Class RationalNumber

java.lang.Object
java.lang.Number
org.apache.commons.imaging.common.RationalNumber
All Implemented Interfaces:
Serializable
public class RationalNumber extends Number
Rational number, as used by the TIFF image format.

The TIFF format specifies two data types for rational numbers based on a pair of 32-bit integers. Rational is based on unsigned 32-bit integers and SRational is based on signed 32-bit integers. This treatment is problematic in Java because Java does not support unsigned types. To address this challenge, this class stores the numerator and divisor in long (64-bit) integers, applying masks as necessary for the unsigned type.

See Also:

  • Field Details

    • serialVersionUID

      private static final long serialVersionUID
      See Also:

    • TOLERANCE

      private static final double TOLERANCE
      See Also:

    • SHALLOW_SIZE

      public static final int SHALLOW_SIZE
      See Also:

    • numerator

      public final long numerator

    • divisor

      public final long divisor

    • unsignedType

      public final boolean unsignedType

  • Constructor Details

    • RationalNumber

      public RationalNumber(int numerator, int divisor)
      Constructs an instance based on signed integers
      Parameters:
      numerator - a 32-bit signed integer
      divisor - a non-zero 32-bit signed integer

    • RationalNumber

      public RationalNumber(int numerator, int divisor, boolean unsignedType)
      Constructs an instance supports either signed or unsigned integers.
      Parameters:
      numerator - a numerator in the indicated form (signed or unsigned)
      divisor - a non-zero divisor in the indicated form (signed or unsigned)
      unsignedType - indicates whether the input values are to be treated as unsigned.

    • RationalNumber

      private RationalNumber(long numerator, long divisor, boolean unsignedType)
      A private constructor for methods such as negate() that create instances of this class using the content of the current instance.
      Parameters:
      numerator - a valid numerator
      divisor - a valid denominator
      unsignedType - indicates how numerator and divisor values are to be interpreted.

  • Method Details

    • factoryMethod

      static RationalNumber factoryMethod(long n, long d)

    • gcd

      private static long gcd(long a, long b)
      Gets the greatest common divisor

    • valueOf

      public static RationalNumber valueOf(double value)
      Calculate rational number using successive approximations.
      Parameters:
      value - rational number double value
      Returns:
      the RationalNumber representation of the double value

    • doubleValue

      public double doubleValue()
      Specified by:
      doubleValue in class Number

    • floatValue

      public float floatValue()
      Specified by:
      floatValue in class Number

    • intValue

      public int intValue()
      Specified by:
      intValue in class Number

    • longValue

      public long longValue()
      Specified by:
      longValue in class Number

    • negate

      public RationalNumber negate()
      Negates the value of the RationalNumber. If the numerator of this instance has its high-order bit set, then its value is too large to be treated as a Java 32-bit signed integer. In such a case, the only way that a RationalNumber instance can be negated is to divide both terms by a common divisor, if a non-zero common divisor exists. However, if no such divisor exists, there is no numerically correct way to perform the negation. When a negation cannot be performed correctly, this method throws an unchecked exception.
      Returns:
      a valid instance with a negated value.

    • toDisplayString

      public String toDisplayString()

    • toString

      public String toString()
      Overrides:
      toString in class Object