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hash.h revision 1.2 
      1 /*	$NetBSD: hash.h,v 1.2 2002/06/30 14:17:45 lukem 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	8.1 (Berkeley) 6/6/93
     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 	void		*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;
     68 				/* Pointers to Hash_Entry, one
     69 				 * for each bucket in the table. */
     70 	int 	size;		/* Actual size of array. */
     71 	int 	numEntries;	/* Number of entries in the table. */
     72 	int 	mask;		/* Used to select bits for hashing. */
     73 } Hash_Table;
     74 
     75 /*
     76  * The following structure is used by the searching routines
     77  * to record where we are in the search.
     78  */
     79 
     80 typedef struct Hash_Search {
     81 	Hash_Table	*tablePtr;	/* Table being searched. */
     82 	int	 	nextIndex;	/* Next bucket to check (after
     83 					 * current). */
     84 	Hash_Entry 	*hashEntryPtr;	/* Next entry to check in current
     85 					 * bucket. */
     86 } Hash_Search;
     87 
     88 /*
     89  * Macros.
     90  */
     91 
     92 /*
     93  * void *Hash_GetValue(h)
     94  *     Hash_Entry *h;
     95  */
     96 
     97 #define Hash_GetValue(h) ((h)->clientData)
     98 
     99 /*
    100  * Hash_SetValue(h, val);
    101  *     Hash_Entry *h;
    102  *     char *val;
    103  */
    104 
    105 #define Hash_SetValue(h, val) ((h)->clientData = (void *) (val))
    106 
    107 /*
    108  * Hash_GetKey(h);
    109  *     Hash_Entry *h;
    110  */
    111 
    112 #define Hash_GetKey(h) ((h)->name)
    113 
    114 /*
    115  * Hash_Size(n) returns the number of words in an object of n bytes
    116  */
    117 
    118 #define	Hash_Size(n)	(((n) + sizeof (int) - 1) / sizeof (int))
    119 
    120 void Hash_InitTable(Hash_Table *, int);
    121 void Hash_DeleteTable(Hash_Table *);
    122 Hash_Entry *Hash_FindEntry(Hash_Table *, char *);
    123 Hash_Entry *Hash_CreateEntry(Hash_Table *, char *, int *);
    124 void Hash_DeleteEntry(Hash_Table *, Hash_Entry *);
    125 Hash_Entry *Hash_EnumFirst(Hash_Table *, Hash_Search *);
    126 Hash_Entry *Hash_EnumNext(Hash_Search *);
    127 
    128 #endif /* _HASH */
    129