113 lines
2.5 KiB
Mathematica
113 lines
2.5 KiB
Mathematica
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/*
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Copyright (C) 2000-2004 SKYRIX Software AG
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This file is part of OGo
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OGo is free software; you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License as published by the
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Free Software Foundation; either version 2, or (at your option) any
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later version.
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OGo is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with OGo; see the file COPYING. If not, write to the
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Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
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02111-1307, USA.
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*/
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#include "SOGoLRUCache.h"
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#include "common.h"
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@interface SOGoLRUCacheItem : NSObject
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{
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id object;
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unsigned useCount;
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}
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- (id)initWithObject:(id)_obj;
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- (id)object;
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- (unsigned)useCount;
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@end
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@implementation SOGoLRUCacheItem
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- (id)initWithObject:(id)_obj {
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self = [super init];
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if(self) {
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ASSIGN(self->object, _obj);
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self->useCount = 1;
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}
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return self;
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}
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- (id)object {
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self->useCount++;
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return self->object;
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}
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- (unsigned)useCount {
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return self->useCount;
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}
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@end
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@implementation SOGoLRUCache
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- (id)initWithCacheSize:(unsigned)_size {
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self = [super init];
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if(self) {
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self->size = _size;
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self->entries = [[NSMutableDictionary alloc] initWithCapacity:_size];
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}
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return self;
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}
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- (void)dealloc {
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[self->entries release];
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[super dealloc];
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}
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- (void)addObject:(id)_obj forKey:(id)_key {
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SOGoLRUCacheItem *item;
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NSAssert(_obj, @"Attempt to insert nil object!");
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if([self->entries count] >= self->size) {
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/* need to find minimum and get rid of it */
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NSEnumerator *keyEnum;
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SOGoLRUCacheItem *item;
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id key, leastUsedItemKey;
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unsigned minimumUseCount = INT_MAX;
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keyEnum = [self->entries keyEnumerator];
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while((key = [keyEnum nextObject])) {
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item = [self->entries objectForKey:key];
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if([item useCount] < minimumUseCount) {
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minimumUseCount = [item useCount];
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leastUsedItemKey = key;
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}
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}
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[self->entries removeObjectForKey:leastUsedItemKey];
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}
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item = [[SOGoLRUCacheItem alloc] initWithObject:_obj];
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[self->entries setObject:item forKey:_key];
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[item release];
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}
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- (id)objectForKey:(id)_key {
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SOGoLRUCacheItem *item;
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item = [self->entries objectForKey:_key];
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if(!item)
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return nil;
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return [item object];
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}
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@end
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