(): dropping cache size to " << size << "\n");
   DEBUG_MAKE_INDENT(3);

   GCriticalSectionLock lock(&class_lock);
   
   if (size==0)
   {
      list.empty();
      cur_size=0;
   } else
      if (list.size()>20)
      {
	    // More than 20 elements in the cache: use qsort to
	    // sort them before picking up the oldest
	 GTArray<void *> item_arr(list.size()-1);
	 GPosition pos;
	 int i;
	 for(pos=list, i=0;pos;++pos, i++)
	 {
	    GP<Item> item=list[pos];
	    item->list_pos=pos;
	    item_arr[i]=item;
	 }

	 qsort(&item_arr[0], item_arr.size(), sizeof(item_arr[0]), Item::qsort_func);

	 for(i=0;i<item_arr.size() && cur_size>(int) size;i++)
	 {
	    Item * item=(Item *) item_arr[i];
	    cur_size-=item->get_size();
	    GP<DjVuFile> file=item->file;
	    list.del(item->list_pos);
	    file_cleared(file);
	    if (cur_size<=0) cur_size=calculate_size();
	 }
      } else
      {
	    // Less than 20 elements: no reason to presort
	 while(cur_size>(int) size)
	 {
	    if (!list.size())
	    {
		  // Oops. Discrepancy due to an item changed its size
	       cur_size=0;
	       break;
	    }

	       // Remove the oldest cache item
	    GPosition oldest_pos=list;
	    GPosition pos=list;
	    for(++pos;pos;++pos)
	       if (list[pos]->get_time()<list[oldest_pos]->get_time())
		  oldest_pos=pos;
	    cur_size-=list[oldest_pos]->get_size();
	    GP<DjVuFile> file=list[oldest_pos]->file;
	    list.del(oldest_pos);
	    file_cleared(file);

	       // cur_size *may* become negative because items may change their
	       // size after they've been added to the cache
	    if (cur_size<=0) cur_size=calculate_size();
	 }
      }
   
   DEBUG_MSG("done: current cache size=" << cur_size << "\n");
}

int
DjVuFileCache::calculate_size(void)
{
   GCriticalSectionLock lock(&class_lock);
   
   int size=0;
   for(GPosition pos=list;pos;++pos)
      size+=list[pos]->get_size();
   return size;
}

void
DjVuFileCache::del_file(const DjVuFile * file)
{
   DEBUG_MSG("DjVuFileCache::del_file(): Removing an item from cache\n");
   DEBUG_MAKE_INDENT(3);

   GCriticalSectionLock lock(&class_lock);

   for(GPosition pos=list;pos;++pos)
      if (list[pos]->get_file()==file)
      {
	 GP<DjVuFile> file=list[pos]->get_file();
	 cur_size-=list[pos]->get_size();
	 list.del(pos);
	 file_deleted(file);
	 break;
      }
   if (cur_size<0) cur_size=calculate_size();
   DEBUG_MSG("current cache size=" << cur_size << "\n");
}

GPList<DjVuFileCache::Item>
DjVuFileCache::get_items(void)
{
   GCriticalSectionLock lock(&class_lock);

   return list;
}

void
DjVuFileCache::file_added(const GP<DjVuFile> &) {}

void
DjVuFileCache::file_deleted(const GP<DjVuFile> &) {}

void
DjVuFileCache::file_cleared(const GP<DjVuFile> &) {}

#ifdef HAVE_NAMESPACES
}
# ifndef NOT_USING_DJVU_NAMESPACE
using namespace DJVU;
# endif
#endif