hash_func.h

Go to the documentation of this file.

/*
 * $Id: hash_func.h 4518 2008-07-28 15:39:28Z henningw $
 *
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio 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
 *
 * Kamailio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * History:
 *---------
 *
 * 2006-01-20 - new_hash1() added; support for configurable hash size
 *              added (bogdan)
 * 2006-03-13 - new_hash1() and new_hash2() merged into core_hash();
 *              added core_case_hash() for case insensitive hashes;
 *              all TM dependet stuff moved to TM config file (bogdan)
 */

/*!
 * \file
 * \brief Hash functions
 */


#ifndef _HASH_FUNC_H_
#define _HASH_FUNC_H_

#include "str.h"


#define ch_h_inc h+=v^(v>>3)
#define ch_icase(_c) (((_c)>='A'&&(_c)<='Z')?((_c)|0x20):(_c))
static inline unsigned int core_hash(const str *s1, const str *s2, const unsigned int size)
{
   char *p, *end;
   register unsigned v;
   register unsigned h;

   h=0;

   end=s1->s+s1->len;
   for ( p=s1->s ; p<=(end-4) ; p+=4 ){
      v=(*p<<24)+(p[1]<<16)+(p[2]<<8)+p[3];
      ch_h_inc;
   }
   v=0;
   for (; p<end ; p++){ v<<=8; v+=*p;}
   ch_h_inc;

   if (s2) {
      end=s2->s+s2->len;
      for (p=s2->s; p<=(end-4); p+=4){
         v=(*p<<24)+(p[1]<<16)+(p[2]<<8)+p[3];
         ch_h_inc;
      }
      v=0;
      for (; p<end ; p++){ v<<=8; v+=*p;}
      ch_h_inc;
   }
   h=((h)+(h>>11))+((h>>13)+(h>>23));
   return size?((h)&(size-1)):h;
}


static inline unsigned int core_case_hash( str *s1, str *s2, unsigned int size)
{
   char *p, *end;
   register unsigned v;
   register unsigned h;

   h=0;

   end=s1->s+s1->len;
   for ( p=s1->s ; p<=(end-4) ; p+=4 ){
      v=(ch_icase(*p)<<24)+(ch_icase(p[1])<<16)+(ch_icase(p[2])<<8)
         + ch_icase(p[3]);
      ch_h_inc;
   }
   v=0;
   for (; p<end ; p++){ v<<=8; v+=ch_icase(*p);}
   ch_h_inc;

   if (s2) {
      end=s2->s+s2->len;
      for (p=s2->s; p<=(end-4); p+=4){
         v=(ch_icase(*p)<<24)+(ch_icase(p[1])<<16)+(ch_icase(p[2])<<8)
            + ch_icase(p[3]);
         ch_h_inc;
      }
      v=0;
      for (; p<end ; p++){ v<<=8; v+=ch_icase(*p);}
      ch_h_inc;
   }
   h=((h)+(h>>11))+((h>>13)+(h>>23));
   return size?((h)&(size-1)):h;
}


#endif

---