/*
 * JISConvert.cs - Implementation of the "System.Text.JISConvert" class.
 *
 * Copyright (c) 2002  Southern Storm Software, Pty Ltd
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

namespace C1.C1Zip
{
    using System;

    // This class assists other encoding classes in converting back
    // and forth between JIS character sets and Unicode.  It uses
    // several large tables to do this, some of which are stored in
    // the resource section of the assembly for efficient access.
    internal sealed class JISConvert
    {
        // Table identifiers.
        private const int JISX0208_To_Unicode = 1;
        private const int JISX0212_To_Unicode = 2;
        private const int CJK_To_JIS = 3;
        private const int Greek_To_JIS = 4;
        private const int Extra_To_JIS = 5;

        // Public access to the conversion tables.
        public byte[] jisx0208ToUnicode;
        public byte[] jisx0212ToUnicode;
        public byte[] cjkToJis;
        public byte[] greekToJis;
        public byte[] extraToJis;

        // Constructor.
        private JISConvert()
        {
            // Load the conversion tables.
            CodeTable table = new CodeTable("jis.table");
            jisx0208ToUnicode = table.GetSection(JISX0208_To_Unicode);
            jisx0212ToUnicode = table.GetSection(JISX0212_To_Unicode);
            cjkToJis = table.GetSection(CJK_To_JIS);
            greekToJis = table.GetSection(Greek_To_JIS);
            extraToJis = table.GetSection(Extra_To_JIS);
            table.Dispose();
        }

        // The one and only JIS conversion object in the system.
        private static JISConvert convert;
        static readonly object lockobj = new object();
        // Get the primary JIS conversion object.
        public static JISConvert Convert
        {
            get
            {
                lock (lockobj)
                {
                    if (convert != null)
                    {
                        return convert;
                    }
                    else
                    {
                        convert = new JISConvert();
                        return convert;
                    }
                }
            }
        }
    }
}
