add more algo

commands/crc16/crc16.go

@@ -0,0 +1,112 @@
+package crc16
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"hash_utils/tools"
+	"os"
+
+	"github.com/google/subcommands"
+	"github.com/sigurn/crc16"
+)
+
+type (
+	CRC16Cmd struct {
+		file  string
+		table string
+	}
+)
+
+var (
+	tables = []crc16.Params{
+		crc16.CRC16_ARC,
+		crc16.CRC16_AUG_CCITT,
+		crc16.CRC16_BUYPASS,
+		crc16.CRC16_CCITT_FALSE,
+		crc16.CRC16_CDMA2000,
+		crc16.CRC16_CRC_A,
+		crc16.CRC16_DDS_110,
+		crc16.CRC16_DECT_R,
+		crc16.CRC16_DECT_X,
+		crc16.CRC16_DNP,
+		crc16.CRC16_EN_13757,
+		crc16.CRC16_GENIBUS,
+		crc16.CRC16_KERMIT,
+		crc16.CRC16_MAXIM,
+		crc16.CRC16_MCRF4XX,
+		crc16.CRC16_MODBUS,
+		crc16.CRC16_RIELLO,
+		crc16.CRC16_T10_DIF,
+		crc16.CRC16_TELEDISK,
+		crc16.CRC16_TMS37157,
+		crc16.CRC16_USB,
+		crc16.CRC16_XMODEM,
+		crc16.CRC16_X_25,
+	}
+)
+
+func (*CRC16Cmd) Name() string     { return "crc16" }
+func (*CRC16Cmd) Synopsis() string { return "" }
+func (*CRC16Cmd) Usage() string {
+	res := "Usage: hash_utils crc16\n\n"
+	res += "Algorithm available:\n"
+	for _, table := range tables {
+		res += "  - " + table.Name + "\n"
+	}
+	res += "\nOptions:\n"
+	return res
+}
+
+func (p *CRC16Cmd) SetFlags(f *flag.FlagSet) {
+	f.StringVar(&p.file, "file", "", "get the checksum of a file")
+	f.StringVar(&p.table, "table", crc16.CRC16_ARC.Name, "Predefined CRC-16 algorithms")
+}
+
+func (p *CRC16Cmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) subcommands.ExitStatus {
+	var err error
+	param := crc16.CRC16_ARC
+	if len(p.table) > 0 {
+		param, err = parse(p.table)
+		if err != nil {
+			fmt.Printf("Available tables: ")
+			for _, table := range tables {
+				fmt.Printf("%s ", table.Name)
+			}
+			fmt.Println()
+			fmt.Fprintln(os.Stderr, "error:", err)
+
+			return subcommands.ExitFailure
+		}
+	}
+
+	if len(p.file) > 0 {
+		b, err := os.ReadFile(p.file)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, "error: failed to read file:", err)
+			return subcommands.ExitFailure
+		}
+
+		h := tools.CRC16(b, param)
+
+		fmt.Printf("%s: %s\n", f.Name(), h)
+
+		return subcommands.ExitSuccess
+	}
+
+	for _, arg := range f.Args() {
+		h := tools.CRC16([]byte(arg), param)
+		fmt.Printf("%s: %s\n", arg, h)
+	}
+
+	return subcommands.ExitSuccess
+}
+
+func parse(tableName string) (crc16.Params, error) {
+	for _, table := range tables {
+		if table.Name == tableName {
+			return table, nil
+		}
+	}
+	return crc16.CRC16_ARC, fmt.Errorf("invalid table name: %s", tableName)
+}