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.\"    notice, this list of conditions and the following disclaimer in the
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.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
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.\"    may be used to endorse or promote products derived from this software
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.\"	@(#)hash.3	8.6 (Berkeley) 8/18/94
.\"
.\" Japanese Version Copyright (c) 1999 Shouichi Saito
.\"	all rights reserved.
.\" Translated Mon Jul 26 14:22:49 JST 1999
.\"	by Shouichi Saito <ss236rx@ymg.urban.ne.jp>
.\" Proofed Tue Aug 17 1999 by NAKANO Takeo <nakano@apm.seikei.ac.jp>
.\" Updated 2008-02-10, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v2.77
.\"
.\"WORD:	access method		᥽å
.\"WORD:	bucket			Хå
.\"
.TH HASH 3 1994-08-18 "" "Linux Programmer's Manual"
.UC 7
.SH ̾
hash \- hash ǡ١ؤΥ᥽å
.SH 
.nf
.ft B
#include <sys/types.h>
#include <db.h>
.ft R
.fi
.SH 
롼
.BR dbopen (3)
ϥǡ١եФ饤֥ꥤ󥿡եǤ롣
ݡȤƤեեޥåȤΤҤȤĤ hash ե뤬롣
ǡ١ؤΥ᥽åɤ˴ؤŪʵҤ
.BR dbopen (3)
˽񤫤Ƥ롣
Υޥ˥奢ڡǤ hash ͭξˤĤƤΤߵҤ롣
.PP
hash ǡ¤ϡĥǽưŪϥå她Ǥ롣
.PP
.BR dbopen (3)
Ϥ hash ᥽åɤͭΥǡ¤Τϡ
.I <db.h>
󥯥롼ɥեǰʲΤ褦Ƥ롣
.in +4n
.nf

typedef struct {
    unsigned int       bsize;
    unsigned int       ffactor;
    unsigned int       nelem;
    unsigned int       cachesize;
    uint32_t         (*hash)(const void *, size_t);
    int         lorder;
} HASHINFO;
.fi
.in
.PP
ι¤ΤǤʲ˼
.TP 10
.I bsize
hash ơ֥Хå (table bucket) Υ롣
ǥեȤ 256 ХȤǤ롣
ǥ֤ơ֥ǡƥब礭ơ֥Ǥ
ڡ礭ۤɤ
.TP
.I ffactor
桼˾ hash ơ֥̩٤Ǥ롣
Ϥ줾ΥХåȤ˳ǼǤ륭γǤꡢ
hash ơ֥硦̾Ѥ롣
ǥեȤ 8 Ǥ롣
.TP
.I nelem
hash ơ֥κǽޤ˸ѤäͤǤ롣
ͤåȤƤʤäꡢޤ㤯åȤƤȡ
hash ơ֥ϥäƤ˱Ƴĥ롣
ѥեޥ󥹤 (餯դ٤) 롣
ǥեͤ 1 Ǥ롣
.TP
.I cachesize
ꥭåκ (Хñ) λ͡
ͤ
.BR ޤǻͤǤ 
᥽åɤϤͤۤγƤ뤳Ȥ⤢롣
.TP
.I hash
ϥ桼 hash ؿǤ롣
ƤΥǡФƤޤѤ hash ؿȸΤϤʤ顢
ΥǡåȤФƤȤ߹ߤ hash ؿǤ
ѥեޥ󥹤㤤Ȥ⤢뤫⤷ʤ
桼 hash ؿĤΰȤʤƤϤʤʤ (Хʸ
ؤΥݥ󥿤ȡĹ)
 hash ͤȤƻȤ 32ӥåȤ֤ͤʤƤϤʤʤ
.TP
.I lorder
ǡ١˳ǼƤ᥿ǡͤΥХȥ
οϡɽΤǤ롣
㤨Хӥåǥʤ顢οͤ 4,321 Ȥʤ롣
.I lorder
 0 (ꤵƤʤ)硢ߤΥۥ
ǻȤƤ¤ӽ礬Ȥ롣
ե뤬¸ߤ硢ꤷ̵ͤ뤵ĥ꡼
˻ꤵƤͤȤ롣
.PP
.\"NAKANO the tree  the hash, Ǥ礦.
ե뤬¸ߤƤ (ޤ
.B O_TRUNC
ե饰ꤵƤʤ) ȡ
.IR bsize ,
.IR ffactor ,
.IR lorder ,
.I nelem
˻ꤵ줿̵ͤ뤵졢
ϥå夬줿˻ȤäͤȤ롣
.PP
hash ؿꤵȡ
.I hash_open
ϥǡ١줿˻ꤵƤ
hash ؿȺꤵ줿 hash ؿƱɤĴ١
ƱǤʤˤϼԤ롣
.PP
.BR dbm (3),

.BR ndbm (3)
˵ҤƤ롼ؤβߴ뤿Υ󥿡ե
¸ߤ롣Υ󥿡եϰΥեե
ޥåȤȤϸߴʤ
.SH 顼
.I hash
᥽åɥ롼ϡԤȥ饤֥롼
.BR dbopen (3)
ǻꤵƤ륨顼˱
.I errno
򥻥åȤ롣
.SH Х
ХȥȤƤϥӥåǥȥȥ륨ǥΤߤ
ݡȤƤ롣
.SH Ϣ
.BR btree (3),
.BR dbopen (3),
.BR mpool (3),
.BR recno (3)
.sp
.IR "Dynamic Hash Tables" ,
Per-Ake Larson, Communications of the ACM, April 1988.
.sp
.IR "A New Hash Package for UNIX" ,
Margo Seltzer, USENIX Proceedings, Winter 1991.