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         /* if this backet is the head of the linked listed, len denotes the
  39          * 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         /* number of empty hash buckets */
  55         _Atomic uint_fast32_t empty;
  56         /* sum of squares of bucket length */
  57         _Atomic uint_fast32_t ssq;
  58 };
  59
  60 struct hash {
  61         /* Hash backet. */
  62         struct hash_backet **index;
  63
  64         /* Hash table size. Must be power of 2 */
  65         unsigned int size;
  66
  67         /* Key make function. */
  68         unsigned int (*hash_key)(void *);
  69
  70         /* Data compare function. */
  71         int (*hash_cmp)(const void *, const void *);
  72
  73         /* Backet alloc. */
  74         unsigned long count;
  75
  76         struct hashstats stats;
  77
  78         /* hash name */
  79         char *name;
  80 };
  81
  82 #define hashcount(X) ((X)->count)
  83
  84 extern struct hash *hash_create(unsigned int (*)(void *),
  85                                 int (*)(const void *, const void *),
  86                                 const char *);
  87 extern struct hash *hash_create_size(unsigned int, unsigned int (*)(void *),
  88                                      int (*)(const void *, const void *),
  89                                      const char *);
  90
  91 extern void *hash_get(struct hash *, void *, void *(*)(void *));
  92 extern void *hash_alloc_intern(void *);
  93 extern void *hash_lookup(struct hash *, void *);
  94 extern void *hash_release(struct hash *, void *);
  95
  96 extern void hash_iterate(struct hash *, void (*)(struct hash_backet *, void *),
  97                          void *);
  98
  99 extern void hash_walk(struct hash *, int (*)(struct hash_backet *, void *),
 100                       void *);
 101
 102 extern void hash_clean(struct hash *, void (*)(void *));
 103 extern void hash_free(struct hash *);
 104
 105 extern unsigned int string_hash_make(const char *);
 106
 107 extern void hash_cmd_init(void);
 108
 109 #endif /* _ZEBRA_HASH_H */