blob: b1efae057318cc2308d345fea1c0577b2d5b3195 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
/*-------------------------------------------------------------------------
*
* hashfn.c
* Hash functions for use in dynahash.c hashtables
*
*
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/hash/hashfn.c,v 1.17 2002/06/20 20:29:40 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/hash.h"
#include "utils/hsearch.h"
/*
* string_hash: hash function for keys that are null-terminated strings.
*
* NOTE: since dynahash.c backs this up with a fixed-length memcmp(),
* the key must actually be zero-padded to the specified maximum length
* to work correctly. However, if it is known that nothing after the
* first zero byte is interesting, this is the right hash function to use.
*
* NOTE: this is the default hash function if none is specified.
*/
uint32
string_hash(void *key, int keysize)
{
return DatumGetUInt32(hash_any((unsigned char *) key, strlen((char *) key)));
}
/*
* tag_hash: hash function for fixed-size tag values
*/
uint32
tag_hash(void *key, int keysize)
{
return DatumGetUInt32(hash_any((unsigned char *) key, keysize));
}
|
