1 // DoublyLinkedList DataStructure example
   2 #include <stdlib.h>
   3 #include <string.h>
   4 
   5 #include "DoublyLinkedList.h"
   6 
   7 void dlist_init(DList *list, void (*destroy)(void *data)) {
   8     list->size = 0;
   9     list->destroy = destroy;
  10     list->head = NULL;
  11     list->tail = NULL;
  12     return;
  13 }
  14 
  15 void dlist_destroy(DList *list) {
  16     void *data;
  17     while(dlist_size(list) > 0) {
  18         if(dlist_remove(list, dlist_tail(list), (void **)&data) == 0 &&
  19                 list->destroy != NULL) {
  20             list->destroy(data);
  21         }
  22     }
  23     memset(list, 0, sizeof(DList));
  24     return;
  25 }
  26 
  27 int dlist_ins_next(DList *list, DListElmt *element, const void *data) {
  28     DListElmt *new_element;
  29     if(element == NULL && dlist_size(list) != 0)
  30         return -1;
  31     if((new_element = (DListElmt *)malloc(sizeof(DListElmt)))== NULL)
  32         return -1;
  33     
  34     new_element->data = (void *)data;
  35     if(dlist_size(list) == 0) {
  36         list->head = new_element;
  37         list->head->prev = NULL;
  38         list->head->next = NULL;
  39         list->tail = new_element;
  40     } else {
  41         new_element->next = element->next;
  42         new_element->prev = element;
  43         if(element->next == NULL)
  44             list->tail = new_element;
  45         else
  46             element->next->prev = new_element;
  47         element->next = new_element;
  48     }
  49     list->size++;
  50     return 0;
  51 }
  52 
  53 int dlist_ins_prev(DList *list, DListElmt *element, const void *data) {
  54     DListElmt *new_element;
  55     if(element == NULL && dlist_size(list) != 0)
  56         return -1;
  57     if((new_element = (DListElmt *)malloc(sizeof(DListElmt))) == NULL)
  58         return -1;
  59 
  60     new_element->data = (void *)data;
  61     if(dlist_size(list) == 0) {
  62         list->head = new_element;
  63         list->head->prev = NULL;
  64         list->head->next = NULL;
  65         list->tail = new_element;
  66     } else {
  67         new_element->next = element;
  68         new_element->prev = element->prev;
  69         if(element->prev = NULL)
  70             list->head = new_element;
  71         else
  72             element->prev->next = new_element;
  73         element->prev = new_element;
  74     }
  75     list->size++;
  76     return 0;
  77 }
  78 
  79 int dlist_remove(DList *list, DListElmt *element, void **data) {
  80     if(element == NULL || dlist_size(list) == 0)
  81         return -1;
  82 
  83     *data = element->data;
  84     if(element == list->head) {
  85         list->head = element->next;
  86         if(list->head == NULL)
  87             list->tail = NULL;
  88         else
  89             element->next->prev = NULL;
  90     } else {
  91         element->prev->next = element->next;
  92         if(element->next == NULL)
  93             list->tail = element->prev;
  94         else
  95             element->next->prev = element->prev;
  96     }
  97     free(element);
  98     list->size--;
  99     return 0;
 100 }
 101 
 102