1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright (c) 2001 by Sun Microsystems, Inc.
24  * All rights reserved.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * Routines for manipulating stacks
31  */
32 
33 #include <stdio.h>
34 #include <assert.h>
35 #include <stdlib.h>
36 
37 #include "stack.h"
38 #include "memory.h"
39 
40 #define	STACK_SEEDSIZE	5
41 
42 struct stk {
43 	int st_nument;
44 	int st_top;
45 	void **st_data;
46 
47 	void (*st_free)(void *);
48 };
49 
50 stk_t *
stack_new(void (* freep)(void *))51 stack_new(void (*freep)(void *))
52 {
53 	stk_t *sp;
54 
55 	sp = xmalloc(sizeof (stk_t));
56 	sp->st_nument = STACK_SEEDSIZE;
57 	sp->st_top = -1;
58 	sp->st_data = xmalloc(sizeof (void *) * sp->st_nument);
59 	sp->st_free = freep;
60 
61 	return (sp);
62 }
63 
64 void
stack_free(stk_t * sp)65 stack_free(stk_t *sp)
66 {
67 	int i;
68 
69 	if (sp->st_free) {
70 		for (i = 0; i <= sp->st_top; i++)
71 			sp->st_free(sp->st_data[i]);
72 	}
73 	free(sp->st_data);
74 	free(sp);
75 }
76 
77 void *
stack_pop(stk_t * sp)78 stack_pop(stk_t *sp)
79 {
80 	assert(sp->st_top >= 0);
81 
82 	return (sp->st_data[sp->st_top--]);
83 }
84 
85 void *
stack_peek(stk_t * sp)86 stack_peek(stk_t *sp)
87 {
88 	if (sp->st_top == -1)
89 		return (NULL);
90 
91 	return (sp->st_data[sp->st_top]);
92 }
93 
94 void
stack_push(stk_t * sp,void * data)95 stack_push(stk_t *sp, void *data)
96 {
97 	sp->st_top++;
98 
99 	if (sp->st_top == sp->st_nument) {
100 		sp->st_nument += STACK_SEEDSIZE;
101 		sp->st_data = xrealloc(sp->st_data,
102 		    sizeof (void *) * sp->st_nument);
103 	}
104 
105 	sp->st_data[sp->st_top] = data;
106 }
107 
108 int
stack_level(stk_t * sp)109 stack_level(stk_t *sp)
110 {
111 	return (sp->st_top + 1);
112 }
113