#include <stdlib.h>
#include "shape.h"

struct shape
{
    void *obj;
    shape_area_t area;
    shape_destroy_t destroy;
};

double shape_area(struct shape *shape)
{
    return shape->area(shape->obj);
}

void shape_destroy(struct shape *shape)
{
    shape->destroy(shape->obj);
    free(shape);
}

struct shape *shape_create(
    void *obj,
    shape_area_t area,
    shape_destroy_t destroy)
{
    struct shape *shape = malloc(sizeof(shape));
    shape->obj = obj;
    shape->area = area;
    shape->destroy = destroy;
    return shape;
}