38 lines
709 B
Objective-C
38 lines
709 B
Objective-C
#import "Queue.h"
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#import "Constraints.h"
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@implementation Queue {
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@private NSMutableArray* items;
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}
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-(id) init {
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if (self = [super init]) {
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self->items = [NSMutableArray array];
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}
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return self;
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}
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-(void) enqueue:(id)item {
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[items addObject:item];
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}
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-(id) tryDequeue {
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if (self.count == 0) return nil;
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return [self dequeue];
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}
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-(id) dequeue {
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requireState(self.count > 0);
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id result = items[0];
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[items removeObjectAtIndex:0];
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return result;
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}
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-(id) peek {
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requireState(self.count > 0);
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return items[0];
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}
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-(id) peekAt:(NSUInteger)offset {
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require(offset < self.count);
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return items[offset];
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}
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-(NSUInteger) count {
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return items.count;
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}
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@end
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