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
17 struct stack {
18 int num_elems;
19 int max_elems;
20 size_t elem_size;
21 char *data;
22 };
23
stack_create(size_t elem_size,int max_elems)24 struct 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
stack_destroy(struct stack * s)43 void stack_destroy(struct stack *s)
44 {
45 free(s->data);
46 free(s);
47 }
48
stack_push(struct stack * s,void * data)49 int 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
stack_pop(struct stack * s,void * data)60 int 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