/*

 * JBoss, Home of Professional Open Source

 * Copyright 2011, Red Hat, Inc. and individual contributors

 * by the @authors tag. See the copyright.txt in the distribution for a

 * full listing of individual contributors.

 *

 * This 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 2.1 of

 * the License, or (at your option) any later version.

 *

 * This software 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this software; if not, write to the Free

 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA

 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.

 */



package org.mobicents.protocols.ss7.map.primitives;



import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;



import org.mobicents.protocols.ss7.map.api.MAPException;

import org.mobicents.protocols.ss7.map.api.MAPParsingComponentException;

import org.mobicents.protocols.ss7.map.api.MAPParsingComponentExceptionReason;



/**

 * 

 * @author amit bhayani

 * @author sergey vetyutnev

 * 

 */

public abstract class TbcdString implements MAPAsnPrimitive {



	protected static int DIGIT_1_MASK = 0x0F;

	protected static int DIGIT_2_MASK = 0xF0;



	public static String decodeString(InputStream ansIS, int length) throws IOException, MAPParsingComponentException {

		StringBuilder s = new StringBuilder();

		for (int i1 = 0; i1 < length; i1++) {

			int b = ansIS.read();



			int digit1 = (b & DIGIT_1_MASK);

			if (digit1 == 15) {

				// this is mask

			} else {

				s.append(decodeNumber(digit1));

			}



			int digit2 = ((b & DIGIT_2_MASK) >> 4);

			if (digit2 == 15) {

				// this is mask

			} else {

				s.append(decodeNumber(digit2));

			}

		}



		return s.toString();

	}



	public static void encodeString(OutputStream asnOs, String data) throws MAPException {

		char[] chars = data.toCharArray();

		for (int i = 0; i < chars.length; i = i + 2) {

			char a = chars[i];



			int digit1 = encodeNumber(a);

			int digit2;

			if ((i + 1) == chars.length) {

				// add the filler instead

				digit2 = 15;

			} else {

				char b = chars[i + 1];

				digit2 = encodeNumber(b);

			}



			int digit = (digit2 << 4) | digit1;



			try {

				asnOs.write(digit);

			} catch (IOException e) {

				throw new MAPException("Error when encoding TbcdString: " + e.getMessage(), e);

			}

		}

		

	}

	

	protected static int encodeNumber(char c) throws MAPException {

		switch (c) {

		case '0':

			return 0;

		case '1':

			return 1;

		case '2':

			return 2;

		case '3':

			return 3;

		case '4':

			return 4;

		case '5':

			return 5;

		case '6':

			return 6;

		case '7':

			return 7;

		case '8':

			return 8;

		case '9':

			return 9;

		case '*':

			return 10;

		case '#':

			return 11;

		case 'a':

			return 12;

		case 'b':

			return 13;

		case 'c':

			return 14;

		default:

			throw new MAPException(

					"char should be between 0 - 9, *, #, a, b, c for Telephony Binary Coded Decimal String. Received "

							+ c);



		}

	}



	protected static char decodeNumber(int i) throws MAPParsingComponentException {

		switch (i) {

		case 0:

			return '0';

		case 1:

			return '1';

		case 2:

			return '2';

		case 3:

			return '3';

		case 4:

			return '4';

		case 5:

			return '5';

		case 6:

			return '6';

		case 7:

			return '7';

		case 8:

			return '8';

		case 9:

			return '9';

		case 10:

			return '*';

		case 11:

			return '#';

		case 12:

			return 'a';

		case 13:

			return 'b';

		case 14:

			return 'c';

			// case 15:

			// return 'd';

		default:

			throw new MAPParsingComponentException(

					"Integer should be between 0 - 15 for Telephony Binary Coded Decimal String. Received "

							+ i, MAPParsingComponentExceptionReason.MistypedParameter);



		}

	}

}