Queue.md

Generic queue implementation

This is a generic queue implementation. A queue is a FIFO (first in, first out) data structure that supports two main operations: adding data to the queue (enqueue) and retrieving the least recently added item (dequeue). Additionally, it should be possible to know the size of a queue and whether it is_empty.

API

The Queue API is detailed below.

Fields:

• Node* first -- the least recently added node
• Node* last -- the most recently added node
• unsigned int size -- number of items in the queue

Methods (assume queue is a Queue*):

• Queue* queue_create() -- Creates a new Queue and returns a pointer to it, or NULL in case of failure.
• queue->free(Queue* queue) -- Frees the given queue.
• queue->is_empty(Queue* queue) -- Returns true if the queue is empty, false otherwise.
• queue->enqueue(Queue* queue, void* data) -- Adds the data to the queue. Returns 0 on success and -1 on failure.
• queue->dequeue(Queue* queue) -- Removes and returns the least recently added item of the queue. Returns NULL if the queue is null or empty.
• queue->contains(Queue* queue, void* item) -- Returns true if the queue contains the item, and false otherwise.

For more details:

• Queue header file
• Queue implementation