1/*
2 * Copyright 2011 Tresys Technology, LLC. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 *    1. Redistributions of source code must retain the above copyright notice,
8 *       this list of conditions and the following disclaimer.
9 *
10 *    2. Redistributions in binary form must reproduce the above copyright notice,
11 *       this list of conditions and the following disclaimer in the documentation
12 *       and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY TRESYS TECHNOLOGY, LLC ``AS IS'' AND ANY EXPRESS
15 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
16 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
17 * EVENT SHALL TRESYS TECHNOLOGY, LLC OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
18 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
19 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
21 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
22 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
23 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 *
25 * The views and conclusions contained in the software and documentation are those
26 * of the authors and should not be interpreted as representing official policies,
27 * either expressed or implied, of Tresys Technology, LLC.
28 */
29
30#include <stdlib.h>
31
32#include "cil_internal.h"
33#include "cil_log.h"
34#include "cil_mem.h"
35#include "cil_stack.h"
36
37
38#define CIL_STACK_INIT_SIZE 16
39
40void cil_stack_init(struct cil_stack **stack)
41{
42	struct cil_stack *new_stack = cil_malloc(sizeof(*new_stack));
43	new_stack->stack = cil_malloc(sizeof(*(new_stack->stack)) * CIL_STACK_INIT_SIZE);
44	new_stack->size = CIL_STACK_INIT_SIZE;
45	new_stack->pos = -1;
46	*stack = new_stack;
47}
48
49void cil_stack_destroy(struct cil_stack **stack)
50{
51	if (stack == NULL || *stack == NULL) {
52		return;
53	}
54
55	free((*stack)->stack);
56	free(*stack);
57	*stack = NULL;
58}
59
60void cil_stack_empty(struct cil_stack *stack)
61{
62	stack->pos = -1;
63}
64
65int cil_stack_is_empty(struct cil_stack *stack)
66{
67	return (stack->pos == -1);
68}
69
70void cil_stack_push(struct cil_stack *stack, enum cil_flavor flavor, void *data)
71{
72	stack->pos++;
73
74	if (stack->pos == stack->size) {
75		stack->size *= 2;
76		stack->stack = cil_realloc(stack->stack, sizeof(*stack->stack) * stack->size);
77	}
78
79	stack->stack[stack->pos].flavor = flavor;
80	stack->stack[stack->pos].data = data;
81}
82
83struct cil_stack_item *cil_stack_pop(struct cil_stack *stack)
84{
85	if (stack->pos == -1) {
86		return NULL;
87	}
88
89	stack->pos--;
90	return &stack->stack[stack->pos + 1];
91}
92
93struct cil_stack_item *cil_stack_peek(struct cil_stack *stack)
94{
95	if (stack->pos < 0) {
96		return NULL;
97	}
98
99	return &stack->stack[stack->pos];
100}
101
102struct cil_stack_item *cil_stack_peek_at(struct cil_stack *stack, int pos)
103{
104	int peekpos = stack->pos - pos;
105
106	if (peekpos < 0 || peekpos > stack->pos) {
107		return NULL;
108	}
109
110	return &stack->stack[peekpos];
111}
112