1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 /** 18 * @author Elena Semukhina 19 */ 20 21 package org.apache.harmony.tests.java.math; 22 23 import junit.framework.TestCase; 24 import java.math.BigInteger; 25 26 /** 27 * Class: java.math.BigInteger 28 * Methods: modPow, modInverse, and gcd 29 */ 30 public class BigIntegerModPowTest extends TestCase { 31 /** 32 * modPow: non-positive modulus 33 */ 34 public void testModPowException() { 35 byte aBytes[] = {1, 2, 3, 4, 5, 6, 7}; 36 byte eBytes[] = {1, 2, 3, 4, 5}; 37 byte mBytes[] = {1, 2, 3}; 38 int aSign = 1; 39 int eSign = 1; 40 int mSign = -1; 41 BigInteger aNumber = new BigInteger(aSign, aBytes); 42 BigInteger exp = new BigInteger(eSign, eBytes); 43 BigInteger modulus = new BigInteger(mSign, mBytes); 44 try { 45 aNumber.modPow(exp, modulus); 46 fail("ArithmeticException has not been caught"); 47 } catch (ArithmeticException e) { 48 } 49 50 try { 51 BigInteger.ZERO.modPow(new BigInteger("-1"), new BigInteger("10")); 52 fail("ArithmeticException has not been caught"); 53 } catch (ArithmeticException e) { 54 // expected 55 } 56 } 57 58 /** 59 * modPow: positive exponent 60 */ 61 public void testModPowPosExp() { 62 byte aBytes[] = {-127, 100, 56, 7, 98, -1, 39, -128, 127, 75, 48, -7}; 63 byte eBytes[] = {27, -15, 65, 39}; 64 byte mBytes[] = {-128, 2, 3, 4, 5}; 65 int aSign = 1; 66 int eSign = 1; 67 int mSign = 1; 68 byte rBytes[] = {113, 100, -84, -28, -85}; 69 BigInteger aNumber = new BigInteger(aSign, aBytes); 70 BigInteger exp = new BigInteger(eSign, eBytes); 71 BigInteger modulus = new BigInteger(mSign, mBytes); 72 BigInteger result = aNumber.modPow(exp, modulus); 73 byte resBytes[] = new byte[rBytes.length]; 74 resBytes = result.toByteArray(); 75 for(int i = 0; i < resBytes.length; i++) { 76 assertTrue(resBytes[i] == rBytes[i]); 77 } 78 assertEquals("incorrect sign", 1, result.signum()); 79 } 80 81 /** 82 * modPow: negative exponent 83 */ 84 public void testModPowNegExp() { 85 byte aBytes[] = {-127, 100, 56, 7, 98, -1, 39, -128, 127, 75, 48, -7}; 86 byte eBytes[] = {27, -15, 65, 39}; 87 byte mBytes[] = {-128, 2, 3, 4, 5}; 88 int aSign = 1; 89 int eSign = -1; 90 int mSign = 1; 91 byte rBytes[] = {12, 118, 46, 86, 92}; 92 BigInteger aNumber = new BigInteger(aSign, aBytes); 93 BigInteger exp = new BigInteger(eSign, eBytes); 94 BigInteger modulus = new BigInteger(mSign, mBytes); 95 BigInteger result = aNumber.modPow(exp, modulus); 96 byte resBytes[] = new byte[rBytes.length]; 97 resBytes = result.toByteArray(); 98 for(int i = 0; i < resBytes.length; i++) { 99 assertTrue(resBytes[i] == rBytes[i]); 100 } 101 assertEquals("incorrect sign", 1, result.signum()); 102 } 103 104 public void testModPowZeroExp() { 105 BigInteger exp = new BigInteger("0"); 106 BigInteger[] base = new BigInteger[] {new BigInteger("-1"), new BigInteger("0"), new BigInteger("1")}; 107 BigInteger[] mod = new BigInteger[] {new BigInteger("2"), new BigInteger("10"), new BigInteger("2147483648")}; 108 109 for (int i = 0; i < base.length; ++i) { 110 for (int j = 0; j < mod.length; ++j) { 111 assertEquals(base[i] + " modePow(" + exp + ", " + mod[j] 112 + ") should be " + BigInteger.ONE, BigInteger.ONE, 113 base[i].modPow(exp, mod[j])); 114 } 115 } 116 117 mod = new BigInteger[] {new BigInteger("1")}; 118 for (int i = 0; i < base.length; ++i) { 119 for (int j = 0; j < mod.length; ++j) { 120 assertEquals(base[i] + " modePow(" + exp + ", " + mod[j] 121 + ") should be " + BigInteger.ZERO, BigInteger.ZERO, 122 base[i].modPow(exp, mod[j])); 123 } 124 } 125 } 126 127 /** 128 * modInverse: non-positive modulus 129 */ 130 public void testmodInverseException() { 131 byte aBytes[] = {1, 2, 3, 4, 5, 6, 7}; 132 byte mBytes[] = {1, 2, 3}; 133 int aSign = 1; 134 int mSign = -1; 135 BigInteger aNumber = new BigInteger(aSign, aBytes); 136 BigInteger modulus = new BigInteger(mSign, mBytes); 137 try { 138 aNumber.modInverse(modulus); 139 fail("ArithmeticException has not been caught"); 140 } catch (ArithmeticException e) { 141 } 142 } 143 144 /** 145 * modInverse: non-invertible number 146 */ 147 public void testmodInverseNonInvertible() { 148 byte aBytes[] = {-15, 24, 123, 56, -11, -112, -34, -98, 8, 10, 12, 14, 25, 125, -15, 28, -127}; 149 byte mBytes[] = {-12, 1, 0, 0, 0, 23, 44, 55, 66}; 150 int aSign = 1; 151 int mSign = 1; 152 BigInteger aNumber = new BigInteger(aSign, aBytes); 153 BigInteger modulus = new BigInteger(mSign, mBytes); 154 try { 155 aNumber.modInverse(modulus); 156 fail("ArithmeticException has not been caught"); 157 } catch (ArithmeticException e) { 158 } 159 } 160 161 /** 162 * modInverse: positive number 163 */ 164 public void testmodInversePos1() { 165 byte aBytes[] = {24, 123, 56, -11, -112, -34, -98, 8, 10, 12, 14, 25, 125, -15, 28, -127}; 166 byte mBytes[] = {122, 45, 36, 100, 122, 45}; 167 int aSign = 1; 168 int mSign = 1; 169 byte rBytes[] = {47, 3, 96, 62, 87, 19}; 170 BigInteger aNumber = new BigInteger(aSign, aBytes); 171 BigInteger modulus = new BigInteger(mSign, mBytes); 172 BigInteger result = aNumber.modInverse(modulus); 173 byte resBytes[] = new byte[rBytes.length]; 174 resBytes = result.toByteArray(); 175 for(int i = 0; i < resBytes.length; i++) { 176 assertTrue(resBytes[i] == rBytes[i]); 177 } 178 assertEquals("incorrect sign", 1, result.signum()); 179 } 180 181 /** 182 * modInverse: positive number (another case: a < 0) 183 */ 184 public void testmodInversePos2() { 185 byte aBytes[] = {15, 24, 123, 56, -11, -112, -34, -98, 8, 10, 12, 14, 25, 125, -15, 28, -127}; 186 byte mBytes[] = {2, 122, 45, 36, 100}; 187 int aSign = 1; 188 int mSign = 1; 189 byte rBytes[] = {1, -93, 40, 127, 73}; 190 BigInteger aNumber = new BigInteger(aSign, aBytes); 191 BigInteger modulus = new BigInteger(mSign, mBytes); 192 BigInteger result = aNumber.modInverse(modulus); 193 byte resBytes[] = new byte[rBytes.length]; 194 resBytes = result.toByteArray(); 195 for(int i = 0; i < resBytes.length; i++) { 196 assertTrue(resBytes[i] == rBytes[i]); 197 } 198 assertEquals("incorrect sign", 1, result.signum()); 199 } 200 201 /** 202 * modInverse: negative number 203 */ 204 public void testmodInverseNeg1() { 205 byte aBytes[] = {15, 24, 123, 56, -11, -112, -34, -98, 8, 10, 12, 14, 25, 125, -15, 28, -127}; 206 byte mBytes[] = {2, 122, 45, 36, 100}; 207 int aSign = -1; 208 int mSign = 1; 209 byte rBytes[] = {0, -41, 4, -91, 27}; 210 BigInteger aNumber = new BigInteger(aSign, aBytes); 211 BigInteger modulus = new BigInteger(mSign, mBytes); 212 BigInteger result = aNumber.modInverse(modulus); 213 byte resBytes[] = new byte[rBytes.length]; 214 resBytes = result.toByteArray(); 215 for(int i = 0; i < resBytes.length; i++) { 216 assertTrue(resBytes[i] == rBytes[i]); 217 } 218 assertEquals("incorrect sign", 1, result.signum()); 219 } 220 221 /** 222 * modInverse: negative number (another case: x < 0) 223 */ 224 public void testmodInverseNeg2() { 225 byte aBytes[] = {-15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57}; 226 byte mBytes[] = {122, 2, 4, 122, 2, 4}; 227 byte rBytes[] = {85, 47, 127, 4, -128, 45}; 228 BigInteger aNumber = new BigInteger(aBytes); 229 BigInteger modulus = new BigInteger(mBytes); 230 BigInteger result = aNumber.modInverse(modulus); 231 byte resBytes[] = new byte[rBytes.length]; 232 resBytes = result.toByteArray(); 233 for(int i = 0; i < resBytes.length; i++) { 234 assertTrue(resBytes[i] == rBytes[i]); 235 } 236 assertEquals("incorrect sign", 1, result.signum()); 237 } 238 239 /** 240 * gcd: the second number is zero 241 */ 242 public void testGcdSecondZero() { 243 byte aBytes[] = {15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57}; 244 byte bBytes[] = {0}; 245 int aSign = 1; 246 int bSign = 1; 247 byte rBytes[] = {15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57}; 248 BigInteger aNumber = new BigInteger(aSign, aBytes); 249 BigInteger bNumber = new BigInteger(bSign, bBytes); 250 BigInteger result = aNumber.gcd(bNumber); 251 byte resBytes[] = new byte[rBytes.length]; 252 resBytes = result.toByteArray(); 253 for(int i = 0; i < resBytes.length; i++) { 254 assertTrue(resBytes[i] == rBytes[i]); 255 } 256 assertEquals("incorrect sign", 1, result.signum()); 257 } 258 259 /** 260 * gcd: the first number is zero 261 */ 262 public void testGcdFirstZero() { 263 byte aBytes[] = {0}; 264 byte bBytes[] = {15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57}; 265 int aSign = 1; 266 int bSign = 1; 267 byte rBytes[] = {15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57}; 268 BigInteger aNumber = new BigInteger(aSign, aBytes); 269 BigInteger bNumber = new BigInteger(bSign, bBytes); 270 BigInteger result = aNumber.gcd(bNumber); 271 byte resBytes[] = new byte[rBytes.length]; 272 resBytes = result.toByteArray(); 273 for(int i = 0; i < resBytes.length; i++) { 274 assertTrue(resBytes[i] == rBytes[i]); 275 } 276 assertEquals("incorrect sign", 1, result.signum()); 277 } 278 279 /** 280 * gcd: the first number is ZERO 281 */ 282 public void testGcdFirstZERO() { 283 byte bBytes[] = {15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57}; 284 int bSign = 1; 285 byte rBytes[] = {15, 24, 123, 57, -15, 24, 123, 57, -15, 24, 123, 57}; 286 BigInteger aNumber = BigInteger.ZERO; 287 BigInteger bNumber = new BigInteger(bSign, bBytes); 288 BigInteger result = aNumber.gcd(bNumber); 289 byte resBytes[] = new byte[rBytes.length]; 290 resBytes = result.toByteArray(); 291 for(int i = 0; i < resBytes.length; i++) { 292 assertTrue(resBytes[i] == rBytes[i]); 293 } 294 assertEquals("incorrect sign", 1, result.signum()); 295 } 296 297 /** 298 * gcd: both numbers are zeros 299 */ 300 public void testGcdBothZeros() { 301 byte rBytes[] = {0}; 302 BigInteger aNumber = new BigInteger("0"); 303 BigInteger bNumber = BigInteger.valueOf(0L); 304 BigInteger result = aNumber.gcd(bNumber); 305 byte resBytes[] = result.toByteArray(); 306 for(int i = 0; i < resBytes.length; i++) { 307 assertTrue(resBytes[i] == rBytes[i]); 308 } 309 assertEquals("incorrect sign", 0, result.signum()); 310 } 311 312 /** 313 * gcd: the first number is longer 314 */ 315 public void testGcdFirstLonger() { 316 byte aBytes[] = {-15, 24, 123, 56, -11, -112, -34, -98, 8, 10, 12, 14, 25, 125, -15, 28, -127}; 317 byte bBytes[] = {-12, 1, 0, 0, 0, 23, 44, 55, 66}; 318 int aSign = 1; 319 int bSign = 1; 320 byte rBytes[] = {7}; 321 BigInteger aNumber = new BigInteger(aSign, aBytes); 322 BigInteger bNumber = new BigInteger(bSign, bBytes); 323 BigInteger result = aNumber.gcd(bNumber); 324 byte resBytes[] = new byte[rBytes.length]; 325 resBytes = result.toByteArray(); 326 for(int i = 0; i < resBytes.length; i++) { 327 assertTrue(resBytes[i] == rBytes[i]); 328 } 329 assertEquals("incorrect sign", 1, result.signum()); 330 } 331 332 /** 333 * gcd: the second number is longer 334 */ 335 public void testGcdSecondLonger() { 336 byte aBytes[] = {-12, 1, 0, 0, 0, 23, 44, 55, 66}; 337 byte bBytes[] = {-15, 24, 123, 56, -11, -112, -34, -98, 8, 10, 12, 14, 25, 125, -15, 28, -127}; 338 int aSign = 1; 339 int bSign = 1; 340 byte rBytes[] = {7}; 341 BigInteger aNumber = new BigInteger(aSign, aBytes); 342 BigInteger bNumber = new BigInteger(bSign, bBytes); 343 BigInteger result = aNumber.gcd(bNumber); 344 byte resBytes[] = new byte[rBytes.length]; 345 resBytes = result.toByteArray(); 346 for(int i = 0; i < resBytes.length; i++) { 347 assertTrue(resBytes[i] == rBytes[i]); 348 } 349 assertEquals("incorrect sign", 1, result.signum()); 350 } 351 } 352
