Package com.google.zxing.common.reedsolomon

Class GenericGFPoly

java.lang.Object

com.google.zxing.common.reedsolomon.GenericGFPoly

final class GenericGFPoly
extends Object

Represents a polynomial whose coefficients are elements of a GF. Instances of this class are immutable.

Much credit is due to William Rucklidge since portions of this code are an indirect port of his C++ Reed-Solomon implementation.

Author:

Sean Owen

Constructor Summary

Constructors

Constructor	Description
GenericGFPoly(GenericGF field, int[] coefficients)

Method Summary

Modifier and Type	Method	Description
(package private) GenericGFPoly	addOrSubtract(GenericGFPoly other)
(package private) GenericGFPoly[]	divide(GenericGFPoly other)
(package private) int	evaluateAt(int a)
(package private) int	getCoefficient(int degree)
(package private) int[]	getCoefficients()
(package private) int	getDegree()
(package private) boolean	isZero()
(package private) GenericGFPoly	multiply(int scalar)
(package private) GenericGFPoly	multiply(GenericGFPoly other)
(package private) GenericGFPoly	multiplyByMonomial(int degree, int coefficient)
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

GenericGFPoly

GenericGFPoly(GenericGF field,
              int[] coefficients)

Parameters:

field - the GenericGF instance representing the field to use to perform computations

coefficients - coefficients as ints representing elements of GF(size), arranged from most significant (highest-power term) coefficient to least significant

Throws:

IllegalArgumentException - if argument is null or empty, or if leading coefficient is 0 and this is not a constant polynomial (that is, it is not the monomial "0")

Method Detail

getCoefficients

int[] getCoefficients()

getDegree

int getDegree()

Returns:

degree of this polynomial

isZero

boolean isZero()

Returns:

true iff this polynomial is the monomial "0"

getCoefficient

int getCoefficient(int degree)

Returns:

coefficient of x^degree term in this polynomial

evaluateAt

int evaluateAt(int a)

Returns:

evaluation of this polynomial at a given point

addOrSubtract

GenericGFPoly addOrSubtract(GenericGFPoly other)

multiply

GenericGFPoly multiply(GenericGFPoly other)

multiply

GenericGFPoly multiply(int scalar)

multiplyByMonomial

GenericGFPoly multiplyByMonomial(int degree,
                                 int coefficient)

divide

GenericGFPoly[] divide(GenericGFPoly other)

toString

public String toString()

Overrides:

toString in class Object