3 files changed, 36 insertions, 0 deletions
diff --git a/internal/nametransform/longnames.go b/internal/nametransform/longnames.go
index 7a6d413..1bbcbb6 100644
--- a/internal/nametransform/longnames.go
+++ b/internal/nametransform/longnames.go
@@ -69,6 +69,13 @@ func IsLongContent(cName string) bool {
 	return NameType(cName) == LongNameContent
 }
 
+// RemoveLongNameSuffix removes the ".name" suffix from cName, returning the corresponding
+// content file name.
+// No check is made if cName actually is a LongNameFilename.
+func RemoveLongNameSuffix(cName string) string {
+	return cName[:len(cName)-len(LongNameSuffix)]
+}
+
 // ReadLongName - read cName + ".name" from the directory opened as dirfd.
 //
 // Symlink-safe through Openat().
diff --git a/internal/nametransform/longnames_test.go b/internal/nametransform/longnames_test.go
index 8fa19fe..4210492 100644
--- a/internal/nametransform/longnames_test.go
+++ b/internal/nametransform/longnames_test.go
@@ -20,3 +20,11 @@ func TestIsLongName(t *testing.T) {
 		t.Errorf("False positive")
 	}
 }
+
+func TestRemoveLongNameSuffix(t *testing.T) {
+	filename := "gocryptfs.longname.LkwUdALvV_ANnzQN6ZZMYnxxfARD3IeZWCKnxGJjYmU=.name"
+	content := "gocryptfs.longname.LkwUdALvV_ANnzQN6ZZMYnxxfARD3IeZWCKnxGJjYmU="
+	if RemoveLongNameSuffix(filename) != content {
+		t.Error(".name suffix not removed")
+	}
+}
diff --git a/internal/nametransform/names.go b/internal/nametransform/names.go
index 20fbede..d5c2c8b 100644
--- a/internal/nametransform/names.go
+++ b/internal/nametransform/names.go
@@ -17,6 +17,17 @@ const (
 	NameMax = 255
 )
 
+// NameTransformer is an interface used to transform filenames.
+type NameTransformer interface {
+	DecryptName(cipherName string, iv []byte) (string, error)
+	EncryptName(plainName string, iv []byte) string
+	EncryptAndHashName(name string, iv []byte) (string, error)
+	HashLongName(name string) string
+	WriteLongNameAt(dirfd int, hashName string, plainName string) error
+	B64EncodeToString(src []byte) string
+	B64DecodeString(s string) ([]byte, error)
+}
+
 // NameTransform is used to transform filenames.
 type NameTransform struct {
 	emeCipher *eme.EMECipher
@@ -88,3 +99,13 @@ func (n *NameTransform) EncryptName(plainName string, iv []byte) (cipherName64 s
 	cipherName64 = n.B64.EncodeToString(bin)
 	return cipherName64
 }
+
+// B64EncodeToString returns a Base64-encoded string
+func (n *NameTransform) B64EncodeToString(src []byte) string {
+	return n.B64.EncodeToString(src)
+}
+
+// B64DecodeString decodes a Base64-encoded string
+func (n *NameTransform) B64DecodeString(s string) ([]byte, error) {
+	return n.B64.DecodeString(s)
+}