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package jcgp.backend.function;
/**
* Integer wrapper type for unsigned integer values.
* <br><br>
* Java offers no support for unsigned types save from
* unsigned conversion methods. This class uses those methods
* to simulate the unsigned int data type, useful for circuit
* truth table encodings.
* <br><br>
* When a string representation of an unsigned integer is parsed
* using Integer.parseUnsignedInt(), an Integer is created using
* all 32 bits for unsigned magnitude. The integer however is still
* signed and will behave as such for all arithmetic operations.
* Bitwise operations can still be performed as they work at the bit
* level, making this data type particularly suitable for circuit design.
* <br><br>
* TODO in the unlikely event that unsigned integers are natively
* implemented in Java, they should be used instead of this class.
* <br><br>
* Why are unsigned integers not supported?<br>
* http://stackoverflow.com/questions/430346/why-doesnt-java-support-unsigned-ints
*
* @author Eduardo Pedroni
* @see Integer
*
*/
public class UnsignedInteger {
private Integer value;
/**
* Makes a new instance of UnsignedInteger with a specified value.
*
* @param i the value with which to initialise.
*/
public UnsignedInteger(int i) {
value = new Integer(i);
}
/**
* Makes a new instance of UnsignedInteger from the string representation
* of an unsigned integer.
*
* @param i the string with which to initialise.
*/
public UnsignedInteger(String i) {
value = Integer.parseUnsignedInt(i);
}
/**
* @return the wrapped Integer object.
*/
public Integer get() {
return value;
}
@Override
public String toString() {
/*
* It is important to override this so that
* the visual representation of the integer
* is unsigned as well.
*/
return Integer.toUnsignedString(value);
}
}
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