Adding upstream version 3.5.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

bz2.go

@@ -0,0 +1,64 @@
+package archiver
+
+import (
+	"fmt"
+	"io"
+	"path/filepath"
+
+	"github.com/dsnet/compress/bzip2"
+)
+
+// Bz2 facilitates bzip2 compression.
+type Bz2 struct {
+	CompressionLevel int
+}
+
+// Compress reads in, compresses it, and writes it to out.
+func (bz *Bz2) Compress(in io.Reader, out io.Writer) error {
+	w, err := bzip2.NewWriter(out, &bzip2.WriterConfig{
+		Level: bz.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 (bz *Bz2) Decompress(in io.Reader, out io.Writer) error {
+	r, err := bzip2.NewReader(in, nil)
+	if err != nil {
+		return err
+	}
+	defer r.Close()
+	_, err = io.Copy(out, r)
+	return err
+}
+
+// CheckExt ensures the file extension matches the format.
+func (bz *Bz2) CheckExt(filename string) error {
+	if filepath.Ext(filename) != ".bz2" {
+		return fmt.Errorf("filename must have a .bz2 extension")
+	}
+	return nil
+}
+
+func (bz *Bz2) String() string { return "bz2" }
+
+// NewBz2 returns a new, default instance ready to be customized and used.
+func NewBz2() *Bz2 {
+	return &Bz2{
+		CompressionLevel: bzip2.DefaultCompression,
+	}
+}
+
+// Compile-time checks to ensure type implements desired interfaces.
+var (
+	_ = Compressor(new(Bz2))
+	_ = Decompressor(new(Bz2))
+)
+
+// DefaultBz2 is a default instance that is conveniently ready to use.
+var DefaultBz2 = NewBz2()