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