/*
 * Copyright (c) 2017, Andreas Fagschlunger. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package at.o2xfs.emv.util;

import at.o2xfs.common.Bytes;

public final class CompressedNumeric {

	private static final int PAD = 0x0F;

	private static final char[] NUMS = new char[] { '0', '1', '2', '3', '4',
			'5', '6', '7', '8', '9' };

	private CompressedNumeric() {
		throw new AssertionError();
	}

	public final static String toString(byte[] cn) {
		char[] value = new char[cn.length * 2];
		int count = 0;
		for (byte b : cn) {
			int hiNibble = Bytes.toInt(b) >>> 4;
			if (hiNibble == PAD) {
				break;
			}
			value[count++] = NUMS[hiNibble];
			int loNibble = b & PAD;
			if (loNibble == PAD) {
				break;
			}
			value[count++] = NUMS[loNibble];
		}
		return new String(value, 0, count);
	}
}