1 /* 2 * (C) 2005-2011 by Pablo Neira Ayuso <pablo (at) netfilter.org> 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 */ 9 10 #include <stdio.h> 11 #include <stdlib.h> 12 #include <string.h> 13 #include <errno.h> 14 15 #include "internal/stack.h" 16 17 struct stack { 18 int num_elems; 19 int max_elems; 20 size_t elem_size; 21 char *data; 22 }; 23 24 struct stack *stack_create(size_t elem_size, int max_elems) 25 { 26 struct stack *s; 27 28 s = calloc(sizeof(struct stack), 1); 29 if (s == NULL) 30 return NULL; 31 32 s->data = calloc(elem_size * max_elems, 1); 33 if (s->data == NULL) { 34 free(s); 35 return NULL; 36 } 37 s->elem_size = elem_size; 38 s->max_elems = max_elems; 39 40 return s; 41 } 42 43 void stack_destroy(struct stack *s) 44 { 45 free(s->data); 46 free(s); 47 } 48 49 int stack_push(struct stack *s, void *data) 50 { 51 if (s->num_elems >= s->max_elems) { 52 errno = ENOSPC; 53 return -1; 54 } 55 memcpy(s->data + (s->elem_size * s->num_elems), data, s->elem_size); 56 s->num_elems++; 57 return 0; 58 } 59 60 int stack_pop(struct stack *s, void *data) 61 { 62 if (s->num_elems <= 0) { 63 errno = EINVAL; 64 return -1; 65 } 66 s->num_elems--; 67 memcpy(data, s->data + (s->elem_size * s->num_elems), s->elem_size); 68 return 0; 69 } 70
