glibc/locale/hashval.h
Roland McGrath a3f9038c87 Roland McGrath <roland@redhat.com>
* locale/hashval.h (compute_hashval): Use prototype defn.
	(hashval_t): New macro, defined to unsigned long int
	if not already defined.
	(compute_hashval): Return hashval_t instead of unsigned long int.
	* locale/loadarchive.c (hashval_t): New macro.
	* locale/programs/locarchive.c: Include hashval.h directly instead
	of simple-hash.h.
	(compute_hashval, hashval_t): Define these macros first.
	(insert_name): Use archive_hashval instead of compute_hashval.
	(add_locale, delete_locales_from_archive): Likewise.

2002-08-28  Jakub Jelinek  <jakub@redhat.com>
2002-08-28 07:29:53 +00:00

45 lines
1.6 KiB
C

/* Implement simple hashing table with string based keys.
Copyright (C) 1994-1997, 2000, 2001, 2002 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, October 1994.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef hashval_t
# define hashval_t unsigned long int
#endif
#include <limits.h> /* For CHAR_BIT. */
hashval_t
compute_hashval (const void *key, size_t keylen)
{
size_t cnt;
hashval_t hval;
/* Compute the hash value for the given string. The algorithm
is taken from [Aho,Sethi,Ullman], modified to reduce the number of
collisions for short strings with very varied bit patterns.
See http://www.clisp.org/haible/hashfunc.html. */
cnt = 0;
hval = keylen;
while (cnt < keylen)
{
hval = (hval << 9) | (hval >> (sizeof hval * CHAR_BIT - 9));
hval += (hashval_t) *(((char *) key) + cnt++);
}
return hval != 0 ? hval : ~((hashval_t) 0);
}