`package `**crc32**
Import Path
hash/crc32* (on golang.org and go.dev)*
Dependency Relation
imports 6 packages, and imported by 3 packages
Involved Source Files
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.
crc32_amd64.go
crc32_generic.go
crc32_amd64.s
Code Examples
package main
import (
"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))
}
Package-Level Type Names* (only one)*
Package-Level Functions* (total 6)*
Checksum returns the CRC-32 checksum of data
using the polynomial represented by the Table.
ChecksumIEEE returns the CRC-32 checksum of data
using the IEEE polynomial.
MakeTable returns a Table constructed from the specified polynomial.
The contents of this Table must not be modified.
New 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.
NewIEEE 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.
Update returns the result of adding the bytes in p to the crc.
Package-Level Variables* (only one)*
IEEETable is the table for the IEEE polynomial.
Package-Level Constants* (total 4)*
Castagnoli's polynomial, used in iSCSI.
Has better error detection characteristics than IEEE.
https://dx.doi.org/10.1109/26.231911
IEEE is by far and away the most common CRC-32 polynomial.
Used by ethernet (IEEE 802.3), v.42, fddi, gzip, zip, png, ...
Koopman's polynomial.
Also has better error detection characteristics than IEEE.
https://dx.doi.org/10.1109/DSN.2002.1028931
The size of a CRC-32 checksum in bytes.

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