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CFBinaryHeap Reference

Derived from	CFType
Framework	CoreFoundation/CoreFoundation.h
Companion guide	Collections Programming Topics for Cocoa
Declared in	CFBinaryHeap.h

Overview

CFBinaryHeap implements a container that stores values sorted using a binary search algorithm. All binary heaps are mutable; there is not a separate immutable variety. Binary heaps can be useful as priority queues.

Functions

CFBinaryHeapAddValue

Adds a value to a binary heap.

void CFBinaryHeapAddValue (
   CFBinaryHeapRef heap,
   const void *value
);

Parameters

heap: The binary heap to use.
value: The value to add to the binary heap. The value is retained by the binary heap using the retain callback provided in the CFBinaryHeapCallBacks structure when the binary heap was created.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapApplyFunction

Iteratively applies a function to all the values in a binary heap.

void CFBinaryHeapApplyFunction (
   CFBinaryHeapRef heap,
   CFBinaryHeapApplierFunction applier,
   void *context
);

Parameters

heap: The binary heap to use.
applier: The callback function to call once for each value in heap.
context: A program-defined value that is passed to the applier callback function, but is otherwise unused by this function.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapContainsValue

Returns whether a given value is in a binary heap.

Boolean CFBinaryHeapContainsValue (
   CFBinaryHeapRef heap,
   const void *value
);

Parameters

heap: The binary heap to search.
value: The value for which to find matches in the binary heap. The compare callback provided in the CFBinaryHeapCallBacks structure when the binary heap was created is used to compare values. If value, or any of the values in the binary heap, are not understood by the compare callback, the behavior is undefined.

Return Value

true if value is a member of heap, false otherwise.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapCreate

Creates a new mutable or fixed-mutable binary heap.

CFBinaryHeapRef CFBinaryHeapCreate (
   CFAllocatorRef allocator,
   CFIndex capacity,
   const CFBinaryHeapCallBacks *callBacks,
   const CFBinaryHeapCompareContext *compareContext
);

Parameters

allocator: The allocator to use to allocate memory for the new object. Pass NULL or kCFAllocatorDefault to use the current default allocator.
capacity: The maximum number of values that can be contained by the binary heap. The binary heap starts empty and can grow to this number of values. If this parameter is 0, the binary heap's maximum capacity is limited only by memory.
callBacks: A pointer to a CFBinaryHeapCallBacks structure initialized with the callbacks that operate on the values placed into the binary heap. If the binary heap will be holding CFString objects, pass the kCFStringBinaryHeapCallBacks constant. This functions makes a copy of the contents of the callbacks structure, so that a pointer to a structure on the stack can be passed in, or can be reused for multiple binary heap creations. This callbacks parameter may not be NULL.
compareContext: Not used. Pass NULL.

Return Value

A new CFBinaryHeap object. Ownership follows the Create Rule.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapCreateCopy

Creates a new mutable or fixed-mutable binary heap with the values from a pre-existing binary heap.

CFBinaryHeapRef CFBinaryHeapCreateCopy (
   CFAllocatorRef allocator,
   CFIndex capacity,
   CFBinaryHeapRef heap
);

Parameters

allocator: The allocator to use to allocate memory for the new object. Pass NULL or kCFAllocatorDefault to use the current default allocator.
capacity: The maximum number of values that can be contained by the binary heap. The binary heap starts with the same number of values as heap and can grow to this number of values. If this parameter is 0, the binary heap's maximum capacity is limited only by memory. If nonzero, capacity must be large enough to hold all the values in heap.
heap: The binary heap which is to be copied. The values from the binary heap are copied as pointers into the new binary heap (that is, the values themselves are copied, not that to which the values point, if anything). However, the values are also retained by the new binary heap.

Return Value

A new CFBinaryHeap object holding the same values as heap. The new binary heap uses the same callbacks as heap. Ownership follows the Create Rule.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapGetCount

Returns the number of values currently in a binary heap.

CFIndex CFBinaryHeapGetCount (
   CFBinaryHeapRef heap
);

Parameters

heap: The binary heap to use.

Return Value

The number of values in heap.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapGetCountOfValue

Counts the number of times a given value occurs in a binary heap.

CFIndex CFBinaryHeapGetCountOfValue (
   CFBinaryHeapRef heap,
   const void *value
);

Parameters

heap: The binary heap to search.
value: The value for which to find matches in the binary heap. The compare callback provided in the CFBinaryHeapCallBacks structure when the binary heap was created is used to compare. If value, or any of the values in the binary heap, are not understood by the compare callback, the behavior is undefined.

Return Value

The number of times value occurs in heap.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapGetMinimum

Returns the minimum value in a binary heap.

const void * CFBinaryHeapGetMinimum (
   CFBinaryHeapRef heap
);

Parameters

heap: The binary heap to use.

Return Value

The minimum value in heap as determined by the binary heap’s compare callback. If heap contains several equal minimum values, any one may be returned. If the value is a Core Foundation object, ownership follows the Get Rule.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapGetMinimumIfPresent

Returns the minimum value in a binary heap, if present.

Boolean CFBinaryHeapGetMinimumIfPresent (
   CFBinaryHeapRef heap,
   const void **value
);

Parameters

heap: The binary heap to use.
value: On return, the minimum value in heap as determined by the binary heap’s compare callback. If heap contains several equal minimum values, any one may be returned. If the value is a Core Foundation object, ownership follows the Get Rule.

Return Value

true if a minimum value exists in heap, false otherwise. false is returned only if heap is empty.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapGetTypeID

Returns the type identifier of the CFBinaryHeap opaque type.

CFTypeID CFBinaryHeapGetTypeID (
   void
);

Return Value

The type identifier of the CFBinaryHeap opaque type.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapGetValues

Copies all the values from a binary heap into a sorted C array.

void CFBinaryHeapGetValues (
   CFBinaryHeapRef heap,
   const void **values
);

Parameters

heap: The binary heap to use.
values: On return, the memory pointed to by this argument holds a C array of all the values in heap, sorted from minimum to maximum values. You must allocate sufficient memory to hold all the values in heap before calling this function. If the values are Core Foundation objects, ownership follows the Get Rule.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapRemoveAllValues

Removes all values from a binary heap, making it empty.

void CFBinaryHeapRemoveAllValues (
   CFBinaryHeapRef heap
);

Parameters

heap: The binary heap to use.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapRemoveMinimumValue

Removes the minimum value from a binary heap.

void CFBinaryHeapRemoveMinimumValue (
   CFBinaryHeapRef heap
);

Parameters

heap: The binary heap to use.

Discussion

If heap contains several equal minimum values, only one of them is removed. If heap is empty, this function does nothing.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

Callbacks

CFBinaryHeapApplierFunction

Callback function used to apply a function to all members of a binary heap.

typedef void (*CFBinaryHeapApplierFunction) (
   const void *val,
   void *context
);

If you name your function MyCallBack, you would declare it like this:

void MyCallBack (
   const void *val,
   void *context
);

Parameters

val: The current value from the binary heap.
context: The program-defined context parameter given to the CFBinaryHeapApplyFunction function.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapCompareCallBack

Callback function used to compare two members of a binary heap.

typedef CFComparisonResult (*CFBinaryHeapCompareCallBack) (
   const void *ptr1,
   const void *ptr2,
   void *info
);

If you name your function MyCallBack, you would declare it like this:

CFComparisonResult MyCallBack (
   const void *ptr1,
   const void *ptr2,
   void *info
);

Parameters

ptr1: First value to compare.
ptr2: Second value to compare.
info: Not used. Should always be NULL.

Return Value

kCFCompareLessThan if ptr1 is less than ptr2, kCFCompareEqualTo if ptr1 and ptr2 are equal, or kCFCompareGreaterThan if ptr1 is greater than ptr2.

CFBinaryHeapCopyDescriptionCallBack

Callback function used to get a description of a value in a binary heap.

typedef CFStringRef (*CFBinaryHeapCopyDescriptionCallBack) (
   const void *ptr
);

If you name your function MyCallBack, you would declare it like this:

CFStringRef MyCallBack (
   const void *ptr
);

Parameters

ptr: The value to be described.

CFBinaryHeapReleaseCallBack

Callback function used to release a value before it is removed from a binary heap.

typedef void (*CFBinaryHeapReleaseCallBack) (
   CFAllocatorRef allocator,
   const void *ptr
);

If you name your function MyCallBack, you would declare it like this:

void MyCallBack (
   CFAllocatorRef allocator,
   const void *ptr
);

Parameters

allocator: The binary heap’s allocator.
ptr: The value to release.

CFBinaryHeapRetainCallBack

Callback function used to retain a value being added to a binary heap.

typedef const void *(*CFBinaryHeapRetainCallBack) (
   CFAllocatorRef allocator,
   const void *ptr
);

If you name your function MyCallBack, you would declare it like this:

const void *MyCallBack (
   CFAllocatorRef allocator,
   const void *ptr
);

Parameters

allocator: The binary heap’s allocator.
ptr: The value to retain.

Return Value

The value to store in the binary heap, which is usually the ptr parameter passed to this callback, but may be a different value if a different value should be stored in the binary heap.

Data Types

CFBinaryHeapCallBacks

Structure containing the callbacks for values for a CFBinaryHeap object.

struct CFBinaryHeapCallBacks {
   CFIndex version;
   CFBinaryHeapRetainCallBack retain;
   CFBinaryHeapReleaseCallBack release;
   CFAllocatorCopyDescriptionCallBack copyDescription;
   CFBinaryHeapCompareCallBack compare;
};
typedef struct CFBinaryHeapCallBacks CFBinaryHeapCallBacks;

Fields

version: The version number of the structure type being passed in as a parameter to the CFBinaryHeap creation functions. This structure is version 0.
retain: The callback used to add a retain for the binary heap on values as they are put into the binary heap. This callback returns the value to use as the value in the binary heap, which is usually the value parameter passed to this callback, but may be a different value if a different value should be added to the binary heap. If this field is NULL, the binary heap does nothing to retain a value being added.
release: The callback used to remove a retain previously added for the binary heap from values as they are removed from the binary heap. If this field is NULL, the binary heap does nothing to release a value being removed.
copyDescription: The callback used to create a descriptive string representation of each value in the binary heap. This is used by the CFCopyDescription function. If this field is NULL, the binary heap constructs a CFString object describing the value based on its pointer value.
compare: The callback used to compare values in the binary heap in some operations. This field cannot be NULL.

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h

CFBinaryHeapCompareContext

Not used.

struct CFBinaryHeapCompareContext {
   CFIndex version;
   void *info;
   CFAllocatorRetainCallBack retain;
   CFAllocatorReleaseCallBack release;
   CFAllocatorCopyDescriptionCallBack copyDescription;
};
typedef struct CFBinaryHeapCompareContext CFBinaryHeapCompareContext;

Availability

Available in Mac OS X v10.0 and later.

Declared In

CFBinaryHeap.h