Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
import java.math.BigInteger;

public class Main {
    public static byte[] generateJSF(BigInteger g, BigInteger h) {
        byte[] jsf = new byte[(Math.max(g.bitLength(), h.bitLength()) + 1)];
        BigInteger k0 = g;
        BigInteger k1 = h;
        int d0 = 0;
        int d1 = 0;
        int offset = 0;
        int j = 0;
        while (true) {
            if ((d0 | d1) == 0 && k0.bitLength() <= offset && k1.bitLength() <= offset) {
                break;
            }
            int n0 = ((k0.intValue() >>> offset) + d0) & 7;
            int n1 = ((k1.intValue() >>> offset) + d1) & 7;
            int u0 = n0 & 1;
            if (u0 != 0) {
                u0 -= n0 & 2;
                if (n0 + u0 == 4 && (n1 & 3) == 2) {
                    u0 = -u0;
                }
            }
            int u1 = n1 & 1;
            if (u1 != 0) {
                u1 -= n1 & 2;
                if (n1 + u1 == 4 && (n0 & 3) == 2) {
                    u1 = -u1;
                }
            }
            if ((d0 << 1) == u0 + 1) {
                d0 ^= 1;
            }
            if ((d1 << 1) == u1 + 1) {
                d1 ^= 1;
            }
            offset++;
            if (offset == 30) {
                offset = 0;
                k0 = k0.shiftRight(30);
                k1 = k1.shiftRight(30);
            }
            int j2 = j + 1;
            jsf[j] = (byte) ((u0 << 4) | (u1 & 15));
            j = j2;
        }
        if (jsf.length > j) {
            return trim(jsf, j);
        }
        return jsf;
    }

    private static byte[] trim(byte[] a, int length) {
        byte[] result = new byte[length];
        System.arraycopy(a, 0, result, 0, result.length);
        return result;
    }

    private static int[] trim(int[] a, int length) {
        int[] result = new int[length];
        System.arraycopy(a, 0, result, 0, result.length);
        return result;
    }
}