#include "vector.h"

#include <assert.h>
#include <stdint.h>
#include <stdlib.h>

#define INITIAL_CAPACITY 64

vector *
v_new(void (*elt_dtor)(void *))
{
	vector *v = malloc(sizeof *v);
	void **elts = malloc(INITIAL_CAPACITY * sizeof *elts);
	if (!v || !elts)
	{
		free(v);
		free(elts);
		return NULL;
	}
	*v = (vector){
		.capacity = INITIAL_CAPACITY,
		.elts = elts,
		.elt_dtor = elt_dtor
	};
	return v;
}

void
v_free(vector *v)
{
	if (!v)
		return;
	v_clear(v);
	free(v->elts);
	free(v);
}

size_t
v_length(const vector *v)
{
	return v ? v->length : SIZE_MAX;
}

bool
v_set_length(vector *v, size_t len)
{
	if (!v || len == SIZE_MAX)
		return false;
	if (v->elt_dtor) /* free any, if necessary */
		for (size_t i = len; i < v->length; i++)
			v->elt_dtor(v->elts[i]);
	if (!v_reserve_capacity(v, len))
		return false;
	for (size_t i = v->length; i < len; i++)
		v->elts[i] = NULL;
	v->length = len;
	return true;
}

size_t
v_capacity(const vector *v)
{
	return v ? v->capacity : 0;
}

size_t v_reserve_capacity(vector *v, size_t desired)
{
	if (!v)
		return 0;
	if (desired <= v->capacity)
		return v->capacity;
	size_t n;
	for (n = v->capacity; n < desired && n < SIZE_MAX/2; n *= 2)
		;
	if (n < desired)
		n = desired; /* desired >= SIZE_MAX/2 */
	void **enlarged = realloc(v->elts, n);
	if (!enlarged)
		return v->capacity;
	v->elts = enlarged;
	v->capacity = n;
	return n;
}

void
v_clear(vector *v)
{
	assert(v_set_length(v, 0));
}