/* * Copyright (C) 2018 The Android Open Source Project * * Licensed 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. */ import java.math.BigInteger; // This is motivated by the assumption that BigInteger allocates malloc memory // underneath. That's true (in 2018) on Android. public class Main { public static void main(String[] args) throws Exception { final int nIters = 20_000; // Presumed < 1_000_000. final BigInteger big2_20 = BigInteger.valueOf(1024*1024); // 2^20 BigInteger huge = BigInteger.valueOf(1).shiftLeft(4_000_000); // ~0.5MB for (int i = 0; i < nIters; ++i) { // 10 GB total huge = huge.add(BigInteger.ONE); } if (huge.bitLength() != 4_000_001) { System.out.println("Wrong answer length: " + huge.bitLength()); } else if (huge.mod(big2_20).compareTo(BigInteger.valueOf(nIters)) != 0) { System.out.println("Wrong answer: ..." + huge.mod(big2_20)); } else { System.out.println("Test complete"); } } }