// SPDX-License-Identifier: GPL-2.0
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/*
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* Simple pointer stack
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*
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* (c) 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
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*/
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#include "pstack.h"
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#include "debug.h"
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#include <linux/kernel.h>
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#include <linux/zalloc.h>
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#include <stdlib.h>
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#include <string.h>
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struct pstack {
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unsigned short top;
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unsigned short max_nr_entries;
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void *entries[];
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};
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struct pstack *pstack__new(unsigned short max_nr_entries)
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{
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struct pstack *pstack = zalloc((sizeof(*pstack) +
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max_nr_entries * sizeof(void *)));
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if (pstack != NULL)
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pstack->max_nr_entries = max_nr_entries;
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return pstack;
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}
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void pstack__delete(struct pstack *pstack)
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{
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free(pstack);
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}
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bool pstack__empty(const struct pstack *pstack)
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{
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return pstack->top == 0;
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}
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void pstack__remove(struct pstack *pstack, void *key)
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{
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unsigned short i = pstack->top, last_index = pstack->top - 1;
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while (i-- != 0) {
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if (pstack->entries[i] == key) {
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if (i < last_index)
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memmove(pstack->entries + i,
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pstack->entries + i + 1,
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(last_index - i) * sizeof(void *));
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--pstack->top;
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return;
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}
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}
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pr_err("%s: %p not on the pstack!\n", __func__, key);
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}
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void pstack__push(struct pstack *pstack, void *key)
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{
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if (pstack->top == pstack->max_nr_entries) {
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pr_err("%s: top=%d, overflow!\n", __func__, pstack->top);
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return;
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}
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pstack->entries[pstack->top++] = key;
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}
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void *pstack__pop(struct pstack *pstack)
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{
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void *ret;
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if (pstack->top == 0) {
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pr_err("%s: underflow!\n", __func__);
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return NULL;
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}
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ret = pstack->entries[--pstack->top];
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pstack->entries[pstack->top] = NULL;
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return ret;
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}
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void *pstack__peek(struct pstack *pstack)
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{
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if (pstack->top == 0)
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return NULL;
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return pstack->entries[pstack->top - 1];
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}
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