On 09/27/2012 05:13 AM, Paul Eggert wrote:
> On 09/26/2012 09:40 AM, Jim Meyering wrote:
>> Yes, switching it to LGPLv2+ is fine with me.
> OK, thanks, I did that.
Thank you. Attached you'll find a patch to add hash_pjw_s() and a
different patch which returns the full number if requested in hash_pjw().
regards,
Nikos
>From 82b53fda2a73bbdbd7483fb0a74dc00ada7a0b64 Mon Sep 17 00:00:00 2001
From: Nikos Mavrogiannopoulos <n...@gnutls.org>
Date: Thu, 27 Sep 2012 08:42:55 +0200
Subject: [PATCH 2/2] If tablesize is zero then return the full h.
---
lib/hash-pjw.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/lib/hash-pjw.c b/lib/hash-pjw.c
index 0966598..927271d 100644
--- a/lib/hash-pjw.c
+++ b/lib/hash-pjw.c
@@ -36,5 +36,8 @@ hash_pjw (const void *x, size_t tablesize)
for (s = x; *s; s++)
h = *s + ((h << 9) | (h >> (SIZE_BITS - 9)));
- return h % tablesize;
+ if (tablesize)
+ return h % tablesize;
+ else
+ return h;
}
--
1.7.10.4
>From d48f54a232b388c184124cc0b2e7998662cb4091 Mon Sep 17 00:00:00 2001
From: Nikos Mavrogiannopoulos <n...@gnutls.org>
Date: Thu, 27 Sep 2012 08:42:07 +0200
Subject: [PATCH 1/2] Added hash-pjw-s.
---
lib/hash-pjw-s.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
lib/hash-pjw-s.h | 23 +++++++++++++++++++++++
modules/hash-pjw-s | 22 ++++++++++++++++++++++
3 files changed, 89 insertions(+)
create mode 100644 lib/hash-pjw-s.c
create mode 100644 lib/hash-pjw-s.h
create mode 100644 modules/hash-pjw-s
diff --git a/lib/hash-pjw-s.c b/lib/hash-pjw-s.c
new file mode 100644
index 0000000..9baaf35
--- /dev/null
+++ b/lib/hash-pjw-s.c
@@ -0,0 +1,44 @@
+/* hash-pjw.c -- compute a hash value from a NUL-terminated string.
+
+ Copyright (C) 2001, 2003, 2006, 2009-2012 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 3 of the License, 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, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+#include "hash-pjw.h"
+
+#include <limits.h>
+
+#define SIZE_BITS (sizeof (size_t) * CHAR_BIT)
+
+/* A hash function for char* strings of known size using
+ the method described by Bruno Haible.
+ See http://www.haible.de/bruno/hashfunc.html. */
+
+size_t
+hash_pjw_s (const void *x, size_t x_size, size_t tablesize)
+{
+ const unsigned char *s=x;
+ size_t h = 0;
+ unsigned i;
+
+ for (i=0; i<x_size;i++)
+ h = s[i] + ((h << 9) | (h >> (SIZE_BITS - 9)));
+
+ if (tablesize)
+ return h % tablesize;
+ else
+ return h;
+}
diff --git a/lib/hash-pjw-s.h b/lib/hash-pjw-s.h
new file mode 100644
index 0000000..197eaa5
--- /dev/null
+++ b/lib/hash-pjw-s.h
@@ -0,0 +1,23 @@
+/* hash-pjw.h -- declaration for a simple hash function
+ Copyright (C) 2001, 2003, 2009-2012 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 3 of the License, 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, see <http://www.gnu.org/licenses/>. */
+
+#include <stddef.h>
+
+/* Compute a hash code for a NUL-terminated string starting at X,
+ and return the hash code modulo TABLESIZE.
+ The result is platform dependent: it depends on the size of the 'size_t'
+ type and on the signedness of the 'char' type. */
+extern size_t hash_pjw_s (void const *x, size_t tablesize) _GL_ATTRIBUTE_PURE;
diff --git a/modules/hash-pjw-s b/modules/hash-pjw-s
new file mode 100644
index 0000000..1748e65
--- /dev/null
+++ b/modules/hash-pjw-s
@@ -0,0 +1,22 @@
+Description:
+Compute a hash value for a string of known size.
+
+Files:
+lib/hash-pjw-s.h
+lib/hash-pjw-s.c
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+lib_SOURCES += hash-pjw-s.h hash-pjw-s.c
+
+Include:
+"hash-pjw-s.h"
+
+License:
+LGPLv2+
+
+Maintainer:
+Jim Meyering
--
1.7.10.4
