86 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Simple pointer stack4 *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 15struct pstack {16 unsigned short top;17 unsigned short max_nr_entries;18 void *entries[];19};20 21struct 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 30void pstack__delete(struct pstack *pstack)31{32 free(pstack);33}34 35bool pstack__empty(const struct pstack *pstack)36{37 return pstack->top == 0;38}39 40void 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 57void 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 66void *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 80void *pstack__peek(struct pstack *pstack)81{82 if (pstack->top == 0)83 return NULL;84 return pstack->entries[pstack->top - 1];85}86