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 12 struct pstack { 13 unsigned short top; 14 unsigned short max_nr_entries; 15 void *entries[0]; 16 }; 17 18 struct 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 27 void pstack__delete(struct pstack *pstack) 28 { 29 free(pstack); 30 } 31 32 bool pstack__empty(const struct pstack *pstack) 33 { 34 return pstack->top == 0; 35 } 36 37 void 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 54 void 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 63 void *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