Replace all occurrences of NULL with NULLPTR for unified C and C++ null pointer handling

xtoskrnl/ke/amd64/krnlinit.cc

@@ -99,7 +99,8 @@ KE::KernelInit::StartKernel(VOID)
     CurrentProcess->Quantum = MAXCHAR;
 
     /* Initialize Idle thread */
-    KThread::InitializeThread(CurrentProcess, CurrentThread, nullptr, nullptr, nullptr, nullptr, nullptr, AR::ProcSup::GetBootStack(), TRUE);
+    KThread::InitializeThread(CurrentProcess, CurrentThread, NULLPTR, NULLPTR, NULLPTR,
+                              NULLPTR, NULLPTR, AR::ProcSup::GetBootStack(), TRUE);
     CurrentThread->NextProcessor = Prcb->CpuNumber;
     CurrentThread->Priority = THREAD_HIGH_PRIORITY;
     CurrentThread->State = Running;

xtoskrnl/ke/amd64/kthread.cc

@@ -99,7 +99,7 @@ KE::KThread::InitializeThreadContext(IN PKTHREAD Thread,
         Thread->NpxState = NPX_STATE_UNUSED;
 
         /* Set thread start address */
-        ThreadFrame->StartFrame.Return = (ULONG64)NULL;
+        ThreadFrame->StartFrame.Return = (ULONG64)NULLPTR;
     }
 
     /* Initialize thread startup information */

xtoskrnl/ke/apc.cc

@@ -83,7 +83,7 @@ KE::Apc::InitializeApc(IN PKAPC Apc,
     {
         /* Set context and mode for special APC */
         Apc->ApcMode = KernelMode;
-        Apc->NormalContext = NULL;
+        Apc->NormalContext = NULLPTR;
     }
 
     /* Mark APC as not inserted yet */

xtoskrnl/ke/bootinfo.cc

@@ -44,7 +44,7 @@ KE::BootInformation::GetFirmwareType(VOID)
  *        Supplies a pointer to a null-terminated wide string specifying the name of the parameter to search for.
  *
  * @param Parameter
- *        Supplies a pointer to a variable that receives a pointer to the matching parameter, or NULL if not found.
+ *        Supplies a pointer to a variable that receives a pointer to the matching parameter, or NULLPTR if not found.
  *
  * @return This routine returns a status code.
  *
@@ -74,7 +74,7 @@ KE::BootInformation::GetKernelParameter(IN PCWSTR ParameterName,
     }
 
     /* Assume the requested parameter is not present in the kernel parameters */
-    *Parameter = nullptr;
+    *Parameter = NULLPTR;
 
     /* Start searching from the beginning of the list */
     SearchStart = InitializationBlock->KernelParameters;

xtoskrnl/ke/dpc.cc

@@ -39,7 +39,7 @@ KE::Dpc::InitializeDpc(IN PKDPC Dpc,
     /* Initialize DPC routine and context data */
     Dpc->DeferredContext = DpcContext;
     Dpc->DeferredRoutine = DpcRoutine;
-    Dpc->DpcData = NULL;
+    Dpc->DpcData = NULLPTR;
 }
 
 /**
@@ -72,7 +72,7 @@ KE::Dpc::InitializeThreadedDpc(IN PKDPC Dpc,
     /* Initialize DPC routine and context data */
     Dpc->DeferredContext = DpcContext;
     Dpc->DeferredRoutine = DpcRoutine;
-    Dpc->DpcData = NULL;
+    Dpc->DpcData = NULLPTR;
 }
 
 /**

xtoskrnl/ke/i686/krnlinit.cc

@@ -99,7 +99,8 @@ KE::KernelInit::StartKernel(VOID)
     CurrentProcess->Quantum = MAXCHAR;
 
     /* Initialize Idle thread */
-    KThread::InitializeThread(CurrentProcess, CurrentThread, nullptr, nullptr, nullptr, nullptr, nullptr, AR::ProcSup::GetBootStack(), TRUE);
+    KThread::InitializeThread(CurrentProcess, CurrentThread, NULLPTR, NULLPTR, NULLPTR,
+                              NULLPTR, NULLPTR, AR::ProcSup::GetBootStack(), TRUE);
     CurrentThread->NextProcessor = Prcb->CpuNumber;
     CurrentThread->Priority = THREAD_HIGH_PRIORITY;
     CurrentThread->State = Running;

xtoskrnl/ke/krnlinit.cc

@@ -47,7 +47,7 @@ KeStartXtSystem(IN PKERNEL_INITIALIZATION_BLOCK Parameters)
     }
 
     /* Initialize boot CPU */
-    AR::ProcSup::InitializeProcessor(NULL);
+    AR::ProcSup::InitializeProcessor(NULLPTR);
 
     /* Initialize system resources */
     SystemResources::InitializeResources();

xtoskrnl/ke/kthread.cc

@@ -131,7 +131,7 @@ KE::KThread::InitializeThread(IN PKPROCESS Process,
 
     /* Initialize kernel-mode suspend APC */
     Apc::InitializeApc(&Thread->SuspendApc, Thread, OriginalApcEnvironment, SuspendNop,
-                       SuspendRundown, SuspendThread, KernelMode, NULL);
+                       SuspendRundown, SuspendThread, KernelMode, NULLPTR);
 
     /* Initialize suspend semaphore */
     Semaphore::InitializeSemaphore(&Thread->SuspendSemaphore, 0, 2);
@@ -179,8 +179,8 @@ KE::KThread::InitializeThread(IN PKPROCESS Process,
         {
             /* Deallocate stack */
             MM::KernelPool::FreeKernelStack(Stack, FALSE);
-            Thread->InitialStack = NULL;
-            Thread->StackBase = NULL;
+            Thread->InitialStack = NULLPTR;
+            Thread->StackBase = NULLPTR;
         }
 
         /* Thread initialization failed */

xtoskrnl/ke/sysres.cc

@@ -104,8 +104,8 @@ KE::SystemResources::GetSystemResource(IN SYSTEM_RESOURCE_TYPE ResourceType,
     /* Check if resource was found */
     if(ListEntry == &ResourcesListHead)
     {
-        /* Resource not found, return NULL */
-        Resource = nullptr;
+        /* Resource not found, return NULLPTR */
+        Resource = NULLPTR;
         Status = STATUS_NOT_FOUND;
     }