freeacs/freeacs

/*
 * This file is part of JSTUN.
 *
 * Copyright (c) 2005 Thomas King <king@t-king.de> - All rights
 * reserved.
 *
 * This software is licensed under either the GNU Public License (GPL),
 * or the Apache 2.0 license. Copies of both license agreements are
 * included in this distribution.
 */
package de.javawi.jstun.util;

public class Utility {
  public static byte integerToOneByte(int value) throws UtilityException {
    if (value > Math.pow(2, 15) || value < 0) {
      throw new UtilityException("Integer value " + value + " is larger than 2^15");
    }
    return (byte) (value & 0xFF);
  }

  public static byte[] integerToTwoBytes(int value) throws UtilityException {
    byte[] result = new byte[2];
    if (value > Math.pow(2, 31) || value < 0) {
      throw new UtilityException("Integer value " + value + " is larger than 2^31");
    }
    result[0] = (byte) ((value >>> 8) & 0xFF);
    result[1] = (byte) (value & 0xFF);
    return result;
  }

  public static int oneByteToInteger(byte value) {
    return value & 0xFF;
  }

  public static int twoBytesToInteger(byte[] value) throws UtilityException {
    if (value.length < 2) {
      throw new UtilityException("Byte array too short!");
    }
    int temp0 = value[0] & 0xFF;
    int temp1 = value[1] & 0xFF;
    return (temp0 << 8) + temp1;
  }

  public static long fourBytesToLong(byte[] value) throws UtilityException {
    if (value.length < 4) {
      throw new UtilityException("Byte array too short!");
    }
    int temp0 = value[0] & 0xFF;
    int temp1 = value[1] & 0xFF;
    int temp2 = value[2] & 0xFF;
    int temp3 = value[3] & 0xFF;
    return ((long) temp0 << 24) + (temp1 << 16) + (temp2 << 8) + temp3;
  }
}