gf

package
Version: v0.6.2 Latest Latest
Warning

This package is not in the latest version of its module.

Go to latest
Published: Jun 17, 2015 License: AGPL-3.0, BSD-3-Clause Imports: 1 Imported by: 0

Documentation

Overview

Package gf implements arithmetic over Galois Fields. Generalized for any valid order.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type Field

type Field struct {
	// contains filtered or unexported fields
}

A Field represents an instance of GF(order) defined by a specific polynomial.

func NewField

func NewField(order, poly, α int) *Field

NewField returns a new field corresponding to the polynomial poly and generator α. The choice of generator α only affects the Exp and Log operations.

func (*Field) Add

func (f *Field) Add(x, y byte) byte

Add returns the sum of x and y in the field.

func (*Field) Exp

func (f *Field) Exp(e int) byte

Exp returns the base-α exponential of e in the field. If e < 0, Exp returns 0.

func (*Field) Inv

func (f *Field) Inv(x byte) byte

Inv returns the multiplicative inverse of x in the field. If x == 0, Inv returns 0.

func (*Field) Log

func (f *Field) Log(x byte) int

Log returns the base-α logarithm of x in the field. If x == 0, Log returns -1.

func (*Field) Mul

func (f *Field) Mul(x, y byte) byte

Mul returns the product of x and y in the field.

func (*Field) Syndrome

func (f *Field) Syndrome(message []byte, paritySymbolCount, offset int) (syndrome []byte)

Calculate syndrome for a message encoded using the field generated for a particular Reed-Solomon polynomial. Offset defines the coefficient offset.

Source Files

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL