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decompress.go
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decompress.go
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package cli
import (
"bufio"
"errors"
"io"
"os"
lzstring "github.com/daku10/go-lz-string"
"github.com/spf13/cobra"
)
func newDecompressCmd(config *Config) *cobra.Command {
var flagMethodEnum methodEnum = methodInvalidUTF16
var decompressCmd = &cobra.Command{
Use: "decompress",
Short: "decompress input using lz-string",
Long: `Decompress input using lz-string. If no file is specified, input is from standard input. Input format is depends on the compression method. Output format is UTF-8 string`,
Example: " go-lz-string decompress input.txt -m base64 -o output.txt",
Args: cobra.MaximumNArgs(1),
RunE: func(cmd *cobra.Command, args []string) error {
var inputFilename string
if len(args) > 0 {
inputFilename = args[0]
}
outputFilename, err := cmd.Flags().GetString("output")
if err != nil {
return err
}
var reader io.Reader
if inputFilename == "" {
reader = cmd.InOrStdin()
} else {
f, err := os.Open(inputFilename)
if err != nil {
return err
}
reader = f
defer f.Close()
}
var buf *bufio.Writer
if outputFilename == "" {
buf = bufio.NewWriter(cmd.OutOrStdout())
} else {
outputF, err := os.Create(outputFilename)
if err != nil {
return err
}
buf = bufio.NewWriter(outputF)
defer outputF.Close()
}
defer buf.Flush()
return doDecompress(reader, buf, flagMethodEnum)
},
}
decompressCmd.SetIn(config.In)
decompressCmd.SetOut(config.Out)
decompressCmd.SetErr(config.Err)
decompressCmd.Flags().StringP("output", "o", "", "Print the output to the output file instead of the standard output.")
decompressCmd.Flags().VarP(&flagMethodEnum, "method", "m", `Compression method.
invalid-utf16: invalid UTF-16(input format must be UTF-16 Little Endian No BOM. Sometimes it contains invalid UTF-16 code unit)
base64: base64(input format must be UTF-8)
utf16: valid UTF-16(input format must be UTF-16 Little Endian No BOM)
uint8array: uint8 array(input format must be []byte)
encodedURIComponent: URL safe strings like base64(input format must be UTF-8)
`)
return decompressCmd
}
func readAsUint16Array(reader io.Reader) ([]uint16, error) {
result := make([]uint16, 0)
tmp := make([]byte, 2)
for {
n, err := reader.Read(tmp)
if err == io.EOF {
break
}
if n != 2 {
return nil, errors.New("not Uint16 Array")
}
result = append(result, uint16(tmp[0])|uint16(tmp[1])<<8)
}
return result, nil
}
func doDecompress(reader io.Reader, writer io.Writer, method methodEnum) error {
var result string
switch method {
case methodInvalidUTF16:
input, err := readAsUint16Array(reader)
if err != nil {
return err
}
result, err = lzstring.Decompress(input)
if err != nil {
return err
}
case methodUTF16:
input, err := readAsUint16Array(reader)
if err != nil {
return err
}
result, err = lzstring.DecompressFromUTF16(input)
if err != nil {
return err
}
case methodBase64:
input, err := io.ReadAll(reader)
if err != nil {
return err
}
inputString := string(input)
result, err = lzstring.DecompressFromBase64(inputString)
if err != nil {
return err
}
case methodEncodedURIComponent:
input, err := io.ReadAll(reader)
if err != nil {
return err
}
inputString := string(input)
result, err = lzstring.DecompressFromEncodedURIComponent(inputString)
if err != nil {
return err
}
case methodUint8Array:
input, err := io.ReadAll(reader)
if err != nil {
return err
}
result, err = lzstring.DecompressFromUint8Array(input)
if err != nil {
return err
}
default:
return errors.New("invalid method is specified")
}
_, err := writer.Write([]byte(result))
if err != nil {
return err
}
return nil
}