diff --git a/reactos/include/ddk/ntifs.h b/reactos/include/ddk/ntifs.h
index 510f67073b7..3e40ea7cd02 100644
--- a/reactos/include/ddk/ntifs.h
+++ b/reactos/include/ddk/ntifs.h
@@ -5024,6 +5024,31 @@ RtlNtStatusToDosError (
     IN NTSTATUS Status
 );
 
+NTSYSAPI
+ULONG
+NTAPI
+RtlxUnicodeStringToOemSize(
+    PCUNICODE_STRING UnicodeString
+    );
+
+NTSYSAPI
+ULONG
+NTAPI
+RtlxOemStringToUnicodeSize(
+    PCOEM_STRING OemString
+);
+
+#define RtlOemStringToUnicodeSize(STRING) (                 \
+    NLS_MB_OEM_CODE_PAGE_TAG ?                              \
+    RtlxOemStringToUnicodeSize(STRING) :                    \
+    ((STRING)->Length + sizeof(ANSI_NULL)) * sizeof(WCHAR)  \
+)
+
+#define RtlOemStringToCountedUnicodeSize(STRING) (                    \
+    (ULONG)(RtlOemStringToUnicodeSize(STRING) - sizeof(UNICODE_NULL)) \
+)
+
+
 NTSYSAPI
 NTSTATUS
 NTAPI
@@ -5246,6 +5271,42 @@ RtlValidSid (
     IN PSID Sid
 );
 
+//
+// RTL time functions
+//
+
+NTSYSAPI
+BOOLEAN
+NTAPI
+RtlTimeToSecondsSince1980 (
+    PLARGE_INTEGER Time,
+    PULONG ElapsedSeconds
+);
+
+NTSYSAPI
+VOID
+NTAPI
+RtlSecondsSince1980ToTime (
+    ULONG ElapsedSeconds,
+    PLARGE_INTEGER Time
+);
+
+NTSYSAPI
+BOOLEAN
+NTAPI
+RtlTimeToSecondsSince1970 (
+    PLARGE_INTEGER Time,
+    PULONG ElapsedSeconds
+);
+
+NTSYSAPI
+VOID
+NTAPI
+RtlSecondsSince1970ToTime (
+    ULONG ElapsedSeconds,
+    PLARGE_INTEGER Time
+);
+
 NTKERNELAPI
 NTSTATUS
 NTAPI