Commit | Line | Data |
---|---|---|
3e1bbdc3 ACM |
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 | #include <linux/kernel.h> | |
10 | #include <stdlib.h> | |
11 | ||
12 | struct pstack { | |
13 | unsigned short top; | |
14 | unsigned short max_nr_entries; | |
15 | void *entries[0]; | |
16 | }; | |
17 | ||
18 | struct pstack *pstack__new(unsigned short max_nr_entries) | |
19 | { | |
20 | struct pstack *self = zalloc((sizeof(*self) + | |
21 | max_nr_entries * sizeof(void *))); | |
22 | if (self != NULL) | |
23 | self->max_nr_entries = max_nr_entries; | |
24 | return self; | |
25 | } | |
26 | ||
27 | void pstack__delete(struct pstack *self) | |
28 | { | |
29 | free(self); | |
30 | } | |
31 | ||
32 | bool pstack__empty(const struct pstack *self) | |
33 | { | |
34 | return self->top == 0; | |
35 | } | |
36 | ||
37 | void pstack__remove(struct pstack *self, void *key) | |
38 | { | |
39 | unsigned short i = self->top, last_index = self->top - 1; | |
40 | ||
41 | while (i-- != 0) { | |
42 | if (self->entries[i] == key) { | |
43 | if (i < last_index) | |
44 | memmove(self->entries + i, | |
45 | self->entries + i + 1, | |
46 | (last_index - i) * sizeof(void *)); | |
47 | --self->top; | |
48 | return; | |
49 | } | |
50 | } | |
51 | pr_err("%s: %p not on the pstack!\n", __func__, key); | |
52 | } | |
53 | ||
54 | void pstack__push(struct pstack *self, void *key) | |
55 | { | |
56 | if (self->top == self->max_nr_entries) { | |
57 | pr_err("%s: top=%d, overflow!\n", __func__, self->top); | |
58 | return; | |
59 | } | |
60 | self->entries[self->top++] = key; | |
61 | } | |
62 | ||
63 | void *pstack__pop(struct pstack *self) | |
64 | { | |
65 | void *ret; | |
66 | ||
67 | if (self->top == 0) { | |
68 | pr_err("%s: underflow!\n", __func__); | |
69 | return NULL; | |
70 | } | |
71 | ||
72 | ret = self->entries[--self->top]; | |
73 | self->entries[self->top] = NULL; | |
74 | return ret; | |
75 | } |