org.novelang.build.unicode.UnicodeNamesTextReader.java Source code

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Here is the source code for org.novelang.build.unicode.UnicodeNamesTextReader.java

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/*
 * Copyright (C) 2011 Laurent Caillette
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.novelang.build.unicode;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Reads Unicode character names from a property file {@value #RESOURCE_NAME}.
 * The file may contain duplicate keys.
 *
 * @author Laurent Caillette
 */
/*package*/ class UnicodeNamesTextReader {

    private static final Logger LOGGER = LoggerFactory.getLogger(UnicodeNamesTextReader.class);

    /**
     * <a href="http://www.unicode.org/Public/5.2.0/ucd/UnicodeData.txt" >Unicode 5.2</a>
     */
    private static final String RESOURCE_NAME = "UnicodeData.txt";

    private static final String DESCRIPTOR_TEXT = "(?:\\w| |-|/|,|<|>|\\(|\\))*";
    private static final String IGNORED_DESCRIPTOR = "(?:" + DESCRIPTOR_TEXT + ";)";
    private static final String USEFUL_DESCRIPTOR = "(" + DESCRIPTOR_TEXT + ");";

    private static final Pattern PROPERTY_LINE_PATTERN = Pattern.compile("(\\w{4});" + USEFUL_DESCRIPTOR
            + IGNORED_DESCRIPTOR + "{8}" + USEFUL_DESCRIPTOR + IGNORED_DESCRIPTOR + "{3}" + "(?:\\w*)");

    static {
        LOGGER.debug("Crafted regex: " + PROPERTY_LINE_PATTERN.pattern());
    }

    private static String readProperties() throws IOException {

        final URL resource = UnicodeNamesTextReader.class.getResource(RESOURCE_NAME);
        LOGGER.info("Reading " + resource.toExternalForm());
        final InputStream inputStream = resource.openStream();
        return IOUtils.toString(inputStream);
    }

    public Map<Character, String> loadNames() throws IOException {
        return extractNames(readProperties());
    }

    /*package*/ Map<Character, String> extractNames(final String names) throws IOException {
        final Map<Character, String> characterToNameMap = Maps.newHashMapWithExpectedSize(256 * 256);
        final Matcher matcher = PROPERTY_LINE_PATTERN.matcher(names);
        int limiter = 0;

        while (matcher.find() /*&& limiter < 150*/ ) {
            final String code = matcher.group(1);
            if (code.length() == 4) {
                final String name;
                final String casualName = matcher.group(2);
                if ("<control>".equals(casualName)) {
                    final String controlName = matcher.group(3);
                    name = controlName;
                } else {
                    name = casualName;
                }

                final int codeAsInt = Integer.parseInt(code, 16); // Be confident!
                final Character character = (char) codeAsInt;
                final String existing = characterToNameMap.get(character);
                if (existing == null && !"".equals(name)) {
                    // Retain first definition, seems that most interesting appear first.
                    characterToNameMap.put(character, name);
                    //          LOG.info( "Added " + ( ( int ) character ) + " as '" + name + "'" +
                    //                  ( character != limiter ? " OOOPS!" : "" )
                    //          ) ;
                }
            }
            limiter++;
        }
        return ImmutableMap.copyOf(characterToNameMap);
    }

}