Back to index...

	/*
	* Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code 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 General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package javax.smartcardio;

	import java.util.*;

	/**
	* A Smart Card's answer-to-reset bytes. A Card's ATR object can be obtained
	* by calling {@linkplain Card#getATR}.
	* This class does not attempt to verify that the ATR encodes a semantically
	* valid structure.
	*
	* <p>Instances of this class are immutable. Where data is passed in or out
	* via byte arrays, defensive cloning is performed.
	*
	* @see Card#getATR
	*
	* @since 1.6
	* @author Andreas Sterbenz
	* @author JSR 268 Expert Group
	*/
	public final class ATR implements java.io.Serializable {

	private static final long serialVersionUID = 6695383790847736493L;

	private byte[] atr;

	private transient int startHistorical, nHistorical;

	/**
	* Constructs an ATR from a byte array.
	*
	* @param atr the byte array containing the answer-to-reset bytes
	* @throws NullPointerException if <code>atr</code> is null
	*/
	public ATR(byte[] atr) {
	this.atr = atr.clone();
	parse();
	}

	private void parse() {
	if (atr.length < 2) {
	return;
	}
	if ((atr[0] != 0x3b) && (atr[0] != 0x3f)) {
	return;
	}
	int t0 = (atr[1] & 0xf0) >> 4;
	int n = atr[1] & 0xf;
	int i = 2;
	while ((t0 != 0) && (i < atr.length)) {
	if ((t0 & 1) != 0) {
	i++;
	}
	if ((t0 & 2) != 0) {
	i++;
	}
	if ((t0 & 4) != 0) {
	i++;
	}
	if ((t0 & 8) != 0) {
	if (i >= atr.length) {
	return;
	}
	t0 = (atr[i++] & 0xf0) >> 4;
	} else {
	t0 = 0;
	}
	}
	int k = i + n;
	if ((k == atr.length) \|\| (k == atr.length - 1)) {
	startHistorical = i;
	nHistorical = n;
	}
	}

	/**
	* Returns a copy of the bytes in this ATR.
	*
	* @return a copy of the bytes in this ATR.
	*/
	public byte[] getBytes() {
	return atr.clone();
	}

	/**
	* Returns a copy of the historical bytes in this ATR.
	* If this ATR does not contain historical bytes, an array of length
	* zero is returned.
	*
	* @return a copy of the historical bytes in this ATR.
	*/
	public byte[] getHistoricalBytes() {
	byte[] b = new byte[nHistorical];
	System.arraycopy(atr, startHistorical, b, 0, nHistorical);
	return b;
	}

	/**
	* Returns a string representation of this ATR.
	*
	* @return a String representation of this ATR.
	*/
	public String toString() {
	return "ATR: " + atr.length + " bytes";
	}

	/**
	* Compares the specified object with this ATR for equality.
	* Returns true if the given object is also an ATR and its bytes are
	* identical to the bytes in this ATR.
	*
	* @param obj the object to be compared for equality with this ATR
	* @return true if the specified object is equal to this ATR
	*/
	public boolean equals(Object obj) {
	if (this == obj) {
	return true;
	}
	if (obj instanceof ATR == false) {
	return false;
	}
	ATR other = (ATR)obj;
	return Arrays.equals(this.atr, other.atr);
	}

	/**
	* Returns the hash code value for this ATR.
	*
	* @return the hash code value for this ATR.
	*/
	public int hashCode() {
	return Arrays.hashCode(atr);
	}

	private void readObject(java.io.ObjectInputStream in)
	throws java.io.IOException, ClassNotFoundException {
	atr = (byte[])in.readUnshared();
	parse();
	}

	}

Back to index...