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hash.h revision 1.10
      1 /*	$NetBSD: hash.h,v 1.10 2009/01/24 10:59:09 dsl Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
      5  *
      6  * This code is derived from software contributed to Berkeley by
      7  * Adam de Boor.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  *
     33  *	from: @(#)hash.h	8.1 (Berkeley) 6/6/93
     34  */
     35 
     36 /*
     37  * Copyright (c) 1988, 1989 by Adam de Boor
     38  * Copyright (c) 1989 by Berkeley Softworks
     39  * All rights reserved.
     40  *
     41  * This code is derived from software contributed to Berkeley by
     42  * Adam de Boor.
     43  *
     44  * Redistribution and use in source and binary forms, with or without
     45  * modification, are permitted provided that the following conditions
     46  * are met:
     47  * 1. Redistributions of source code must retain the above copyright
     48  *    notice, this list of conditions and the following disclaimer.
     49  * 2. Redistributions in binary form must reproduce the above copyright
     50  *    notice, this list of conditions and the following disclaimer in the
     51  *    documentation and/or other materials provided with the distribution.
     52  * 3. All advertising materials mentioning features or use of this software
     53  *    must display the following acknowledgement:
     54  *	This product includes software developed by the University of
     55  *	California, Berkeley and its contributors.
     56  * 4. Neither the name of the University nor the names of its contributors
     57  *    may be used to endorse or promote products derived from this software
     58  *    without specific prior written permission.
     59  *
     60  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     61  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     62  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     63  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     64  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     65  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     66  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     67  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     68  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     69  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     70  * SUCH DAMAGE.
     71  *
     72  *	from: @(#)hash.h	8.1 (Berkeley) 6/6/93
     73  */
     74 
     75 /* hash.h --
     76  *
     77  * 	This file contains definitions used by the hash module,
     78  * 	which maintains hash tables.
     79  */
     80 
     81 #ifndef	_HASH
     82 #define	_HASH
     83 
     84 /*
     85  * The following defines one entry in the hash table.
     86  */
     87 
     88 typedef struct Hash_Entry {
     89     struct Hash_Entry *next;		/* Used to link together all the
     90     					 * entries associated with the same
     91 					 * bucket. */
     92     union {
     93 	void	      *clientPtr;	/* Arbitrary pointer */
     94 	time_t	      clientTime;	/* Arbitrary Time */
     95     } clientInfo;
     96     unsigned	      namehash;		/* hash value of key */
     97     char	      name[1];		/* key string */
     98 } Hash_Entry;
     99 
    100 typedef struct Hash_Table {
    101     struct Hash_Entry **bucketPtr;/* Pointers to Hash_Entry, one
    102     				 * for each bucket in the table. */
    103     int 	size;		/* Actual size of array. */
    104     int 	numEntries;	/* Number of entries in the table. */
    105     int 	mask;		/* Used to select bits for hashing. */
    106 } Hash_Table;
    107 
    108 /*
    109  * The following structure is used by the searching routines
    110  * to record where we are in the search.
    111  */
    112 
    113 typedef struct Hash_Search {
    114     Hash_Table  *tablePtr;	/* Table being searched. */
    115     int 	nextIndex;	/* Next bucket to check (after current). */
    116     Hash_Entry 	*hashEntryPtr;	/* Next entry to check in current bucket. */
    117 } Hash_Search;
    118 
    119 /*
    120  * Macros.
    121  */
    122 
    123 /*
    124  * void * Hash_GetValue(h)
    125  *     Hash_Entry *h;
    126  */
    127 
    128 #define Hash_GetValue(h) ((h)->clientInfo.clientPtr)
    129 #define Hash_GetTimeValue(h) ((h)->clientInfo.clientTime)
    130 
    131 /*
    132  * Hash_SetValue(h, val);
    133  *     Hash_Entry *h;
    134  *     char *val;
    135  */
    136 
    137 #define Hash_SetValue(h, val) ((h)->clientInfo.clientPtr = (val))
    138 #define Hash_SetTimeValue(h, val) ((h)->clientInfo.clientTime = (val))
    139 
    140 /*
    141  * Hash_Size(n) returns the number of words in an object of n bytes
    142  */
    143 
    144 #define	Hash_Size(n)	(((n) + sizeof (int) - 1) / sizeof (int))
    145 
    146 void Hash_InitTable(Hash_Table *, int);
    147 void Hash_DeleteTable(Hash_Table *);
    148 Hash_Entry *Hash_FindEntry(Hash_Table *, const char *);
    149 Hash_Entry *Hash_CreateEntry(Hash_Table *, const char *, Boolean *);
    150 void Hash_DeleteEntry(Hash_Table *, Hash_Entry *);
    151 Hash_Entry *Hash_EnumFirst(Hash_Table *, Hash_Search *);
    152 Hash_Entry *Hash_EnumNext(Hash_Search *);
    153 
    154 #endif /* _HASH */
    155