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//
// 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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