minio/cmd/erasure-demo/decode.go
2014-11-30 13:54:31 -08:00

78 lines
1.6 KiB
Go

package main
import (
"io/ioutil"
"log"
"os"
"strconv"
"strings"
"github.com/codegangsta/cli"
"github.com/minio-io/minio/pkgs/erasure"
)
func decode(c *cli.Context) {
// check if minio-encode called without parameters
if len(c.Args()) != 1 {
cli.ShowCommandHelp(c, "decode")
return
}
// get input path
inputFilePath := c.Args().Get(0)
// get output path
outputFilePath := inputFilePath
if c.String("output") != "" {
outputFilePath = c.String("output")
}
protectionLevel := c.String("protection-level")
protectionLevelSplit := strings.Split(protectionLevel, ",")
if len(protectionLevelSplit) != 2 {
log.Fatal("Malformed input for protection-level")
}
k, err := strconv.Atoi(protectionLevelSplit[0])
if err != nil {
log.Fatal(err)
}
m, err := strconv.Atoi(protectionLevelSplit[1])
if err != nil {
log.Fatal(err)
}
// get chunks
chunks := make([][]byte, k+m)
for i := 0; i < k+m; i++ {
chunks[i], _ = ioutil.ReadFile(inputFilePath + "." + strconv.Itoa(i))
}
// 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.ParseEncoderParams(k, m, erasure.CAUCHY)
// decode data
decodedData, err := erasure.Decode(chunks, erasureParameters, length)
if err != nil {
log.Fatal(err)
}
// write decode data out
if _, err := os.Stat(outputFilePath); os.IsNotExist(err) {
ioutil.WriteFile(outputFilePath, decodedData, 0600)
} else {
log.Fatal("Output file already exists")
}
}