Merge tag 'kbuild-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy...
[linux-2.6-microblaze.git] / tools / perf / util / pstack.c
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
15 struct pstack {
16         unsigned short  top;
17         unsigned short  max_nr_entries;
18         void            *entries[0];
19 };
20
21 struct 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
30 void pstack__delete(struct pstack *pstack)
31 {
32         free(pstack);
33 }
34
35 bool pstack__empty(const struct pstack *pstack)
36 {
37         return pstack->top == 0;
38 }
39
40 void 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
57 void 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
66 void *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
80 void *pstack__peek(struct pstack *pstack)
81 {
82         if (pstack->top == 0)
83                 return NULL;
84         return pstack->entries[pstack->top - 1];
85 }