3 files changed, 32 insertions, 0 deletions
diff --git a/src/internal/ntapi.c b/src/internal/ntapi.c
index 6421cb1..f0b4431 100644
--- a/src/internal/ntapi.c
+++ b/src/internal/ntapi.c
@@ -167,6 +167,7 @@ static int32_t __fastcall __ntapi_init_once(ntapi_vtbl ** pvtbl)
 	__ntapi->tt_open_keyed_object_directory			= __ntapi_tt_open_keyed_object_directory;
 	__ntapi->tt_create_keyed_object_directory_entry		= __ntapi_tt_create_keyed_object_directory_entry;
 	__ntapi->tt_sid_copy					= __ntapi_tt_sid_copy;
+	__ntapi->tt_sid_compare					= __ntapi_tt_sid_compare;
 
 	/* nt_crc32.h */
 	__ntapi->tt_buffer_crc32 				= __ntapi_tt_buffer_crc32;
diff --git a/src/internal/ntapi_fnapi.h b/src/internal/ntapi_fnapi.h
index c8567f1..5aaae4c 100644
--- a/src/internal/ntapi_fnapi.h
+++ b/src/internal/ntapi_fnapi.h
@@ -29,6 +29,7 @@ ntapi_tt_create_keyed_object_directory		__ntapi_tt_create_keyed_object_directory
 ntapi_tt_open_keyed_object_directory		__ntapi_tt_open_keyed_object_directory;
 ntapi_tt_create_keyed_object_directory_entry	__ntapi_tt_create_keyed_object_directory_entry;
 ntapi_tt_sid_copy				__ntapi_tt_sid_copy;
+ntapi_tt_sid_compare				__ntapi_tt_sid_compare;
 
 /* nt_crc32.h */
 ntapi_tt_buffer_crc32				__ntapi_tt_buffer_crc32;
diff --git a/src/object/ntapi_tt_sid.c b/src/object/ntapi_tt_sid.c
index d93775c..a35b9a7 100644
--- a/src/object/ntapi_tt_sid.c
+++ b/src/object/ntapi_tt_sid.c
@@ -21,3 +21,33 @@ void __stdcall __ntapi_tt_sid_copy(
 	for (i=0; i<src->sub_authority_count; i++)
 		dst->sub_authority[i] = src->sub_authority[i];
 }
+
+int32_t __stdcall __ntapi_tt_sid_compare(
+	__in	const nt_sid *	sida,
+	__in	const nt_sid *	sidb)
+{
+	int			i;
+	int32_t			a;
+	int32_t			b;
+	const unsigned char *	va;
+	const unsigned char *	vb;
+
+	if ((a = sida->revision) - (b = sidb->revision))
+		return a-b;
+
+	if ((a = sida->sub_authority_count) - (b = sidb->sub_authority_count))
+		return a-b;
+
+	va=sida->identifier_authority.value;
+	vb=sidb->identifier_authority.value;
+
+	for (i=0; i<6; i++)
+		if ((a = va[i]) - (b = vb[i]))
+			return a-b;
+
+	for (i=0; i<sida->sub_authority_count; i++)
+		if ((a = sida->sub_authority[i]) - (b = sidb->sub_authority[i]))
+			return a-b;
+
+	return 0;
+}