[PRINTING] Implement the undocumented MarshallDownStructure, MarshallDownStructuresArray, MarshallUpStructure, and MarshallUpStructuresArray to the extent I need and could find out through black-box testing.

PDBs reveal that these functions are also used in winspool.drv, but not imported from spoolss.dll to retain the client/server architecture.
As winspool.drv highly benefits from the MarshallUp* functions, I put them in a source file shared between spoolss.dll and winspool.drv.

The added API Tests cover my testing and all implemented features.
One more item done from https://reactos.org/wiki/Printing !

win32ss/printing/base/marshalling.c

@@ -0,0 +1,212 @@
+/*
+ * PROJECT:     ReactOS Printing Stack Marshalling Functions
+ * LICENSE:     GPL-2.0+ (https://spdx.org/licenses/GPL-2.0+)
+ * PURPOSE:     Marshalling functions
+ * COPYRIGHT:   Copyright 2015-2018 Colin Finck (colin@reactos.org)
+ */
+
+
+/**
+ * @name MarshallDownStructure
+ *
+ * Prepare a structure for marshalling/serialization by replacing absolute pointer addresses in its fields by relative offsets.
+ *
+ * @param pStructure
+ * Pointer to the structure to operate on.
+ *
+ * @param pInfo
+ * Array of MARSHALLING_INFO elements containing information about the fields of the structure as well as how to modify them.
+ * See the documentation on MARSHALLING_INFO for more information.
+ * You have to indicate the end of the array by setting the dwOffset field to MAXDWORD.
+ *
+ * @param cbStructureSize
+ * Size in bytes of the structure.
+ * This parameter is unused in my implementation.
+ *
+ * @param bSomeBoolean
+ * Unknown boolean value, set to TRUE.
+ *
+ * @return
+ * TRUE if the structure was successfully adjusted, FALSE otherwise.
+ */
+BOOL WINAPI
+MarshallDownStructure(PVOID pStructure, const MARSHALLING_INFO* pInfo, DWORD cbStructureSize, BOOL bSomeBoolean)
+{
+    // Sanity checks
+    if (!pStructure || !pInfo)
+    {
+        SetLastError(ERROR_INVALID_PARAMETER);
+        return FALSE;
+    }
+
+    // Loop until we reach an element with offset set to MAXDWORD.
+    while (pInfo->dwOffset != MAXDWORD)
+    {
+        PULONG_PTR pCurrentField = (PULONG_PTR)((PBYTE)pStructure + pInfo->dwOffset);
+
+        if (pInfo->bAdjustAddress && *pCurrentField)
+        {
+            // Make a relative offset out of the absolute pointer address.
+            *pCurrentField -= (ULONG_PTR)pStructure;
+        }
+
+        // Advance to the next field description.
+        pInfo++;
+    }
+
+    return TRUE;
+}
+
+/**
+ * @name MarshallDownStructuresArray
+ *
+ * Prepare an array of structures for marshalling/serialization by replacing absolute pointer addresses in its fields by relative offsets.
+ *
+ * @param pStructuresArray
+ * Pointer to the array of structures to operate on.
+ *
+ * @param cElements
+ * Number of array elements.
+ *
+ * @param pInfo
+ * Array of MARSHALLING_INFO elements containing information about the fields of the structure as well as how to modify them.
+ * See the documentation on MARSHALLING_INFO for more information.
+ * You have to indicate the end of the array by setting the dwOffset field to MAXDWORD.
+ *
+ * @param cbStructureSize
+ * Size in bytes of each structure array element.
+ *
+ * @param bSomeBoolean
+ * Unknown boolean value, set to TRUE.
+ *
+ * @return
+ * TRUE if the array was successfully adjusted, FALSE otherwise.
+ */
+BOOL WINAPI
+MarshallDownStructuresArray(PVOID pStructuresArray, DWORD cElements, const MARSHALLING_INFO* pInfo, DWORD cbStructureSize, BOOL bSomeBoolean)
+{
+    PBYTE pCurrentElement = pStructuresArray;
+
+    // Call MarshallDownStructure on all array elements given by cElements of cbStructureSize.
+    while (cElements--)
+    {
+        if (!MarshallDownStructure(pCurrentElement, pInfo, cbStructureSize, bSomeBoolean))
+            return FALSE;
+
+        // Advance to the next array element.
+        pCurrentElement += cbStructureSize;
+    }
+
+    return TRUE;
+}
+
+/**
+ * @name MarshallUpStructure
+ *
+ * Unmarshall/deserialize a structure previuosly marshalled by MarshallDownStructure by replacing relative offsets in its fields
+ * by absolute pointer addresses again.
+ *
+ * @param cbSize
+ * Size in bytes of the memory allocated for both the structure and its data.
+ * The function will check if all relative offsets are within the bounds given by this size.
+ *
+ * @param pStructure
+ * Pointer to the structure to operate on.
+ *
+ * @param pInfo
+ * Array of MARSHALLING_INFO elements containing information about the fields of the structure as well as how to modify them.
+ * See the documentation on MARSHALLING_INFO for more information.
+ * You have to indicate the end of the array by setting the dwOffset field to MAXDWORD.
+ *
+ * @param cbStructureSize
+ * Size in bytes of the structure.
+ * This parameter is unused in my implementation.
+ *
+ * @param bSomeBoolean
+ * Unknown boolean value, set to TRUE.
+ *
+ * @return
+ * TRUE if the structure was successfully adjusted, FALSE otherwise.
+ */
+BOOL WINAPI
+MarshallUpStructure(DWORD cbSize, PVOID pStructure, const MARSHALLING_INFO* pInfo, DWORD cbStructureSize, BOOL bSomeBoolean)
+{
+    // Sanity checks
+    if (!pStructure || !pInfo)
+    {
+        SetLastError(ERROR_INVALID_PARAMETER);
+        return FALSE;
+    }
+
+    // Loop until we reach an element with offset set to MAXDWORD.
+    while (pInfo->dwOffset != MAXDWORD)
+    {
+        PULONG_PTR pCurrentField = (PULONG_PTR)((PBYTE)pStructure + pInfo->dwOffset);
+
+        if (pInfo->bAdjustAddress && *pCurrentField)
+        {
+            // Verify that the offset in the current field is within the bounds given by cbSize.
+            if (cbSize <= *pCurrentField)
+            {
+                SetLastError(ERROR_INVALID_DATA);
+                return FALSE;
+            }
+
+            // Make an absolute pointer address out of the relative offset.
+            *pCurrentField += (ULONG_PTR)pStructure;
+        }
+
+        // Advance to the next field description.
+        pInfo++;
+    }
+
+    return TRUE;
+}
+
+/**
+ * @name MarshallUpStructuresArray
+ *
+ * Unmarshall/deserialize an array of structures previuosly marshalled by MarshallDownStructuresArray by replacing relative offsets
+ * in its fields by absolute pointer addresses again.
+ *
+ * @param cbSize
+ * Size in bytes of the memory allocated for the entire structure array and its data.
+ * The function will check if all relative offsets are within the bounds given by this size.
+ *
+ * @param pStructuresArray
+ * Pointer to the array of structures to operate on.
+ *
+ * @param cElements
+ * Number of array elements.
+ *
+ * @param pInfo
+ * Array of MARSHALLING_INFO elements containing information about the fields of the structure as well as how to modify them.
+ * See the documentation on MARSHALLING_INFO for more information.
+ * You have to indicate the end of the array by setting the dwOffset field to MAXDWORD.
+ *
+ * @param cbStructureSize
+ * Size in bytes of each structure array element.
+ *
+ * @param bSomeBoolean
+ * Unknown boolean value, set to TRUE.
+ *
+ * @return
+ * TRUE if the array was successfully adjusted, FALSE otherwise.
+ */
+BOOL WINAPI
+MarshallUpStructuresArray(DWORD cbSize, PVOID pStructuresArray, DWORD cElements, const MARSHALLING_INFO* pInfo, DWORD cbStructureSize, BOOL bSomeBoolean)
+{
+    PBYTE pCurrentElement = pStructuresArray;
+
+    // Call MarshallUpStructure on all array elements given by cElements of cbStructureSize.
+    while (cElements--)
+    {
+        if (!MarshallUpStructure(cbSize, pCurrentElement, pInfo, cbStructureSize, bSomeBoolean))
+            return FALSE;
+
+        // Advance to the next array element.
+        pCurrentElement += cbStructureSize;
+    }
+
+    return TRUE;
+}

win32ss/printing/base/spoolss/CMakeLists.txt

@@ -2,6 +2,7 @@
 spec2def(spoolss.dll spoolss.spec ADD_IMPORTLIB)
 
 list(APPEND SOURCE
+    ../marshalling.c
     context.c
     jobs.c
     main.c

win32ss/printing/base/spoolss/precomp.h

@@ -18,6 +18,7 @@
 #include <ndk/rtlfuncs.h>
 
 #include <spoolss.h>
+#include <marshalling/marshalling.h>
 
 #include <wine/debug.h>
 WINE_DEFAULT_DEBUG_CHANNEL(spoolss);

win32ss/printing/base/spoolss/spoolss.spec

@@ -97,9 +97,9 @@
 @ stub LoadDriverWithVersion
 @ stub LogWmiTraceEvent
 @ stdcall MarshallDownStructure(ptr ptr long long)
-@ stub MarshallDownStructuresArray
-@ stub MarshallUpStructure
-@ stub MarshallUpStructuresArray
+@ stdcall MarshallDownStructuresArray(ptr long ptr long long)
+@ stdcall MarshallUpStructure(long ptr ptr long long)
+@ stdcall MarshallUpStructuresArray(long ptr long ptr long long)
 @ stub MIDL_user_allocate1
 @ stub MIDL_user_free1
 @ stub OldGetPrinterDriverW

win32ss/printing/base/spoolss/tools.c

@@ -8,56 +8,6 @@
 #include "precomp.h"
 
 
-/**
- * @name MarshallDownStructure
- *
- * Prepare a structure for marshalling/serialization by replacing absolute pointer addresses in its fields by relative offsets.
- *
- * @param pStructure
- * Pointer to the structure to operate on.
- *
- * @param pParameters
- * Array of MARSHALL_DOWN_INFO elements containing information about the fields of the structure as well as how to modify them.
- * See the documentation on MARSHALL_DOWN_INFO for more information.
- * You have to indicate the end of the array by setting the dwOffset field to MAXDWORD.
- *
- * @param cbStructureSize
- * Apparently, this is the size in bytes of the structure given through pStructure under Windows.
- * This parameter is unused in my implementation.
- *
- * @param bSomeBoolean
- * Unknown boolean value
- *
- * @return
- * TRUE if the structure was successfully adjusted, FALSE otherwise.
- */
-BOOL WINAPI
-MarshallDownStructure(PVOID pStructure, PMARSHALL_DOWN_INFO pParameters, DWORD cbStructureSize, BOOL bSomeBoolean)
-{
-    // Sanity checks
-    if (!pStructure || !pParameters)
-    {
-        SetLastError(ERROR_INVALID_PARAMETER);
-        return FALSE;
-    }
-
-    // Loop until we reach an element with offset set to MAXDWORD.
-    while (pParameters->dwOffset != MAXDWORD)
-    {
-        if (pParameters->bAdjustAddress)
-        {
-            // Apply the byte offset on pStructure. There must be a pointer at this position, whose address we're adjusting
-            // by subtracting the address of pStructure from it.
-            *((PULONG_PTR)((PBYTE)pStructure + pParameters->dwOffset)) -= (ULONG_PTR)pStructure;
-        }
-
-        // Advance to the next element description.
-        pParameters++;
-    }
-
-    return TRUE;
-}
-
 /**
  * @name PackStrings
  *

win32ss/printing/base/spoolsv/precomp.h

@@ -17,8 +17,10 @@
 #include <winspool.h>
 #include <winsplp.h>
 #include <winspool_s.h>
+#include <ndk/rtlfuncs.h>
 
 #include <spoolss.h>
+#include <marshalling/marshalling.h>
 
 #include <wine/debug.h>
 WINE_DEFAULT_DEBUG_CHANNEL(spoolsv);

win32ss/printing/base/winspool/CMakeLists.txt

@@ -4,6 +4,7 @@ add_rpc_files(client ${REACTOS_SOURCE_DIR}/sdk/include/reactos/idl/winspool.idl)
 spec2def(winspool.drv winspool.spec ADD_IMPORTLIB)
 
 list(APPEND SOURCE
+    ../marshalling.c
     devmode.c
     forms.c
     jobs.c

win32ss/printing/base/winspool/precomp.h

@@ -15,8 +15,10 @@
 #include <winreg.h>
 #include <winspool.h>
 #include <winspool_c.h>
+#include <ndk/rtlfuncs.h>
 
 #include <spoolss.h>
+#include <marshalling/marshalling.h>
 
 #include <wine/debug.h>
 WINE_DEFAULT_DEBUG_CHANNEL(winspool);