Generic queue

Overview

Type generic queue which grows when you add elements.
Add/remove from head/tail is possible so it can be used as list, stack,
queue, dequeue etc.
Just copy sc_queue.h and sc_queue.c to your project.

Usage

#include "sc_queue.h"

#include <stdio.h>

int main(int argc, char *argv[])
{
    int *queue;
    int elem;

    sc_queue_create(queue, 0);

    sc_queue_add_last(queue, 2);
    sc_queue_add_last(queue, 3);
    sc_queue_add_last(queue, 4);
    sc_queue_add_first(queue, 1);

    sc_queue_foreach (queue, elem) {
        printf("elem = [%d] \n", elem);
    }

    elem = sc_queue_remove_last(queue);
    printf("Last element was : [%d] \n", elem);

    elem = sc_queue_remove_first(queue);
    printf("First element was : [%d] \n", elem);

    sc_queue_destroy(queue);

    return 0;
}

Internals

Memory

Single allocation for all the data.
Lazy allocation. No memory allocation until first 'add'.

Performance

As all the items are in a single contiguous memory, it gives the best
performance you can expect.
Keeps separate first and last element indexes, when you remove an element,
it doesn't move elements to fill the space.

Note

Queue pointer is not stable, it may change if we expand the memory. If you
pass the queue to another function which can add items, do it by passing
reference of the queue pointer :

void some_function_to_add_elems(long **q)
{
    sc_queue_add_last(*q, 500);
}

int main(int argc, char *argv[])
{
    long *q;

    sc_queue_create(q, 0);
    sc_queue_add_last(q, 300);
    
    some_function_to_add_elems(&q);
    sc_array_destroy(q);
}