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 *self = zalloc((sizeof(*self) + 21 max_nr_entries * sizeof(void *))); 22 if (self != NULL) 23 self->max_nr_entries = max_nr_entries; 24 return self; 25 } 26 27 void pstack__delete(struct pstack *self) 28 { 29 free(self); 30 } 31 32 bool pstack__empty(const struct pstack *self) 33 { 34 return self->top == 0; 35 } 36 37 void pstack__remove(struct pstack *self, void *key) 38 { 39 unsigned short i = self->top, last_index = self->top - 1; 40 41 while (i-- != 0) { 42 if (self->entries[i] == key) { 43 if (i < last_index) 44 memmove(self->entries + i, 45 self->entries + i + 1, 46 (last_index - i) * sizeof(void *)); 47 --self->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 *self, void *key) 55 { 56 if (self->top == self->max_nr_entries) { 57 pr_err("%s: top=%d, overflow!\n", __func__, self->top); 58 return; 59 } 60 self->entries[self->top++] = key; 61 } 62 63 void *pstack__pop(struct pstack *self) 64 { 65 void *ret; 66 67 if (self->top == 0) { 68 pr_err("%s: underflow!\n", __func__); 69 return NULL; 70 } 71 72 ret = self->entries[--self->top]; 73 self->entries[self->top] = NULL; 74 return ret; 75 } 76