100 lines
2.8 KiB
C++
100 lines
2.8 KiB
C++
/*
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* CDE - Common Desktop Environment
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*
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* Copyright (c) 1993-2012, The Open Group. All rights reserved.
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*
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* These libraries and programs are free software; you can
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* redistribute them and/or modify them under the terms of the GNU
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* Lesser General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* These libraries and programs are distributed in the hope that
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* they will be useful, but WITHOUT ANY WARRANTY; without even the
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* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU Lesser General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with these libraries and programs; if not, write
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* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
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* Floor, Boston, MA 02110-1301 USA
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*/
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/* $XConsortium: page_cache.h /main/3 1996/06/11 17:44:27 cde-hal $ */
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#ifndef _page_cache_h
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#define _page_cache_h 1
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class page;
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class page_storage;
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#define MMDB_CACHED_PAGES 100
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#define MIN_MMDB_CACHED_PAGES 10
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#include "dstr/bset.h"
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class page_cache_local_part
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{
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protected:
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int f_num_cached_pages ; // number of cached pages
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heap f_free_space; // a heap recording free
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// space on each page
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bset f_page_pool_index; // index to pages in the pool
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int f_current_page_num;
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page* f_current_page_ptr;
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public:
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page_cache_local_part(unsigned int exp_cached_page);
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virtual ~page_cache_local_part();
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// init the heap
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Boolean init_heap(page_storage*);
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Boolean quit_heap(page_storage*);
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// does the cache hold page 'page_num'?
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page* in_cache(page_storage* st, int page_num);
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// get a non-empty page
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fbytes_t* find_host_page(page_storage*, Boolean& new_page, int len = 0);
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void adjust_heap(fbytes_t* v, Boolean new_page);
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friend class page_cache_global_part ;
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};
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class lru;
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class page_cache_global_part
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{
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public:
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//////////////////////////////////////////////////////////////////////
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// The default value (0) triggers the constructor to
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// search for the value in the shell variable MMDB_CACHED_PAGES.
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// If the varialble is undefind, the value set by const MMDB_CACHED_PAGES
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// will be used.
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//////////////////////////////////////////////////////////////////////
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page_cache_global_part(unsigned int total_allowed_pages = 0);
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virtual ~page_cache_global_part() ;
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void remove_pages(page_storage* st);
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// return a free page frame from cache
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page* load_new_page(page_storage*, int page_num, Boolean byteOrder);
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ostream& print_cached_pages(ostream&); // show cached pages.
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friend class page_cache_local_part;
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friend class page_storage;
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friend void remove_from_global_cache(const void*);
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protected:
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unsigned int f_total_allowed_pages;
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lru f_replace_policy;
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};
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#endif
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