// The MIT License (MIT)

//

// Copyright (c) 2017 Robert C. Seacord

//

// Permission is hereby granted, free of charge, to any person obtaining a copy

// of this software and associated documentation files (the "Software"), to deal

// in the Software without restriction, including without limitation the rights

// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the Software is

// furnished to do so, subject to the following conditions:

//

// The above copyright notice and this permission notice shall be included in all

// copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

// SOFTWARE.

package NUM03J;

import java.io.DataInputStream;

import java.io.DataOutputStream;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.math.BigInteger;

class UnsignedInteger {

// @return int read from specified DataInputStream

private static int getIntegerWrong(DataInputStream dis) throws IOException {

return dis.readInt();

}

// @return long read from specified DataInputStream

private static long getInteger(DataInputStream dis) throws IOException {

// The readInt() method assumes signed values and returns a signed int;

// the return value is converted to a long by sign extension. The code

// uses an & operation to mask off the upper 32 bits of the long,

// producing a value in the range of a 32-bit unsigned integer, as

// intended.

return dis.readInt() & 0xFFFFFFFFL; // mask with 32 one-bits

}

// @return long read from specified DataInputStream

private static long getULong(DataInputStream dis) throws IOException {

return dis.readLong();

}

public static void main(String[] args) throws IOException {

try (

// create output stream from file

DataOutputStream dos = new DataOutputStream(new FileOutputStream("test.txt"))//$NON-NLS-1$

) {

// write out "unsigned int" values

dos.writeInt(0xFFFFFFFF); // 4,294,967,295

dos.writeInt(0xFFFFFFFF); // 4294967295

dos.writeInt(0xFFFFFFFF); // 4294967295

dos.writeInt(0xFFFFFFFF); // 4294967295

}

// create input stream from file input stream

FileInputStream is = new FileInputStream("test.txt"); //$NON-NLS-1$

// create data input stream

try (DataInputStream dis = new DataInputStream(is)) {

int int_a = getIntegerWrong(dis);

System.out.println("incorrect value = " + int_a); //$NON-NLS-1$

long long_a = getInteger(dis);

System.out.println("correct value = " + long_a); //$NON-NLS-1$

// answer should be 18446744073709551615UL

Long long_bi = getULong(dis);

BigInteger bi = new BigInteger(long_bi.toString());

// add 2^^64 if the sign bit is set

if (bi.testBit(63))

bi = bi.add(new BigInteger("2").pow(64)); //$NON-NLS-1$

System.out.println("bi = " + bi); //$NON-NLS-1$

}

// ---------- Add code here -----------------------------

}

}

/*

* // Java SE 8 // Convert to unsigned string with a radix value of 10

* System.out.println("Unsigned Integer Max Value = " +

* Integer.toUnsignedString(int_a));

* System.out.println("Unsigned Long Max Value = " +

* Long.toUnsignedString(long_bi));

*

* // Divide Integer.MAX_VALUE by int_a (signed and unsigned)

* System.out.println("Signed quotient = " + Integer.MAX_VALUE / int_a);

* System.out.println("Unsigned quotient = " +

* Integer.divideUnsigned(Integer.MAX_VALUE, int_a));

*/