/**
 * Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
 *
 * Licensed under the Universal Permissive License v 1.0 as shown at
 * http://oss.oracle.com/licenses/upl
 *
 */
#define _GNU_SOURCE
#include "vec.h"
#include "malloc.h"
#include <assert.h>

struct vec {
    size_t n;
    size_t limit;
    struct vecitem **items;
};

struct vec *mk_vec(void) {
    struct vec *MALLOC(v);
    size_t init = 2;
    struct vecitem **MALLOC_N(items, init);
    *v = (struct vec){0, init, items};
    return v;
}
struct vec *vec_destroy(struct vec *vec) {
    assert(vec->n == 0);
    FREE(vec->items);
    FREE(vec);
    return NULL;
}

size_t vec_size(const struct vec *vec) {
    return vec->n;
}

struct vecitem *vec_fetch(const struct vec *vec, size_t i) {
    if (i < vec->n) return vec->items[i];
    else return NULL;
}

void vec_push(struct vec *vec, struct vecitem *item) {
    if (vec->n >= vec->limit) {
        vec->limit *= 2;
        REALLOC(vec->items, vec->limit);
    }
    assert(vec->n < vec->limit);
    vec->items[vec->n++] = item;
}

struct vecitem* vec_pop(struct vec *vec) {
    if (vec->n) {
        if (vec->limit > 4
            && vec->n * 4 < vec->limit)
        {
            vec->limit /= 2;
            assert(vec->n < vec->limit);
            REALLOC(vec->items, vec->limit);
        }
        return vec->items[--vec->n];
    } else {
        return NULL;
    }
}

struct vecitem* vec_peek(struct vec *vec) {
    if (vec->n) return vec->items[vec->n-1];
    else return NULL;
}

static int vec_compar(const void *av, const void *bv, void *compar_f) {
    struct vecitem * const *ap = av;
    struct vecitem * const *bp = bv;
    int (*compar)(const struct vecitem *, const struct vecitem *) = compar_f;
    return compar(*ap, *bp);
}

void vec_sort(struct vec *vec,
              int (*compar)(const struct vecitem *, const struct vecitem *)) {
    qsort_r(vec->items, vec->n, sizeof(vec->items[0]),
            vec_compar, compar);
}