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
  32 /* Expansion threshold */
  33 #define HASH_THRESHOLD(used, size) ((used) > (size))
  34
  35 #define HASHWALK_CONTINUE 0
  36 #define HASHWALK_ABORT -1
  37
  38 struct hash_backet {
  39         /* if this backet is the head of the linked listed, len denotes the
  40          * number of
  41          * elements in the list */
  42         int len;
  43
  44         /* Linked list.  */
  45         struct hash_backet *next;
  46
  47         /* Hash key. */
  48         unsigned int key;
  49
  50         /* Data.  */
  51         void *data;
  52 };
  53
  54 struct hashstats {
  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         /* Hash backet. */
  63         struct hash_backet **index;
  64
  65         /* Hash table size. Must be power of 2 */
  66         unsigned int size;
  67
  68         /* If max_size is 0 there is no limit */
  69         unsigned int max_size;
  70
  71         /* Key make function. */
  72         unsigned int (*hash_key)(void *);
  73
  74         /* Data compare function. */
  75         int (*hash_cmp)(const void *, const void *);
  76
  77         /* Backet alloc. */
  78         unsigned long count;
  79
  80         struct hashstats stats;
  81
  82         /* hash name */
  83         char *name;
  84 };
  85
  86 #define hashcount(X) ((X)->count)
  87
  88 extern struct hash *hash_create(unsigned int (*)(void *),
  89                                 int (*)(const void *, const void *),
  90                                 const char *);
  91 extern struct hash *hash_create_size(unsigned int, unsigned int (*)(void *),
  92                                      int (*)(const void *, const void *),
  93                                      const char *);
  94
  95 extern void *hash_get(struct hash *, void *, void *(*)(void *));
  96 extern void *hash_alloc_intern(void *);
  97 extern void *hash_lookup(struct hash *, void *);
  98 extern void *hash_release(struct hash *, void *);
  99
 100 extern void hash_iterate(struct hash *, void (*)(struct hash_backet *, void *),
 101                          void *);
 102
 103 extern void hash_walk(struct hash *, int (*)(struct hash_backet *, void *),
 104                       void *);
 105
 106 extern void hash_clean(struct hash *, void (*)(void *));
 107 extern void hash_free(struct hash *);
 108
 109 /*
 110  * Converts a hash table to an unsorted linked list.
 111  * Does not modify the hash table in any way.
 112  *
 113  * hash
 114  *    the hash to convert
 115  */
 116 extern struct list *hash_to_list(struct hash *hash);
 117
 118 extern unsigned int string_hash_make(const char *);
 119
 120 extern void hash_cmd_init(void);
 121
 122 #endif /* _ZEBRA_HASH_H */