Fix: got length of cyphertext is less than 0 error on empty file read

1. Fix: got length of cyphertext is less than 0 error on empty file read.

dalmdl/corefdb/bucket.go

@@ -387,6 +387,10 @@ func readNormalFileUsingFp(fp *os.File, rs *gjson.Result, secParams securitymdl.
 		return nil, err
 	}
 
+	if len(ba) == 0 {
+		return ba, nil
+	}
+
 	if secParams.EnableSecurity {
 		// _, fileName := filepath.Split(fp.Name())
 		key, err := securitymdl.GenSecKeyBytes(fp.Name(), rs)
@@ -613,7 +617,7 @@ func saveDatInLazyBucket(bucket *Bucket, fp *os.File, data *gjson.Result, secPar
 			Identifier:    fp.Name(),
 			InterfaceData: "",
 			SaveFn: func() lazywriter.SaveDataFn {
-				if bucket.BucketType == BucketTypeSimple {
+				if bucket.BucketType == BucketTypeAppend {
 					return lazyCallBackFn
 				}