/*

   Derby - Class org.apache.derby.client.net.EbcdicCcsidManager

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

*/

package org.apache.derby.client.net;

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import org.apache.derby.client.am.Agent;
import org.apache.derby.client.am.SqlException;
import org.apache.derby.client.am.ClientMessageId;
import org.apache.derby.shared.common.reference.SQLState;

/**
 * A concrete implementation of a CcsidMgr used to convert between Java UCS2 and Ebcdic as needed to handle character
 * DDM Parameters.  This implementation only supports converting from the ASCII invariant of UNICODE to Ebcdic.  This
 * should be fine since this class is intended for converting DDM Parameter data only.
 */
class EbcdicCcsidManager extends CcsidManager {

    private static final int[] conversionArrayToEbcdic = {
        0x0000, 0x0001, 0x0002, 0x0003, 0x0037, 0x002d, 0x002e, 0x002f
        , 0x0016, 0x0005, 0x0025, 0x000b, 0x000c, 0x000d, 0x000e, 0x000f
        , 0x0010, 0x0011, 0x0012, 0x0013, 0x003c, 0x003d, 0x0032, 0x0026
        , 0x0018, 0x0019, 0x003f, 0x0027, 0x001c, 0x001d, 0x001e, 0x001f
        , 0x0040, 0x004f, 0x007f, 0x007b, 0x005b, 0x006c, 0x0050, 0x007d
        , 0x004d, 0x005d, 0x005c, 0x004e, 0x006b, 0x0060, 0x004b, 0x0061
        , 0x00f0, 0x00f1, 0x00f2, 0x00f3, 0x00f4, 0x00f5, 0x00f6, 0x00f7
        , 0x00f8, 0x00f9, 0x007a, 0x005e, 0x004c, 0x007e, 0x006e, 0x006f
        , 0x007c, 0x00c1, 0x00c2, 0x00c3, 0x00c4, 0x00c5, 0x00c6, 0x00c7
        , 0x00c8, 0x00c9, 0x00d1, 0x00d2, 0x00d3, 0x00d4, 0x00d5, 0x00d6
        , 0x00d7, 0x00d8, 0x00d9, 0x00e2, 0x00e3, 0x00e4, 0x00e5, 0x00e6
        , 0x00e7, 0x00e8, 0x00e9, 0x004a, 0x00e0, 0x005a, 0x005f, 0x006d
        , 0x0079, 0x0081, 0x0082, 0x0083, 0x0084, 0x0085, 0x0086, 0x0087
        , 0x0088, 0x0089, 0x0091, 0x0092, 0x0093, 0x0094, 0x0095, 0x0096
        , 0x0097, 0x0098, 0x0099, 0x00a2, 0x00a3, 0x00a4, 0x00a5, 0x00a6
        , 0x00a7, 0x00a8, 0x00a9, 0x00c0, 0x00bb, 0x00d0, 0x00a1, 0x0007
        , 0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0015, 0x0006, 0x0017
        , 0x0028, 0x0029, 0x002a, 0x002b, 0x002c, 0x0009, 0x000a, 0x001b
        , 0x0030, 0x0031, 0x001a, 0x0033, 0x0034, 0x0035, 0x0036, 0x0008
        , 0x0038, 0x0039, 0x003a, 0x003b, 0x0004, 0x0014, 0x003e, 0x00ff
        , 0x0041, 0x00aa, 0x00b0, 0x00b1, 0x009f, 0x00b2, 0x006a, 0x00b5
        , 0x00bd, 0x00b4, 0x009a, 0x008a, 0x00ba, 0x00ca, 0x00af, 0x00bc
        , 0x0090, 0x008f, 0x00ea, 0x00fa, 0x00be, 0x00a0, 0x00b6, 0x00b3
        , 0x009d, 0x00da, 0x009b, 0x008b, 0x00b7, 0x00b8, 0x00b9, 0x00ab
        , 0x0064, 0x0065, 0x0062, 0x0066, 0x0063, 0x0067, 0x009e, 0x0068
        , 0x0074, 0x0071, 0x0072, 0x0073, 0x0078, 0x0075, 0x0076, 0x0077
        , 0x00ac, 0x0069, 0x00ed, 0x00ee, 0x00eb, 0x00ef, 0x00ec, 0x00bf
        , 0x0080, 0x00fd, 0x00fe, 0x00fb, 0x00fc, 0x00ad, 0x00ae, 0x0059
        , 0x0044, 0x0045, 0x0042, 0x0046, 0x0043, 0x0047, 0x009c, 0x0048
        , 0x0054, 0x0051, 0x0052, 0x0053, 0x0058, 0x0055, 0x0056, 0x0057
        , 0x008c, 0x0049, 0x00cd, 0x00ce, 0x00cb, 0x00cf, 0x00cc, 0x00e1
        , 0x0070, 0x00dd, 0x00de, 0x00db, 0x00dc, 0x008d, 0x008e, 0x00df
    };

    private static final int[] conversionArrayToUCS2 = {
        0x0000, 0x0001, 0x0002, 0x0003, 0x009C, 0x0009, 0x0086, 0x007F
        , 0x0097, 0x008D, 0x008E, 0x000B, 0x000C, 0x000D, 0x000E, 0x000F
        , 0x0010, 0x0011, 0x0012, 0x0013, 0x009D, 0x0085, 0x0008, 0x0087
        , 0x0018, 0x0019, 0x0092, 0x008F, 0x001C, 0x001D, 0x001E, 0x001F
        , 0x0080, 0x0081, 0x0082, 0x0083, 0x0084, 0x000A, 0x0017, 0x001B
        , 0x0088, 0x0089, 0x008A, 0x008B, 0x008C, 0x0005, 0x0006, 0x0007
        , 0x0090, 0x0091, 0x0016, 0x0093, 0x0094, 0x0095, 0x0096, 0x0004
        , 0x0098, 0x0099, 0x009A, 0x009B, 0x0014, 0x0015, 0x009E, 0x001A
        , 0x0020, 0x00A0, 0x00E2, 0x00E4, 0x00E0, 0x00E1, 0x00E3, 0x00E5
        , 0x00E7, 0x00F1, 0x005B, 0x002E, 0x003C, 0x0028, 0x002B, 0x0021
        , 0x0026, 0x00E9, 0x00EA, 0x00EB, 0x00E8, 0x00ED, 0x00EE, 0x00EF
        , 0x00EC, 0x00DF, 0x005D, 0x0024, 0x002A, 0x0029, 0x003B, 0x005E
        , 0x002D, 0x002F, 0x00C2, 0x00C4, 0x00C0, 0x00C1, 0x00C3, 0x00C5
        , 0x00C7, 0x00D1, 0x00A6, 0x002C, 0x0025, 0x005F, 0x003E, 0x003F
        , 0x00F8, 0x00C9, 0x00CA, 0x00CB, 0x00C8, 0x00CD, 0x00CE, 0x00CF
        , 0x00CC, 0x0060, 0x003A, 0x0023, 0x0040, 0x0027, 0x003D, 0x0022
        , 0x00D8, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067
        , 0x0068, 0x0069, 0x00AB, 0x00BB, 0x00F0, 0x00FD, 0x00FE, 0x00B1
        , 0x00B0, 0x006A, 0x006B, 0x006C, 0x006D, 0x006E, 0x006F, 0x0070
        , 0x0071, 0x0072, 0x00AA, 0x00BA, 0x00E6, 0x00B8, 0x00C6, 0x00A4
        , 0x00B5, 0x007E, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077, 0x0078
        , 0x0079, 0x007A, 0x00A1, 0x00BF, 0x00D0, 0x00DD, 0x00DE, 0x00AE
        , 0x00A2, 0x00A3, 0x00A5, 0x00B7, 0x00A9, 0x00A7, 0x00B6, 0x00BC
        , 0x00BD, 0x00BE, 0x00AC, 0x007C, 0x00AF, 0x00A8, 0x00B4, 0x00D7
        , 0x007B, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047
        , 0x0048, 0x0049, 0x00AD, 0x00F4, 0x00F6, 0x00F2, 0x00F3, 0x00F5
        , 0x007D, 0x004A, 0x004B, 0x004C, 0x004D, 0x004E, 0x004F, 0x0050
        , 0x0051, 0x0052, 0x00B9, 0x00FB, 0x00FC, 0x00F9, 0x00FA, 0x00FF
        , 0x005C, 0x00F7, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057, 0x0058
        , 0x0059, 0x005A, 0x00B2, 0x00D4, 0x00D6, 0x00D2, 0x00D3, 0x00D5
        , 0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037
        , 0x0038, 0x0039, 0x00B3, 0x00DB, 0x00DC, 0x00D9, 0x00DA, 0x009F
    };

    public EbcdicCcsidManager() {
        super((byte) 0x40, // 0x40 is the ebcdic space character
                (byte) 0x4B,
                new byte[]{//02132002jev begin
                    //     '0',       '1',       '2',       '3',      '4',
                    (byte) 0xf0, (byte) 0xf1, (byte) 0xf2, (byte) 0xf3, (byte) 0xf4,
                    //     '5',       '6',       '7',       '8',      '9',
                    (byte) 0xf5, (byte) 0xf6, (byte) 0xf7, (byte) 0xf8, (byte) 0xf9,
                    //     'A',       'B',       'C',       'D',      'E',
                    (byte) 0xc1, (byte) 0xc2, (byte) 0xc3, (byte) 0xc4, (byte) 0xc5,
                    //      'F'
                    (byte) 0xc6},
                new byte[]{
                    //     'G',       'H',       'I',       'J',      'K',
                    (byte) 0xc7, (byte) 0xc8, (byte) 0xc9, (byte) 0xd1, (byte) 0xd2,
                    //     'L',       'M',       'N',       '0',      'P',
                    (byte) 0xd3, (byte) 0xd4, (byte) 0xd5, (byte) 0xd6, (byte) 0xd7,
                    //     'A',       'B',       'C',       'D',      'E',
                    (byte) 0xc1, (byte) 0xc2, (byte) 0xc3, (byte) 0xc4, (byte) 0xc5,
                    //      'F'
                    (byte) 0xc6}                     //02132002jev end
        );
    }

    public byte[] convertFromJavaString(String sourceString, Agent agent)
            throws SqlException {
        CharBuffer src = CharBuffer.wrap(sourceString);
        ByteBuffer dest = ByteBuffer.allocate(sourceString.length());
        startEncoding();
        encode(src, dest, agent);
        return dest.array();
    }

    public void startEncoding() {
        // We don't have a CharsetEncoder instance to reset, or any other
        // internal state associated with earlier encode() calls. Do nothing.
    }

    public boolean encode(CharBuffer src, ByteBuffer dest, Agent agent)
            throws SqlException {
        // Encode as many characters as the destination buffer can hold.
        int charsToEncode = Math.min(src.remaining(), dest.remaining());
        for (int i = 0; i < charsToEncode; i++) {
            char c = src.get();
            if (c > 0xff) {
                throw new SqlException(agent.logWriter_,
                    new ClientMessageId(
                        SQLState.CANT_CONVERT_UNICODE_TO_EBCDIC));
            } else {
                dest.put((byte) conversionArrayToEbcdic[c]);
            }
        }

        if (src.remaining() == 0) {
            // All characters have been encoded. We're done.
            return true;
        } else {
            // We still have more characters to encode, but no room in
            // destination buffer.
            return false;
        }
    }

    String convertToJavaString(byte[] sourceBytes, int offset, int numToConvert) {
        int i = 0, j = 0;
        char[] theChars = new char[numToConvert];
        int num = 0;

        for (i = offset; i < (offset + numToConvert); i++) {
            num = (sourceBytes[i] < 0) ? (sourceBytes[i] + 256) : sourceBytes[i];
            theChars[j] = (char) conversionArrayToUCS2[num];
            j++;
        }
        return new String(theChars);
    }
}
