plantuml/src/net/sourceforge/plantuml/dedication/QBlock.java

126 lines
3.2 KiB
Java

/* ========================================================================
* PlantUML : a free UML diagram generator
* ========================================================================
*
* (C) Copyright 2009-2017, Arnaud Roques
*
* Project Info: http://plantuml.com
*
* If you like this project or if you find it useful, you can support us at:
*
* http://plantuml.com/patreon (only 1$ per month!)
* http://plantuml.com/paypal
*
* This file is part of PlantUML.
*
* PlantUML 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.
*
* PlantUML 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
*
* Original Author: Arnaud Roques
*
*
*/
package net.sourceforge.plantuml.dedication;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.math.BigInteger;
import net.sourceforge.plantuml.version.Magic;
public class QBlock {
private final BigInteger big;
public static QBlock read(InputStream source, int size) throws IOException {
final byte[] block = new byte[size + 1];
for (int i = 0; i < size; i++) {
final int read = source.read();
if (read == -1) {
if (i == 0) {
return null;
}
break;
}
block[i + 1] = (byte) read;
}
return new QBlock(new BigInteger(block));
}
public static QBlock fromMagic(Magic magic) {
final byte[] buffer = magic.getBuffer();
final byte[] block = new byte[buffer.length + 1];
System.arraycopy(buffer, 0, block, 1, buffer.length);
final BigInteger big = new BigInteger(block);
return new QBlock(big);
}
public Magic toMagic() {
final Magic magic = new Magic();
magic.set(0, getData512());
return magic;
}
public QBlock(BigInteger number) {
this.big = number;
}
public QBlock change(BigInteger E, BigInteger N) {
final BigInteger changed = big.modPow(E, N);
return new QBlock(changed);
}
private byte[] getData512() {
final byte[] nb = big.toByteArray();
if (nb.length == 512) {
return nb;
}
final byte[] result = new byte[512];
if (nb.length < 512) {
System.arraycopy(nb, 0, result, 512 - nb.length, nb.length);
} else {
System.arraycopy(nb, nb.length - 512, result, 0, 512);
}
return result;
}
public byte[] getDataRaw() {
return big.toByteArray();
}
@Override
public String toString() {
return big.toByteArray().length + " " + big.toString(36);
}
public void write(OutputStream os, int size) throws IOException {
final byte[] data = big.toByteArray();
final int start = data.length - size;
if (start < 0) {
for (int i = 0; i < -start; i++) {
os.write(0);
}
}
for (int i = Math.max(start, 0); i < data.length; i++) {
int b = data[i];
os.write(b);
}
}
}