Queue structure

This project is based on GenericMap by mystborn, so there similar function names and structures

A simple queue of objects. Internally it is implemented as a circular buffer, so Push is O(n). Pop is O(1).

Defining a Type

Use the macro shlDeclareQueue to generate the type and function definitions. It has the following arguments:

Argument	Description
typeName	The name of the generated type. This will also prefix all of the function names.
itemType	The type of the list elements.

Use the macro shlDefineQueue to generate the function implementations.

Argument	Description
typeName	The name of the generated type. This will also prefix all of the function names.
itemType	The type of the list elements.

#include "queue.h"

shlDeclareQueue(IntList, int)
shlDefineQueue(IntList, int)

This list allows the following operations:

Function	Description	Return type
Init(typeName* queue, typeName Options options)	Initializes the data needed for the queue.	void
Free(typeName* queue)	Frees the data used by the queue. It doesn't free the queue itself.	void
Push(typeName* queue, itemType value)	Push an element in the top of the queue.	void
Peek(typeName* queue)	Gets the top of the queue without removing it.	itemType
Pop(typeName* queue)	Remove the top of the queue.	_itemType _
Contains(typeName* queue, itemType value)	Return true if an object is contained in the queue.	bool
Clear(typeName* queue)	Clear the queue, freeing every element if a freeFn was provided. Doesn't free the queue itself.	void

Options

Each definition of a queue declare a struct typeName Options that is used to initialize the queue. The struct has the following members:

Name	Type	Description
equalsFn	bool (*)(const itemType, const itemType)	(optional) A pointer to a function that takes two elements, and returns true if the elements are equals, and returns false otherwise. If no equalsFn is provided then the operation Contains always return false.
freeFn	void (*)(itemType)	(optional) A pointer to a function that takes an element and free it. If no freeFn is provided, then the operation Clear and Free doesn't free the elements and the user of the queue is the responsible for free the elements.
defaultValue	itemType	The value to return when you apply the Pop operation and the queue is empty.

Example:

#include <stdio.h>

#include "queue.h"

bool intEquals(const int x, const int y)
{
    return x == y;
}

shlDeclareQueue(IntQueue, int)
shlDefineQueue(IntQueue, int)

int main()
{
    IntQueueOptions options = (IntQueueOptions){0};
    options.defaultValue = 0;
    options.equalsFn = intEquals;

    IntQueue queue;
    IntQueueInit(&queue, options);

    for (int i = 0; i < 100; i++)
        IntQueuePush(&queue, i);

    int sum = 0;

    // sum all the numbers in the queue
    while (queue.count > 0)
    {
        int value = IntQueuePop(&queue);
        sum += value;
    }

    printf("The sum of the elements of the queue is %d\n", sum);

    return 0;
}