71 lines
1.6 KiB
Go
71 lines
1.6 KiB
Go
// 提供CRC32校验和计算功能
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package crc32
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import (
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"encoding/hex"
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"fmt"
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"hash/crc32"
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"io"
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"os"
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)
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type CRC32Mode int
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const (
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IEEE CRC32Mode = iota
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Castagnoli
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Koopman
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)
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// 选择一个CRC32校验表
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func tableSelect(mode CRC32Mode) *crc32.Table {
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switch mode {
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case IEEE:
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return crc32.IEEETable
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case Castagnoli:
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return crc32.MakeTable(crc32.Castagnoli)
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case Koopman:
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return crc32.MakeTable(crc32.Koopman)
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default:
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return crc32.IEEETable
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}
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}
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// 计算给定字节数组的CRC32校验和，返回字节数组
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func CRC32(data []byte, mode ...CRC32Mode) []byte {
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crcTable := append(mode, IEEE)
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hasher := crc32.New(tableSelect(crcTable[0]))
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hasher.Write(data)
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return hasher.Sum(nil)
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}
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// 计算给定字节数组的CRC32校验和，返回十六进制字符串
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func CRC32Hex(data []byte, mode ...CRC32Mode) string {
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return hex.EncodeToString(CRC32(data, mode...))
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}
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// 计算指定文件的CRC32校验和，返回字节数组
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func SumFile(file string, mode ...CRC32Mode) ([]byte, error) {
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f, err := os.Open(file)
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if err != nil {
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return nil, fmt.Errorf("未能打开指定文件，%w", err)
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}
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defer f.Close()
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crcTable := append(mode, IEEE)
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hasher := crc32.New(tableSelect(crcTable[0]))
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if _, err := io.Copy(hasher, f); err != nil {
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return nil, fmt.Errorf("未能读取指定文件的内容，%w", err)
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}
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return hasher.Sum(nil), nil
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}
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// 计算指定文件的CRC32校验和，返回十六进制字符串
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func SumFileHex(file string, mode ...CRC32Mode) (string, error) {
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hash, err := SumFile(file, mode...)
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if err != nil {
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return "", err
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}
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return hex.EncodeToString(hash), nil
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}
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