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