Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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}