Adding minio-decode

Makefile

@@ -11,6 +11,7 @@ test: build-erasure
 
 install: build-erasure
 	godep go install github.com/minio-io/minio/cmd/minio-encode
+	godep go install github.com/minio-io/minio/cmd/minio-decode
 
 save:
 	godep save ./...

cmd/minio-decode/main.go

@@ -0,0 +1,95 @@
+package main
+
+import (
+	"io/ioutil"
+	"log"
+	"os"
+	"strconv"
+
+	"github.com/codegangsta/cli"
+	"github.com/minio-io/minio/erasure"
+)
+
+func main() {
+	app := cli.NewApp()
+	app.Name = "minio-encode"
+	app.Usage = "erasure encode a byte stream"
+	app.Flags = []cli.Flag{
+		cli.StringFlag{
+			Name:  "input,i",
+			Value: "",
+			Usage: "Input file",
+		},
+		cli.StringFlag{
+			Name:  "output,o",
+			Value: "",
+			Usage: "Output file",
+		},
+		cli.IntFlag{
+			Name:  "k",
+			Value: 10,
+			Usage: "k value of encoder parameters",
+		},
+		cli.IntFlag{
+			Name:  "m",
+			Value: 5,
+			Usage: "m value of encoder parameters",
+		},
+	}
+	app.Action = func(c *cli.Context) {
+		// check if minio-encode called without parameters
+		if len(c.Args()) == 1 {
+			cli.ShowAppHelp(c)
+		}
+
+		// get input path
+		if c.String("input") == "" {
+			log.Fatal("No input specified")
+		}
+		inputFilePath := c.String("input")
+
+		// get output path
+		outputFilePath := inputFilePath
+		if c.String("output") != "" {
+			outputFilePath = c.String("output")
+		}
+
+		k := c.Int("k")
+		m := c.Int("m")
+
+		// get chunks
+		chunks := make([][]byte, k+m)
+		for i := 0; i < k+m; i++ {
+			var err error
+			chunks[i], err = ioutil.ReadFile(inputFilePath + "." + strconv.Itoa(i))
+			if err != nil {
+				log.Fatal(err)
+			}
+		}
+
+		// get length
+		lengthBytes, err := ioutil.ReadFile(inputFilePath + ".length")
+		if err != nil {
+			log.Fatal(err)
+		}
+		lengthString := string(lengthBytes)
+		length, err := strconv.Atoi(lengthString)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		// set up encoder
+		erasureParameters, _ := erasure.ValidateParams(k, m, 8, erasure.CAUCHY)
+		encoder := erasure.NewEncoder(erasureParameters)
+
+		// decode data
+		decodedData, err := encoder.Decode(chunks, length)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		// write decode data out
+		ioutil.WriteFile(outputFilePath, decodedData, 0600)
+	}
+	app.Run(os.Args)
+}

cmd/minio-encode/main.go

@@ -74,12 +74,13 @@ func main() {
 		encoder := erasure.NewEncoder(erasureParameters)
 
 		// encode data
-		encodedData, _ := encoder.Encode(input)
+		encodedData, length := encoder.Encode(input)
 
 		// write encoded data out
 		for key, data := range encodedData {
 			ioutil.WriteFile(outputFilePath+"."+strconv.Itoa(key), data, 0600)
 		}
+		ioutil.WriteFile(outputFilePath+".length", []byte(strconv.Itoa(length)), 0600)
 	}
 	app.Run(os.Args)
 }