    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.lang3.text.translate;
    018
    019import java.io.IOException;
    020import java.io.Writer;
    021
    022/**
    023 * Translates escaped Unicode values of the form \\u+\d\d\d\d back to
    024 * Unicode. It supports multiple 'u' characters and will work with or
    025 * without the +.
    026 *
    027 * @since 3.0
    028 * @deprecated As of 3.6, use Apache Commons Text
    029 * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/translate/UnicodeUnescaper.html">
    030 * UnicodeUnescaper</a> instead
    031 */
    032@Deprecated
    033public class UnicodeUnescaper extends CharSequenceTranslator {
    034
    035    /**
    036     * {@inheritDoc}
    037     */
    038    @Override
    039    public int translate(final CharSequence input, final int index, final Writer out) throws IOException {
    040        if (input.charAt(index) == '\\' && index + 1 < input.length() && input.charAt(index + 1) == 'u') {
    041            // consume optional additional 'u' chars
    042            int i = 2;
    043            while (index + i < input.length() && input.charAt(index + i) == 'u') {
    044                i++;
    045            }
    046
    047            if (index + i < input.length() && input.charAt(index + i) == '+') {
    048                i++;
    049            }
    050
    051            if (index + i + 4 <= input.length()) {
    052                // Get 4 hex digits
    053                final CharSequence unicode = input.subSequence(index + i, index + i + 4);
    054
    055                try {
    056                    final int value = Integer.parseInt(unicode.toString(), 16);
    057                    out.write((char) value);
    058                } catch (final NumberFormatException nfe) {
    059                    throw new IllegalArgumentException("Unable to parse unicode value: " + unicode, nfe);
    060                }
    061                return i + 4;
    062            }
    063            throw new IllegalArgumentException("Less than 4 hex digits in unicode value: '" + input.subSequence(index, input.length())
    064                    + "' due to end of CharSequence");
    065        }
    066        return 0;
    067    }
    068}