Index: drivers/video/videoprt/videoprt.c
===================================================================
--- drivers/video/videoprt/videoprt.c	(revision 51378)
+++ drivers/video/videoprt/videoprt.c	(working copy)
@@ -73,53 +73,83 @@
    ((PMINIPORT_DPC_ROUTINE)SystemArgument1)(HwDeviceExtension, SystemArgument2);
 }
 
+static BOOLEAN UnicodeStringStartsWith(
+   IN PCUNICODE_STRING Haystack,
+   IN PCUNICODE_STRING Needle,
+   IN BOOLEAN CaseInSensitive)
+{
+   UNICODE_STRING HaystackStart;
+
+   if (Haystack->Length < Needle->Length)
+      return FALSE;
+
+   HaystackStart = *Haystack;
+   HaystackStart.Length = Needle->Length;
+
+   return RtlCompareUnicodeString(&HaystackStart, Needle, CaseInSensitive) == 0;
+}
+
+static BOOLEAN SkipIfUnicodeStartsWithString(
+   IN OUT PUNICODE_STRING Haystack,
+   IN PCWSTR NeedleString,
+   IN BOOLEAN CaseInSensitive)
+{
+   UNICODE_STRING Needle;
+
+   RtlInitUnicodeString(&Needle, NeedleString);
+
+   if (!UnicodeStringStartsWith(Haystack, &Needle, CaseInSensitive))
+      return FALSE;
+
+   Haystack->Buffer += Needle.Length / sizeof Needle.Buffer[0];
+   Haystack->Length -= Needle.Length;
+   Haystack->MaximumLength -= Needle.Length;
+
+   return TRUE;
+}
+
+static VOID SkipCharUnicodeString(
+   IN OUT PUNICODE_STRING String)
+{
+   String->Buffer++;
+   String->Length -= sizeof String->Buffer[0];
+   String->MaximumLength -= sizeof String->Buffer[0];
+}
+
 NTSTATUS
 IntCreateRegistryPath(
    IN PCUNICODE_STRING DriverRegistryPath,
    OUT PUNICODE_STRING DeviceRegistryPath)
 {
-   static WCHAR RegistryMachineSystem[] = L"\\REGISTRY\\MACHINE\\SYSTEM\\";
-   static WCHAR CurrentControlSet[] = L"CURRENTCONTROLSET\\";
-   static WCHAR ControlSet[] = L"CONTROLSET";
-   static WCHAR Insert1[] = L"Hardware Profiles\\Current\\System\\CurrentControlSet\\";
-   static WCHAR Insert2[] = L"\\Device0";
+   static const WCHAR RegistryMachineSystem[] = L"\\REGISTRY\\MACHINE\\SYSTEM\\";
+   static const WCHAR CurrentControlSet[] = L"CURRENTCONTROLSET\\";
+   static const WCHAR ControlSet[] = L"CONTROLSET";
+   static const WCHAR Insert1[] = L"Hardware Profiles\\Current\\System\\CurrentControlSet\\";
+   static const WCHAR Insert2[] = L"\\Device0";
    BOOLEAN Valid;
    UNICODE_STRING AfterControlSet;
 
    AfterControlSet = *DriverRegistryPath;
    /* Check if path begins with \\REGISTRY\\MACHINE\\SYSTEM\\ */
-   Valid = (DriverRegistryPath->Length > sizeof(RegistryMachineSystem) &&
-            0 == _wcsnicmp(DriverRegistryPath->Buffer, RegistryMachineSystem,
-            wcslen(RegistryMachineSystem)));
+   Valid = SkipIfUnicodeStartsWithString(&AfterControlSet, RegistryMachineSystem, TRUE);
    if (Valid)
    {
-      AfterControlSet.Buffer += wcslen(RegistryMachineSystem);
-      AfterControlSet.Length -= sizeof(RegistryMachineSystem) - sizeof(UNICODE_NULL);
-
       /* Check if path contains CURRENTCONTROLSET */
-      if (AfterControlSet.Length > sizeof(CurrentControlSet) &&
-          0 == _wcsnicmp(AfterControlSet.Buffer, CurrentControlSet, wcslen(CurrentControlSet)))
+      if (SkipIfUnicodeStartsWithString(&AfterControlSet, CurrentControlSet, TRUE))
       {
-         AfterControlSet.Buffer += wcslen(CurrentControlSet);
-         AfterControlSet.Length -= sizeof(CurrentControlSet) - sizeof(UNICODE_NULL);
+         Valid = TRUE;
       }
       /* Check if path contains CONTROLSETnum */
-      else if (AfterControlSet.Length > sizeof(ControlSet) &&
-               0 == _wcsnicmp(AfterControlSet.Buffer, ControlSet, wcslen(ControlSet)))
+      else if (SkipIfUnicodeStartsWithString(&AfterControlSet, ControlSet, TRUE))
       {
-         AfterControlSet.Buffer += wcslen(ControlSet);
-         AfterControlSet.Length -= sizeof(ControlSet) - sizeof(UNICODE_NULL);
          while (AfterControlSet.Length > 0 &&
                 *AfterControlSet.Buffer >= L'0' &&
                 *AfterControlSet.Buffer <= L'9')
          {
-            AfterControlSet.Buffer++;
-            AfterControlSet.Length -= sizeof(WCHAR);
+            SkipCharUnicodeString(&AfterControlSet);
          }
          Valid = (AfterControlSet.Length > 0 && L'\\' == *AfterControlSet.Buffer);
-         AfterControlSet.Buffer++;
-         AfterControlSet.Length -= sizeof(WCHAR);
-         AfterControlSet.MaximumLength = AfterControlSet.Length;
+         SkipCharUnicodeString(&AfterControlSet);
       }
       else
       {
@@ -136,10 +166,11 @@
       if (DeviceRegistryPath->Buffer != NULL)
       {
          /* Build device path */
-         wcsncpy(DeviceRegistryPath->Buffer,
-                 DriverRegistryPath->Buffer,
-                 AfterControlSet.Buffer - DriverRegistryPath->Buffer);
          DeviceRegistryPath->Length = (AfterControlSet.Buffer - DriverRegistryPath->Buffer) * sizeof(WCHAR);
+         RtlCopyMemory(DeviceRegistryPath->Buffer,
+                       DriverRegistryPath->Buffer,
+                       DeviceRegistryPath->Length);
+
          RtlAppendUnicodeToString(DeviceRegistryPath, Insert1);
          RtlAppendUnicodeStringToString(DeviceRegistryPath, &AfterControlSet);
          RtlAppendUnicodeToString(DeviceRegistryPath, Insert2);