/*
* 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.
*/
/**
* @author Elena Semukhina
*/
package org.apache.harmony.tests.java.math;
import junit.framework.TestCase;
import java.math.BigInteger;
/**
* Class: java.math.BigInteger
* Methods: modPow, modInverse, and gcd
*/
public class BigIntegerModPowTest extends TestCase {
/**
* modPow: non-positive modulus
*/
public void testModPowException() {
byte aBytes[] = {1, 2, 3, 4, 5, 6, 7};
byte eBytes[] = {1, 2, 3, 4, 5};
byte mBytes[] = {1, 2, 3};
int aSign = 1;
int eSign = 1;
int mSign = -1;
BigInteger aNumber = new BigInteger(aSign, aBytes);
BigInteger exp = new BigInteger(eSign, eBytes);
BigInteger modulus = new BigInteger(mSign, mBytes);
try {
aNumber.modPow(exp, modulus);
fail("ArithmeticException has not been caught");
} catch (ArithmeticException e) {
}
try {
BigInteger.ZERO.modPow(new BigInteger("-1"), new BigInteger("10"));
fail("ArithmeticException has not been caught");
} catch (ArithmeticException e) {
// expected
}
}
/**
* modPow: positive exponent
*/
public void testModPowPosExp() {
byte aBytes[] = {-127, 100, 56, 7, 98, -1, 39, -128, 127, 75, 48, -7};
byte eBytes[] = {27, -15, 65, 39};
byte mBytes[] = {-128, 2, 3, 4, 5};
int aSign = 1;
int eSign = 1;
int mSign = 1;
byte rBytes[] = {113, 100, -84, -28, -85};
BigInteger aNumber = new BigInteger(aSign, aBytes);
BigInteger exp = new BigInteger(eSign, eBytes);
BigInteger modulus = new BigInteger(mSign, mBytes);
BigInteger result = aNumber.modPow(exp, modulus);
byte resBytes[] = new byte[rBytes.length];
resBytes = result.toByteArray();
for(int i = 0; i < resBytes.length; i++) {
assertTrue(resBytes[i] == rBytes[i]);
}
assertEquals("incorrect sign", 1, result.signum());
}
/**
* modPow: negative exponent
*/
public void testModPowNegExp() {
byte aBytes[] = {-127, 100, 56, 7, 98, -1, 39, -128, 127, 75, 48, -7};
byte eBytes[] = {27, -15, 65, 39};
byte mBytes[] = {-128, 2, 3, 4, 5};
int aSign = 1;
int eSign = -1;
int mSign = 1;
byte rBytes[] = {12, 118, 46, 86, 92};
BigInteger aNumber = new BigInteger(aSign, aBytes);
BigInteger exp = new BigInteger(eSign, eBytes);
BigInteger modulus = new BigInteger(mSign, mBytes);
BigInteger result = aNumber.modPow(exp, modulus);
byte resBytes[] = new byte[rBytes.length];
resBytes = result.toByteArray();
for(int i = 0; i < resBytes.length; i++) {
assertTrue(resBytes[i] == rBytes[i]);
}
assertEquals("incorrect sign", 1, result.signum());
}
public void testModPowZeroExp() {
BigInteger exp = new BigInteger("0");
BigInteger[] base = new BigInteger[] {new BigInteger("-1"), new BigInteger("0"), new BigInteger("1")};
BigInteger[] mod = new BigInteger[] {new BigInteger("2"), new BigInteger("10"), new BigInteger("2147483648")};
for (int i = 0; i < base.length; ++i) {
for (int j = 0; j < mod.length; ++j) {
assertEquals(base[i] + " modePow(" + exp + ", " + mod[j]
+ ") should be " + BigInteger.ONE, BigInteger.ONE,
base[i].modPow(exp, mod[j]));
}
}
mod = new BigInteger[] {new BigInteger("1")};
for (int i = 0; i < base.length; ++i) {
for (int j = 0; j < mod.length; ++j) {
assertEquals(base[i] + " modePow(" + exp + ", " + mod[j]
+ ") should be " + BigInteger.ZERO, BigInteger.ZERO,
base[i].modPow(exp, mod[j]));
}
}
}
/**
* modInverse: non-positive modulus
*/
public void testmodInverseException() {
byte aBytes[] = {1, 2, 3, 4, 5, 6, 7};
byte mBytes[] = {1, 2, 3};
int aSign = 1;
int mSign = -1;
BigInteger aNumber = new BigInteger(aSign, aBytes);
BigInteger modulus = new BigInteger(mSign, mBytes);
try {
aNumber.modInverse(modulus);
fail("ArithmeticException has not been caught");
} catch (ArithmeticException e) {
}
}
/**
* modInverse: non-invertible number
*/
public void testmodInverseNonInvertible() {
byte aBytes[] = {-15, 24, 123, 56, -11, -112, -34, -98, 8, 10, 12, 14, 25, 125, -15, 28, -127};
byte mBytes[] = {-12, 1, 0, 0, 0, 23, 44, 55, 66};
int aSign = 1;
int mSign = 1;
BigInteger aNumber = new BigInteger(aSign, aBytes);
BigInteger modulus = new BigInteger(mSign, mBytes);
try {
aNumber.modInverse(modulus);
fail("ArithmeticException has not been caught");
} catch (ArithmeticException e) {
}
}
/**
* modInverse: positive number
*/
public void testmodInversePos1() {
byte aBytes[] = {24, 123, 56, -11, -112, -34, -98, 8, 10, 12, 14, 25, 125, -15, 28, -127};
byte mBytes[] = {122, 45, 36, 100, 122, 45};
int aSign = 1;
int mSign = 1;
byte rBytes[] = {47, 3, 96, 62, 87, 19};
BigInteger aNumber = new BigInteger(aSign, aBytes);
BigInteger modulus = new BigInteger(mSign, mBytes);
BigInteger result = aNumber.modInverse(modulus);
byte resBytes[] = new byte[rBytes.length];
resBytes = result.toByteArray();
for(int i = 0; i < resBytes.length; i++) {
assertTrue(resBytes[i] == rBytes[i]);
}
assertEquals("incorrect sign", 1, result.signum());
}
/**
* modInverse: positive number (another case: a < 0)
*/
public void testmodInversePos2() {
byte aBytes[] = {15, 24, 123, 56, -11, -112, -34, -98, 8, 10, 12, 14, 25, 125, -15, 28, -127};
byte mBytes[] = {2, 122, 45, 36, 100};
int aSign = 1;
int mSign = 1;
byte rBytes[] = {1, -93, 40, 127, 73};
BigInteger aNumber = new BigInteger(aSign, aBytes);
BigInteger modulus = new BigInteger(mSign, mBytes);
BigInteger result = aNumber.modInverse(modulus);
byte resBytes[] = new byte[rBytes.length];
resBytes = result.toByteArray();
for(int i = 0; i < resBytes.length; i++) {
assertTrue(resBytes[i] == rBytes[i]);
}
assertEquals("incorrect sign", 1, result.signum());
}
/**
* modInverse: negative number
*/
public void testmodInverseNeg1() {
byte aBytes[] = {15, 24, 123, 56, -11, -112, -34, -98, 8, 10, 12, 14, 25, 125, -15, 28, -127};
byte mBytes[] = {2, 122, 45, 36, 100};
int aSign = -1;
int mSign = 1;
byte rBytes[] = {0, -41, 4, -91, 27};
BigInteger aNumber = new BigInteger(aSign, aBytes);
BigInteger modulus = new BigInteger(mSign, mBytes);
BigInteger result = aNumber.modInverse(modulus);
byte resBytes[] = new byte[rBytes.length];
resBytes = result.toByteArray();
for(int i = 0; i < resBytes.length; i++) {
assertTrue(resBytes[i] == rBytes[i]);
}
assertEquals("incorrect sign", 1, result.signum());
}
/**
* modInverse: negative number (another case: x < 0)
*/
public void testmodInverseNeg2() {
byte aBytes[] = {-15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57};
byte mBytes[] = {122, 2, 4, 122, 2, 4};
byte rBytes[] = {85, 47, 127, 4, -128, 45};
BigInteger aNumber = new BigInteger(aBytes);
BigInteger modulus = new BigInteger(mBytes);
BigInteger result = aNumber.modInverse(modulus);
byte resBytes[] = new byte[rBytes.length];
resBytes = result.toByteArray();
for(int i = 0; i < resBytes.length; i++) {
assertTrue(resBytes[i] == rBytes[i]);
}
assertEquals("incorrect sign", 1, result.signum());
}
/**
* gcd: the second number is zero
*/
public void testGcdSecondZero() {
byte aBytes[] = {15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57};
byte bBytes[] = {0};
int aSign = 1;
int bSign = 1;
byte rBytes[] = {15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57};
BigInteger aNumber = new BigInteger(aSign, aBytes);
BigInteger bNumber = new BigInteger(bSign, bBytes);
BigInteger result = aNumber.gcd(bNumber);
byte resBytes[] = new byte[rBytes.length];
resBytes = result.toByteArray();
for(int i = 0; i < resBytes.length; i++) {
assertTrue(resBytes[i] == rBytes[i]);
}
assertEquals("incorrect sign", 1, result.signum());
}
/**
* gcd: the first number is zero
*/
public void testGcdFirstZero() {
byte aBytes[] = {0};
byte bBytes[] = {15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57};
int aSign = 1;
int bSign = 1;
byte rBytes[] = {15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57};
BigInteger aNumber = new BigInteger(aSign, aBytes);
BigInteger bNumber = new BigInteger(bSign, bBytes);
BigInteger result = aNumber.gcd(bNumber);
byte resBytes[] = new byte[rBytes.length];
resBytes = result.toByteArray();
for(int i = 0; i < resBytes.length; i++) {
assertTrue(resBytes[i] == rBytes[i]);
}
assertEquals("incorrect sign", 1, result.signum());
}
/**
* gcd: the first number is ZERO
*/
public void testGcdFirstZERO() {
byte bBytes[] = {15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57};
int bSign = 1;
byte rBytes[] = {15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57};
BigInteger aNumber = BigInteger.ZERO;
BigInteger bNumber = new BigInteger(bSign, bBytes);
BigInteger result = aNumber.gcd(bNumber);
byte resBytes[] = new byte[rBytes.length];
resBytes = result.toByteArray();
for(int i = 0; i < resBytes.length; i++) {
assertTrue(resBytes[i] == rBytes[i]);
}
assertEquals("incorrect sign", 1, result.signum());
}
/**
* gcd: both numbers are zeros
*/
public void testGcdBothZeros() {
byte rBytes[] = {0};
BigInteger aNumber = new BigInteger("0");
BigInteger bNumber = BigInteger.valueOf(0L);
BigInteger result = aNumber.gcd(bNumber);
byte resBytes[] = result.toByteArray();
for(int i = 0; i < resBytes.length; i++) {
assertTrue(resBytes[i] == rBytes[i]);
}
assertEquals("incorrect sign", 0, result.signum());
}
/**
* gcd: the first number is longer
*/
public void testGcdFirstLonger() {
byte aBytes[] = {-15, 24, 123, 56, -11, -112, -34, -98, 8, 10, 12, 14, 25, 125, -15, 28, -127};
byte bBytes[] = {-12, 1, 0, 0, 0, 23, 44, 55, 66};
int aSign = 1;
int bSign = 1;
byte rBytes[] = {7};
BigInteger aNumber = new BigInteger(aSign, aBytes);
BigInteger bNumber = new BigInteger(bSign, bBytes);
BigInteger result = aNumber.gcd(bNumber);
byte resBytes[] = new byte[rBytes.length];
resBytes = result.toByteArray();
for(int i = 0; i < resBytes.length; i++) {
assertTrue(resBytes[i] == rBytes[i]);
}
assertEquals("incorrect sign", 1, result.signum());
}
/**
* gcd: the second number is longer
*/
public void testGcdSecondLonger() {
byte aBytes[] = {-12, 1, 0, 0, 0, 23, 44, 55, 66};
byte bBytes[] = {-15, 24, 123, 56, -11, -112, -34, -98, 8, 10, 12, 14, 25, 125, -15, 28, -127};
int aSign = 1;
int bSign = 1;
byte rBytes[] = {7};
BigInteger aNumber = new BigInteger(aSign, aBytes);
BigInteger bNumber = new BigInteger(bSign, bBytes);
BigInteger result = aNumber.gcd(bNumber);
byte resBytes[] = new byte[rBytes.length];
resBytes = result.toByteArray();
for(int i = 0; i < resBytes.length; i++) {
assertTrue(resBytes[i] == rBytes[i]);
}
assertEquals("incorrect sign", 1, result.signum());
}
}