de.mirkosertic.bytecoder.classlib.java.lang.TMath Maven / Gradle / Ivy

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There is a newer version: 2024-05-10
/*
 * Copyright 2018 Mirko Sertic
 *
 * 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.
 */
package de.mirkosertic.bytecoder.classlib.java.lang;

import de.mirkosertic.bytecoder.api.SubstitutesInClass;

@SubstitutesInClass(completeReplace = true)
public class TMath {

    public static final double E = 2.7182818284590452354;
    public static final double PI = 3.14159265358979323846;

    private static class FloatExponents {
        public static float[] exponents = { 0x1p1f, 0x1p2f, 0x1p4f, 0x1p8f, 0x1p16f, 0x1p32f, 0x1p64f };
        public static float[] negativeExponents = { 0x1p-1f, 0x1p-2f, 0x1p-4f, 0x1p-8f, 0x1p-16f, 0x1p-32f,
                0x1p-64f };
        public static float[] negativeExponents2 = { 0x1p-0f, 0x1p-1f, 0x1p-3f, 0x1p-7f, 0x1p-15f, 0x1p-31f,
                0x1p-63f };
    }

    public static float abs(float a) {
        if (a<0) {
            return -a;
        }
        return a;
    }

    public static double abs(double a) {
        if (a<0) {
            return -a;
        }
        return a;
    }

    public static native double sqrt(double aValue);

    public static native double ceil(double aValue);

    public static native float getNaN();

    public static native double floor(double aValue);

    public static native double sin(double aValue);

    public static native double cos(double aValue);

    public static native double random();

    public static native double toRadians(double aValue);

    public static native double toDegrees(double aValue);

    public static native double tan(double aValue);

    public static native long max(long aValue1, long aValue2);

    public static native int max(int aValue1, int aValue2);

    public static native int min(int aValue1, int aValue2);

    public static int getExponent(float f) {
        f = abs(f);
        int exp = 0;
        float[] exponents = FloatExponents.exponents;
        float[] negativeExponents = FloatExponents.negativeExponents;
        float[] negativeExponents2 = FloatExponents.negativeExponents2;
        if (f > 1) {
            int expBit = 1 << (exponents.length - 1);
            for (int i = exponents.length - 1; i >= 0; --i) {
                if (f >= exponents[i]) {
                    f *= negativeExponents[i];
                    exp |= expBit;
                }
                expBit >>>= 1;
            }
        } else if (f < 1) {
            int expBit = 1 << (negativeExponents.length - 1);
            int offset = 0;
            if (f < 0x1p-126) {
                f *= 0x1p23f;
                offset = 23;
            }
            for (int i = negativeExponents2.length - 1; i >= 0; --i) {
                if (f < negativeExponents2[i]) {
                    f *= exponents[i];
                    exp |= expBit;
                }
                expBit >>>= 1;
            }
            exp = -(exp + offset);
        }
        return exp;
    }
}