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