1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.lang3.text.translate;
18
19 import java.io.IOException;
20 import java.io.Writer;
21 import java.util.Arrays;
22 import java.util.EnumSet;
23
24 /**
25 * Translate XML numeric entities of the form &#[xX]?\d+;? to
26 * the specific codepoint.
27 *
28 * Note that the semi-colon is optional.
29 *
30 * @since 3.0
31 * @version $Id: NumericEntityUnescaper.java 1436770 2013-01-22 07:09:45Z ggregory $
32 */
33 public class NumericEntityUnescaper extends CharSequenceTranslator {
34
35 public static enum OPTION { semiColonRequired, semiColonOptional, errorIfNoSemiColon }
36
37 // TODO?: Create an OptionsSet class to hide some of the conditional logic below
38 private final EnumSet<OPTION> options;
39
40 /**
41 * Create a UnicodeUnescaper.
42 *
43 * The constructor takes a list of options, only one type of which is currently
44 * available (whether to allow, error or ignore the semi-colon on the end of a
45 * numeric entity to being missing).
46 *
47 * For example, to support numeric entities without a ';':
48 * new NumericEntityUnescaper(NumericEntityUnescaper.OPTION.semiColonOptional)
49 * and to throw an IllegalArgumentException when they're missing:
50 * new NumericEntityUnescaper(NumericEntityUnescaper.OPTION.errorIfNoSemiColon)
51 *
52 * Note that the default behaviour is to ignore them.
53 *
54 * @param options to apply to this unescaper
55 */
56 public NumericEntityUnescaper(final OPTION... options) {
57 if(options.length > 0) {
58 this.options = EnumSet.copyOf(Arrays.asList(options));
59 } else {
60 this.options = EnumSet.copyOf(Arrays.asList(new OPTION[] { OPTION.semiColonRequired }));
61 }
62 }
63
64 /**
65 * Whether the passed in option is currently set.
66 *
67 * @param option to check state of
68 * @return whether the option is set
69 */
70 public boolean isSet(final OPTION option) {
71 return options == null ? false : options.contains(option);
72 }
73
74 /**
75 * {@inheritDoc}
76 */
77 @Override
78 public int translate(final CharSequence input, final int index, final Writer out) throws IOException {
79 final int seqEnd = input.length();
80 // Uses -2 to ensure there is something after the &#
81 if(input.charAt(index) == '&' && index < seqEnd - 2 && input.charAt(index + 1) == '#') {
82 int start = index + 2;
83 boolean isHex = false;
84
85 final char firstChar = input.charAt(start);
86 if(firstChar == 'x' || firstChar == 'X') {
87 start++;
88 isHex = true;
89
90 // Check there's more than just an x after the &#
91 if(start == seqEnd) {
92 return 0;
93 }
94 }
95
96 int end = start;
97 // Note that this supports character codes without a ; on the end
98 while(end < seqEnd && ( input.charAt(end) >= '0' && input.charAt(end) <= '9' ||
99 input.charAt(end) >= 'a' && input.charAt(end) <= 'f' ||
100 input.charAt(end) >= 'A' && input.charAt(end) <= 'F' ) )
101 {
102 end++;
103 }
104
105 final boolean semiNext = end != seqEnd && input.charAt(end) == ';';
106
107 if(!semiNext) {
108 if(isSet(OPTION.semiColonRequired)) {
109 return 0;
110 } else
111 if(isSet(OPTION.errorIfNoSemiColon)) {
112 throw new IllegalArgumentException("Semi-colon required at end of numeric entity");
113 }
114 }
115
116 int entityValue;
117 try {
118 if(isHex) {
119 entityValue = Integer.parseInt(input.subSequence(start, end).toString(), 16);
120 } else {
121 entityValue = Integer.parseInt(input.subSequence(start, end).toString(), 10);
122 }
123 } catch(final NumberFormatException nfe) {
124 return 0;
125 }
126
127 if(entityValue > 0xFFFF) {
128 final char[] chrs = Character.toChars(entityValue);
129 out.write(chrs[0]);
130 out.write(chrs[1]);
131 } else {
132 out.write(entityValue);
133 }
134
135 return 2 + end - start + (isHex ? 1 : 0) + (semiNext ? 1 : 0);
136 }
137 return 0;
138 }
139 }