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git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@14298 72102866-910b-0410-8b05-ffd578937521
109 lines
1.9 KiB
Objective-C
109 lines
1.9 KiB
Objective-C
/** Implementation for NSNull for GNUStep
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Copyright (C) 2000 Free Software Foundation, Inc.
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Written by: Richard Frith-Macdonald <rfm@gnu.org>
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Date: 2000
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This file is part of the GNUstep Base Library.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library 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 GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111 USA.
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<title>NSNull class reference</title>
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$Date$ $Revision$
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*/
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#include <Foundation/NSNull.h>
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/**
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* An object to use as a placeholder - in collections for instance.
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*/
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@implementation NSNull
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static NSNull *null = 0;
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+ (id) allocWithZone: (NSZone*)z
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{
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return null;
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}
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+ (id) alloc
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{
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return null;
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}
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+ (void) initialize
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{
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if (null == 0)
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{
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null = (NSNull*)NSAllocateObject(self, 0, NSDefaultMallocZone());
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}
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}
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/**
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* Return an object that can be used as a placeholder in a collection.
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* This method always returns the same object.
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*/
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+ (NSNull*) null
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{
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return null;
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}
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- (id) autorelease
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{
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return self;
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}
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- (id) copyWithZone: (NSZone*)z
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{
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return self;
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}
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- (id) copy
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{
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return self;
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}
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- (void) dealloc
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{
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}
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- (void) encodeWithCoder: (NSCoder*)aCoder
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{
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}
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- (id) initWithCoder: (NSCoder*)aCoder
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{
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return self;
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}
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- (BOOL) isEqual: (id)other
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{
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if (other == self)
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return YES;
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else
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return NO;
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}
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- (void) release
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{
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}
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- (id) retain
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{
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return self;
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}
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@end
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