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-rw-r--r--locale/hashval.h41
1 files changed, 41 insertions, 0 deletions
diff --git a/locale/hashval.h b/locale/hashval.h
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+/* 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.  */
+
+unsigned long
+compute_hashval (key, keylen)
+     const void *key;
+     size_t keylen;
+{
+  size_t cnt;
+  unsigned long int 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 >> (LONGBITS - 9));
+      hval += (unsigned long int) *(((char *) key) + cnt++);
+    }
+  return hval != 0 ? hval : ~((unsigned long) 0);
+}