crc64

Documentation

Overview

Package crc64 implements the 64-bit cyclic redundancy check, or CRC-64, checksum. See http://en.wikipedia.org/wiki/Cyclic_redundancy_check for information.

Index

• Constants
• func Checksum(data []byte, tab *Table) uint64
• func New(tab *Table) hash.Hash64
• func Update(crc uint64, tab *Table, p []byte) uint64
• type Table
  • func MakeTable(poly uint64) *Table

Constants

const (
	// The ISO polynomial, defined in ISO 3309 and used in HDLC.
	ISO = 0xD800000000000000

	// The ECMA polynomial, defined in ECMA 182.
	ECMA = 0xC96C5795D7870F42
)

Predefined polynomials.

const Size = 8

The size of a CRC-64 checksum in bytes.

Functions

func Checksum

func Checksum(data []byte, tab *Table) uint64

Checksum returns the CRC-64 checksum of data using the polynomial represented by the Table.

func New

func New(tab *Table) hash.Hash64

New creates a new hash.Hash64 computing the CRC-64 checksum using the polynomial represented by the Table. Its Sum method will lay the value out in big-endian byte order. The returned Hash64 also implements encoding.BinaryMarshaler and encoding.BinaryUnmarshaler to marshal and unmarshal the internal state of the hash.

func Update

func Update(crc uint64, tab *Table, p []byte) uint64

Update returns the result of adding the bytes in p to the crc.

Types

type Table

type Table [256]uint64

Table is a 256-word table representing the polynomial for efficient processing.

func MakeTable

func MakeTable(poly uint64) *Table

MakeTable returns a Table constructed from the specified polynomial. The contents of this Table must not be modified.