/*
 *  Java HTML Tidy - JTidy
 *  HTML parser and pretty printer
 *
 *  Copyright (c) 1998-2000 World Wide Web Consortium (Massachusetts
 *  Institute of Technology, Institut National de Recherche en
 *  Informatique et en Automatique, Keio University). All Rights
 *  Reserved.
 *
 *  Contributing Author(s):
 *
 *     Dave Raggett <dsr@w3.org>
 *     Andy Quick <ac.quick@sympatico.ca> (translation to Java)
 *     Gary L Peskin <garyp@firstech.com> (Java development)
 *     Sami Lempinen <sami@lempinen.net> (release management)
 *     Fabrizio Giustina <fgiust at users.sourceforge.net>
 *
 *  The contributing author(s) would like to thank all those who
 *  helped with testing, bug fixes, and patience.  This wouldn't
 *  have been possible without all of you.
 *
 *  COPYRIGHT NOTICE:
 * 
 *  This software and documentation is provided "as is," and
 *  the copyright holders and contributing author(s) make no
 *  representations or warranties, express or implied, including
 *  but not limited to, warranties of merchantability or fitness
 *  for any particular purpose or that the use of the software or
 *  documentation will not infringe any third party patents,
 *  copyrights, trademarks or other rights. 
 *
 *  The copyright holders and contributing author(s) will not be
 *  liable for any direct, indirect, special or consequential damages
 *  arising out of any use of the software or documentation, even if
 *  advised of the possibility of such damage.
 *
 *  Permission is hereby granted to use, copy, modify, and distribute
 *  this source code, or portions hereof, documentation and executables,
 *  for any purpose, without fee, subject to the following restrictions:
 *
 *  1. The origin of this source code must not be misrepresented.
 *  2. Altered versions must be plainly marked as such and must
 *     not be misrepresented as being the original source.
 *  3. This Copyright notice may not be removed or altered from any
 *     source or altered source distribution.
 * 
 *  The copyright holders and contributing author(s) specifically
 *  permit, without fee, and encourage the use of this source code
 *  as a component for supporting the Hypertext Markup Language in
 *  commercial products. If you use this source code in a product,
 *  acknowledgment is not required but would be appreciated.
 *
 */
package org.w3c.tidy;

import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;


/**
 * Entity hash table.
 * @author Dave Raggett <a href="mailto:dsr@w3.org">dsr@w3.org </a>
 * @author Andy Quick <a href="mailto:ac.quick@sympatico.ca">ac.quick@sympatico.ca </a> (translation to Java)
 * @author Fabrizio Giustina
 * @version $Revision: 1.1 $ ($Author: thorben $)
 */
public final class EntityTable
{

    /**
     * the default entity table.
     */
    private static EntityTable defaultEntityTable;

    /**
     * Known entities.
     */
    private static Entity[] entities = {
        new Entity("nbsp", 160),
        new Entity("iexcl", 161),
        new Entity("cent", 162),
        new Entity("pound", 163),
        new Entity("curren", 164),
        new Entity("yen", 165),
        new Entity("brvbar", 166),
        new Entity("sect", 167),
        new Entity("uml", 168),
        new Entity("copy", 169),
        new Entity("ordf", 170),
        new Entity("laquo", 171),
        new Entity("not", 172),
        new Entity("shy", 173),
        new Entity("reg", 174),
        new Entity("macr", 175),
        new Entity("deg", 176),
        new Entity("plusmn", 177),
        new Entity("sup2", 178),
        new Entity("sup3", 179),
        new Entity("acute", 180),
        new Entity("micro", 181),
        new Entity("para", 182),
        new Entity("middot", 183),
        new Entity("cedil", 184),
        new Entity("sup1", 185),
        new Entity("ordm", 186),
        new Entity("raquo", 187),
        new Entity("frac14", 188),
        new Entity("frac12", 189),
        new Entity("frac34", 190),
        new Entity("iquest", 191),
        new Entity("Agrave", 192),
        new Entity("Aacute", 193),
        new Entity("Acirc", 194),
        new Entity("Atilde", 195),
        new Entity("Auml", 196),
        new Entity("Aring", 197),
        new Entity("AElig", 198),
        new Entity("Ccedil", 199),
        new Entity("Egrave", 200),
        new Entity("Eacute", 201),
        new Entity("Ecirc", 202),
        new Entity("Euml", 203),
        new Entity("Igrave", 204),
        new Entity("Iacute", 205),
        new Entity("Icirc", 206),
        new Entity("Iuml", 207),
        new Entity("ETH", 208),
        new Entity("Ntilde", 209),
        new Entity("Ograve", 210),
        new Entity("Oacute", 211),
        new Entity("Ocirc", 212),
        new Entity("Otilde", 213),
        new Entity("Ouml", 214),
        new Entity("times", 215),
        new Entity("Oslash", 216),
        new Entity("Ugrave", 217),
        new Entity("Uacute", 218),
        new Entity("Ucirc", 219),
        new Entity("Uuml", 220),
        new Entity("Yacute", 221),
        new Entity("THORN", 222),
        new Entity("szlig", 223),
        new Entity("agrave", 224),
        new Entity("aacute", 225),
        new Entity("acirc", 226),
        new Entity("atilde", 227),
        new Entity("auml", 228),
        new Entity("aring", 229),
        new Entity("aelig", 230),
        new Entity("ccedil", 231),
        new Entity("egrave", 232),
        new Entity("eacute", 233),
        new Entity("ecirc", 234),
        new Entity("euml", 235),
        new Entity("igrave", 236),
        new Entity("iacute", 237),
        new Entity("icirc", 238),
        new Entity("iuml", 239),
        new Entity("eth", 240),
        new Entity("ntilde", 241),
        new Entity("ograve", 242),
        new Entity("oacute", 243),
        new Entity("ocirc", 244),
        new Entity("otilde", 245),
        new Entity("ouml", 246),
        new Entity("divide", 247),
        new Entity("oslash", 248),
        new Entity("ugrave", 249),
        new Entity("uacute", 250),
        new Entity("ucirc", 251),
        new Entity("uuml", 252),
        new Entity("yacute", 253),
        new Entity("thorn", 254),
        new Entity("yuml", 255),
        new Entity("fnof", 402),
        new Entity("Alpha", 913),
        new Entity("Beta", 914),
        new Entity("Gamma", 915),
        new Entity("Delta", 916),
        new Entity("Epsilon", 917),
        new Entity("Zeta", 918),
        new Entity("Eta", 919),
        new Entity("Theta", 920),
        new Entity("Iota", 921),
        new Entity("Kappa", 922),
        new Entity("Lambda", 923),
        new Entity("Mu", 924),
        new Entity("Nu", 925),
        new Entity("Xi", 926),
        new Entity("Omicron", 927),
        new Entity("Pi", 928),
        new Entity("Rho", 929),
        new Entity("Sigma", 931),
        new Entity("Tau", 932),
        new Entity("Upsilon", 933),
        new Entity("Phi", 934),
        new Entity("Chi", 935),
        new Entity("Psi", 936),
        new Entity("Omega", 937),
        new Entity("alpha", 945),
        new Entity("beta", 946),
        new Entity("gamma", 947),
        new Entity("delta", 948),
        new Entity("epsilon", 949),
        new Entity("zeta", 950),
        new Entity("eta", 951),
        new Entity("theta", 952),
        new Entity("iota", 953),
        new Entity("kappa", 954),
        new Entity("lambda", 955),
        new Entity("mu", 956),
        new Entity("nu", 957),
        new Entity("xi", 958),
        new Entity("omicron", 959),
        new Entity("pi", 960),
        new Entity("rho", 961),
        new Entity("sigmaf", 962),
        new Entity("sigma", 963),
        new Entity("tau", 964),
        new Entity("upsilon", 965),
        new Entity("phi", 966),
        new Entity("chi", 967),
        new Entity("psi", 968),
        new Entity("omega", 969),
        new Entity("thetasym", 977),
        new Entity("upsih", 978),
        new Entity("piv", 982),
        new Entity("bull", 8226),
        new Entity("hellip", 8230),
        new Entity("prime", 8242),
        new Entity("Prime", 8243),
        new Entity("oline", 8254),
        new Entity("frasl", 8260),
        new Entity("weierp", 8472),
        new Entity("image", 8465),
        new Entity("real", 8476),
        new Entity("trade", 8482),
        new Entity("alefsym", 8501),
        new Entity("larr", 8592),
        new Entity("uarr", 8593),
        new Entity("rarr", 8594),
        new Entity("darr", 8595),
        new Entity("harr", 8596),
        new Entity("crarr", 8629),
        new Entity("lArr", 8656),
        new Entity("uArr", 8657),
        new Entity("rArr", 8658),
        new Entity("dArr", 8659),
        new Entity("hArr", 8660),
        new Entity("forall", 8704),
        new Entity("part", 8706),
        new Entity("exist", 8707),
        new Entity("empty", 8709),
        new Entity("nabla", 8711),
        new Entity("isin", 8712),
        new Entity("notin", 8713),
        new Entity("ni", 8715),
        new Entity("prod", 8719),
        new Entity("sum", 8721),
        new Entity("minus", 8722),
        new Entity("lowast", 8727),
        new Entity("radic", 8730),
        new Entity("prop", 8733),
        new Entity("infin", 8734),
        new Entity("ang", 8736),
        new Entity("and", 8743),
        new Entity("or", 8744),
        new Entity("cap", 8745),
        new Entity("cup", 8746),
        new Entity("int", 8747),
        new Entity("there4", 8756),
        new Entity("sim", 8764),
        new Entity("cong", 8773),
        new Entity("asymp", 8776),
        new Entity("ne", 8800),
        new Entity("equiv", 8801),
        new Entity("le", 8804),
        new Entity("ge", 8805),
        new Entity("sub", 8834),
        new Entity("sup", 8835),
        new Entity("nsub", 8836),
        new Entity("sube", 8838),
        new Entity("supe", 8839),
        new Entity("oplus", 8853),
        new Entity("otimes", 8855),
        new Entity("perp", 8869),
        new Entity("sdot", 8901),
        new Entity("lceil", 8968),
        new Entity("rceil", 8969),
        new Entity("lfloor", 8970),
        new Entity("rfloor", 8971),
        new Entity("lang", 9001),
        new Entity("rang", 9002),
        new Entity("loz", 9674),
        new Entity("spades", 9824),
        new Entity("clubs", 9827),
        new Entity("hearts", 9829),
        new Entity("diams", 9830),
        new Entity("quot", 34),
        new Entity("amp", 38),
        new Entity("lt", 60),
        new Entity("gt", 62),
        new Entity("OElig", 338),
        new Entity("oelig", 339),
        new Entity("Scaron", 352),
        new Entity("scaron", 353),
        new Entity("Yuml", 376),
        new Entity("circ", 710),
        new Entity("tilde", 732),
        new Entity("ensp", 8194),
        new Entity("emsp", 8195),
        new Entity("thinsp", 8201),
        new Entity("zwnj", 8204),
        new Entity("zwj", 8205),
        new Entity("lrm", 8206),
        new Entity("rlm", 8207),
        new Entity("ndash", 8211),
        new Entity("mdash", 8212),
        new Entity("lsquo", 8216),
        new Entity("rsquo", 8217),
        new Entity("sbquo", 8218),
        new Entity("ldquo", 8220),
        new Entity("rdquo", 8221),
        new Entity("bdquo", 8222),
        new Entity("dagger", 8224),
        new Entity("Dagger", 8225),
        new Entity("permil", 8240),
        new Entity("lsaquo", 8249),
        new Entity("rsaquo", 8250),
        new Entity("euro", 8364)};

    /**
     * Entity map.
     */
    private Map entityHashtable = new Hashtable();

    /**
     * use getDefaultEntityTable to get an entity table instance.
     */
    private EntityTable()
    {
        super();
    }

    /**
     * installs an entity.
     * @param ent entity
     * @return installed Entity
     */
    private Entity install(Entity ent)
    {
        return (Entity) this.entityHashtable.put(ent.getName(), ent);
    }

    /**
     * Lookup an entity by its name.
     * @param name entity name
     * @return entity
     */
    public Entity lookup(String name)
    {
        return (Entity) this.entityHashtable.get(name);
    }

    /**
     * Returns the entity code for the given entity name.
     * @param name entity name
     * @return entity code or 0 for unknown entity names
     */
    public int entityCode(String name)
    {
        // entity starting with "&" returns zero on error.
        int c;

        if (name.length() <= 1)
        {
            return 0;
        }

        // numeric entitity: name = "&#" followed by number
        if (name.charAt(1) == '#')
        {
            c = 0; // zero on missing/bad number

            // 'x' prefix denotes hexadecimal number format
            try
            {
                if (name.length() >= 4 && name.charAt(2) == 'x')
                {
                    c = Integer.parseInt(name.substring(3), 16);
                }
                else if (name.length() >= 3)
                {
                    c = Integer.parseInt(name.substring(2));
                }
            }
            catch (NumberFormatException e)
            {
                // ignore
            }

            return c;
        }

        // Named entity: name ="&" followed by a name
        Entity ent = lookup(name.substring(1));
        if (ent != null)
        {
            return ent.getCode();
        }

        return 0; // zero signifies unknown entity name
    }

    /**
     * Returns the entity name for the given entity code.
     * @param code entity code
     * @return entity name or null for unknown entity codes
     */
    public String entityName(short code)
    {
        String name = null;
        Entity ent;
        Iterator en = this.entityHashtable.values().iterator();
        while (en.hasNext())
        {
            ent = (Entity) en.next();
            if (ent.getCode() == code)
            {
                name = ent.getName();
                break;
            }
        }
        return name;
    }

    /**
     * Returns the default entity table instance.
     * @return entity table instance
     */
    public static EntityTable getDefaultEntityTable()
    {
        if (defaultEntityTable == null)
        {
            defaultEntityTable = new EntityTable();
            for (int i = 0; i < entities.length; i++)
            {
                defaultEntityTable.install(entities[i]);
            }
        }
        return defaultEntityTable;
    }

}