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/* Implementation for Objective-C LinkedList collection object
Copyright (C) 1993,1994 Free Software Foundation, Inc.
Written by: R. Andrew McCallum <mccallum@gnu.ai.mit.edu>
Date: May 1993
This file is part of the GNU Objective C Class Library.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <objects/LinkedList.h>
#include <objects/IndexedCollectionPrivate.h>
#include <objects/Coder.h>
@implementation LinkedList
+ initialize
{
if (self == [LinkedList class])
[self setVersion:0]; /* beta release */
return self;
}
/* This is the designated initializer of this class */
- init
{
[super initWithType:@encode(id)];
_count = 0;
_first_link = nil;
return self;
}
/* Archiving must mimic the above designated initializer */
+ _newCollectionWithCoder: (Coder*)aCoder
{
LinkedList *n;
n = [super _newCollectionWithCoder:aCoder];
n->_count = 0;
n->_first_link = nil;
return n;
}
- (void) _encodeContentsWithCoder: (Coder*)aCoder
{
[aCoder startEncodingInterconnectedObjects];
[super _encodeContentsWithCoder:aCoder];
[aCoder finishEncodingInterconnectedObjects];
}
- (void) _decodeContentsWithCoder: (Coder*)aCoder
{
[aCoder startDecodingInterconnectedObjects];
[super _decodeContentsWithCoder:aCoder];
[aCoder finishDecodingInterconnectedObjects];
}
- _readInit: (TypedStream*)aStream
{
[super _readInit:aStream];
_count = 0;
_first_link = nil;
return self;
}
/* Empty copy must empty an allocCopy'ed version of self */
- emptyCopy
{
LinkedList *copy = [super emptyCopy];
copy->_count = 0;
copy->_first_link = nil;
return copy;
}
/* This must work without sending any messages to content objects */
- empty
{
_count = 0;
_first_link = nil;
return self;
}
/* Override the designated initializer for our superclass IndexedCollection
to make sure we have object values. */
- initWithType: (const char *)contentEncoding
{
if (!ENCODING_IS_OBJECT(contentEncoding))
[self error:"LinkedList contents must be objects conforming to "
"<LinkedListComprising> protocol"];
[self init];
return self;
}
/* These next four methods are the only ones that change the values of
the instance variables _count, _first_link, except for
"-initDescription:". */
- (elt) removeElement: (elt)oldElement
{
if (_first_link == oldElement.id_u)
{
if (_count > 1)
_first_link = [oldElement.id_u nextLink];
else
_first_link = nil;
}
[[oldElement.id_u nextLink] setPrevLink:[oldElement.id_u prevLink]];
[[oldElement.id_u prevLink] setNextLink:[oldElement.id_u nextLink]];
_count--;
return oldElement;
}
- insertElement: (elt)newElement after: (elt)oldElement
{
if (_count == 0)
{
/* link to self */
_first_link = newElement.id_u;
[newElement.id_u setNextLink:newElement.id_u];
[newElement.id_u setPrevLink:newElement.id_u];
}
else
{
[newElement.id_u setNextLink:[oldElement.id_u nextLink]];
[newElement.id_u setPrevLink:oldElement.id_u];
[[oldElement.id_u nextLink] setPrevLink:newElement.id_u];
[oldElement.id_u setNextLink:newElement.id_u];
}
_count++;
return self;
}
- insertElement: (elt)newElement before: (elt)oldElement
{
if (oldElement.id_u == _first_link)
_first_link = newElement.id_u;
if (_count == 0)
{
/* Link to self */
[newElement.id_u setNextLink:newElement.id_u];
[newElement.id_u setPrevLink:newElement.id_u];
}
else
{
[newElement.id_u setPrevLink:[oldElement.id_u prevLink]];
[newElement.id_u setNextLink:oldElement.id_u];
[[oldElement.id_u prevLink] setNextLink:newElement.id_u];
[oldElement.id_u setPrevLink:newElement.id_u];
}
_count++;
return self;
}
- (elt) replaceElement: (elt)oldElement with: (elt)newElement
{
if (oldElement.id_u == _first_link)
_first_link = newElement.id_u;
[newElement.id_u setNextLink:[oldElement.id_u nextLink]];
[newElement.id_u setPrevLink:[oldElement.id_u prevLink]];
[[oldElement.id_u prevLink] setNextLink:newElement.id_u];
[[oldElement.id_u nextLink] setPrevLink:newElement.id_u];
return oldElement;
}
/* End of methods that change the instance variables. */
- appendElement: (elt)newElement
{
if (_count)
[self insertElement:newElement after:[self lastElement]];
else
[self insertElement:newElement after:nil];
return self;
}
- prependElement: (elt)newElement
{
[self insertElement:newElement before:_first_link];
return self;
}
- insertElement: (elt)newElement atIndex: (unsigned)index
{
CHECK_INDEX_RANGE_ERROR(index, (_count+1));
if (index == _count)
[self insertElement:newElement after:[self lastElement]];
else
[self insertElement:newElement before:[self elementAtIndex:index]];
return self;
}
- (elt) removeElementAtIndex: (unsigned)index
{
CHECK_INDEX_RANGE_ERROR(index, _count);
return [self removeElement:[self elementAtIndex:index]];
}
- (elt) elementAtIndex: (unsigned)index
{
id <LinkedListComprising> aLink;
CHECK_INDEX_RANGE_ERROR(index, _count);
if (index < _count / 2)
for (aLink = _first_link;
index;
aLink = [aLink nextLink], index--)
;
else
for (aLink = [_first_link prevLink], index = _count - index - 1;
index;
aLink = [aLink prevLink], index--)
;
return aLink;
}
- (elt) firstElement
{
return _first_link;
}
- (elt) lastElement
{
if (_count)
return [_first_link prevLink];
else
return NO_ELEMENT_FOUND_ERROR();
}
- (elt) successorOfElement: (elt)oldElement
{
id nextElement = [oldElement.id_u nextLink];
if (_first_link == nextElement)
return nil;
else
return (elt)nextElement;
}
- (elt) predecessorOfElement: (elt)oldElement
{
if (_first_link == oldElement.id_u)
return nil;
else
return (elt)[oldElement.id_u prevLink];
}
- (BOOL) getNextElement:(elt *)anElementPtr withEnumState: (void**)enumState
{
if (*enumState == _first_link)
return NO;
else if (!(*enumState))
*enumState = _first_link;
*anElementPtr = *enumState;
*enumState = [(id)(*enumState) nextLink];
return YES;
}
- (BOOL) getPrevElement:(elt *)anElementPtr withEnumState: (void**)enumState
{
if (*enumState == _first_link)
return NO;
if (!(*enumState))
*enumState = _first_link;
*enumState = [(id)(*enumState) prevLink];
*anElementPtr = *enumState;
return YES;
}
- withElementsCall: (void(*)(elt))aFunc whileTrue:(BOOL *)flag
{
id link;
unsigned i;
for (link = _first_link, i = 0;
*flag && i < _count;
link = [link nextLink], i++)
{
(*aFunc)(link);
}
return self;
}
- withElementsInReverseCall: (void(*)(elt))aFunc whileTrue:(BOOL *)flag
{
id link;
unsigned i;
if (!_first_link)
return self;
for (link = [_first_link prevLink], i = 0;
*flag && i < _count;
link = [link prevLink], i++)
{
(*aFunc)(link);
}
return self;
}
- (unsigned) count
{
return _count;
}
@end
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