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 #include "frratomic.h"
  26
  27 DECLARE_MTYPE(HASH)
  28 DECLARE_MTYPE(HASH_BACKET)
  29
  30 /* Default hash table size.  */
  31 #define HASH_INITIAL_SIZE     256       /* initial number of backets. */
  32 #define HASH_THRESHOLD        10        /* expand when backet. */
  33
  34 #define HASHWALK_CONTINUE 0
  35 #define HASHWALK_ABORT -1
  36
  37 struct hash_backet
  38 {
  39   /* if this backet is the head of the linked listed, len denotes the number of
  40    * elements in the list */
  41   int len;
  42
  43   /* Linked list.  */
  44   struct hash_backet *next;
  45
  46   /* Hash key. */
  47   unsigned int key;
  48
  49   /* Data.  */
  50   void *data;
  51 };
  52
  53 struct hashstats
  54 {
  55   /* number of empty hash buckets */
  56   _Atomic uint_fast32_t empty;
  57   /* sum of squares of bucket length */
  58   _Atomic uint_fast32_t ssq;
  59 };
  60
  61 struct hash
  62 {
  63   /* Hash backet. */
  64   struct hash_backet **index;
  65
  66   /* Hash table size. Must be power of 2 */
  67   unsigned int size;
  68
  69   /* If expansion failed. */
  70   int no_expand;
  71
  72   /* Key make function. */
  73   unsigned int (*hash_key) (void *);
  74
  75   /* Data compare function. */
  76   int (*hash_cmp) (const void *, const void *);
  77
  78   /* Backet alloc. */
  79   unsigned long count;
  80
  81   struct hashstats stats;
  82
  83   /* hash name */
  84   char *name;
  85 };
  86
  87 #define hashcount(X) ((X)->count)
  88
  89 extern struct hash *hash_create (unsigned int (*) (void *),
  90                                  int (*) (const void *, const void *),
  91                                  const char *);
  92 extern struct hash *hash_create_size (unsigned int, unsigned int (*) (void *),
  93                                       int (*) (const void *, const void *),
  94                                       const char *);
  95
  96 extern void *hash_get (struct hash *, void *, void * (*) (void *));
  97 extern void *hash_alloc_intern (void *);
  98 extern void *hash_lookup (struct hash *, void *);
  99 extern void *hash_release (struct hash *, void *);
 100
 101 extern void hash_iterate (struct hash *,
 102                    void (*) (struct hash_backet *, void *), void *);
 103
 104 extern void hash_walk (struct hash *,
 105                    int (*) (struct hash_backet *, void *), void *);
 106
 107 extern void hash_clean (struct hash *, void (*) (void *));
 108 extern void hash_free (struct hash *);
 109
 110 extern unsigned int string_hash_make (const char *);
 111
 112 extern void hash_cmd_init (void);
 113
 114 #endif /* _ZEBRA_HASH_H */