lib/standard/string: Fixed implementation of hash function for Text variants.

Signed-off-by: Lucas Bajolet <r4pass@hotmail.com>

diff --git a/lib/standard/string.nit b/lib/standard/string.nit
index d09aadc..8531476 100644 (file)
--- 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 (file)
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 (file)
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
+