RosettaCodeData/Task/Priority-queue/Objective-C/priority-queue.m

69 lines
2.0 KiB
Objective-C

#import <Foundation/Foundation.h>
const void *PQRetain(CFAllocatorRef allocator, const void *ptr) {
return [(id)ptr retain];
}
void PQRelease(CFAllocatorRef allocator, const void *ptr) {
[(id)ptr release];
}
CFComparisonResult PQCompare(const void *ptr1, const void *ptr2, void *unused) {
return [(id)ptr1 compare:(id)ptr2];
}
@interface Task : NSObject {
int priority;
NSString *name;
}
- (id)initWithPriority:(int)p andName:(NSString *)n;
- (NSComparisonResult)compare:(Task *)other;
@end
@implementation Task
- (id)initWithPriority:(int)p andName:(NSString *)n {
if ((self = [super init])) {
priority = p;
name = [n copy];
}
return self;
}
- (void)dealloc {
[name release];
[super dealloc];
}
- (NSString *)description {
return [NSString stringWithFormat:@"%d, %@", priority, name];
}
- (NSComparisonResult)compare:(Task *)other {
if (priority == other->priority)
return NSOrderedSame;
else if (priority < other->priority)
return NSOrderedAscending;
else
return NSOrderedDescending;
}
@end
int main (int argc, const char *argv[]) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
CFBinaryHeapCallBacks callBacks = {0, PQRetain, PQRelease, NULL, PQCompare};
CFBinaryHeapRef pq = CFBinaryHeapCreate(NULL, 0, &callBacks, NULL);
CFBinaryHeapAddValue(pq, [[[Task alloc] initWithPriority:3 andName:@"Clear drains"] autorelease]);
CFBinaryHeapAddValue(pq, [[[Task alloc] initWithPriority:4 andName:@"Feed cat"] autorelease]);
CFBinaryHeapAddValue(pq, [[[Task alloc] initWithPriority:5 andName:@"Make tea"] autorelease]);
CFBinaryHeapAddValue(pq, [[[Task alloc] initWithPriority:1 andName:@"Solve RC tasks"] autorelease]);
CFBinaryHeapAddValue(pq, [[[Task alloc] initWithPriority:2 andName:@"Tax return"] autorelease]);
while (CFBinaryHeapGetCount(pq) != 0) {
Task *task = (id)CFBinaryHeapGetMinimum(pq);
NSLog(@"%@", task);
CFBinaryHeapRemoveMinimumValue(pq);
}
CFRelease(pq);
[pool drain];
return 0;
}