Imported Upstream version 0.5.5

[pkg/abook.git] / intl / hash-string.h

diff --git a/intl/hash-string.h b/intl/hash-string.h
new file mode 100644 (file)
index 0000000..093e3b1
--- /dev/null
+++ b/intl/hash-string.h
@@ -0,0 +1,48 @@
+/* Description of GNU message catalog format: string hashing function.
+   Copyright (C) 1995, 1997-1998, 2000-2003 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify it
+   under the terms of the GNU Library 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library 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.  */
+
+/* @@ end of prolog @@ */
+
+/* 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 inline unsigned long int
+hash_string (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 char) *str++;
+      g = hval & ((unsigned long int) 0xf << (HASHWORDBITS - 4));
+      if (g != 0)
+       {
+         hval ^= g >> (HASHWORDBITS - 8);
+         hval ^= g;
+       }
+    }
+  return hval;
+}