X-Git-Url: http://git.ithinksw.org/ITFoundation.git/blobdiff_plain/f53b25adbb0e87abd41713a586d3c723ebeb8ff0..68089b190f6a03c185722c8532197dacabf52f8d:/ArrayQueue.m

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+/************************
+A Cocoa DataStructuresFramework
+Copyright (C) 2002  Phillip Morelock in the United States
+http://www.phillipmorelock.com
+Other copyrights for this specific file as acknowledged herein.
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 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
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*******************************/
+
+/////SEE LICENSE FILE FOR LICENSE INFORMATION///////
+
+#import "ArrayQueue.h"
+
+@implementation ArrayQueue
+
+- init
+{
+    return [self initWithCapacity:10];
+}
+
+-initWithCapacity:(unsigned)capacity
+{
+    self = [super init];
+    
+    theQ = [[NSMutableArray alloc] initWithCapacity:capacity];
+    
+    backIndex = -1;
+    frontIndex = 0;
+    qSize = 0;
+    
+    niller = [[NSString stringWithFormat:@"nothing"] retain];
+    
+    return self;
+}
+
+-(void) dealloc
+{
+    [theQ release];
+    [niller release];
+    [super dealloc];
+}
+
+-(BOOL) enqueue: (id)enqueuedObj
+{
+    if ( enqueuedObj == nil )
+	return NO;
+    
+    ++backIndex;
+    [theQ insertObject:enqueuedObj atIndex:backIndex];
+    ++qSize;
+    return YES;
+}
+
+- dequeue
+{
+    id theObj;
+
+    if ( qSize < 1 )
+	return nil;
+    
+    //decrement the size of the Q
+    --qSize;
+
+    //get it and retain it
+    theObj = [[theQ objectAtIndex:frontIndex] retain];
+    [theQ replaceObjectAtIndex:frontIndex withObject:niller];
+    
+    //now increment front -- if we have large array and we've "caught up" with
+    //the back, then let's dealloc and start over.
+    ++frontIndex;
+    if (frontIndex > 25 && qSize < 0)
+    {
+	[self removeAllObjects];
+    }
+    
+    return [theObj autorelease];
+}
+
+-(unsigned) count
+{
+    return qSize;
+}
+
+//simple BOOL for whether the queue is empty or not.
+-(BOOL) isEmpty
+{
+    if ( qSize < 1)
+	return YES;
+    else
+	return NO;
+}
+
+-(void) removeAllObjects
+{
+    if (theQ)
+	[theQ release];
+    
+    theQ = [[NSMutableArray alloc] initWithCapacity:10];
+    backIndex = -1;
+    frontIndex = 0;
+    qSize = 0;
+
+}
+
++(ArrayQueue *)queueWithArray:(NSArray *)array
+                  ofOrder:(BOOL)direction
+{
+    ArrayQueue *q;
+    int i,s;
+    
+    q = [[ArrayQueue alloc] init];
+    s = [array count];
+    i = 0;
+    
+    if (!array || !s)
+    {}//nada
+    else if (direction)//so the order to dequeue will be from 0...n
+    {
+        while (i < s)
+            [q enqueue: [array objectAtIndex: i++]];
+    }
+    else //order to dequeue will be n...0
+    {
+        while (s > i)
+            [q enqueue: [array objectAtIndex: --s]];
+    }
+
+    return [q autorelease];
+}
+
+
+@end