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 12struct pstack { 13 unsigned short top; 14 unsigned short max_nr_entries; 15 void *entries[0]; 16}; 17 18struct pstack *pstack__new(unsigned short max_nr_entries) 19{ 20 struct pstack *pstack = zalloc((sizeof(*pstack) + 21 max_nr_entries * sizeof(void *))); 22 if (pstack != NULL) 23 pstack->max_nr_entries = max_nr_entries; 24 return pstack; 25} 26 27void pstack__delete(struct pstack *pstack) 28{ 29 free(pstack); 30} 31 32bool pstack__empty(const struct pstack *pstack) 33{ 34 return pstack->top == 0; 35} 36 37void pstack__remove(struct pstack *pstack, void *key) 38{ 39 unsigned short i = pstack->top, last_index = pstack->top - 1; 40 41 while (i-- != 0) { 42 if (pstack->entries[i] == key) { 43 if (i < last_index) 44 memmove(pstack->entries + i, 45 pstack->entries + i + 1, 46 (last_index - i) * sizeof(void *)); 47 --pstack->top; 48 return; 49 } 50 } 51 pr_err("%s: %p not on the pstack!\n", __func__, key); 52} 53 54void pstack__push(struct pstack *pstack, void *key) 55{ 56 if (pstack->top == pstack->max_nr_entries) { 57 pr_err("%s: top=%d, overflow!\n", __func__, pstack->top); 58 return; 59 } 60 pstack->entries[pstack->top++] = key; 61} 62 63void *pstack__pop(struct pstack *pstack) 64{ 65 void *ret; 66 67 if (pstack->top == 0) { 68 pr_err("%s: underflow!\n", __func__); 69 return NULL; 70 } 71 72 ret = pstack->entries[--pstack->top]; 73 pstack->entries[pstack->top] = NULL; 74 return ret; 75} 76