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 */ 017 package org.apache.commons.lang3.text.translate; 018 019 import java.io.IOException; 020 import java.io.Writer; 021 022 import java.util.EnumSet; 023 import java.util.Arrays; 024 025 /** 026 * Translates escaped unicode values of the form \\u+\d\d\d\d back to 027 * unicode. 028 * 029 * @author Apache Software Foundation 030 * @since 3.0 031 * @version $Id: UnicodeUnescaper.java 967237 2010-07-23 20:08:57Z mbenson $ 032 */ 033 public class UnicodeUnescaper extends CharSequenceTranslator { 034 035 public static enum OPTION { escapePlus } 036 037 // TODO: Create an OptionsSet class to hide some of the conditional logic below 038 private final EnumSet<OPTION> options; 039 040 public UnicodeUnescaper(OPTION... options) { 041 if(options.length > 0) { 042 this.options = EnumSet.copyOf(Arrays.asList(options)); 043 } else { 044 this.options = null; 045 } 046 } 047 048 public boolean isSet(OPTION opt) { 049 return (options == null) ? false : options.contains(opt); 050 } 051 052 /** 053 * {@inheritDoc} 054 */ 055 @Override 056 public int translate(CharSequence input, int index, Writer out) throws IOException { 057 if(input.charAt(index) == '\\') { 058 if( (index + 1 < input.length()) && input.charAt(index + 1) == 'u') { 059 // consume optional additional 'u' chars 060 int i=2; 061 while( (index + i < input.length()) && input.charAt(index + i) == 'u') { 062 i++; 063 } 064 065 // consume + symbol in \\u+0045 066 if(isSet(OPTION.escapePlus)) { 067 if( (index + i < input.length()) && (input.charAt(index + i) == '+') ) { 068 i++; 069 } 070 } 071 072 if( (index + i + 4 <= input.length()) ) { 073 // Get 4 hex digits 074 CharSequence unicode = input.subSequence(index + i, index + i + 4); 075 076 try { 077 int value = Integer.parseInt(unicode.toString(), 16); 078 out.write((char) value); 079 } catch (NumberFormatException nfe) { 080 throw new IllegalArgumentException("Unable to parse unicode value: " + unicode, nfe); 081 } 082 return i + 4; 083 } else { 084 throw new IllegalArgumentException("Less than 4 hex digits in unicode value: '" + 085 input.subSequence(index, input.length()) + 086 "' due to end of CharSequence"); 087 } 088 } 089 } 090 return 0; 091 } 092 }