Response.java

import java.io.*;
import java.net.*;
import java.util.HexFormat;
import java.util.Random;


public class Response {

    private int cursor;
    private byte[] data;
    private int response_id;
    private int QR;
    private int ANCOUNT;
    private int NSCOUNT;
    private int ARCOUNT;
    private int authority;
    private int truncated;
    private int rcode;
    private String[] answersName;
    private String[] answersAddress;
    private String[] nameServersName;
    private String[] nameServersAddress;


    public Response(byte[] responseData) {
        data = responseData;
        cursor = 11;
        response_id = this.data[1];
        QR = this.data[2] >> 7;
        authority = (this.data[2] >> 2) & 1;
        truncated = (this.data[2] >> 1) & 1;
        rcode = this.data[3];
        ANCOUNT = this.data[7];
        NSCOUNT = this.data[9];
        ARCOUNT = this.data[11];
        this.answersName = new String[ANCOUNT];
        this.answersAddress = new String[ANCOUNT];
        this.nameServersName = new String[NSCOUNT];
        this.nameServersAddress = new String[NSCOUNT];

        while(this.data[cursor] != 1){
            cursor += 1;
        }
        
        cursor += 3;


        for (int resI = 0; resI < ANCOUNT; resI++){

            this.answersName[resI] = getName();
            cursor += 10;
            
            this.answersAddress[resI] = parseAnswer();
        }

        for (int resI = 0; resI < NSCOUNT; resI++){
            this.nameServersName[resI] = getName();
            cursor += 10;
            
            this.nameServersAddress[resI] = getServerName();
            cursor += 1;
        }
    }

    private String getCompressedName(int compressedCursor) {
        String address = "";

        while (this.data[compressedCursor] != 0) {
            byte byteVal = (byte)HexFormat.fromHexDigits("C0");


            int length = this.data[compressedCursor] & 0xFF ;

            if (this.data[compressedCursor] == byteVal){
                compressedCursor += 1;
                address += getCompressedName(this.data[compressedCursor]);
                return address;
            }
            else {
                for(int x = 0; x <= length; x++){
                    if (this.data[compressedCursor] == 0) {
                        break;
                    }
                    if (this.data[compressedCursor] < 0x10){
                        address += '.';
                    }
                    else{
                        address += (char)this.data[compressedCursor];
                    }
                    compressedCursor += 1;
                }
            }

        }
        
        return address;
    }

    public String getName() {
        String address = "";
        byte byteVal = (byte)HexFormat.fromHexDigits("C0");


        while (this.data[cursor] != 0){

            if (this.data[cursor] == byteVal){
                cursor += 1;
                address += getCompressedName(this.data[cursor]);
                return address;
            }
            else {
                int length = this.data[cursor] & 0xFF;
                cursor += 1;
                for(int x = 0; x < length; x++){
                    if (this.data[cursor] == byteVal){
                        cursor += 1;
                        address += getCompressedName(this.data[cursor]);
                        return address;
                    }
                    else{
                        if (this.data[cursor] < 0x10){
                            address += '.';
                        }
                        else{
                            address += (char)this.data[cursor];
                        }
                        cursor += 1;
                    }
                }
                address += '.';
            }
        }

        return address;
    }

    private String getCompressedServerName(int compressedCursor) {
        String address = "";

        while (this.data[compressedCursor] != 0) {
            byte byteVal = (byte)HexFormat.fromHexDigits("C0");


            int length = this.data[compressedCursor] & 0xFF;

            if (this.data[compressedCursor] == byteVal){
                compressedCursor += 1;
                address += getCompressedServerName(this.data[compressedCursor]);
                return address;
            }
            else {
                for(int x = 0; x <= length; x++){
                    if (this.data[compressedCursor] == 0) {
                        break;
                    }
                    if (this.data[compressedCursor] < 0x10){
                        address += '.';
                    }
                    else{
                        address += (char)this.data[compressedCursor];
                    }
                    compressedCursor += 1;
                }
            }

        }
        
        return address;
    }

    private String getServerName() {
        String address = "";
        byte byteVal = (byte)HexFormat.fromHexDigits("C0");


        while (this.data[cursor] != 0){

            if (this.data[cursor] == byteVal){
                cursor += 1;
                address += getCompressedServerName(this.data[cursor] & 0xFF);
                return address;
            }
            else {
                int length = this.data[cursor]  & 0xFF;
                cursor += 2;
                for(int x = 0; x < length - 2; x++){
                    if (this.data[cursor] == byteVal){
                        cursor += 1;
                        address += getCompressedServerName(this.data[cursor] & 0xFF);
                        return address;
                    }
                    else{
                        if (this.data[cursor] < 0x10){
                            address += '.';
                        }
                        else{
                            address += (char)this.data[cursor];
                        }
                        cursor += 1;
                    }
                }
            }
        }

        return address;
    }


    private String parseAnswer() {
        String address = "";
        byte byteVal = (byte)HexFormat.fromHexDigits("C0");

        while (this.data[cursor] != 0){

            if (this.data[cursor] == byteVal){
                cursor += 1;
                address += getCompressedServerName(this.data[cursor]);
                return address;
            }
            else {
                int length = this.data[cursor] & 0xFF;
                cursor += 1;
                for(int x = 0; x < length; x++){

                    if (this.data[cursor] == byteVal){
                        cursor += 1;
                        address += getCompressedServerName(this.data[cursor]);
                        return address;
                    }
                    else{
                        address += (int)this.data[cursor] & 0xFF;
                        address += '.';
                        cursor += 1;
                    }
                }
                break;
            }
        }

        return address;
    }


    public int getAnswersCount(){
        return this.ANCOUNT;
    }

    public int getNameServerCount(){
        return this.NSCOUNT;
    }

    public String[] getAnswersNames(){
        return this.answersName;
    }

    public String[] getAnswersAddress(){
        return this.answersAddress;
    }

    public String[] getNameServersName(){
        return this.nameServersName;
    }

    public String[] getNameServersAddress(){
        return this.nameServersAddress;
    }

    public byte[] getRawResponse(){
        return this.data;
    }

    public boolean isTruncated(){
        return this.truncated == 1;
    }

    public boolean isAuthority(){
        return this.authority == 1;
    }

    public boolean isError(){
        return this.rcode != 0;
    }

    public int errorCode(){
        return this.rcode;
    }
}