Adding erasure package to wrap versioned erasure. Ensures we always write latest version.

pkg/storage/donut/erasure/erasure.go

@@ -0,0 +1,37 @@
+package erasure
+
+import (
+	"errors"
+	"io"
+
+	"github.com/minio-io/minio/pkg/storage/donut/erasure/erasure1"
+)
+
+type EncoderTechnique int
+
+const (
+	// Vandermonde matrix type
+	Vandermonde EncoderTechnique = iota
+	// Cauchy matrix type
+	Cauchy
+)
+
+// Write latest donut format
+func Write(target io.Writer, key string, part uint8, length uint32, k, m uint8, technique EncoderTechnique, data io.Reader) error {
+	var versionedTechnique erasure1.EncoderTechnique
+	switch {
+	case technique == Vandermonde:
+		versionedTechnique = erasure1.Vandermonde
+	case technique == Cauchy:
+		versionedTechnique = erasure1.Cauchy
+	default:
+		errors.New("Unknown encoder technique")
+	}
+	return erasure1.Write(target, key, part, length, k, m, versionedTechnique, data)
+}
+
+// Read any donut format
+func Read(reader io.Reader) (io.Reader, error) {
+	// when version2 is created, create a method in version2 that can transform version1 structure to version2
+	return nil, errors.New("Not Implemented")
+}