GNU Linux-libre 4.19.211-gnu1
[releases.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 "util.h"
9 #include "pstack.h"
10 #include "debug.h"
11 #include <linux/kernel.h>
12 #include <stdlib.h>
13
14 struct pstack {
15         unsigned short  top;
16         unsigned short  max_nr_entries;
17         void            *entries[0];
18 };
19
20 struct 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
29 void pstack__delete(struct pstack *pstack)
30 {
31         free(pstack);
32 }
33
34 bool pstack__empty(const struct pstack *pstack)
35 {
36         return pstack->top == 0;
37 }
38
39 void 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
56 void 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
65 void *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
79 void *pstack__peek(struct pstack *pstack)
80 {
81         if (pstack->top == 0)
82                 return NULL;
83         return pstack->entries[pstack->top - 1];
84 }