package org.invisibletech;

import java.nio.ByteBuffer;
import java.util.Optional;

public class IndicateSign {

    public static int signOf(double d) {
        Double validated = Optional.of(d).filter(x -> !Double.isNaN(x)).orElseThrow(() -> new IllegalArgumentException("NaN has no sign."));
        
        byte[] array = ByteBuffer.allocate(Double.BYTES).putDouble(validated).array();
        
        return testSignage(array);
    }

    public static int signOf(long l) {
        byte[] array = ByteBuffer.allocate(Long.BYTES).putLong(l).array();
        
        return testSignage(array);
    }

    private static int testSignage(byte[] array) {
        return (array[0] & 0x80) != 0 ? -1 : 1;
    }

}