Allow the use of embedded NULs in keys.

2 files changed, 15 insertions, 36 deletions

diff --git a/lib/hash.cc b/lib/hash.cc
index 72a287f..b5bb4ad 100644
--- a/lib/hash.cc
+++ b/lib/hash.cc
@@ -1,36 +1,27 @@
 /* 
-Copyright (C) 1990 Free Software Foundation
+Copyright (C) 1990, 2000 Free Software Foundation
     written by Doug Lea (dl@rocky.oswego.edu)
-
-This file is part of the GNU C++ Library.  This library 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 of the License, or (at your
-option) any later version.  This 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 Library General Public License for more details.
-You should have received a copy of the GNU Library General Public
-License along with this library; if not, write to the Free Software
-Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */
 
 #include <hash.h>
 
 /*
- some useful hash functions
+ Some useful hash function.
+ It's not a particularly good hash function (<< 5 would be better than << 4),
+ but people believe in it because it comes from Dragon book.
 */
 
-unsigned int hashpjw (const char* x) // From Dragon book, p436
+unsigned int
+hashpjw (const char *x, unsigned int len) // From Dragon book, p436
 {
   unsigned int h = 0;
   unsigned int g;
 
-  while (*x != 0)
-  {
-    h = (h << 4) + (unsigned char) *x++;
-    if ((g = h & 0xf0000000) != 0)
-      h = (h ^ (g >> 24)) ^ g;
-  }
+  for (; len > 0; len--)
+    {
+      h = (h << 4) + (unsigned char) *x++;
+      if ((g = h & 0xf0000000) != 0)
+        h = (h ^ (g >> 24)) ^ g;
+    }
   return h;
 }
diff --git a/lib/hash.h b/lib/hash.h
index a5f324b..5dbc92b 100644
--- a/lib/hash.h
+++ b/lib/hash.h
@@ -1,27 +1,15 @@
 // This may look like C code, but it is really -*- C++ -*-
 
 /* 
-Copyright (C) 1988, 1992 Free Software Foundation
+Copyright (C) 1988, 1992, 2000 Free Software Foundation
     written by Doug Lea (dl@rocky.oswego.edu)
-
-This file is part of the GNU C++ Library.  This library 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 of the License, or (at your
-option) any later version.  This 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 Library General Public License for more details.
-You should have received a copy of the GNU Library General Public
-License along with this library; if not, write to the Free Software
-Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */
 
 #ifndef _hash_h
 #define _hash_h 1
 
-/* a hash function for null-terminated char* strings using the
+/* a hash function for char[] arrays using the
    method described in Aho, Sethi, & Ullman, p 436. */
-extern unsigned int hashpjw (const char*);
+extern unsigned int hashpjw (const char *string, unsigned int len);
 
 #endif