diff --git a/pkg/storage/donut/bucket.go b/pkg/storage/donut/bucket.go
index bac6baa06..8116c1c89 100644
--- a/pkg/storage/donut/bucket.go
+++ b/pkg/storage/donut/bucket.go
@@ -160,36 +160,36 @@ func (b bucket) ListObjects(prefix, marker, delimiter string, maxkeys int) ([]st
 	for objectName := range bucketMetadata.Buckets[b.getBucketName()].BucketObjects {
 		if strings.HasPrefix(objectName, strings.TrimSpace(prefix)) {
 			if objectName > marker {
-				objects = appendUniq(objects, objectName)
+				objects = AppendU(objects, objectName)
 			}
 		}
 	}
 	if strings.TrimSpace(prefix) != "" {
-		objects = removePrefix(objects, prefix)
+		objects = TrimPrefix(objects, prefix)
 	}
 	var prefixes []string
 	var filteredObjects []string
 	if strings.TrimSpace(delimiter) != "" {
-		filteredObjects = filterDelimited(objects, delimiter)
-		prefixes = filterNotDelimited(objects, delimiter)
-		prefixes = extractDelimited(prefixes, delimiter)
-		prefixes = uniqueObjects(prefixes)
+		filteredObjects = HasNoDelimiter(objects, delimiter)
+		prefixes = HasDelimiter(objects, delimiter)
+		prefixes = SplitDelimiter(prefixes, delimiter)
+		prefixes = SortU(prefixes)
 	} else {
 		filteredObjects = objects
 	}
 	var results []string
 	var commonPrefixes []string
 
+	for _, commonPrefix := range prefixes {
+		commonPrefixes = AppendU(commonPrefixes, prefix+commonPrefix)
+	}
 	sort.Strings(filteredObjects)
 	for _, objectName := range filteredObjects {
 		if len(results) >= maxkeys {
 			isTruncated = true
 			break
 		}
-		results = appendUniq(results, prefix+objectName)
-	}
-	for _, commonPrefix := range prefixes {
-		commonPrefixes = appendUniq(commonPrefixes, prefix+commonPrefix)
+		results = AppendU(results, prefix+objectName)
 	}
 	sort.Strings(results)
 	sort.Strings(commonPrefixes)
diff --git a/pkg/storage/donut/common.go b/pkg/storage/donut/common.go
index fcafb7177..9fbb18eb6 100644
--- a/pkg/storage/donut/common.go
+++ b/pkg/storage/donut/common.go
@@ -1,3 +1,19 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package donut
 
 import (
@@ -5,7 +21,8 @@ import (
 	"strings"
 )
 
-func appendUniq(slice []string, i string) []string {
+// AppendU append to an input slice if the element is unique and provides a new slice
+func AppendU(slice []string, i string) []string {
 	for _, ele := range slice {
 		if ele == i {
 			return slice
@@ -14,17 +31,8 @@ func appendUniq(slice []string, i string) []string {
 	return append(slice, i)
 }
 
-func filterPrefix(objects []string, prefix string) []string {
-	var results []string
-	for _, object := range objects {
-		if strings.HasPrefix(object, prefix) {
-			results = append(results, object)
-		}
-	}
-	return results
-}
-
-func removePrefix(objects []string, prefix string) []string {
+// TrimPrefix trims off a prefix string from all the elements in a given slice
+func TrimPrefix(objects []string, prefix string) []string {
 	var results []string
 	for _, object := range objects {
 		results = append(results, strings.TrimPrefix(object, prefix))
@@ -32,7 +40,8 @@ func removePrefix(objects []string, prefix string) []string {
 	return results
 }
 
-func filterDelimited(objects []string, delim string) []string {
+// HasNoDelimiter provides a new slice from an input slice which has elements without delimiter
+func HasNoDelimiter(objects []string, delim string) []string {
 	var results []string
 	for _, object := range objects {
 		if !strings.Contains(object, delim) {
@@ -42,7 +51,8 @@ func filterDelimited(objects []string, delim string) []string {
 	return results
 }
 
-func filterNotDelimited(objects []string, delim string) []string {
+// HasDelimiter provides a new slice from an input slice which has elements with a delimiter
+func HasDelimiter(objects []string, delim string) []string {
 	var results []string
 	for _, object := range objects {
 		if strings.Contains(object, delim) {
@@ -52,7 +62,8 @@ func filterNotDelimited(objects []string, delim string) []string {
 	return results
 }
 
-func extractDelimited(objects []string, delim string) []string {
+// SplitDelimiter provides a new slice from an input slice by splitting a delimiter
+func SplitDelimiter(objects []string, delim string) []string {
 	var results []string
 	for _, object := range objects {
 		parts := strings.Split(object, delim)
@@ -61,7 +72,8 @@ func extractDelimited(objects []string, delim string) []string {
 	return results
 }
 
-func uniqueObjects(objects []string) []string {
+// SortU sort a slice in lexical order, removing duplicate elements
+func SortU(objects []string) []string {
 	objectMap := make(map[string]string)
 	for _, v := range objects {
 		objectMap[v] = v