package archiver import ( "fmt" "io" "path/filepath" "github.com/klauspost/compress/gzip" "github.com/klauspost/pgzip" ) // Gz facilitates gzip compression. type Gz struct { CompressionLevel int SingleThreaded bool } // Compress reads in, compresses it, and writes it to out. func (gz *Gz) Compress(in io.Reader, out io.Writer) error { var w io.WriteCloser var err error if gz.SingleThreaded { w, err = gzip.NewWriterLevel(out, gz.CompressionLevel) } else { w, err = pgzip.NewWriterLevel(out, gz.CompressionLevel) } if err != nil { return err } defer w.Close() _, err = io.Copy(w, in) return err } // Decompress reads in, decompresses it, and writes it to out. func (gz *Gz) Decompress(in io.Reader, out io.Writer) error { var r io.ReadCloser var err error if gz.SingleThreaded { r, err = gzip.NewReader(in) } else { r, err = pgzip.NewReader(in) } if err != nil { return err } defer r.Close() _, err = io.Copy(out, r) return err } // CheckExt ensures the file extension matches the format. func (gz *Gz) CheckExt(filename string) error { if filepath.Ext(filename) != ".gz" { return fmt.Errorf("filename must have a .gz extension") } return nil } func (gz *Gz) String() string { return "gz" } // NewGz returns a new, default instance ready to be customized and used. func NewGz() *Gz { return &Gz{ CompressionLevel: gzip.DefaultCompression, } } // Compile-time checks to ensure type implements desired interfaces. var ( _ = Compressor(new(Gz)) _ = Decompressor(new(Gz)) ) // DefaultGz is a default instance that is conveniently ready to use. var DefaultGz = NewGz()