#include <string.h>

#include "wv_vec.h"

void wv_vec_init(struct wv_vec *v, size_t unit_size)
{
	v->data = NULL;
	v->len = 0;
	v->cap = 0;
	v->unit_size = unit_size;
}

void wv_vec_push(struct wv_vec *v, const void *item)
{
	if (v->len >= v->cap) {
		v->cap = (v->cap == 0) ? 8 : v->cap * 2;
		v->data = realloc(v->data, v->cap * v->unit_size);
	}
	void *target = (char *)v->data + (v->len * v->unit_size);
	memcpy(target, item, v->unit_size);
	v->len++;
}

void *wv_vec_pop(struct wv_vec *v)
{
	if (v->len == 0) 
		return NULL;

	v->len--;
	return (char *)v->data + (v->len * v->unit_size);
}

void *wv_vec_last(struct wv_vec *v)
{
	if (v->len == 0) 
		return NULL;
	return (char *)v->data + ((v->len - 1) * v->unit_size);
}

void wv_vec_free(struct wv_vec *v)
{
	free(v->data);
	v->data = NULL;
	v->len = v->cap = 0;
}