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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
3e1bbdc3 ACM |
2 | /* |
3 | * Simple pointer stack | |
4 | * | |
5 | * (c) 2010 Arnaldo Carvalho de Melo <acme@redhat.com> | |
6 | */ | |
7 | ||
3e1bbdc3 | 8 | #include "pstack.h" |
84f5d36f | 9 | #include "debug.h" |
3e1bbdc3 | 10 | #include <linux/kernel.h> |
7f7c536f | 11 | #include <linux/zalloc.h> |
3e1bbdc3 | 12 | #include <stdlib.h> |
8520a98d | 13 | #include <string.h> |
3e1bbdc3 ACM |
14 | |
15 | struct pstack { | |
16 | unsigned short top; | |
17 | unsigned short max_nr_entries; | |
6549a8c0 | 18 | void *entries[]; |
3e1bbdc3 ACM |
19 | }; |
20 | ||
21 | struct pstack *pstack__new(unsigned short max_nr_entries) | |
22 | { | |
61e94515 ACM |
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; | |
3e1bbdc3 ACM |
28 | } |
29 | ||
61e94515 | 30 | void pstack__delete(struct pstack *pstack) |
3e1bbdc3 | 31 | { |
61e94515 | 32 | free(pstack); |
3e1bbdc3 ACM |
33 | } |
34 | ||
61e94515 | 35 | bool pstack__empty(const struct pstack *pstack) |
3e1bbdc3 | 36 | { |
61e94515 | 37 | return pstack->top == 0; |
3e1bbdc3 ACM |
38 | } |
39 | ||
61e94515 | 40 | void pstack__remove(struct pstack *pstack, void *key) |
3e1bbdc3 | 41 | { |
61e94515 | 42 | unsigned short i = pstack->top, last_index = pstack->top - 1; |
3e1bbdc3 ACM |
43 | |
44 | while (i-- != 0) { | |
61e94515 | 45 | if (pstack->entries[i] == key) { |
3e1bbdc3 | 46 | if (i < last_index) |
61e94515 ACM |
47 | memmove(pstack->entries + i, |
48 | pstack->entries + i + 1, | |
3e1bbdc3 | 49 | (last_index - i) * sizeof(void *)); |
61e94515 | 50 | --pstack->top; |
3e1bbdc3 ACM |
51 | return; |
52 | } | |
53 | } | |
54 | pr_err("%s: %p not on the pstack!\n", __func__, key); | |
55 | } | |
56 | ||
61e94515 | 57 | void pstack__push(struct pstack *pstack, void *key) |
3e1bbdc3 | 58 | { |
61e94515 ACM |
59 | if (pstack->top == pstack->max_nr_entries) { |
60 | pr_err("%s: top=%d, overflow!\n", __func__, pstack->top); | |
3e1bbdc3 ACM |
61 | return; |
62 | } | |
61e94515 | 63 | pstack->entries[pstack->top++] = key; |
3e1bbdc3 ACM |
64 | } |
65 | ||
61e94515 | 66 | void *pstack__pop(struct pstack *pstack) |
3e1bbdc3 ACM |
67 | { |
68 | void *ret; | |
69 | ||
61e94515 | 70 | if (pstack->top == 0) { |
3e1bbdc3 ACM |
71 | pr_err("%s: underflow!\n", __func__); |
72 | return NULL; | |
73 | } | |
74 | ||
61e94515 ACM |
75 | ret = pstack->entries[--pstack->top]; |
76 | pstack->entries[pstack->top] = NULL; | |
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77 | return ret; |
78 | } | |
c8539e3f NK |
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 | } |