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39 lines
1.5 KiB
39 lines
1.5 KiB
/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import java.math.BigInteger;
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// This is motivated by the assumption that BigInteger allocates malloc memory
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// underneath. That's true (in 2018) on Android.
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public class Main {
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public static void main(String[] args) throws Exception {
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final int nIters = 20_000; // Presumed < 1_000_000.
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final BigInteger big2_20 = BigInteger.valueOf(1024*1024); // 2^20
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BigInteger huge = BigInteger.valueOf(1).shiftLeft(4_000_000); // ~0.5MB
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for (int i = 0; i < nIters; ++i) { // 10 GB total
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huge = huge.add(BigInteger.ONE);
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}
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if (huge.bitLength() != 4_000_001) {
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System.out.println("Wrong answer length: " + huge.bitLength());
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} else if (huge.mod(big2_20).compareTo(BigInteger.valueOf(nIters)) != 0) {
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System.out.println("Wrong answer: ..." + huge.mod(big2_20));
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} else {
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System.out.println("Test complete");
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}
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}
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}
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