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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
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 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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package compiler.intrinsics;
import java.util.random.RandomGenerator;
import java.util.random.RandomGeneratorFactory;

public class TestDoubleClassCheck {
    RandomGenerator rng;
    int BUFFER_SIZE = 1024;
    double[] inputs;
    boolean[] outputs;

    public TestDoubleClassCheck() {
        outputs = new boolean[BUFFER_SIZE];
        inputs = new double[BUFFER_SIZE];
        RandomGenerator rng = RandomGeneratorFactory.getDefault().create(0);
        double input;
        for (int i = 0; i < BUFFER_SIZE; i++) {
            if (i % 5 == 0) {
                input = (i%2 == 0) ? Double.NEGATIVE_INFINITY : Double.POSITIVE_INFINITY;
            }
            else if (i % 3 == 0) input = Double.NaN;
            else input = rng.nextDouble();
            inputs[i] = input;
        }
    }

    public void checkResult(String method) {
        for (int i=0; i < BUFFER_SIZE; i++) {
            boolean expected = doubleClassCheck(inputs[i], method);
            if (expected != outputs[i]) {
                String errorMsg = "Correctness check failed for Double." + method +
                "() for input = " + inputs[i];
                throw new RuntimeException(errorMsg);
            }
        }
    }

    public boolean doubleClassCheck(double f, String method) {
        long infBits = Double.doubleToRawLongBits(Double.POSITIVE_INFINITY);
        long bits =  Double.doubleToRawLongBits(f);
        bits = bits & Long.MAX_VALUE;
        switch (method) {
            case "isFinite": return (bits < infBits);
            case "isInfinite": return (bits == infBits);
            case "isNaN": return (bits > infBits);
            default: throw new IllegalArgumentException("incorrect method for Double");
        }
    }

}