豆子笔记

包 Hash 提供了哈希函数接口。 子包 crc32 实现 32 位循环冗余校验或 CRC-32 校验和。

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))
}