open-keychain/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/tpdu/IBlock.java
2017-12-15 16:03:36 +01:00

55 lines
1.9 KiB
Java

/*
* Copyright (C) 2017 Schürmann & Breitmoser GbR
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.sufficientlysecure.keychain.securitytoken.usb.tpdu;
import org.sufficientlysecure.keychain.securitytoken.usb.UsbTransportException;
class IBlock extends Block {
static final byte MASK_IBLOCK = (byte) 0b10000000;
static final byte MASK_VALUE_IBLOCK = (byte) 0b00000000;
private static final byte BIT_SEQUENCE = 6;
private static final byte BIT_CHAINING = 5;
IBlock(BlockChecksumAlgorithm checksumType, byte[] data) throws UsbTransportException {
super(checksumType, data);
if ((getPcb() & MASK_IBLOCK) != MASK_VALUE_IBLOCK) {
throw new IllegalArgumentException("Data contained incorrect block type!");
}
}
IBlock(BlockChecksumAlgorithm checksumType, byte nad, byte sequence, boolean chaining, byte[] apdu, int offset,
int length)
throws UsbTransportException {
super(checksumType, nad,
(byte) (((sequence & 1) << BIT_SEQUENCE) | (chaining ? 1 << BIT_CHAINING : 0)),
apdu, offset, length);
}
byte getSequence() {
return (byte) ((getPcb() >> BIT_SEQUENCE) & 1);
}
boolean getChaining() {
return ((getPcb() >> BIT_CHAINING) & 1) != 0;
}
}