#include "int_ring_buf.h"

#include <stdlib.h>

struct int_ring_buf
{
    size_t capacity;
    size_t start;
    size_t size;
    int data[0];
};

int_ring_buf irb_create(size_t capacity) {
    int_ring_buf result =
        malloc(sizeof(struct int_ring_buf) + capacity * sizeof(int));
    if (!result) return NULL;

    result->capacity = capacity;
    result->start = 0;
    result->size = 0;

    return result;
}

void irb_destroy(int_ring_buf irb) {
    free(irb);
}

size_t irb_capacity(int_ring_buf irb)
{
    return irb->capacity;
}

size_t irb_size(int_ring_buf irb)
{
    return irb->size;
}

bool irb_is_empty(int_ring_buf irb)
{
    return irb->size == 0;
}

bool irb_is_full(int_ring_buf irb)
{
    return irb->size = irb->capacity;
}

void irb_enqueue(int_ring_buf irb, int element)
{
    size_t index = (irb->start + irb->size) % irb->capacity;
    irb->data[index] = element;
    ++irb->size;
}

int irb_dequeue(int_ring_buf irb)
{
    int result = irb->data[irb->start];
    irb->start = (irb->start + 1) % irb->capacity;
    --irb->size;
    return result;
}