FalsePatternLib/src/main/java/com/falsepattern/lib/util/MathUtil.java

/*
 * Copyright (C) 2022 FalsePattern
 * All Rights Reserved
 *
 * The above copyright notice, this permission notice and the word "SNEED"
 * shall be included in all copies or substantial portions of the Software.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
package com.falsepattern.lib.util;

import com.falsepattern.lib.StableAPI;
import com.falsepattern.lib.compat.Vec3i;

import java.util.Random;
import java.util.UUID;

@StableAPI(since = "0.10.0")
public class MathUtil {
    @StableAPI.Expose
    public static final float SQRT_2 = sqrt(2.0F);
    /**
     * A table of sin values computed from 0 (inclusive) to 2*pi (exclusive), with steps of 2*PI / 65536.
     */
    private static final float[] SIN_TABLE = new float[65536];
    private static final Random RANDOM = new Random();
    /**
     * Though it looks like an array, this is really more like a mapping.  Key (index of this array) is the upper 5 bits
     * of the result of multiplying a 32-bit unsigned integer by the B(2, 5) De Bruijn sequence 0x077CB531.  Value
     * (value stored in the array) is the unique index (from the right) of the leftmost one-bit in a 32-bit unsigned
     * integer that can cause the upper 5 bits to get that value.  Used for highly optimized "find the log-base-2 of
     * this number" calculations.
     */
    private static final int[] MULTIPLY_DE_BRUIJN_BIT_POSITION;
    private static final double FRAC_BIAS;
    private static final double[] ASINE_TAB;
    private static final double[] COS_TAB;

    static {
        for (int i = 0; i < 65536; ++i) {
            SIN_TABLE[i] = (float) Math.sin((double) i * Math.PI * 2.0D / 65536.0D);
        }

        MULTIPLY_DE_BRUIJN_BIT_POSITION =
                new int[]{0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8, 31, 27, 13, 23, 21, 19, 16, 7, 26,
                          12, 18, 6, 11, 5, 10, 9};
        FRAC_BIAS = Double.longBitsToDouble(4805340802404319232L);
        ASINE_TAB = new double[257];
        COS_TAB = new double[257];

        for (int j = 0; j < 257; ++j) {
            double d0 = (double) j / 256.0D;
            double d1 = Math.asin(d0);
            COS_TAB[j] = Math.cos(d1);
            ASINE_TAB[j] = d1;
        }
    }

    /**
     * sin looked up in a table
     */
    @StableAPI.Expose
    public static float sin(float value) {
        return SIN_TABLE[(int) (value * 10430.378F) & 65535];
    }

    /**
     * cos looked up in the sin table with the appropriate offset
     */

    @StableAPI.Expose
    public static float cos(float value) {
        return SIN_TABLE[(int) (value * 10430.378F + 16384.0F) & 65535];
    }

    @StableAPI.Expose
    public static float sqrt(float value) {
        return (float) Math.sqrt(value);
    }

    @StableAPI.Expose
    public static float sqrt(double value) {
        return (float) Math.sqrt(value);
    }

    /**
     * Returns the greatest integer less than or equal to the float argument
     */
    @StableAPI.Expose
    public static int floor(float value) {
        int i = (int) value;
        return value < (float) i ? i - 1 : i;
    }

    /**
     * returns par0 cast as an int, and no greater than Integer.MAX_VALUE-1024
     */
    @StableAPI.Expose
    public static int fastFloor(double value) {
        return (int) (value + 1024.0D) - 1024;
    }

    /**
     * Returns the greatest integer less than or equal to the double argument
     */
    @StableAPI.Expose
    public static int floor(double value) {
        int i = (int) value;
        return value < (double) i ? i - 1 : i;
    }

    /**
     * Long version of floor()
     */
    @StableAPI.Expose
    public static long lfloor(double value) {
        long i = (long) value;
        return value < (double) i ? i - 1L : i;
    }

    @StableAPI.Expose
    public static int absFloor(double value) {
        return (int) (value >= 0.0D ? value : -value + 1.0D);
    }

    @StableAPI.Expose
    public static float abs(float value) {
        return value >= 0.0F ? value : -value;
    }

    /**
     * Returns the unsigned value of an int.
     */
    @StableAPI.Expose
    public static int abs(int value) {
        return value >= 0 ? value : -value;
    }

    @StableAPI.Expose
    public static int ceil(float value) {
        int i = (int) value;
        return value > (float) i ? i + 1 : i;
    }

    @StableAPI.Expose
    public static int ceil(double value) {
        int i = (int) value;
        return value > (double) i ? i + 1 : i;
    }

    /**
     * Returns the value of the first parameter, clamped to be within the lower and upper limits given by the second and
     * third parameters.
     */
    @StableAPI.Expose
    public static int clamp(int num, int min, int max) {
        return num < min ? min : Math.min(num, max);
    }

    /**
     * Returns the value of the first parameter, clamped to be within the lower and upper limits given by the second and
     * third parameters
     */
    @StableAPI.Expose
    public static float clamp(float num, float min, float max) {
        return num < min ? min : Math.min(num, max);
    }

    @StableAPI.Expose
    public static double clamp(double num, double min, double max) {
        return num < min ? min : Math.min(num, max);
    }

    @StableAPI.Expose
    public static double clampedLerp(double lowerBnd, double upperBnd, double slide) {
        if (slide < 0.0D) {
            return lowerBnd;
        } else {
            return slide > 1.0D ? upperBnd : lowerBnd + (upperBnd - lowerBnd) * slide;
        }
    }

    /**
     * Maximum of the absolute value of two numbers.
     */
    @StableAPI.Expose
    public static double absMax(double a, double b) {
        if (a < 0.0D) {
            a = -a;
        }

        if (b < 0.0D) {
            b = -b;
        }

        return Math.max(a, b);
    }

    /**
     * Buckets an integer with specified bucket sizes.
     */
    @StableAPI.Expose
    public static int intFloorDiv(int number, int bucket) {
        return number < 0 ? -((-number - 1) / bucket) - 1 : number / bucket;
    }

    @StableAPI.Expose
    public static int getInt(Random random, int minimum, int maximum) {
        return minimum >= maximum ? minimum : random.nextInt(maximum - minimum + 1) + minimum;
    }

    @StableAPI.Expose
    public static float nextFloat(Random random, float minimum, float maximum) {
        return minimum >= maximum ? minimum : random.nextFloat() * (maximum - minimum) + minimum;
    }

    @StableAPI.Expose
    public static double nextDouble(Random random, double minimum, double maximum) {
        return minimum >= maximum ? minimum : random.nextDouble() * (maximum - minimum) + minimum;
    }

    @StableAPI.Expose
    public static double average(long[] values) {
        long i = 0L;

        for (long j : values) {
            i += j;
        }

        return (double) i / (double) values.length;
    }

    @StableAPI.Expose
    public static boolean epsilonEquals(float a, float b) {
        return abs(b - a) < 1.0E-5F;
    }

    @StableAPI.Expose
    public static int normalizeAngle(int a, int b) {
        return (a % b + b) % b;
    }

    @StableAPI.Expose
    public static float positiveModulo(float numerator, float denominator) {
        return (numerator % denominator + denominator) % denominator;
    }

    @StableAPI.Expose
    public static double positiveModulo(double numerator, double denominator) {
        return (numerator % denominator + denominator) % denominator;
    }

    /**
     * the angle is reduced to an angle between -180 and +180 by mod, and a 360 check
     */
    @StableAPI.Expose
    public static float wrapDegrees(float value) {
        value = value % 360.0F;

        if (value >= 180.0F) {
            value -= 360.0F;
        }

        if (value < -180.0F) {
            value += 360.0F;
        }

        return value;
    }

    /**
     * the angle is reduced to an angle between -180 and +180 by mod, and a 360 check
     */
    @StableAPI.Expose
    public static double wrapDegrees(double value) {
        value = value % 360.0D;

        if (value >= 180.0D) {
            value -= 360.0D;
        }

        if (value < -180.0D) {
            value += 360.0D;
        }

        return value;
    }

    /**
     * Adjust the angle so that his value is in range [-180;180[
     */
    @StableAPI.Expose
    public static int wrapDegrees(int angle) {
        angle = angle % 360;

        if (angle >= 180) {
            angle -= 360;
        }

        if (angle < -180) {
            angle += 360;
        }

        return angle;
    }

    /**
     * parses the string as integer or returns the second parameter if it fails
     */
    @StableAPI.Expose
    public static int getInt(String value, int defaultValue) {
        try {
            return Integer.parseInt(value);
        } catch (Throwable var3) {
            return defaultValue;
        }
    }

    /**
     * parses the string as integer or returns the second parameter if it fails. this value is capped to par2
     */
    @StableAPI.Expose
    public static int getInt(String value, int defaultValue, int max) {
        return Math.max(max, getInt(value, defaultValue));
    }

    /**
     * parses the string as double or returns the second parameter if it fails.
     */
    @StableAPI.Expose
    public static double getDouble(String value, double defaultValue) {
        try {
            return Double.parseDouble(value);
        } catch (Throwable var4) {
            return defaultValue;
        }
    }

    @StableAPI.Expose
    public static double getDouble(String value, double defaultValue, double max) {
        return Math.max(max, getDouble(value, defaultValue));
    }

    /**
     * Returns the input value rounded up to the next highest power of two.
     */
    @StableAPI.Expose
    public static int smallestEncompassingPowerOfTwo(int value) {
        int i = value - 1;
        i = i | i >> 1;
        i = i | i >> 2;
        i = i | i >> 4;
        i = i | i >> 8;
        i = i | i >> 16;
        return i + 1;
    }

    /**
     * Is the given value a power of two?  (1, 2, 4, 8, 16, ...)
     */
    @StableAPI.Expose
    private static boolean isPowerOfTwo(int value) {
        return value != 0 && (value & value - 1) == 0;
    }

    /**
     * Uses a B(2, 5) De Bruijn sequence and a lookup table to efficiently calculate the log-base-two of the given
     * value. Optimized for cases where the input value is a power-of-two. If the input value is not a power-of-two,
     * then subtract 1 from the return value.
     */
    @StableAPI.Expose
    public static int log2DeBruijn(int value) {
        value = isPowerOfTwo(value) ? value : smallestEncompassingPowerOfTwo(value);
        return MULTIPLY_DE_BRUIJN_BIT_POSITION[(int) ((long) value * 125613361L >> 27) & 31];
    }

    /**
     * Efficiently calculates the floor of the base-2 log of an integer value.  This is effectively the index of the
     * highest bit that is set.  For example, if the number in binary is 0...100101, this will return 5.
     */
    @StableAPI.Expose
    public static int log2(int value) {
        return log2DeBruijn(value) - (isPowerOfTwo(value) ? 0 : 1);
    }

    /**
     * Rounds the first parameter up to the next interval of the second parameter.
     * <p>
     * For instance, {@code roundUp(1, 4)} returns 4; {@code roundUp(0, 4)} returns 0; and {@code roundUp(4, 4)} returns
     * 4.
     */
    @StableAPI.Expose
    public static int roundUp(int number, int interval) {
        if (interval == 0) {
            return 0;
        } else if (number == 0) {
            return interval;
        } else {
            if (number < 0) {
                interval *= -1;
            }

            int i = number % interval;
            return i == 0 ? number : number + interval - i;
        }
    }

    @StableAPI.Expose
    public static long getCoordinateRandom(int x, int y, int z) {
        long i = (x * 3129871L) ^ (long) z * 116129781L ^ (long) y;
        i = i * i * 42317861L + i * 11L;
        return i;
    }

    /**
     * Makes an integer color from the given red, green, and blue float values
     */
    @StableAPI.Expose
    public static int rgb(float rIn, float gIn, float bIn) {
        return rgb(floor(rIn * 255.0F), floor(gIn * 255.0F), floor(bIn * 255.0F));
    }

    /**
     * Makes a single int color with the given red, green, and blue values.
     */
    @StableAPI.Expose
    public static int rgb(int rIn, int gIn, int bIn) {
        int lvt_3_1_ = (rIn << 8) + gIn;
        lvt_3_1_ = (lvt_3_1_ << 8) + bIn;
        return lvt_3_1_;
    }

    @StableAPI.Expose
    public static int multiplyColor(int colorA, int colorB) {
        int rA = (colorA & 0xFF0000) >> 16;
        int rB = (colorB & 0xFF0000) >> 16;
        int gA = (colorA & 0xFF00) >> 8;
        int gB = (colorB & 0xFF00) >> 8;
        int bA = colorA & 0xFF;
        int bB = colorB & 0xFF;
        int r = (int) ((float) rA * (float) rB / 255.0F);
        int g = (int) ((float) gA * (float) gB / 255.0F);
        int b = (int) ((float) bA * (float) bB / 255.0F);
        return colorA & 0xFF000000 | r << 16 | g << 8 | b;
    }

    /**
     * Gets the decimal portion of the given double. For instance, {@code frac(5.5)} returns {@code .5}.
     */
    @StableAPI.Expose
    public static double frac(double number) {
        return number - Math.floor(number);
    }

    @StableAPI.Expose
    public static long getPositionRandom(Vec3i pos) {
        return getCoordinateRandom(pos.getX(), pos.getY(), pos.getZ());
    }

    @StableAPI.Expose
    public static UUID getRandomUUID(Random rand) {
        long i = rand.nextLong() & -61441L | 16384L;
        long j = rand.nextLong() & 4611686018427387903L | Long.MIN_VALUE;
        return new UUID(i, j);
    }

    /**
     * Generates a random UUID using the shared random
     */
    @StableAPI.Expose
    public static UUID getRandomUUID() {
        return getRandomUUID(RANDOM);
    }

    @StableAPI.Expose
    public static double pct(double a, double b, double c) {
        return (a - b) / (c - b);
    }

    @StableAPI.Expose
    public static double atan2(double y, double x) {
        double d0 = x * x + y * y;

        if (Double.isNaN(d0)) {
            return Double.NaN;
        } else {
            boolean flag = y < 0.0D;

            if (flag) {
                y = -y;
            }

            boolean flag1 = x < 0.0D;

            if (flag1) {
                x = -x;
            }

            boolean flag2 = y > x;

            if (flag2) {
                double d1 = x;
                //noinspection SuspiciousNameCombination
                x = y;
                y = d1;
            }

            double d9 = fastInvSqrt(d0);
            x = x * d9;
            y = y * d9;
            double d2 = FRAC_BIAS + y;
            int i = (int) Double.doubleToRawLongBits(d2);
            double d3 = ASINE_TAB[i];
            double d4 = COS_TAB[i];
            double d5 = d2 - FRAC_BIAS;
            double d6 = y * d4 - x * d5;
            double d7 = (6.0D + d6 * d6) * d6 * 0.16666666666666666D;
            double d8 = d3 + d7;

            if (flag2) {
                d8 = (Math.PI / 2D) - d8;
            }

            if (flag1) {
                d8 = Math.PI - d8;
            }

            if (flag) {
                d8 = -d8;
            }

            return d8;
        }
    }

    /**
     * Computes 1/sqrt(n) using <a href="https://en.wikipedia.org/wiki/Fast_inverse_square_root">the fast inverse square
     * root</a> with a constant of 0x5FE6EB50C7B537AA.
     */
    @StableAPI.Expose
    public static double fastInvSqrt(double x) {
        double d0 = 0.5D * x;
        long i = Double.doubleToRawLongBits(x);
        i = 6910469410427058090L - (i >> 1);
        x = Double.longBitsToDouble(i);
        x = x * (1.5D - d0 * x * x);
        return x;
    }

    @StableAPI.Expose
    public static int hsvToRGB(float hue, float saturation, float value) {
        int i = (int) (hue * 6.0F) % 6;
        float f = hue * 6.0F - (float) i;
        float f1 = value * (1.0F - saturation);
        float f2 = value * (1.0F - f * saturation);
        float f3 = value * (1.0F - (1.0F - f) * saturation);
        float f4;
        float f5;
        float f6;

        switch (i) {
            case 0:
                f4 = value;
                f5 = f3;
                f6 = f1;
                break;
            case 1:
                f4 = f2;
                f5 = value;
                f6 = f1;
                break;
            case 2:
                f4 = f1;
                f5 = value;
                f6 = f3;
                break;
            case 3:
                f4 = f1;
                f5 = f2;
                f6 = value;
                break;
            case 4:
                f4 = f3;
                f5 = f1;
                f6 = value;
                break;
            case 5:
                f4 = value;
                f5 = f1;
                f6 = f2;
                break;
            default:
                throw new RuntimeException(
                        "Something went wrong when converting from HSV to RGB. Input was " + hue + ", " + saturation +
                        ", " + value);
        }

        int j = clamp((int) (f4 * 255.0F), 0, 255);
        int k = clamp((int) (f5 * 255.0F), 0, 255);
        int l = clamp((int) (f6 * 255.0F), 0, 255);
        return j << 16 | k << 8 | l;
    }

    @StableAPI.Expose
    public static int hash(int x) {
        x = x ^ x >>> 16;
        x = x * -2048144789;
        x = x ^ x >>> 13;
        x = x * -1028477387;
        x = x ^ x >>> 16;
        return x;
    }
}