1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Simple pointer stack
 4 *
 5 * (c) 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
 6 */
 7
 
 8#include "pstack.h"
 9#include "debug.h"
10#include <linux/kernel.h>
11#include <linux/zalloc.h>
12#include <stdlib.h>
13#include <string.h>
14
15struct pstack {
16	unsigned short	top;
17	unsigned short	max_nr_entries;
18	void		*entries[];
19};
20
21struct pstack *pstack__new(unsigned short max_nr_entries)
22{
23	struct pstack *pstack = zalloc((sizeof(*pstack) +
24				       max_nr_entries * sizeof(void *)));
25	if (pstack != NULL)
26		pstack->max_nr_entries = max_nr_entries;
27	return pstack;
28}
29
30void pstack__delete(struct pstack *pstack)
31{
32	free(pstack);
33}
34
35bool pstack__empty(const struct pstack *pstack)
36{
37	return pstack->top == 0;
38}
39
40void pstack__remove(struct pstack *pstack, void *key)
41{
42	unsigned short i = pstack->top, last_index = pstack->top - 1;
43
44	while (i-- != 0) {
45		if (pstack->entries[i] == key) {
46			if (i < last_index)
47				memmove(pstack->entries + i,
48					pstack->entries + i + 1,
49					(last_index - i) * sizeof(void *));
50			--pstack->top;
51			return;
52		}
53	}
54	pr_err("%s: %p not on the pstack!\n", __func__, key);
55}
56
57void pstack__push(struct pstack *pstack, void *key)
58{
59	if (pstack->top == pstack->max_nr_entries) {
60		pr_err("%s: top=%d, overflow!\n", __func__, pstack->top);
61		return;
62	}
63	pstack->entries[pstack->top++] = key;
64}
65
66void *pstack__pop(struct pstack *pstack)
67{
68	void *ret;
69
70	if (pstack->top == 0) {
71		pr_err("%s: underflow!\n", __func__);
72		return NULL;
73	}
74
75	ret = pstack->entries[--pstack->top];
76	pstack->entries[pstack->top] = NULL;
77	return ret;
78}
79
80void *pstack__peek(struct pstack *pstack)
81{
82	if (pstack->top == 0)
83		return NULL;
84	return pstack->entries[pstack->top - 1];
85}

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Simple pointer stack
 4 *
 5 * (c) 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
 6 */
 7
 8#include "util.h"
 9#include "pstack.h"
10#include "debug.h"
11#include <linux/kernel.h>
 
12#include <stdlib.h>
 
13
14struct pstack {
15	unsigned short	top;
16	unsigned short	max_nr_entries;
17	void		*entries[0];
18};
19
20struct pstack *pstack__new(unsigned short max_nr_entries)
21{
22	struct pstack *pstack = zalloc((sizeof(*pstack) +
23				       max_nr_entries * sizeof(void *)));
24	if (pstack != NULL)
25		pstack->max_nr_entries = max_nr_entries;
26	return pstack;
27}
28
29void pstack__delete(struct pstack *pstack)
30{
31	free(pstack);
32}
33
34bool pstack__empty(const struct pstack *pstack)
35{
36	return pstack->top == 0;
37}
38
39void pstack__remove(struct pstack *pstack, void *key)
40{
41	unsigned short i = pstack->top, last_index = pstack->top - 1;
42
43	while (i-- != 0) {
44		if (pstack->entries[i] == key) {
45			if (i < last_index)
46				memmove(pstack->entries + i,
47					pstack->entries + i + 1,
48					(last_index - i) * sizeof(void *));
49			--pstack->top;
50			return;
51		}
52	}
53	pr_err("%s: %p not on the pstack!\n", __func__, key);
54}
55
56void pstack__push(struct pstack *pstack, void *key)
57{
58	if (pstack->top == pstack->max_nr_entries) {
59		pr_err("%s: top=%d, overflow!\n", __func__, pstack->top);
60		return;
61	}
62	pstack->entries[pstack->top++] = key;
63}
64
65void *pstack__pop(struct pstack *pstack)
66{
67	void *ret;
68
69	if (pstack->top == 0) {
70		pr_err("%s: underflow!\n", __func__);
71		return NULL;
72	}
73
74	ret = pstack->entries[--pstack->top];
75	pstack->entries[pstack->top] = NULL;
76	return ret;
77}
78
79void *pstack__peek(struct pstack *pstack)
80{
81	if (pstack->top == 0)
82		return NULL;
83	return pstack->entries[pstack->top - 1];
84}