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hash.h revision 1.4 
      1 /*	$NetBSD: hash.h,v 1.4 1995/06/14 15:19:18 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
      5  * Copyright (c) 1988, 1989 by Adam de Boor
      6  * Copyright (c) 1989 by Berkeley Softworks
      7  * All rights reserved.
      8  *
      9  * This code is derived from software contributed to Berkeley by
     10  * Adam de Boor.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. All advertising materials mentioning features or use of this software
     21  *    must display the following acknowledgement:
     22  *	This product includes software developed by the University of
     23  *	California, Berkeley and its contributors.
     24  * 4. Neither the name of the University nor the names of its contributors
     25  *    may be used to endorse or promote products derived from this software
     26  *    without specific prior written permission.
     27  *
     28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38  * SUCH DAMAGE.
     39  *
     40  *	from: @(#)hash.h	5.4 (Berkeley) 12/28/90
     41  */
     42 
     43 /* hash.h --
     44  *
     45  * 	This file contains definitions used by the hash module,
     46  * 	which maintains hash tables.
     47  */
     48 
     49 #ifndef	_HASH
     50 #define	_HASH
     51 
     52 /*
     53  * The following defines one entry in the hash table.
     54  */
     55 
     56 typedef struct Hash_Entry {
     57     struct Hash_Entry *next;		/* Used to link together all the
     58     					 * entries associated with the same
     59 					 * bucket. */
     60     ClientData	      clientData;	/* Arbitrary piece of data associated
     61     					 * with key. */
     62     unsigned	      namehash;		/* hash value of key */
     63     char	      name[1];		/* key string */
     64 } Hash_Entry;
     65 
     66 typedef struct Hash_Table {
     67     struct Hash_Entry **bucketPtr;/* Pointers to Hash_Entry, one
     68     				 * for each bucket in the table. */
     69     int 	size;		/* Actual size of array. */
     70     int 	numEntries;	/* Number of entries in the table. */
     71     int 	mask;		/* Used to select bits for hashing. */
     72 } Hash_Table;
     73 
     74 /*
     75  * The following structure is used by the searching routines
     76  * to record where we are in the search.
     77  */
     78 
     79 typedef struct Hash_Search {
     80     Hash_Table  *tablePtr;	/* Table being searched. */
     81     int 	nextIndex;	/* Next bucket to check (after current). */
     82     Hash_Entry 	*hashEntryPtr;	/* Next entry to check in current bucket. */
     83 } Hash_Search;
     84 
     85 /*
     86  * Macros.
     87  */
     88 
     89 /*
     90  * ClientData Hash_GetValue(h)
     91  *     Hash_Entry *h;
     92  */
     93 
     94 #define Hash_GetValue(h) ((h)->clientData)
     95 
     96 /*
     97  * Hash_SetValue(h, val);
     98  *     Hash_Entry *h;
     99  *     char *val;
    100  */
    101 
    102 #define Hash_SetValue(h, val) ((h)->clientData = (ClientData) (val))
    103 
    104 /*
    105  * Hash_Size(n) returns the number of words in an object of n bytes
    106  */
    107 
    108 #define	Hash_Size(n)	(((n) + sizeof (int) - 1) / sizeof (int))
    109 
    110 void Hash_InitTable __P((Hash_Table *, int));
    111 void Hash_DeleteTable __P((Hash_Table *));
    112 Hash_Entry *Hash_FindEntry __P((Hash_Table *, char *));
    113 Hash_Entry *Hash_CreateEntry __P((Hash_Table *, char *, Boolean *));
    114 void Hash_DeleteEntry __P((Hash_Table *, Hash_Entry *));
    115 Hash_Entry *Hash_EnumFirst __P((Hash_Table *, Hash_Search *));
    116 Hash_Entry *Hash_EnumNext __P((Hash_Search *));
    117 
    118 #endif /* _HASH */
    119