/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.jss.asn1;

import java.io.CharConversionException;

/**
 * The ASN.1 type <i>TeletexString</i>.
 */
public class TeletexString extends CharacterString implements ASN1Value {

    public static final Tag TAG = new Tag(Tag.UNIVERSAL, 20);

    @Override
    public Tag getTag() {
        return TAG;
    }

    public TeletexString(char[] chars) throws CharConversionException {
        super(chars);
    }

    public TeletexString(String s) throws CharConversionException {
        super(s);
    }

    @Override
    CharConverter getCharConverter() {
        return new TeletexConverter();
    }

    /**
     * Returns a singleton instance of the decoding template for this class.
     * 
     * @return Template.
     */
    public static Template getTemplate() {
        return templateInstance;
    }

    private static final Template templateInstance = new Template();

    // nested class
    public static class Template
            extends CharacterString.Template implements ASN1Template {

        @Override
        protected Tag getTag() {
            return TAG;
        }

        @Override
        public boolean tagMatch(Tag tag) {
            return TAG.equals(tag);
        }

        @Override
        protected CharConverter getCharConverter() {
            return new TeletexConverter();
        }

        @Override
        protected CharacterString generateInstance(char[] bytes)
                throws CharConversionException {
            return new TeletexString(bytes);
        }

        @Override
        protected String typeName() {
            return "TeletexString";
        }
    } // end of Template

    private static class TeletexConverter implements CharConverter {

        @Override
        public char[] byteToChar(byte[] bytes, int offset, int len)
                throws CharConversionException {
            char[] chars = new char[len];

            int b;
            int c;
            for (b = offset, c = 0; c < len; b++, c++) {
                chars[c] = (char) (bytes[b] & 0xff);
            }
            return chars;
        }

        @Override
        public byte[] charToByte(char[] chars, int offset, int len)
                throws CharConversionException {
            byte[] bytes = new byte[len];

            int b;
            int c;
            for (b = 0, c = offset; b < len; b++, c++) {
                if ((chars[c] & 0xff00) != 0) {
                    throw new CharConversionException("Invalid character for" +
                            " TeletexString");
                }
                bytes[b] = (byte) (chars[c] & 0xff);
            }
            return bytes;
        }
    }
}
