dlink.c

   1
   2 /* doubly linked lists */
   3 /* This is free software. No strings attached. No copyright claimed */
   4
   5 #include        <unistd.h>
   6 #include        <stdlib.h>
   7 #include        <string.h>
   8 #include        "dlink.h"
   9
  10
  11 void *dl_head()
  12 {
  13     void *h;
  14     h = dl_alloc(0);
  15     dl_next(h) = h;
  16     dl_prev(h) = h;
  17     return h;
  18 }
  19
  20 void dl_free(void *v)
  21 {
  22     struct __dl_head *vv  = v;
  23     free(vv-1);
  24 }
  25
  26 void dl_init(void *v)
  27 {
  28     dl_next(v) = v;
  29     dl_prev(v) = v;
  30 }
  31
  32 void dl_insert(void *head, void *val)
  33 {
  34     dl_next(val) = dl_next(head);
  35     dl_prev(val) = head;
  36     dl_next(dl_prev(val)) = val;
  37     dl_prev(dl_next(val)) = val;
  38 }
  39
  40 void dl_add(void *head, void *val)
  41 {
  42     dl_prev(val) = dl_prev(head);
  43     dl_next(val) = head;
  44     dl_next(dl_prev(val)) = val;
  45     dl_prev(dl_next(val)) = val;
  46 }
  47
  48 void dl_del(void *val)
  49 {
  50     if (dl_prev(val) == 0 || dl_next(val) == 0)
  51         return;
  52     dl_prev(dl_next(val)) = dl_prev(val);
  53     dl_next(dl_prev(val)) = dl_next(val);
  54     dl_prev(val) = dl_next(val) = 0;
  55 }
  56
  57 char *dl_strndup(char *s, int l)
  58 {
  59     char *n;
  60     if (s == NULL)
  61         return NULL;
  62     n = dl_newv(char, l+1);
  63     if (n == NULL)
  64         return NULL;
  65     else
  66     {
  67         strncpy(n, s, l);
  68         n[l] = 0;
  69         return n;
  70     }
  71 }
  72
  73 char *dl_strdup(char *s)
  74 {
  75     return dl_strndup(s, (int)strlen(s));
  76 }