lib/hash.h

   1 /* Hash routine.
   2  * Copyright (C) 1998 Kunihiro Ishiguro
   3  *
   4  * This file is part of GNU Zebra.
   5  *
   6  * GNU Zebra is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published
   8  * by the Free Software Foundation; either version 2, or (at your
   9  * option) any later version.
  10  *
  11  * GNU Zebra is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #ifndef _ZEBRA_HASH_H
  22 #define _ZEBRA_HASH_H
  23
  24 #include "memory.h"
  25
  26 DECLARE_MTYPE(HASH)
  27 DECLARE_MTYPE(HASH_BACKET)
  28
  29 /* Default hash table size.  */
  30 #define HASH_INITIAL_SIZE     256       /* initial number of backets. */
  31 #define HASH_THRESHOLD        10        /* expand when backet. */
  32
  33 #define HASHWALK_CONTINUE 0
  34 #define HASHWALK_ABORT -1
  35
  36 struct hash_backet
  37 {
  38   /* Linked list.  */
  39   struct hash_backet *next;
  40
  41   /* Hash key. */
  42   unsigned int key;
  43
  44   /* Data.  */
  45   void *data;
  46 };
  47
  48 struct hash
  49 {
  50   /* Hash backet. */
  51   struct hash_backet **index;
  52
  53   /* Hash table size. Must be power of 2 */
  54   unsigned int size;
  55
  56   /* If expansion failed. */
  57   int no_expand;
  58
  59   /* Key make function. */
  60   unsigned int (*hash_key) (void *);
  61
  62   /* Data compare function. */
  63   int (*hash_cmp) (const void *, const void *);
  64
  65   /* Backet alloc. */
  66   unsigned long count;
  67 };
  68
  69 extern struct hash *hash_create (unsigned int (*) (void *),
  70                                  int (*) (const void *, const void *));
  71 extern struct hash *hash_create_size (unsigned int, unsigned int (*) (void *),
  72                                       int (*) (const void *, const void *));
  73
  74 extern void *hash_get (struct hash *, void *, void * (*) (void *));
  75 extern void *hash_alloc_intern (void *);
  76 extern void *hash_lookup (struct hash *, void *);
  77 extern void *hash_release (struct hash *, void *);
  78
  79 extern void hash_iterate (struct hash *,
  80                    void (*) (struct hash_backet *, void *), void *);
  81
  82 extern void hash_walk (struct hash *,
  83                    int (*) (struct hash_backet *, void *), void *);
  84
  85 extern void hash_clean (struct hash *, void (*) (void *));
  86 extern void hash_free (struct hash *);
  87
  88 extern unsigned int string_hash_make (const char *);
  89
  90 #endif /* _ZEBRA_HASH_H */