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150 lines
2.8 KiB
C++
150 lines
2.8 KiB
C++
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#ifdef __GNUC__
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#pragma implementation /* gcc: Class implementation */
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#endif
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#include <global.h>
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#include <my_sys.h>
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#include "cache_manager.h"
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/*
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cache_manager.cc
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-----------------------------------------------------------------------
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The cache_manager class manages a number of blocks (which are allocatable
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units of memory).
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-----------------------------------------------------------------------
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*/
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#define HEADER_LENGTH ALIGN_SIZE(8)
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#define SUFFIX_LENGTH 4
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#define ALLOC_MASK 0x3FFFFFFFL
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#define FREE_BIT (1L << 31)
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#define LOCK_BIT (1L << 30)
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#define SMALLEST_BLOCK 32
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/*
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** Internal Methods
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** --------------------
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*/
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/* list manipulation methods */
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void *cache_manager::init_list(void)
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{
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return;
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}
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void *cache_manager::link_into_abs(void *ptr)
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{
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for (int i(0); (*abs_list)[i] != NULL; i++);
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(*abs_list)[i] = ptr;
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return (abs_list)[i]; // ???
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}
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bool *cache_manager::unlink_from_abs(void *ptr)
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{
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(*ptr) = NULL;
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return;
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}
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/* memory allocation methods */
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void *cache_manager::find_in_llist(uint)
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{
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return;
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}
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void cache_manager::defrag(void)
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{
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printf("Defragging: ..........");
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return;
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}
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/*
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** Public Methods
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** ------------------
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*/
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cache_manager::cache_manager(uint size)
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{
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base_ptr = my_malloc(size, MY_WME); /* MY_WME = write mesg on err */
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return;
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}
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cache_manager::~cache_manager(void)
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{
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free(base_ptr);
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delete base_ptr;
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return;
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}
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void *cache_manager::alloc(uint size)
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{
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void *llist;
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void *abs_ptr;
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size=ALIGN_SIZE(size+HEADER_LENGTH+SUFFIX_LENGTH);
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if (!(llist = find_in_llist(size)))
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{
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//defrag();
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if (!(llist = find_in_llist(size)))
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return 0; /* return null pointer, buffer exhausted! */
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}
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size_of_found_block=int4korr((char*) llist) & ALLOC_MASK;
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// if (size_of_found_block < SMALLEST_BLOCK)
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abs_ptr = link_into_abs(llist);
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return abs_ptr;
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}
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void cache_manager::dealloc(void)
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{
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printf("Deallocating: ..........\n");
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return;
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}
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void cache_manager::clear(void)
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{
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// reset the internal linked list, forgetting all pointers to mem blks
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return;
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}
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