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/10.1109/26.231911Castagnoli = 0x82f63b78// Koopman's polynomial.// Also has better error detection characteristics than IEEE.//https://dx.doi.org/10.1109/DSN.2002.1028931Koopman = 0xeb31d82e)

const Size = 4

var IEEETable = simpleMakeTable(IEEE)

funcChecksum¶

func Checksum(data []byte, tab *Table)uint32

Checksum returns the CRC-32 checksum of datausing the polynomial represented by theTable.

funcChecksumIEEE¶

func ChecksumIEEE(data []byte)uint32

ChecksumIEEE returns the CRC-32 checksum of datausing theIEEE polynomial.

funcNew¶

func New(tab *Table)hash.Hash32

New creates a newhash.Hash32 computing the CRC-32 checksum using thepolynomial represented by theTable. Its Sum method will lay thevalue out in big-endian byte order. The returned Hash32 alsoimplementsencoding.BinaryMarshaler andencoding.BinaryUnmarshaler tomarshal and unmarshal the internal state of the hash.

funcNewIEEE¶

func NewIEEE()hash.Hash32

NewIEEE creates a newhash.Hash32 computing the CRC-32 checksum usingtheIEEE polynomial. Its Sum method will lay the value out inbig-endian byte order. The returned Hash32 also implementsencoding.BinaryMarshaler andencoding.BinaryUnmarshaler to marshaland unmarshal the internal state of the hash.

funcUpdate¶

func Update(crcuint32, tab *Table, p []byte)uint32

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

typeTable¶

type Table [256]uint32

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

func MakeTable(polyuint32) *Table

package mainimport ("fmt""hash/crc32")func main() {// In this package, the CRC polynomial is represented in reversed notation,// or LSB-first representation.//// LSB-first representation is a hexadecimal number with n bits, in which the// most significant bit represents the coefficient of x⁰ and the least significant// bit represents the coefficient of xⁿ⁻¹ (the coefficient for xⁿ is implicit).//// For example, CRC32-Q, as defined by the following polynomial,//x³²+ x³¹+ x²⁴+ x²²+ x¹⁶+ x¹⁴+ x⁸+ x⁷+ x⁵+ x³+ x¹+ x⁰// has the reversed notation 0b11010101100000101000001010000001, so the value// that should be passed to MakeTable is 0xD5828281.crc32q := crc32.MakeTable(0xD5828281)fmt.Printf("%08x\n", crc32.Checksum([]byte("Hello world"), crc32q))}

Output:2964d064