60 lines
2.3 KiB
Java
60 lines
2.3 KiB
Java
/*
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* Copyright (c) 1998, 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/* @test
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* @bug 4181191 8215759
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* @summary test BigInteger modPow method (use -Dseed=X to set PRNG seed)
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* @library /test/lib
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* @build jdk.test.lib.RandomFactory
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* @run main ModPow
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* @key randomness
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*/
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import java.math.BigInteger;
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import java.util.Random;
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import jdk.test.lib.RandomFactory;
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public class ModPow {
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public static void main(String[] args) {
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Random rnd = RandomFactory.getRandom();
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for (int i=0; i<2000; i++) {
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// Clamp random modulus to a positive value or modPow() will
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// throw an ArithmeticException.
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BigInteger m = new BigInteger(800, rnd).max(BigInteger.ONE);
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BigInteger base = new BigInteger(16, rnd);
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if (rnd.nextInt() % 1 == 0)
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base = base.negate();
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BigInteger exp = new BigInteger(8, rnd);
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BigInteger z = base.modPow(exp, m);
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BigInteger w = base.pow(exp.intValue()).mod(m);
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if (!z.equals(w)){
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System.err.println(base +" ** " + exp + " mod "+ m);
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System.err.println("modPow : " + z);
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System.err.println("pow.mod: " + w);
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throw new RuntimeException("BigInteger modPow failure.");
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}
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}
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}
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}
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