Package crc32
Overview ▹
Overview ▾
Package crc32 implements the 32-bit cyclic redundancy check, or CRC-32, checksum. See https://en.wikipedia.org/wiki/Cyclic_redundancy_check for information.
Polynomials are represented in LSB-first form also known as reversed representation.
See https://en.wikipedia.org/wiki/Mathematics_of_cyclic_redundancy_checks#Reversed_representations_and_reciprocal_polynomials for information.
Index ▹
Constants
Predefined polynomials.
const (
// IEEE is by far and away the most common CRC-32 polynomial.
// Used by ethernet (IEEE 802.3), v.42, fddi, gzip, zip, png, ...
IEEE = 0xedb88320
// Castagnoli's polynomial, used in iSCSI.
// Has better error detection characteristics than IEEE.
// https://dx.doi.org/10.1109/26.231911
Castagnoli = 0x82f63b78
// Koopman's polynomial.
// Also has better error detection characteristics than IEEE.
// https://dx.doi.org/10.1109/DSN.2002.1028931
Koopman = 0xeb31d82e
)The size of a CRC-32 checksum in bytes.
const Size = 4Variables
IEEETable is the table for the IEEE polynomial.
var IEEETable = simpleMakeTable(IEEE)func Checksum
func Checksum(data []byte, tab *Table) uint32Checksum returns the CRC-32 checksum of data using the polynomial represented by the Table.
func ChecksumIEEE
func ChecksumIEEE(data []byte) uint32ChecksumIEEE returns the CRC-32 checksum of data using the IEEE polynomial.
func New
func New(tab *Table) hash.Hash32New creates a new hash.Hash32 computing the CRC-32 checksum using the polynomial represented by the Table. Its Sum method will lay the value out in big-endian byte order. The returned Hash32 also implements encoding.BinaryMarshaler and encoding.BinaryUnmarshaler to marshal and unmarshal the internal state of the hash.
func NewIEEE
func NewIEEE() hash.Hash32NewIEEE creates a new hash.Hash32 computing the CRC-32 checksum using the IEEE polynomial. Its Sum method will lay the value out in big-endian byte order. The returned Hash32 also implements encoding.BinaryMarshaler and encoding.BinaryUnmarshaler to marshal and unmarshal the internal state of the hash.
func Update
func Update(crc uint32, tab *Table, p []byte) uint32Update returns the result of adding the bytes in p to the crc.
type Table
Table is a 256-word table representing the polynomial for efficient processing.
type Table [256]uint32func MakeTable
func MakeTable(poly uint32) *TableMakeTable returns a Table constructed from the specified polynomial. The contents of this Table must not be modified.
▹ Example
▾ Example
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