priority.h File Reference

Adaptable priority queue data structure. More...

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Data Structures
struct	PriorityQueueNode
	A node in a priority queue. More...
struct	PriorityQueue
	A priority queue. More...

Typedefs
typedef struct PriorityQueueNode	PriorityQueueNode
	A node in a priority queue. More...
typedef struct PriorityQueue	PriorityQueue
	A priority queue. More...

Functions
PriorityQueue *	priority_queue_create ()
	Creates a new priority queue. More...
PriorityQueueNode *	priority_queue_add (PriorityQueue *queue, int priority, void *data)
	Adds an element to the priority queue. More...
void *	priority_queue_peek (PriorityQueue *queue)
	Returns the data of the element at the front of the priority queue. More...
void *	priority_queue_poll (PriorityQueue *queue)
	Removes and returns the data of the element at the front of the priority queue. More...
void *	priority_queue_remove (PriorityQueue *queue, PriorityQueueNode *node)
	Removes a specific element from the priority queue, frees the node, and returns its data. More...
void	priority_queue_change_priority (PriorityQueue *queue, PriorityQueueNode *node, int new_priority)
	Changes the priority of a specific element in the priority queue. More...
void	priority_queue_free (PriorityQueue *queue)
	Frees a priority queue and all of its elements. More...

Detailed Description

Adaptable priority queue data structure.

This file defines an adaptable priority queue data structure and its associated functions. An adaptable priority queue is a type of priority queue that allows the priorities of its elements to be changed after they have been added to the queue, using so-called location-aware entries.

Adaptable priority queues are typically implemented using a heap data structure, where the priorities of elements are used to determine the order in which they are stored in the heap. The heap property ensures that the element with the highest priority is always at the top of the heap, making it easy to extract the highest-priority element from the queue.

Date

2023-01-02

Author

Merlin Unterfinger

Typedef Documentation

PriorityQueue

typedef struct PriorityQueue PriorityQueue

A priority queue.

Note

The fields of this struct are intended for internal use only and should not be accessed directly

PriorityQueueNode

typedef struct PriorityQueueNode PriorityQueueNode

A node in a priority queue.

Note

The fields of this struct are intended for internal use only and should not be accessed directly

Function Documentation

priority_queue_add()

PriorityQueueNode* priority_queue_add	(	PriorityQueue *	queue,
		int	priority,
		void *	data
	)

Adds an element to the priority queue.

Parameters

queue	The priority queue to add the element to
priority	The priority of the element being added
data	The data of the element being added

Returns

A pointer to the node in the priority queue corresponding to the added element

priority_queue_change_priority()

void priority_queue_change_priority	(	PriorityQueue *	queue,
		PriorityQueueNode *	node,
		int	new_priority
	)

Changes the priority of a specific element in the priority queue.

Parameters

queue	The priority queue
node	The node whose priority is being changed
new_priority	The new priority of the node

priority_queue_create()

PriorityQueue* priority_queue_create

(

)

Creates a new priority queue.

Returns

A pointer to the newly created priority queue

priority_queue_free()

void priority_queue_free

(

PriorityQueue *

queue

)

Frees a priority queue and all of its elements.

Parameters

queue

The priority queue to be freed

priority_queue_peek()

void* priority_queue_peek

(

PriorityQueue *

queue

)

Returns the data of the element at the front of the priority queue.

Parameters

queue

The priority queue

Returns

The data of the element at the front of the queue, or NULL if the queue is empty

priority_queue_poll()

void* priority_queue_poll

(

PriorityQueue *

queue

)

Removes and returns the data of the element at the front of the priority queue.

Parameters

queue

The priority queue

Returns

The data of the element at the front of the queue, or NULL if the queue is empty

priority_queue_remove()

void* priority_queue_remove	(	PriorityQueue *	queue,
		PriorityQueueNode *	node
	)

Removes a specific element from the priority queue, frees the node, and returns its data.

Parameters

queue	The priority queue
node	The node to remove from the priority queue

Returns

The data of the removed node, or NULL if the queue is empty