You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
57 lines
1.3 KiB
57 lines
1.3 KiB
4 years ago
|
package archiver
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
"io"
|
||
|
|
"path/filepath"
|
||
|
|
|
||
|
|
"github.com/pierrec/lz4"
|
||
|
|
)
|
||
|
|
|
||
|
|
// Lz4 facilitates LZ4 compression.
|
||
|
|
type Lz4 struct {
|
||
|
|
CompressionLevel int
|
||
|
|
}
|
||
|
|
|
||
|
|
// Compress reads in, compresses it, and writes it to out.
|
||
|
|
func (lz *Lz4) Compress(in io.Reader, out io.Writer) error {
|
||
|
|
w := lz4.NewWriter(out)
|
||
|
|
w.Header.CompressionLevel = lz.CompressionLevel
|
||
|
|
defer w.Close()
|
||
|
|
_, err := io.Copy(w, in)
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
|
||
|
|
// Decompress reads in, decompresses it, and writes it to out.
|
||
|
|
func (lz *Lz4) Decompress(in io.Reader, out io.Writer) error {
|
||
|
|
r := lz4.NewReader(in)
|
||
|
|
_, err := io.Copy(out, r)
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
|
||
|
|
// CheckExt ensures the file extension matches the format.
|
||
|
|
func (lz *Lz4) CheckExt(filename string) error {
|
||
|
|
if filepath.Ext(filename) != ".lz4" {
|
||
|
|
return fmt.Errorf("filename must have a .lz4 extension")
|
||
|
|
}
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func (lz *Lz4) String() string { return "lz4" }
|
||
|
|
|
||
|
|
// NewLz4 returns a new, default instance ready to be customized and used.
|
||
|
|
func NewLz4() *Lz4 {
|
||
|
|
return &Lz4{
|
||
|
|
CompressionLevel: 9, // https://github.com/lz4/lz4/blob/1b819bfd633ae285df2dfe1b0589e1ec064f2873/lib/lz4hc.h#L48
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Compile-time checks to ensure type implements desired interfaces.
|
||
|
|
var (
|
||
|
|
_ = Compressor(new(Lz4))
|
||
|
|
_ = Decompressor(new(Lz4))
|
||
|
|
)
|
||
|
|
|
||
|
|
// DefaultLz4 is a default instance that is conveniently ready to use.
|
||
|
|
var DefaultLz4 = NewLz4()
|