diff options
author | Elliot Lee <sopwith@src.gnome.org> | 1997-11-24 22:32:04 +0000 |
---|---|---|
committer | Elliot Lee <sopwith@src.gnome.org> | 1997-11-24 22:32:04 +0000 |
commit | 260b95407d215f8ef2bfd90bfdf44e97dc0010ae (patch) | |
tree | 23f04282ba39208dbf92dda5e4fb6d0f8c33f66f /intl/hash-string.h | |
parent | 2928c4e707104b312d1ab3e75e24c57e680313ce (diff) | |
download | shared-mime-info-260b95407d215f8ef2bfd90bfdf44e97dc0010ae.tar.gz |
Initial revision
svn path=/trunk/; revision=50
Diffstat (limited to 'intl/hash-string.h')
-rw-r--r-- | intl/hash-string.h | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/intl/hash-string.h b/intl/hash-string.h new file mode 100644 index 00000000..3b38bd11 --- /dev/null +++ b/intl/hash-string.h @@ -0,0 +1,62 @@ +/* hash-string - Implements a string hashing function. + Copyright (C) 1995 Free Software Foundation, Inc. + +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, or (at your option) +any later version. + +This program 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. */ + +#ifdef HAVE_VALUES_H +# include <values.h> +#endif + +/* @@ end of prolog @@ */ + +#ifndef __P +# if __STDC__ +# define __P(Args) Args +# else +# define __P(Args) () +# endif +#endif + +/* We assume to have `unsigned long int' value with at least 32 bits. */ +#define HASHWORDBITS 32 + + +/* Defines the so called `hashpjw' function by P.J. Weinberger + [see Aho/Sethi/Ullman, COMPILERS: Principles, Techniques and Tools, + 1986, 1987 Bell Telephone Laboratories, Inc.] */ +static unsigned long hash_string __P ((const char *__str_param)); + +static inline unsigned long +hash_string (str_param) + const char *str_param; +{ + unsigned long int hval, g; + const char *str = str_param; + + /* Compute the hash value for the given string. */ + hval = 0; + while (*str != '\0') + { + hval <<= 4; + hval += (unsigned long) *str++; + g = hval & ((unsigned long) 0xf << (HASHWORDBITS - 4)); + if (g != 0) + { + hval ^= g >> (HASHWORDBITS - 8); + hval ^= g; + } + } + return hval; +} |