stack.c

   1 /* linked list stack */
   2
   3 #include "stack.h"
   4 #include <stdlib.h>
   5
   6 stack_t *stack_init()
   7 {
   8         stack_t *stack = malloc(sizeof(stack));
   9         stack->next = NULL;
  10         return stack;
  11 }
  12
  13 int stack_empty(stack_t *stack)
  14 {
  15         return (stack->next == NULL);
  16 }
  17
  18 int stack_push(stack_t *stack, void *user)
  19 {
  20         stack_t *new = malloc(sizeof(stack));
  21         if (!new)
  22                 return 0;
  23
  24         stack_t *tmp = stack->next;
  25         stack->next = new;
  26         new->next = tmp;
  27         new->data = user;
  28         return 1;
  29 }
  30
  31 void *stack_pop(stack_t *stack)
  32 {
  33         void *data;
  34         if (!stack->next) return NULL;
  35
  36         stack_t *tmp = stack->next;
  37         stack->next = tmp->next;
  38
  39         data = tmp->data;
  40         free(tmp);
  41         return data;
  42 }
  43
  44 void stack_destroy(stack_t *stack)
  45 {
  46         while (!stack_empty(stack))
  47                 stack_pop(stack);
  48
  49         free(stack);
  50 }