From 898b4aa2a54a2325e0416fb0cac2d72608368db0 Mon Sep 17 00:00:00 2001
From: Lucas Bajolet <r4pass@hotmail.com>
Date: Tue, 13 May 2014 11:30:12 -0400
Subject: [PATCH] lib/standard/string: Fixed implementation of hash function
 for Text variants.

Signed-off-by: Lucas Bajolet <r4pass@hotmail.com>
---
 lib/standard/string.nit      |   17 ++++++-----------
 tests/sav/test_hash_text.res |    8 ++++++++
 tests/test_hash_text.nit     |   32 ++++++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 11 deletions(-)
 create mode 100644 tests/sav/test_hash_text.res
 create mode 100644 tests/test_hash_text.nit

diff --git a/lib/standard/string.nit b/lib/standard/string.nit
index d09aadc..8531476 100644
--- a/lib/standard/string.nit
+++ b/lib/standard/string.nit
@@ -532,11 +532,9 @@ abstract class Text
 		if hash_cache == null then
 			# djb2 hash algorithm
 			var h = 5381
-			var i = length - 1
 
 			for char in self.chars do
-				h = (h * 32) + h + char.ascii
-				i -= 1
+				h = h.lshift(5) + h + char.ascii
 			end
 
 			hash_cache = h
@@ -862,18 +860,15 @@ class FlatString
 	redef fun hash
 	do
 		if hash_cache == null then
-			# djb2 hash algorythm
+			# djb2 hash algorithm
 			var h = 5381
-			var i = length - 1
+			var i = index_from
 
 			var myitems = items
-			var strStart = index_from
-
-			i += strStart
 
-			while i >= strStart do
-				h = (h * 32) + h + self.items[i].ascii
-				i -= 1
+			while i <= index_to do
+				h = h.lshift(5) + h + myitems[i].ascii
+				i += 1
 			end
 
 			hash_cache = h
diff --git a/tests/sav/test_hash_text.res b/tests/sav/test_hash_text.res
new file mode 100644
index 0000000..310e632
--- /dev/null
+++ b/tests/sav/test_hash_text.res
@@ -0,0 +1,8 @@
+true
+true
+true
+true
+true
+true
+true
+true
diff --git a/tests/test_hash_text.nit b/tests/test_hash_text.nit
new file mode 100644
index 0000000..e655dd8
--- /dev/null
+++ b/tests/test_hash_text.nit
@@ -0,0 +1,32 @@
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+var x = "string__NativeString__to_s_with_length"
+
+var y = "string" + "__" + "NativeString" + "__" + "to_s_with_length"
+
+var z = new FlatBuffer.from("string") + "__" + "NativeString" + "__" + "to_s_with_length"
+
+var a = ["string", "NativeString", "to_s_with_length"].join("__")
+
+print x.hash == y.hash
+print y.hash == z.hash
+print z.hash == a.hash
+print a.hash == x.hash
+
+print x.substring(8,12).hash == y.substring(8,12).hash
+print y.substring(8,12).hash == z.substring(8,12).hash
+print z.substring(8,12).hash == a.substring(8,12).hash
+print a.substring(8,12).hash == x.substring(8,12).hash
+
-- 
1.7.9.5