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authorPixel <>2001-03-29 23:40:57 +0000
committerPixel <>2001-03-29 23:40:57 +0000
commit80fdb0714b75cb240d8b8068d718b915f1904110 (patch)
tree113acad9045d0ad77ba4660ac0540dfc3e5ced8c /intl/hash-string.h
First.start
Diffstat (limited to 'intl/hash-string.h')
-rw-r--r--intl/hash-string.h59
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diff --git a/intl/hash-string.h b/intl/hash-string.h
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+++ b/intl/hash-string.h
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+/* Implements a string hashing function.
+ Copyright (C) 1995, 1997 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 Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+/* @@ end of prolog @@ */
+
+#ifndef PARAMS
+# if __STDC__
+# define PARAMS(Args) Args
+# else
+# define PARAMS(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 PARAMS ((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;
+}