Add everything back into one project hood, still missing iodine

pkg/storage/donut/donut_encoder.go

@@ -0,0 +1,97 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"errors"
+	"strconv"
+
+	"github.com/minio-io/iodine"
+	encoding "github.com/minio-io/minio/pkg/erasure"
+)
+
+// encoder internal struct
+type encoder struct {
+	encoder   *encoding.Erasure
+	k, m      uint8
+	technique encoding.Technique
+}
+
+// getErasureTechnique - convert technique string into Technique type
+func getErasureTechnique(technique string) (encoding.Technique, error) {
+	switch true {
+	case technique == "Cauchy":
+		return encoding.Cauchy, nil
+	case technique == "Vandermonde":
+		return encoding.Cauchy, nil
+	default:
+		return encoding.None, iodine.New(errors.New("Invalid erasure technique"), nil)
+	}
+}
+
+// NewEncoder - instantiate a new encoder
+func NewEncoder(k, m uint8, technique string) (Encoder, error) {
+	errParams := map[string]string{
+		"k":         strconv.FormatUint(uint64(k), 10),
+		"m":         strconv.FormatUint(uint64(m), 10),
+		"technique": technique,
+	}
+	e := encoder{}
+	t, err := getErasureTechnique(technique)
+	if err != nil {
+		return nil, iodine.New(err, errParams)
+	}
+	params, err := encoding.ValidateParams(k, m, t)
+	if err != nil {
+		return nil, iodine.New(err, errParams)
+	}
+	e.encoder = encoding.NewErasure(params)
+	e.k = k
+	e.m = m
+	e.technique = t
+	return e, nil
+}
+
+// TODO - think again if this is needed
+// GetEncodedBlockLen - wrapper around erasure function with the same name
+func (e encoder) GetEncodedBlockLen(dataLength int) (int, error) {
+	if dataLength <= 0 {
+		return 0, iodine.New(errors.New("invalid argument"), nil)
+	}
+	return encoding.GetEncodedBlockLen(dataLength, e.k), nil
+}
+
+// Encode - erasure code input bytes
+func (e encoder) Encode(data []byte) (encodedData [][]byte, err error) {
+	if data == nil {
+		return nil, iodine.New(errors.New("invalid argument"), nil)
+	}
+	encodedData, err = e.encoder.Encode(data)
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	return encodedData, nil
+}
+
+// Decode - erasure decode input encoded bytes
+func (e encoder) Decode(encodedData [][]byte, dataLength int) (data []byte, err error) {
+	decodedData, err := e.encoder.Decode(encodedData, dataLength)
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	return decodedData, nil
+}