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TestLongLong.java
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TestLongLong.java
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/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.examples.pi.math;
import java.math.BigInteger;
import java.util.Random;
import org.junit.Test;
import org.junit.Assert;
public class TestLongLong {
static final Random RAN = new Random();
static final long MASK = (1L << (LongLong.SIZE >> 1)) - 1;
static long nextPositiveLong() {
return RAN.nextLong() & MASK;
}
static void verifyMultiplication(long a, long b) {
final LongLong ll = LongLong.multiplication(new LongLong(), a, b);
final BigInteger bi = BigInteger.valueOf(a).multiply(BigInteger.valueOf(b));
final String s = String.format(
"\na = %x\nb = %x\nll= " + ll + "\nbi= " + bi.toString(16) + "\n", a,
b);
//System.out.println(s);
Assert.assertEquals(s, bi, ll.toBigInteger());
}
@Test
public void testMultiplication() {
for(int i = 0; i < 100; i++) {
final long a = nextPositiveLong();
final long b = nextPositiveLong();
verifyMultiplication(a, b);
}
final long max = Long.MAX_VALUE & MASK;
verifyMultiplication(max, max);
}
@Test
public void testRightShift() {
for(int i = 0; i < 1000; i++) {
final long a = nextPositiveLong();
final long b = nextPositiveLong();
verifyRightShift(a, b);
}
}
private static void verifyRightShift(long a, long b) {
final LongLong ll = new LongLong().set(a, b);
final BigInteger bi = ll.toBigInteger();
final String s = String.format(
"\na = %x\nb = %x\nll= " + ll + "\nbi= " + bi.toString(16) + "\n", a,
b);
Assert.assertEquals(s, bi, ll.toBigInteger());
for (int i = 0; i < LongLong.SIZE >> 1; i++) {
final long result = ll.shiftRight(i) & MASK;
final long expected = bi.shiftRight(i).longValue() & MASK;
Assert.assertEquals(s, expected, result);
}
}
}