package de.tudarmstadt.informatik.hostage.protocol.SMBUtils;

import de.tudarmstadt.informatik.hostage.commons.HelperUtils;


public class NMBStringCoder {

	public static String decodeNBNSName(byte[] name) {
		byte a_ascii = (byte) 'A';
		byte[] reducedA = new byte[name.length];
		for (int i = 0; i < name.length; i++) {
			reducedA[i] = (byte)(name[i] - a_ascii);
		}
		byte[] converted = new byte[reducedA.length / 2];
		for (int i = 0, j = 0; i < name.length && j < converted.length; i+=2, j++) {
			byte b1 = (byte) (reducedA[i]<<4);
			byte b2 = reducedA[i+1];
			converted[j] = (byte) (b1 | b2);
		}
		return new String(converted);
	}
	
	public static byte[] encodeNBNSName(byte[] name) {
		byte a_ascii = (byte) 'A';
		byte[] bytes = name;
		byte[] converted = new byte[bytes.length * 2];
		for (int i = 0, j = 0; i < bytes.length && j < converted.length; i++, j+=2) {
			converted[j] = (byte)(bytes[i]>>4);
			converted[j+1] = (byte)(bytes[i] & 0x0F);
		}
		byte[] addedA = new byte[converted.length];
		for (int i = 0; i < converted.length; i++) {
			addedA[i] = (byte) (converted[i] + a_ascii);
		}
		return addedA;
	}
	
	public static byte[] wrapNBNSName(byte[] name, int service) {
		byte[] nameStart = {0x20};
		byte[] namePadding = null;
		if (name.length < 32) {
			int paddingLen = 32 - name.length;
			namePadding = new byte[paddingLen];
			for (int i = 0; i < namePadding.length; i+=2) {
				if (i == namePadding.length-2) {
					byte[] serviceBytes = NBNS.getServiceBytes(service);
					namePadding[i] = serviceBytes[0];
					namePadding[i+1] = serviceBytes[1];
				} else {
					namePadding[i] = 0x43;
					namePadding[i+1] = 0x041;
				}
			}
		}
		byte[] nameEnd = {0x00};
		return HelperUtils.concat(nameStart, name, namePadding, nameEnd);
	}
}