/*
* @(#) $(JCGO)/goclsp/vm/java/security/VMSecureRandom.java --
* VM specific native SecureRandom "generateSeed" implementation.
**
* Project: JCGO (http://www.ivmaisoft.com/jcgo/)
* Copyright (C) 2001-2008 Ivan Maidanski <ivmai@ivmaisoft.com>
* All rights reserved.
**
* Class specification origin: GNU Classpath v0.93 vm/reference
*/
/*
* This 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 2, or (at your option)
* any later version.
**
* This software 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 (GPL) for more details.
**
* Linking this library statically or dynamically with other modules is
* making a combined work based on this library. Thus, the terms and
* conditions of the GNU General Public License cover the whole
* combination.
**
* As a special exception, the copyright holders of this library give you
* permission to link this library with independent modules to produce an
* executable, regardless of the license terms of these independent
* modules, and to copy and distribute the resulting executable under
* terms of your choice, provided that you also meet, for each linked
* independent module, the terms and conditions of the license of that
* module. An independent module is a module which is not derived from
* or based on this library. If you modify this library, you may extend
* this exception to your version of the library, but you are not
* obligated to do so. If you do not wish to do so, delete this
* exception statement from your version.
*/
package java.security;
import gnu.java.security.hash.Sha160;
final class VMSecureRandom
{
private VMSecureRandom() {}
static int generateSeed(byte[] buf, int offset, int len)
{
long[] vals =
new long[]
{
System.nanoTime(),
Runtime.getRuntime().totalMemory(),
Runtime.getRuntime().freeMemory()
};
Sha160 md = new Sha160();
byte[] bytes = new byte[8];
for (int i = 0; i < vals.length; i++)
{
long v = vals[i];
int intval = (int) (v >>> 32);
bytes[0] = (byte) (intval >>> 24);
bytes[1] = (byte) (intval >>> 16);
bytes[2] = (byte) (intval >>> 8);
bytes[3] = (byte) intval;
intval = (int) v;
bytes[4] = (byte) (intval >>> 24);
bytes[5] = (byte) (intval >>> 16);
bytes[6] = (byte) (intval >>> 8);
bytes[7] = (byte) intval;
md.update(bytes, 0, 8);
}
int ofs = offset;
while (len-- > 0)
{
bytes = md.digest();
buf[ofs++] = bytes[0];
md.update(bytes, 1, md.hashSize() - 1);
}
return ofs - offset;
}
}