1/*
2 * (C) 2005-2011 by Pablo Neira Ayuso <pablo@netfilter.org>
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 */
9
10#include <stdio.h>
11#include <stdlib.h>
12#include <string.h>
13#include <errno.h>
14
15#include "internal/stack.h"
16
17struct stack {
18	int num_elems;
19	int max_elems;
20	size_t elem_size;
21	char *data;
22};
23
24struct stack *stack_create(size_t elem_size, int max_elems)
25{
26	struct stack *s;
27
28	s = calloc(sizeof(struct stack), 1);
29	if (s == NULL)
30		return NULL;
31
32	s->data = calloc(elem_size * max_elems, 1);
33	if (s->data == NULL) {
34		free(s);
35		return NULL;
36	}
37	s->elem_size = elem_size;
38	s->max_elems = max_elems;
39
40	return s;
41}
42
43void stack_destroy(struct stack *s)
44{
45	free(s->data);
46	free(s);
47}
48
49int stack_push(struct stack *s, void *data)
50{
51	if (s->num_elems >= s->max_elems) {
52		errno = ENOSPC;
53		return -1;
54	}
55	memcpy(s->data + (s->elem_size * s->num_elems), data, s->elem_size);
56	s->num_elems++;
57	return 0;
58}
59
60int stack_pop(struct stack *s, void *data)
61{
62	if (s->num_elems <= 0) {
63		errno = EINVAL;
64		return -1;
65	}
66	s->num_elems--;
67	memcpy(data, s->data + (s->elem_size * s->num_elems), s->elem_size);
68	return 0;
69}
70