Use LevelDB storage backend

scanner/blocks.go

@@ -7,6 +7,7 @@ package scanner
 import (
 	"bytes"
 	"crypto/sha256"
+	"fmt"
 	"io"
 )
 
@@ -18,6 +19,10 @@ type Block struct {
 	Hash   []byte
 }
 
+func (b Block) String() string {
+	return fmt.Sprintf("%d/%d/%x", b.Offset, b.Size, b.Hash)
+}
+
 // Blocks returns the blockwise hash of the reader.
 func Blocks(r io.Reader, blocksize int) ([]Block, error) {
 	var blocks []Block