Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4 (http://svn.webkit.org/repository/webkit/trunk@104285)

1 files changed, 47 insertions, 0 deletions

diff --git a/Tools/Scripts/webkitpy/common/editdistance.py b/Tools/Scripts/webkitpy/common/editdistance.py
new file mode 100644
index 000000000..2eccca82d
--- /dev/null
+++ b/Tools/Scripts/webkitpy/common/editdistance.py
@@ -0,0 +1,47 @@
+# Copyright (c) 2011 Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+from array import array
+
+
+def edit_distance(str1, str2):
+    unsignedShort = 'h'
+    distances = [array(unsignedShort, (0,) * (len(str2) + 1)) for i in range(0, len(str1) + 1)]
+    # distances[0][0] = 0 since distance between str1[:0] and str2[:0] is 0
+    for i in range(1, len(str1) + 1):
+        distances[i][0] = i  # Distance between str1[:i] and str2[:0] is i
+
+    for j in range(1, len(str2) + 1):
+        distances[0][j] = j  # Distance between str1[:0] and str2[:j] is j
+
+    for i in range(0, len(str1)):
+        for j in range(0, len(str2)):
+            diff = 0 if str1[i] == str2[j] else 1
+            # Deletion, Insertion, Identical / Replacement
+            distances[i + 1][j + 1] = min(distances[i + 1][j] + 1, distances[i][j + 1] + 1, distances[i][j] + diff)
+    return distances[len(str1)][len(str2)]