source/include/hash.h

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 2.0
   4
   5    Copyright (C) Ying Chen 2000.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #ifndef _HASH_H_
  23 #define _HASH_H_
  24
  25 #define MAX_HASH_TABLE_SIZE    32768
  26 #define HASH_TABLE_INCREMENT  2
  27
  28 typedef int (*compare_function)(char *, char *);
  29 typedef int (*hash_function)(int, char *);
  30
  31 /*
  32  * lru_link: links the node to the LRU list.
  33  * hash_elem: the pointer to the element that is tied onto the link.
  34  */
  35 typedef struct lru_node {
  36         ubi_dlNode lru_link;
  37         void *hash_elem;
  38 } lru_node;
  39
  40 /*
  41  * bucket_link: link the hash element to the bucket chain that it belongs to.
  42  * lru_link: this element ties the hash element to the lru list.
  43  * bucket: a pointer to the hash bucket that this element belongs to.
  44  * value: a pointer to the hash element content. It can be anything.
  45  * key: stores the string key. The hash_element is always allocated with
  46  * more memory space than the structure shown below to accomodate the space
  47  * used for the whole string. But the memory is always appended at the
  48  * end of the structure, so keep "key" at the end of the structure.
  49  * Don't move it.
  50  */
  51 typedef struct hash_element {
  52         ubi_dlNode      bucket_link;
  53         lru_node    lru_link;
  54         ubi_dlList      *bucket;
  55         void    *value;
  56         char key[1];
  57 } hash_element;
  58
  59 /*
  60  * buckets: a list of buckets, implemented as a dLinkList.
  61  * lru_chain: the lru list of all the hash elements.
  62  * num_elements: the # of elements in the hash table.
  63  * size: the hash table size.
  64  * comp_func: the compare function used during hash key comparisons.
  65  */
  66
  67 typedef struct hash_table {
  68         ubi_dlList      *buckets;
  69         ubi_dlList      lru_chain;
  70         int     num_elements;
  71         int     size;
  72         compare_function        comp_func;
  73 } hash_table;
  74
  75 #endif /* _HASH_H_ */