tab.c

   1 #include <string.h>
   2 #include "tab.h"
   3
   4 static int hash(char *s)
   5 {
   6         unsigned h = 0x12345678;
   7         while (*s) {
   8                 h ^= (h >> ((h & 0xf) + 1));
   9                 h += *s++;
  10                 h ^= (h << ((h & 0xf) + 5));
  11         }
  12         h &= (TABITEMS - 1);
  13         return h ? h : 1;
  14 }
  15
  16 void tab_add(struct tab *t, char *s)
  17 {
  18         int h = hash(s);
  19         int i = t->n++;
  20         if (!i)
  21                 i = t->n++;
  22         t->next[i] = t->head[h];
  23         t->head[h] = i;
  24         t->data[i] = s;
  25 }
  26
  27 char *tab_get(struct tab *t, char *s)
  28 {
  29         int h = t->head[hash(s)];
  30         while (h && t->data[h]) {
  31                 if (!strcmp(s, t->data[h]))
  32                         return t->data[h];
  33                 h = t->next[h];
  34         }
  35         return NULL;
  36 }
  37
  38 void tab_del(struct tab *t, char *s)
  39 {
  40         int h = hash(s);
  41         int prev = -1;
  42         while (h && t->data[h]) {
  43                 if (!strcmp(s, t->data[h])) {
  44                         if (prev)
  45                                 t->next[prev] = t->next[h];
  46                         else
  47                                 t->head[h] = t->next[h];
  48                         t->next[h] = 0;
  49                         t->data[h] = NULL;
  50                         return;
  51                 }
  52                 prev = h;
  53                 h = t->next[h];
  54         }
  55 }