/*
* ngIRCd -- The Next Generation IRC Daemon
- * Copyright (c)2001,2002 by Alexander Barton (alex@barton.de)
+ * Copyright (c)2001-2010 Alexander Barton (alex@barton.de)
*
- * Dieses Programm ist freie Software. Sie koennen es unter den Bedingungen
- * der GNU General Public License (GPL), wie von der Free Software Foundation
- * herausgegeben, weitergeben und/oder modifizieren, entweder unter Version 2
- * der Lizenz oder (wenn Sie es wuenschen) jeder spaeteren Version.
- * Naehere Informationen entnehmen Sie bitter der Datei COPYING. Eine Liste
- * der an ngIRCd beteiligten Autoren finden Sie in der Datei AUTHORS.
- *
- * $Id: hash.c,v 1.2 2002/03/14 15:49:36 alex Exp $
- *
- * hash.c: Hash-Werte berechnen
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * Please read the file COPYING, README and AUTHORS for more information.
*/
-
#include "portab.h"
+/**
+ * @file
+ * Hash calculation
+ */
+
#include "imp.h"
#include <assert.h>
+#include <string.h>
+
+#include "defines.h"
+#include "tool.h"
#include "exp.h"
#include "hash.h"
+static UINT32 jenkins_hash PARAMS((UINT8 *k, UINT32 length, UINT32 initval));
-LOCAL UINT32 jenkins_hash( register UINT8 *k, register UINT32 length, register UINT32 initval);
-
-
-GLOBAL UINT32 Hash( CHAR *String )
+/**
+ * Calculate hash value for a given string.
+ *
+ * @param String Input string
+ * @return 32 bit hash value
+ */
+GLOBAL UINT32
+Hash( const char *String )
{
- /* Hash-Wert ueber String berechnen */
- return jenkins_hash( String, strlen( String ), 42 );
-} /* Hash */
+ char buffer[LINE_LEN];
+ strlcpy(buffer, String, sizeof(buffer));
+ return jenkins_hash((UINT8 *)ngt_LowerStr(buffer),
+ (UINT32)strlen(buffer), 42);
+} /* Hash */
/*
- * Die hier verwendete Hash-Funktion stammt aus lookup2.c von Bob Jenkins
- * (URL: <http://burtleburtle.net/bob/c/lookup2.c>). Aus dem Header:
+ * This hash function originates from lookup3.c of Bob Jenkins
+ * (URL: <http://burtleburtle.net/bob/c/lookup3.c>):
* --------------------------------------------------------------------
- * lookup2.c, by Bob Jenkins, December 1996, Public Domain.
- * hash(), hash2(), hash3, and mix() are externally useful functions.
- * Routines to test the hash are included if SELF_TEST is defined.
- * You can use this free for any purpose. It has no warranty.
+ * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
+ * These are functions for producing 32-bit hashes for hash table lookup.
+ * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
+ * are externally useful functions. Routines to test the hash are included
+ * if SELF_TEST is defined. You can use this free for any purpose. It's in
+ * the public domain. It has no warranty.
* --------------------------------------------------------------------
- * nicht alle seiner Funktionen werden hier genutzt.
+ * Not all of his functions are used here.
*/
-
#define hashsize(n) ((UINT32)1<<(n))
#define hashmask(n) (hashsize(n)-1)
+#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
#define mix(a,b,c) \
{ \
- a -= b; a -= c; a ^= (c>>13); \
- b -= c; b -= a; b ^= (a<<8); \
- c -= a; c -= b; c ^= (b>>13); \
- a -= b; a -= c; a ^= (c>>12); \
- b -= c; b -= a; b ^= (a<<16); \
- c -= a; c -= b; c ^= (b>>5); \
- a -= b; a -= c; a ^= (c>>3); \
- b -= c; b -= a; b ^= (a<<10); \
- c -= a; c -= b; c ^= (b>>15); \
+ a -= c; a ^= rot(c, 4); c += b; \
+ b -= a; b ^= rot(a, 6); a += c; \
+ c -= b; c ^= rot(b, 8); b += a; \
+ a -= c; a ^= rot(c,16); c += b; \
+ b -= a; b ^= rot(a,19); a += c; \
+ c -= b; c ^= rot(b, 4); b += a; \
} /* mix */
-
-LOCAL UINT32 jenkins_hash( register UINT8 *k, register UINT32 length, register UINT32 initval)
+#define final(a,b,c) \
+{ \
+ c ^= b; c -= rot(b,14); \
+ a ^= c; a -= rot(c,11); \
+ b ^= a; b -= rot(a,25); \
+ c ^= b; c -= rot(b,16); \
+ a ^= c; a -= rot(c,4); \
+ b ^= a; b -= rot(a,14); \
+ c ^= b; c -= rot(b,24); \
+}
+
+static UINT32
+jenkins_hash(UINT8 *k, UINT32 length, UINT32 initval)
{
/* k: the key
* length: length of the key
* initval: the previous hash, or an arbitrary value
*/
-
- register UINT32 a,b,c,len;
+ UINT32 a,b,c;
/* Set up the internal state */
- len = length;
- a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */
- c = initval; /* the previous hash value */
+ a = b = c = 0xdeadbeef + length + initval;
/* handle most of the key */
- while (len >= 12)
- {
+ while (length > 12) {
a += (k[0] +((UINT32)k[1]<<8) +((UINT32)k[2]<<16) +((UINT32)k[3]<<24));
b += (k[4] +((UINT32)k[5]<<8) +((UINT32)k[6]<<16) +((UINT32)k[7]<<24));
c += (k[8] +((UINT32)k[9]<<8) +((UINT32)k[10]<<16)+((UINT32)k[11]<<24));
mix(a,b,c);
- k += 12; len -= 12;
+ length -= 12;
+ k += 12;
}
- /* handle the last 11 bytes */
- c += length;
- switch(len) /* all the case statements fall through */
+ /*-------------------------------- last block: affect all 32 bits of (c) */
+ switch(length) /* all the case statements fall through */
+
{
- case 11: c+=((UINT32)k[10]<<24);
- case 10: c+=((UINT32)k[9]<<16);
- case 9 : c+=((UINT32)k[8]<<8);
- /* the first byte of c is reserved for the length */
+ case 12: c+=((UINT32)k[11])<<24;
+ case 11: c+=((UINT32)k[10]<<16);
+ case 10: c+=((UINT32)k[9]<<8);
+ case 9 : c+=k[8];
case 8 : b+=((UINT32)k[7]<<24);
case 7 : b+=((UINT32)k[6]<<16);
case 6 : b+=((UINT32)k[5]<<8);
case 3 : a+=((UINT32)k[2]<<16);
case 2 : a+=((UINT32)k[1]<<8);
case 1 : a+=k[0];
- /* case 0: nothing left to add */
+ break;
+ case 0 : return c;
}
- mix(a,b,c);
-
- /* report the result */
+ final(a,b,c);
return c;
} /* jenkins_hash */
-
/* -eof- */
projects / ngircd-alex.git / blobdiff