From 190dd364905c979549f967625427e701bc158140 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BE=90=E6=B6=9B?= <midnite@outlook.com>
Date: Tue, 25 Jul 2023 23:11:48 +0800
Subject: [PATCH] =?UTF-8?q?enhance(crc):CRC=E7=B3=BB=E5=88=97=E6=A0=A1?=
 =?UTF-8?q?=E9=AA=8C=E7=AE=97=E6=B3=95=E5=A2=9E=E5=8A=A0=E4=BD=BF=E7=94=A8?=
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Content-Transfer-Encoding: 8bit

---
 cmd/crc16.go    |  7 +++++++
 cmd/crc32.go    |  7 +++++++
 cmd/crc64.go    |  7 +++++++
 types/endian.go | 28 ++++++++++++++++++++++++++++
 4 files changed, 49 insertions(+)
 create mode 100644 types/endian.go

diff --git a/cmd/crc16.go b/cmd/crc16.go
index 50a6a52..342ec81 100644
--- a/cmd/crc16.go
+++ b/cmd/crc16.go
@@ -11,6 +11,7 @@ import (
 
 var (
 	crc16Algorithm types.CRC16Algorithm = types.CRC16_IBM
+	crc16Endian    types.Endian         = types.LittleEndian
 	crc16File      bool
 )
 
@@ -36,6 +37,11 @@ func crc16Execute(cmd *cobra.Command, args []string) {
 		fmt.Printf("计算CRC16校验值时发生错误：%s\n", err)
 		return
 	}
+	if crc16Endian == types.LittleEndian {
+		for i, j := 0, len(result)-1; i < j; i, j = i+1, j-1 {
+			result[i], result[j] = result[j], result[i]
+		}
+	}
 	var builder strings.Builder
 	for _, b := range result {
 		builder.WriteString(fmt.Sprintf(" %02X", b))
@@ -45,6 +51,7 @@ func crc16Execute(cmd *cobra.Command, args []string) {
 
 func init() {
 	crc16Cmd.PersistentFlags().VarP(&crc16Algorithm, "algorithm", "a", "CRC16算法，可选值有：ccitt, ccitt-false, scsi, ibm, mbus，缺省值为ibm。")
+	crc16Cmd.PersistentFlags().VarP(&crc16Endian, "endian", "e", "字节序，可选值有：big, little，缺省值为little。")
 	crc16Cmd.PersistentFlags().BoolVarP(&crc16File, "file", "f", false, "从文件中读取内容")
 	rootCmd.AddCommand(crc16Cmd)
 }
diff --git a/cmd/crc32.go b/cmd/crc32.go
index e0b8818..314fee7 100644
--- a/cmd/crc32.go
+++ b/cmd/crc32.go
@@ -11,6 +11,7 @@ import (
 
 var (
 	crc32Algorithm types.CRC32Algorithm = types.CRC32_IEEE
+	crc32Endian    types.Endian         = types.LittleEndian
 	crc32File      bool
 )
 
@@ -36,6 +37,11 @@ func crc32Execute(cmd *cobra.Command, args []string) {
 		fmt.Printf("计算CRC32校验值时发生错误：%s\n", err)
 		return
 	}
+	if crc32Endian == types.LittleEndian {
+		for i, j := 0, len(result)-1; i < j; i, j = i+1, j-1 {
+			result[i], result[j] = result[j], result[i]
+		}
+	}
 	var builder strings.Builder
 	for _, b := range result {
 		builder.WriteString(fmt.Sprintf(" %02X", b))
@@ -45,6 +51,7 @@ func crc32Execute(cmd *cobra.Command, args []string) {
 
 func init() {
 	crc32Cmd.PersistentFlags().VarP(&crc32Algorithm, "algorithm", "a", "CRC32算法，可选值有：ieee, castagnoli, koopman，缺省值为ieee。")
+	crc32Cmd.PersistentFlags().VarP(&crc32Endian, "endian", "e", "字节序，可选值有：big, little，缺省值为little。")
 	crc32Cmd.PersistentFlags().BoolVarP(&crc32File, "file", "f", false, "从文件中读取内容")
 	rootCmd.AddCommand(crc32Cmd)
 }
diff --git a/cmd/crc64.go b/cmd/crc64.go
index 648a4aa..cb9003f 100644
--- a/cmd/crc64.go
+++ b/cmd/crc64.go
@@ -11,6 +11,7 @@ import (
 
 var (
 	crc64Algorithm types.CRC64Algorithm = types.CRC64_ISO
+	crc64Endian    types.Endian         = types.LittleEndian
 	crc64File      bool
 )
 
@@ -36,6 +37,11 @@ func crc64Execute(cmd *cobra.Command, args []string) {
 		fmt.Printf("计算CRC64校验值时发生错误：%s\n", err)
 		return
 	}
+	if crc64Endian == types.LittleEndian {
+		for i, j := 0, len(result)-1; i < j; i, j = i+1, j-1 {
+			result[i], result[j] = result[j], result[i]
+		}
+	}
 	var builder strings.Builder
 	for _, b := range result {
 		builder.WriteString(fmt.Sprintf(" %02X", b))
@@ -45,6 +51,7 @@ func crc64Execute(cmd *cobra.Command, args []string) {
 
 func init() {
 	crc64Cmd.PersistentFlags().VarP(&crc64Algorithm, "algorithm", "a", "CRC64算法，可选值有：iso, ecma，缺省值为iso。")
+	crc64Cmd.PersistentFlags().VarP(&crc64Endian, "endian", "e", "字节序，可选值有：big, little，缺省值为little。")
 	crc64Cmd.PersistentFlags().BoolVarP(&crc64File, "file", "f", false, "从文件中读取内容")
 	rootCmd.AddCommand(crc64Cmd)
 }
diff --git a/types/endian.go b/types/endian.go
new file mode 100644
index 0000000..a6eaf53
--- /dev/null
+++ b/types/endian.go
@@ -0,0 +1,28 @@
+package types
+
+import "fmt"
+
+type Endian string
+
+const (
+	BigEndian    Endian = "big"
+	LittleEndian Endian = "little"
+)
+
+func (e *Endian) String() string {
+	return string(*e)
+}
+
+func (e *Endian) Set(s string) error {
+	switch s {
+	case "big", "little":
+		*e = Endian(s)
+		return nil
+	default:
+		return fmt.Errorf("不支持的字节序：%s", s)
+	}
+}
+
+func (e *Endian) Type() string {
+	return "Endian"
+}