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diff --git a/src/org/apache/commons/codec/language/SoundexUtils.java b/src/org/apache/commons/codec/language/SoundexUtils.java
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+/*
+ * Copyright 2001-2004 The Apache Software Foundation.
+ * 
+ * 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.
+ */ 
+
+package org.apache.commons.codec.language;
+
+import org.apache.commons.codec.EncoderException;
+import org.apache.commons.codec.StringEncoder;
+
+/**
+ * Utility methods for {@link Soundex} and {@link RefinedSoundex} classes.
+ * 
+ * @author Apache Software Foundation
+ * @version $Id: SoundexUtils.java,v 1.5 2004/03/17 18:31:35 ggregory Exp $
+ * @since 1.3
+ */
+final class SoundexUtils {
+
+    /**
+     * Cleans up the input string before Soundex processing by only returning
+     * upper case letters.
+     * 
+     * @param str
+     *                  The String to clean.
+     * @return A clean String.
+     */
+    static String clean(String str) {
+        if (str == null || str.length() == 0) {
+            return str;
+        }
+        int len = str.length();
+        char[] chars = new char[len];
+        int count = 0;
+        for (int i = 0; i < len; i++) {
+            if (Character.isLetter(str.charAt(i))) {
+                chars[count++] = str.charAt(i);
+            }
+        }
+        if (count == len) {
+            return str.toUpperCase();
+        }
+        return new String(chars, 0, count).toUpperCase();
+    }
+
+    /**
+     * Encodes the Strings and returns the number of characters in the two
+     * encoded Strings that are the same.
+     * <ul>
+     * <li>For Soundex, this return value ranges from 0 through 4: 0 indicates
+     * little or no similarity, and 4 indicates strong similarity or identical
+     * values.</li>
+     * <li>For refined Soundex, the return value can be greater than 4.</li>
+     * </ul>
+     * 
+     * @param encoder
+     *                  The encoder to use to encode the Strings.
+     * @param s1
+     *                  A String that will be encoded and compared.
+     * @param s2
+     *                  A String that will be encoded and compared.
+     * @return The number of characters in the two Soundex encoded Strings that
+     *             are the same.
+     * 
+     * @see #differenceEncoded(String,String)
+     * @see <a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/tsqlref/ts_de-dz_8co5.asp">
+     *          MS T-SQL DIFFERENCE</a>
+     * 
+     * @throws EncoderException
+     *                  if an error occurs encoding one of the strings
+     */
+    static int difference(StringEncoder encoder, String s1, String s2) throws EncoderException {
+        return differenceEncoded(encoder.encode(s1), encoder.encode(s2));
+    }
+
+    /**
+     * Returns the number of characters in the two Soundex encoded Strings that
+     * are the same.
+     * <ul>
+     * <li>For Soundex, this return value ranges from 0 through 4: 0 indicates
+     * little or no similarity, and 4 indicates strong similarity or identical
+     * values.</li>
+     * <li>For refined Soundex, the return value can be greater than 4.</li>
+     * </ul>
+     * 
+     * @param es1
+     *                  An encoded String.
+     * @param es2
+     *                  An encoded String.
+     * @return The number of characters in the two Soundex encoded Strings that
+     *             are the same.
+     * 
+     * @see <a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/tsqlref/ts_de-dz_8co5.asp">
+     *          MS T-SQL DIFFERENCE</a>
+     */
+    static int differenceEncoded(String es1, String es2) {
+
+        if (es1 == null || es2 == null) {
+            return 0;
+        }
+        int lengthToMatch = Math.min(es1.length(), es2.length());
+        int diff = 0;
+        for (int i = 0; i < lengthToMatch; i++) {
+            if (es1.charAt(i) == es2.charAt(i)) {
+                diff++;
+            }
+        }
+        return diff;
+    }
+
+}