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Diffstat (limited to 'kviewshell/plugins/djvu/libdjvu/DjVuFileCache.h')
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1 files changed, 292 insertions, 0 deletions
diff --git a/kviewshell/plugins/djvu/libdjvu/DjVuFileCache.h b/kviewshell/plugins/djvu/libdjvu/DjVuFileCache.h new file mode 100644 index 00000000..9898b8f3 --- /dev/null +++ b/kviewshell/plugins/djvu/libdjvu/DjVuFileCache.h @@ -0,0 +1,292 @@ +//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.h,v 1.8 2003/11/07 22:08:20 leonb Exp $ +// $Name: release_3_5_15 $ + +#ifndef _DJVUFILECACHE_H +#define _DJVUFILECACHE_H +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif +#if NEED_GNUG_PRAGMAS +# pragma interface +#endif + + +#include "DjVuFile.h" + +#ifndef macintosh //MCW can't compile +# ifndef UNDER_CE +# include <sys/types.h> +# include <time.h> +# endif +#else +# include <time.h> +#endif + + +#ifdef HAVE_NAMESPACES +namespace DJVU { +# ifdef NOT_DEFINED // Just to fool emacs c++ mode +} +#endif +#endif + +/** @name DjVuFileCache.h + Files #"DjVuFileCache.h"# and #"DjVuFileCache.cpp"# implement a simple + caching mechanism for keeping a given number of \Ref{DjVuFile} instances + alive. The cache estimates the size of its elements and gets rid of + the oldest ones when necessary. + + See \Ref{DjVuFileCache} for details. + + @memo Simple DjVuFile caching class. + @author Andrei Erofeev <eaf@geocities.com> + @version #$Id: DjVuFileCache.h,v 1.8 2003/11/07 22:08:20 leonb Exp $# +*/ + +//@{ + +/** #DjVuFileCache# is a simple list of \Ref{DjVuFile} instances. It keeps + track of the total size of all elements and can get rid of the oldest + one once the total size becomes over some threshold. Its main purpose + is to keep the added \Ref{DjVuFile} instances alive until their size + exceeds some given threshold (set by \Ref{set_maximum_size}() function). + The user is supposed to use \Ref{DjVuPortcaster::name_to_port}() to + find a file corresponding to a given name. The cache provides no + naming services */ +#ifdef UNDER_CE +class DjVuFileCache : public GPEnabled +{ +protected: + DjVuFileCache(const int) {} +public: + static GP<DjVuFileCache> create(const int); + virtual ~DjVuFileCache(void); + void del_file(const DjVuFile *) {} + void add_file(const GP<DjVuFile> &) {} + void clear(void) {} + void set_max_size(int) {} + int get_max_size(void) const {return 0;} + void enable(bool en) {} + bool is_enabled(void) const {return false;} +} ; +#else +class DjVuFileCache : public GPEnabled +{ +protected: + DjVuFileCache(const int max_size=5*2*1024*1024); +public: + /** Constructs the #DjVuFileCache# + @param max_size Maximum allowed size of the cache in bytes. */ + static GP<DjVuFileCache> create(const int max_size=5*2*1024*1024); + + virtual ~DjVuFileCache(void); + + /** Removes file #file# from the cache */ + void del_file(const DjVuFile * file); + + /** Adds the given file to the cache. It it's already there, its + timestamp will be refreshed. */ + void add_file(const GP<DjVuFile> & file); + + /** Clears the cache. All items will be deleted. */ + void clear(void); + /** Sets new maximum size. If the total size of all items in the cache + is greater than #max_size#, the cache will be deleting the oldest + items until the size is OK. */ + void set_max_size(int max_size); + + /** Returns the maximum allowed size of the cache. */ + int get_max_size(void) const; + + /** Enables or disables the cache. See \Ref{is_enabled}() for details + @param en - If {\em en} is TRUE, the cache will be enabled. + Otherwise it will be disabled. + */ + void enable(bool en); + + /** Returns #TRUE# if the cache is enabled, #FALSE# otherwise. + When a cache is disabled, \Ref{add_file}(), and + \Ref{del_file}() do nothing. But the {\em maximum size} is preserved + inside the class so that next time the cache is enabled, it will + be configured the same way. Clearly this "enable/disable" thing is + for convenience only. One could easily simulate this behavior by + setting the {\em maximum size} of the cache to #ZERO#. */ + bool is_enabled(void) const; + +public: + class Item; + + class Item : public GPEnabled + { + public: + virtual ~Item(void); + time_t get_time(void) const; + + GP<DjVuFile> get_file(void) const; + unsigned int get_size(void) const; + + void refresh(void); + + public: + GP<DjVuFile> file; + time_t time; + GPosition list_pos; + static int qsort_func(const void * el1, const void * el2); + + Item(void); + Item(const GP<DjVuFile> & xfile); + }; + +protected: + GCriticalSection class_lock; + + /** This function is called right after the given file has been added + to the cache for management. */ + virtual void file_added(const GP<DjVuFile> & file); + /** This function is called when the given file is no longer + managed by the cache. */ + virtual void file_deleted(const GP<DjVuFile> & file); + /** This function is called when after the cache decides to get rid + of the file. */ + virtual void file_cleared(const GP<DjVuFile> & file); + + GPList<Item> get_items(void); +private: + GPList<Item> list; + bool enabled; + int max_size; + int cur_size; + + int calculate_size(void); + void clear_to_size(int size); +}; + + + +//@} + +inline +DjVuFileCache::Item::Item(void) : time(::time(0)) {} + +inline +DjVuFileCache::Item::Item(const GP<DjVuFile> & xfile) : + file(xfile), time(::time(0)) {} + +inline +DjVuFileCache::Item::~Item(void) {} + +inline GP<DjVuFile> +DjVuFileCache::Item::get_file(void) const +{ + return file; +} + +inline unsigned int +DjVuFileCache::Item::get_size(void) const +{ + return file->get_memory_usage(); +} + +inline time_t +DjVuFileCache::Item::get_time(void) const +{ + return time; +} + +inline void +DjVuFileCache::Item::refresh(void) +{ + time=::time(0); +} + +inline +DjVuFileCache::DjVuFileCache(const int xmax_size) : + enabled(true), max_size(xmax_size), cur_size(0) {} + +inline void +DjVuFileCache::clear(void) +{ + clear_to_size(0); +} + +inline bool +DjVuFileCache::is_enabled(void) const +{ + return enabled; +} + +inline int +DjVuFileCache::get_max_size(void) const +{ + return max_size; +} + +#endif + +inline GP<DjVuFileCache> +DjVuFileCache::create(const int max_size) +{ + return new DjVuFileCache(max_size); +} + + +#ifdef HAVE_NAMESPACES +} +# ifndef NOT_USING_DJVU_NAMESPACE +using namespace DJVU; +# endif +#endif +#endif |