diff --git a/bitcask.go b/bitcask.go
index 8129fbe..b3ed79a 100644
--- a/bitcask.go
+++ b/bitcask.go
@@ -284,61 +284,17 @@ func (b *Bitcask) reopen() error {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
-	fns, err := internal.GetDatafiles(b.path)
+	datafiles, lastID, err := loadDatafiles(b.path, b.config.MaxKeySize, b.config.MaxValueSize)
 	if err != nil {
 		return err
 	}
 
-	ids, err := internal.ParseIds(fns)
+	t, err := loadIndex(b.path, b.indexer, b.config.MaxKeySize, datafiles)
 	if err != nil {
 		return err
 	}
 
-	datafiles := make(map[int]data.Datafile, len(ids))
-
-	for _, id := range ids {
-		df, err := data.NewDatafile(b.path, id, true, b.config.MaxKeySize, b.config.MaxValueSize)
-		if err != nil {
-			return err
-		}
-		datafiles[id] = df
-	}
-
-	t, found, err := b.indexer.Load(filepath.Join(b.path, "index"), b.config.MaxKeySize)
-	if err != nil {
-		return err
-	}
-	if !found {
-		for i, df := range datafiles {
-			var offset int64
-			for {
-				e, n, err := df.Read()
-				if err != nil {
-					if err == io.EOF {
-						break
-					}
-					return err
-				}
-
-				// Tombstone value  (deleted key)
-				if len(e.Value) == 0 {
-					t.Delete(e.Key)
-					offset += n
-					continue
-				}
-				item := internal.Item{FileID: ids[i], Offset: offset, Size: n}
-				t.Insert(e.Key, item)
-				offset += n
-			}
-		}
-	}
-
-	var id int
-	if len(ids) > 0 {
-		id = ids[(len(ids) - 1)]
-	}
-
-	curr, err := data.NewDatafile(b.path, id, false, b.config.MaxKeySize, b.config.MaxValueSize)
+	curr, err := data.NewDatafile(b.path, lastID, false, b.config.MaxKeySize, b.config.MaxValueSize)
 	if err != nil {
 		return err
 	}
@@ -486,3 +442,60 @@ func Open(path string, options ...Option) (*Bitcask, error) {
 
 	return bitcask, nil
 }
+
+func loadDatafiles(path string, maxKeySize uint32, maxValueSize uint64) (datafiles map[int]data.Datafile, lastID int, err error) {
+	fns, err := internal.GetDatafiles(path)
+	if err != nil {
+		return nil, 0, err
+	}
+
+	ids, err := internal.ParseIds(fns)
+	if err != nil {
+		return nil, 0, err
+	}
+
+	datafiles = make(map[int]data.Datafile, len(ids))
+	for _, id := range ids {
+		datafiles[id], err = data.NewDatafile(path, id, true, maxKeySize, maxValueSize)
+		if err != nil {
+			return
+		}
+
+	}
+	if len(ids) > 0 {
+		lastID = ids[len(ids)-1]
+	}
+	return
+}
+
+func loadIndex(path string, indexer index.Indexer, maxKeySize uint32, datafiles map[int]data.Datafile) (art.Tree, error) {
+	t, found, err := indexer.Load(filepath.Join(path, "index"), maxKeySize)
+	if err != nil {
+		return nil, err
+	}
+	if !found {
+		for _, df := range datafiles {
+			var offset int64
+			for {
+				e, n, err := df.Read()
+				if err != nil {
+					if err == io.EOF {
+						break
+					}
+					return nil, err
+				}
+
+				// Tombstone value  (deleted key)
+				if len(e.Value) == 0 {
+					t.Delete(e.Key)
+					offset += n
+					continue
+				}
+				item := internal.Item{FileID: df.FileID(), Offset: offset, Size: n}
+				t.Insert(e.Key, item)
+				offset += n
+			}
+		}
+	}
+	return t, nil
+}
diff --git a/cmd/bitcask/export.go b/cmd/bitcask/export.go
index 39c83f2..7f83219 100644
--- a/cmd/bitcask/export.go
+++ b/cmd/bitcask/export.go
@@ -66,11 +66,6 @@ type kvPair struct {
 }
 
 func export(path, output string) int {
-	var (
-		err error
-		w   io.WriteCloser
-	)
-
 	db, err := bitcask.Open(path)
 	if err != nil {
 		log.WithError(err).Error("error opening database")
@@ -78,19 +73,29 @@ func export(path, output string) int {
 	}
 	defer db.Close()
 
-	if output == "-" {
-		w = os.Stdout
-	} else {
-		w, err = os.OpenFile(output, os.O_WRONLY|os.O_CREATE|os.O_EXCL|os.O_TRUNC, 0755)
-		if err != nil {
+	w := os.Stdout
+	if output != "-" {
+		if w, err = os.OpenFile(output, os.O_WRONLY|os.O_CREATE|os.O_EXCL|os.O_TRUNC, 0755); err != nil {
 			log.WithError(err).
 				WithField("output", output).
 				Error("error opening output for writing")
 			return 1
 		}
+		defer w.Close()
 	}
 
-	err = db.Fold(func(key []byte) error {
+	if err = db.Fold(exportKey(db, w)); err != nil {
+		log.WithError(err).
+			WithField("path", path).
+			WithField("output", output).
+			Error("error exporting keys")
+		return 2
+	}
+	return 0
+}
+
+func exportKey(db *bitcask.Bitcask, w io.Writer) func(key []byte) error {
+	return func(key []byte) error {
 		value, err := db.Get(key)
 		if err != nil {
 			log.WithError(err).
@@ -129,14 +134,5 @@ func export(path, output string) int {
 		}
 
 		return nil
-	})
-	if err != nil {
-		log.WithError(err).
-			WithField("path", path).
-			WithField("output", output).
-			Error("error exporting keys")
-		return 2
 	}
-
-	return 0
 }
diff --git a/internal/data/codec/encoder_test.go b/internal/data/codec/encoder_test.go
new file mode 100644
index 0000000..842df0a
--- /dev/null
+++ b/internal/data/codec/encoder_test.go
@@ -0,0 +1,29 @@
+package codec
+
+import (
+	"bytes"
+	"encoding/hex"
+	"testing"
+
+	"github.com/prologic/bitcask/internal"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestEncode(t *testing.T) {
+	t.Parallel()
+	assert := assert.New(t)
+
+	var buf bytes.Buffer
+	encoder := NewEncoder(&buf)
+	_, err := encoder.Encode(internal.Entry{
+		Key:      []byte("mykey"),
+		Value:    []byte("myvalue"),
+		Checksum: 414141,
+		Offset:   424242,
+	})
+
+	expectedHex := "0000000500000000000000076d796b65796d7976616c7565000651bd"
+	if assert.NoError(err) {
+		assert.Equal(expectedHex, hex.EncodeToString(buf.Bytes()))
+	}
+}