mirror of
https://github.com/asterisk/asterisk.git
synced 2025-11-16 23:08:32 +00:00
Version 0.3.0 from FTP
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@578 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Mark Spencer
212
db1-ast/hash/hash_func.c
Executable file
212
db1-ast/hash/hash_func.c
Executable file
@@ -0,0 +1,212 @@
|
||||
/*-
|
||||
* Copyright (c) 1990, 1993
|
||||
* The Regents of the University of California. All rights reserved.
|
||||
*
|
||||
* This code is derived from software contributed to Berkeley by
|
||||
* Margo Seltzer.
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in the
|
||||
* documentation and/or other materials provided with the distribution.
|
||||
* 3. All advertising materials mentioning features or use of this software
|
||||
* must display the following acknowledgement:
|
||||
* This product includes software developed by the University of
|
||||
* California, Berkeley and its contributors.
|
||||
* 4. Neither the name of the University nor the names of its contributors
|
||||
* may be used to endorse or promote products derived from this software
|
||||
* without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
||||
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||||
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
||||
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
||||
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
||||
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
||||
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||||
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||||
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
||||
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
||||
* SUCH DAMAGE.
|
||||
*/
|
||||
|
||||
#if defined(LIBC_SCCS) && !defined(lint)
|
||||
static char sccsid[] = "@(#)hash_func.c 8.2 (Berkeley) 2/21/94";
|
||||
#endif /* LIBC_SCCS and not lint */
|
||||
|
||||
#include <sys/types.h>
|
||||
|
||||
#include <db.h>
|
||||
#include "hash.h"
|
||||
#include "page.h"
|
||||
#include "extern.h"
|
||||
|
||||
static u_int32_t hash1 __P((const void *, size_t));
|
||||
static u_int32_t hash2 __P((const void *, size_t));
|
||||
static u_int32_t hash3 __P((const void *, size_t));
|
||||
static u_int32_t hash4 __P((const void *, size_t));
|
||||
|
||||
/* Global default hash function */
|
||||
u_int32_t (*__default_hash) __P((const void *, size_t)) = hash4;
|
||||
|
||||
/*
|
||||
* HASH FUNCTIONS
|
||||
*
|
||||
* Assume that we've already split the bucket to which this key hashes,
|
||||
* calculate that bucket, and check that in fact we did already split it.
|
||||
*
|
||||
* This came from ejb's hsearch.
|
||||
*/
|
||||
|
||||
#define PRIME1 37
|
||||
#define PRIME2 1048583
|
||||
|
||||
static u_int32_t
|
||||
hash1(keyarg, len)
|
||||
const void *keyarg;
|
||||
register size_t len;
|
||||
{
|
||||
register const u_char *key;
|
||||
register u_int32_t h;
|
||||
|
||||
/* Convert string to integer */
|
||||
for (key = keyarg, h = 0; len--;)
|
||||
h = h * PRIME1 ^ (*key++ - ' ');
|
||||
h %= PRIME2;
|
||||
return (h);
|
||||
}
|
||||
|
||||
/*
|
||||
* Phong's linear congruential hash
|
||||
*/
|
||||
#define dcharhash(h, c) ((h) = 0x63c63cd9*(h) + 0x9c39c33d + (c))
|
||||
|
||||
static u_int32_t
|
||||
hash2(keyarg, len)
|
||||
const void *keyarg;
|
||||
size_t len;
|
||||
{
|
||||
register const u_char *e, *key;
|
||||
register u_int32_t h;
|
||||
register u_char c;
|
||||
|
||||
key = keyarg;
|
||||
e = key + len;
|
||||
for (h = 0; key != e;) {
|
||||
c = *key++;
|
||||
if (!c && key > e)
|
||||
break;
|
||||
dcharhash(h, c);
|
||||
}
|
||||
return (h);
|
||||
}
|
||||
|
||||
/*
|
||||
* This is INCREDIBLY ugly, but fast. We break the string up into 8 byte
|
||||
* units. On the first time through the loop we get the "leftover bytes"
|
||||
* (strlen % 8). On every other iteration, we perform 8 HASHC's so we handle
|
||||
* all 8 bytes. Essentially, this saves us 7 cmp & branch instructions. If
|
||||
* this routine is heavily used enough, it's worth the ugly coding.
|
||||
*
|
||||
* OZ's original sdbm hash
|
||||
*/
|
||||
static u_int32_t
|
||||
hash3(keyarg, len)
|
||||
const void *keyarg;
|
||||
register size_t len;
|
||||
{
|
||||
register const u_char *key;
|
||||
register size_t loop;
|
||||
register u_int32_t h;
|
||||
|
||||
#define HASHC h = *key++ + 65599 * h
|
||||
|
||||
h = 0;
|
||||
key = keyarg;
|
||||
if (len > 0) {
|
||||
loop = (len + 8 - 1) >> 3;
|
||||
|
||||
switch (len & (8 - 1)) {
|
||||
case 0:
|
||||
do {
|
||||
HASHC;
|
||||
/* FALLTHROUGH */
|
||||
case 7:
|
||||
HASHC;
|
||||
/* FALLTHROUGH */
|
||||
case 6:
|
||||
HASHC;
|
||||
/* FALLTHROUGH */
|
||||
case 5:
|
||||
HASHC;
|
||||
/* FALLTHROUGH */
|
||||
case 4:
|
||||
HASHC;
|
||||
/* FALLTHROUGH */
|
||||
case 3:
|
||||
HASHC;
|
||||
/* FALLTHROUGH */
|
||||
case 2:
|
||||
HASHC;
|
||||
/* FALLTHROUGH */
|
||||
case 1:
|
||||
HASHC;
|
||||
} while (--loop);
|
||||
}
|
||||
}
|
||||
return (h);
|
||||
}
|
||||
|
||||
/* Hash function from Chris Torek. */
|
||||
static u_int32_t
|
||||
hash4(keyarg, len)
|
||||
const void *keyarg;
|
||||
register size_t len;
|
||||
{
|
||||
register const u_char *key;
|
||||
register size_t loop;
|
||||
register u_int32_t h;
|
||||
|
||||
#define HASH4a h = (h << 5) - h + *key++;
|
||||
#define HASH4b h = (h << 5) + h + *key++;
|
||||
#define HASH4 HASH4b
|
||||
|
||||
h = 0;
|
||||
key = keyarg;
|
||||
if (len > 0) {
|
||||
loop = (len + 8 - 1) >> 3;
|
||||
|
||||
switch (len & (8 - 1)) {
|
||||
case 0:
|
||||
do {
|
||||
HASH4;
|
||||
/* FALLTHROUGH */
|
||||
case 7:
|
||||
HASH4;
|
||||
/* FALLTHROUGH */
|
||||
case 6:
|
||||
HASH4;
|
||||
/* FALLTHROUGH */
|
||||
case 5:
|
||||
HASH4;
|
||||
/* FALLTHROUGH */
|
||||
case 4:
|
||||
HASH4;
|
||||
/* FALLTHROUGH */
|
||||
case 3:
|
||||
HASH4;
|
||||
/* FALLTHROUGH */
|
||||
case 2:
|
||||
HASH4;
|
||||
/* FALLTHROUGH */
|
||||
case 1:
|
||||
HASH4;
|
||||
} while (--loop);
|
||||
}
|
||||
}
|
||||
return (h);
|
||||
}
|
||||
Reference in New Issue
Block a user