Мой подход к обновлению стоимости. Поскольку CFBinaryHeap не поддерживает обновление значений, я помещаю их в список недействительности, и как только он будет извлечен, объект снова вставлен и будет произведено новое извлечение.
/**
Objective-C wrapper around CFBinaryHeap implementing a priority queue and extended by updating a previous value
*/
NS_ASSUME_NONNULL_BEGIN
@interface BEPriorityQueue<ObjectType, ValueType> : NSObject
- (void)dispose;
@property (nonatomic, readonly) NSUInteger count;
- (void)insert:(ObjectType)object value:(ValueType)value;
- (void)update:(ObjectType)object value:(ValueType)value;
/** returns and removes object with lowest value (highest priority */
- (ObjectType)extractMinimum;
- (BOOL)containsObject:(ObjectType)object;
- (id)valueForObject:(id)object;
- (void)removeAllObjects;
@end
NS_ASSUME_NONNULL_END
С этой реализации:
NS_ASSUME_NONNULL_BEGIN
@interface BEPriorityQueue()
- (CFComparisonResult)compareObject:(id)object1 with:(id)object2;
@end
static CFComparisonResult BEPriorityQueueCompareItems(const void *ptr1, const void *ptr2, void *info)
{
id object1 = (__bridge id)ptr1;
id object2 = (__bridge id)ptr2;
BEPriorityQueue* queue = (__bridge id)info;
return [queue compareObject:object1 with:object2];
}
static const void *BEPriorityQueueItemRetain(CFAllocatorRef allocator, const void *ptr) {
return CFRetain(ptr);
}
static void BEPriorityQueueItemRelease(CFAllocatorRef allocator, const void *ptr) {
CFRelease(ptr);
}
@implementation BEPriorityQueue
{
BOOL _disposed;
CFBinaryHeapRef _binaryHeapRef;
NSMapTable* _objectToValue;
NSMutableSet* _invalidated;
}
- (instancetype)init
{
self = [super init];
if (self)
{
CFBinaryHeapCallBacks callbacks = (CFBinaryHeapCallBacks) {
.version = 0,
.retain = &BEPriorityQueueItemRetain,
.release = &BEPriorityQueueItemRelease,
.copyDescription = &CFCopyDescription,
.compare = &BEPriorityQueueCompareItems
};
CFBinaryHeapCompareContext compareContext = (CFBinaryHeapCompareContext) {
.version = 0,
.info = (__bridge void *)(self),
.retain = NULL,
.release = NULL,
.copyDescription = NULL,
};
_binaryHeapRef = CFBinaryHeapCreate(NULL, 0, &callbacks, &compareContext);
_objectToValue = [NSMapTable strongToStrongObjectsMapTable];
_invalidated = [NSMutableSet set];
}
return self;
}
- (void)dealloc
{
[self dispose];
if (_binaryHeapRef != NULL)
{
CFRelease(_binaryHeapRef);
_binaryHeapRef = NULL;
}
}
- (void)dispose
{
[self removeAllObjects];
_disposed = YES;
}
#pragma mark internal
- (CFComparisonResult)compareObject:(id)object1 with:(id)object2
{
id value1 = [_objectToValue objectForKey:object1];
id value2 = [_objectToValue objectForKey:object2];
return (CFComparisonResult)[value1 compare:value2];
}
#pragma mark interface
- (NSUInteger)count
{
BEEnsureFalse(_disposed);
return (NSUInteger)CFBinaryHeapGetCount(_binaryHeapRef);
}
- (id)extractMinimum
{
BEEnsureFalse(_disposed);
const void *ptr = NULL;
if (!CFBinaryHeapGetMinimumIfPresent(_binaryHeapRef, &ptr))
return nil;
id object = (__bridge id)ptr;
id value = [_objectToValue objectForKey:object];
CFBinaryHeapRemoveMinimumValue(_binaryHeapRef);
[_objectToValue removeObjectForKey:object];
// if the objects was invalidated, it may no longer be the minimum
// therefore reinsert the object and extract again
if ([_invalidated containsObject:object])
{
[_invalidated removeObject:object];
[self insert:object value:value];
return [self extractMinimum];
}
return object;
}
- (void)insert:(id)object value:(id)value
{
BEEnsureFalse(_disposed);
BEEnsureIsNotNil(object);
BEEnsureIsNotNil(value);
BEEnsureTrue([value respondsToSelector:@selector(compare:)]); // <NSComparable>
[_objectToValue setObject:value forKey:object]; // first to be available furing insertion compare
CFBinaryHeapAddValue(_binaryHeapRef, (__bridge void *)object);
}
- (void)update:(id)object value:(id)value
{
BEEnsureFalse(_disposed);
BEEnsureIsNotNil(object);
BEEnsureTrue([value respondsToSelector:@selector(compare:)]); // <NSComparable>
[_objectToValue setObject:value forKey:object]; // first to be available during insertion compare
[_invalidated addObject:object];
}
- (BOOL)containsObject:(id)object
{
BEEnsureFalse(_disposed);
return CFBinaryHeapContainsValue(_binaryHeapRef, (__bridge void *)object);
}
- (id)valueForObject:(id)object
{
return [_objectToValue objectForKey:object];
}
- (void)removeAllObjects
{
CFBinaryHeapRemoveAllValues(_binaryHeapRef);
[_objectToValue removeAllObjects];
[_invalidated removeAllObjects];
}
@end
NS_ASSUME_NONNULL_END
Я думаю, что ближе всего к тому, что вы ищете будет Grand Central Distpatch: http://developer.apple.com/library/mac/#documentation/General /Conceptual/ConcurrencyProgrammingGuide/Introduction/Introduction.html#//apple_ref/doc/uid/TP40008091 –
Похоже, что NSMutableArray, искаженный с помощью функции indexOfObjectPassingTest, будет работать очень хорошо. –
NSOperationQueue выглядит так, как вы ищите. – DiegoMax