/*
* 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();
}
}