    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;
    021import java.util.Arrays;
    022import java.util.Collections;
    023import java.util.EnumSet;
    024
    025/**
    026 * Translate XML numeric entities of the form &amp;#[xX]?\d+;? to
    027 * the specific codepoint.
    028 *
    029 * Note that the semicolon is optional.
    030 *
    031 * @since 3.0
    032 * @deprecated as of 3.6, use commons-text
    033 * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/translate/NumericEntityUnescaper.html">
    034 * NumericEntityUnescaper</a> instead
    035 */
    036@Deprecated
    037public class NumericEntityUnescaper extends CharSequenceTranslator {
    038
    039    /** Enumerates NumericEntityUnescaper options for unescaping. */
    040    public enum OPTION {
    041
    042        /**
    043         * Require a semicolon.
    044         */
    045        semiColonRequired,
    046
    047        /**
    048         * Do not require a semicolon.
    049         */
    050        semiColonOptional,
    051
    052        /**
    053         * Throw an exception if a semicolon is missing.
    054         */
    055        errorIfNoSemiColon
    056    }
    057
    058    // TODO?: Create an OptionsSet class to hide some of the conditional logic below
    059    private final EnumSet<OPTION> options;
    060
    061    /**
    062     * Create a UnicodeUnescaper.
    063     *
    064     * The constructor takes a list of options, only one type of which is currently
    065     * available (whether to allow, error or ignore the semicolon on the end of a
    066     * numeric entity to being missing).
    067     *
    068     * For example, to support numeric entities without a ';':
    069     *    new NumericEntityUnescaper(NumericEntityUnescaper.OPTION.semiColonOptional)
    070     * and to throw an IllegalArgumentException when they're missing:
    071     *    new NumericEntityUnescaper(NumericEntityUnescaper.OPTION.errorIfNoSemiColon)
    072     *
    073     * Note that the default behavior is to ignore them.
    074     *
    075     * @param options to apply to this unescaper
    076     */
    077    public NumericEntityUnescaper(final OPTION... options) {
    078        if (options.length > 0) {
    079            this.options = EnumSet.copyOf(Arrays.asList(options));
    080        } else {
    081            this.options = EnumSet.copyOf(Collections.singletonList(OPTION.semiColonRequired));
    082        }
    083    }
    084
    085    /**
    086     * Whether the passed in option is currently set.
    087     *
    088     * @param option to check state of
    089     * @return whether the option is set
    090     */
    091    public boolean isSet(final OPTION option) {
    092        return options != null && options.contains(option);
    093    }
    094
    095    /**
    096     * {@inheritDoc}
    097     */
    098    @Override
    099    public int translate(final CharSequence input, final int index, final Writer out) throws IOException {
    100        final int seqEnd = input.length();
    101        // Uses -2 to ensure there is something after the &#
    102        if (input.charAt(index) == '&' && index < seqEnd - 2 && input.charAt(index + 1) == '#') {
    103            int start = index + 2;
    104            boolean isHex = false;
    105
    106            final char firstChar = input.charAt(start);
    107            if (firstChar == 'x' || firstChar == 'X') {
    108                start++;
    109                isHex = true;
    110
    111                // Check there's more than just an x after the &#
    112                if (start == seqEnd) {
    113                    return 0;
    114                }
    115            }
    116
    117            int end = start;
    118            // Note that this supports character codes without a ; on the end
    119            while (end < seqEnd && ( input.charAt(end) >= '0' && input.charAt(end) <= '9' ||
    120                                    input.charAt(end) >= 'a' && input.charAt(end) <= 'f' ||
    121                                    input.charAt(end) >= 'A' && input.charAt(end) <= 'F' ) ) {
    122                end++;
    123            }
    124
    125            final boolean semiNext = end != seqEnd && input.charAt(end) == ';';
    126
    127            if (!semiNext) {
    128                if (isSet(OPTION.semiColonRequired)) {
    129                    return 0;
    130                } else
    131                if (isSet(OPTION.errorIfNoSemiColon)) {
    132                    throw new IllegalArgumentException("Semi-colon required at end of numeric entity");
    133                }
    134            }
    135
    136            final int entityValue;
    137            try {
    138                if (isHex) {
    139                    entityValue = Integer.parseInt(input.subSequence(start, end).toString(), 16);
    140                } else {
    141                    entityValue = Integer.parseInt(input.subSequence(start, end).toString(), 10);
    142                }
    143            } catch(final NumberFormatException nfe) {
    144                return 0;
    145            }
    146
    147            if (entityValue > 0xFFFF) {
    148                final char[] chars = Character.toChars(entityValue);
    149                out.write(chars[0]);
    150                out.write(chars[1]);
    151            } else {
    152                out.write(entityValue);
    153            }
    154
    155            return 2 + end - start + (isHex ? 1 : 0) + (semiNext ? 1 : 0);
    156        }
    157        return 0;
    158    }
    159}