From 9d52266f823daf5cb83e3eebe1b9f57594bc9d4a Mon Sep 17 00:00:00 2001
From: matt handler <matt.handler@gmail.com>
Date: Wed, 20 Apr 2011 14:39:20 -0400
Subject: first commit

---
 Classes/HJCircularBuffer.m | 149 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 149 insertions(+)
 create mode 100755 Classes/HJCircularBuffer.m

(limited to 'Classes/HJCircularBuffer.m')

diff --git a/Classes/HJCircularBuffer.m b/Classes/HJCircularBuffer.m
new file mode 100755
index 0000000..ebb682d
--- /dev/null
+++ b/Classes/HJCircularBuffer.m
@@ -0,0 +1,149 @@
+//
+//  HJCircularBuffer.m
+//  hjlib
+//
+//  Copyright Hunter and Johnson 2009, 2010, 2011
+//  HJCache may be used freely in any iOS or Mac application free or commercial.
+//  May be redistributed as source code only if all the original files are included.
+//  See http://www.markj.net/hjcache-iphone-image-cache/
+
+#import "HJCircularBuffer.h"
+
+
+@implementation HJCircularBuffer
+
++(HJCircularBuffer*)bufferWithCapacity:(int)capacity {
+	return [[[HJCircularBuffer alloc] initWithCapacity:capacity] autorelease];
+}
+	
+-(HJCircularBuffer*)initWithCapacity:(int)capacity {
+	[super init];
+	buffer = [[NSMutableArray arrayWithCapacity:capacity] retain];
+	nextIndex=0;
+	NSNull* nullObj = [NSNull null];
+	for (int i=0; i<capacity; i++) {
+		[buffer addObject:nullObj];
+	}
+	return self;
+}
+	
+-(void)dealloc {
+	[buffer release];
+	[super dealloc];
+}
+
+-(int)length {
+	return [buffer count];
+}
+
+/**
+ * Add object to 'end' of buffer.
+ * @return an autoreleased object that had to be removed to make room for the object added. 
+ */
+-(id)addObject:(id)obj {
+	id oldObj = [self swapObject:obj atIndex:nextIndex];
+	nextIndex++;
+	if (nextIndex>=[buffer count]) { 
+		nextIndex=0;
+	}
+	return oldObj;
+}
+
+-(id)swapObject:(id)obj atIndex:(int)i {
+	if ([buffer count]==0) { 
+		return nil; 
+	}
+	id oldObj = [buffer objectAtIndex:i];
+	if (oldObj!=[NSNull null]) {
+		//because when old objObj replaced in the buffer, it will be released and might dealloc:
+		[oldObj retain];
+		[oldObj autorelease];
+	}
+	[buffer replaceObjectAtIndex:nextIndex withObject:obj];
+	if (oldObj!=[NSNull null]) {
+		return oldObj;
+	}
+	return nil;
+}
+
+
+-(int)findIndexOfObject:(id)key {
+	NSNull* nullObj = [NSNull null];
+	id obj;
+	int i = nextIndex-1; //start looking at the last object
+	if (i<0) { i=0; }
+	for (int n = [buffer count]-1; n>=0; n--) {
+		if (i<0) { 
+			i=[buffer count]-1;  //i has to wrap around to the end of the buffer array
+		}
+		obj = [buffer objectAtIndex:i];
+		if (obj!=nullObj) {
+			BOOL result = [obj isEqual:key];
+			if (result) {
+				return i;
+			}
+		}
+		i--; 
+	}
+	return -1;
+}
+
+-(id)findObject:(id)key {
+	int i = [self findIndexOfObject:key];
+	if (i<0) { 
+		return nil;
+	}
+	return [self objectAtIndex:i];
+}
+
+-(id)objectAtIndex:(int)i {
+	id obj = [buffer objectAtIndex:i];
+	if (obj==[NSNull null]) { 
+		return nil; 
+	}
+	return obj;
+}
+
+-(void)removeObjectAtIndex:(int)i {
+	[buffer replaceObjectAtIndex:i withObject:[NSNull null]];
+}	
+
+-(void)removeObject:(id)key {
+	int i = [self findIndexOfObject:key];
+	if (i<0) {
+		return; 
+	}
+	//NSLog(@"remove at index %i",i);
+	[self removeObjectAtIndex:i];
+}
+
+-(NSArray*)allObjects {
+	NSMutableArray* all = [NSMutableArray arrayWithCapacity:[buffer count]];
+	for (id obj in buffer) {
+		if (![obj isKindOfClass:[NSNull class]]) {
+			[all addObject:obj];
+		}
+	}
+	return all;
+}
+
+
++(void)test {
+	/*
+	HJCircularBuffer* b = [HJCircularBuffer bufferWithCapacity:4];
+	
+	id o;
+	o = [b addObject:@"zero"];
+	o = [b addObject:@"one"];
+	o = [b addObject:@"two"];
+	o = [b addObject:@"three"];
+	o = [b addObject:@"andBack"];
+	
+	int i = [b findIndexOfObjectEqualTo:@"two"];
+	o = [b findObjectEqualTo:@"two"];
+	NSLog(@"%@",o);
+	 */
+}
+
+
+@end
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