From 590cbcae2b25030abf35a19b171345a502933b50 Mon Sep 17 00:00:00 2001
From: James Forshaw <tyranid@users.noreply.github.com>
Date: Mon, 19 Aug 2024 13:02:37 -0700
Subject: [PATCH] Added structure alignment types.

---
 NtApiDotNet/Ndr/NdrSimpleTypes.cs    |  4 +++
 NtApiDotNet/Ndr/NdrStructureTypes.cs | 41 ++++++++++++++++++++++++++--
 2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/NtApiDotNet/Ndr/NdrSimpleTypes.cs b/NtApiDotNet/Ndr/NdrSimpleTypes.cs
index a728c74a..e9df7de5 100644
--- a/NtApiDotNet/Ndr/NdrSimpleTypes.cs
+++ b/NtApiDotNet/Ndr/NdrSimpleTypes.cs
@@ -620,6 +620,10 @@ internal static NdrBaseTypeReference Read(NdrParseContext context, BinaryReader
                     case NdrFormatCharacter.FC_STRUCTPAD6:
                     case NdrFormatCharacter.FC_STRUCTPAD7:
                         return new NdrStructurePaddingTypeReference(format);
+                    case NdrFormatCharacter.FC_ALIGNM2:
+                    case NdrFormatCharacter.FC_ALIGNM4:
+                    case NdrFormatCharacter.FC_ALIGNM8:
+                        return new NdrStructureAlignTypeReference(format);
                     case NdrFormatCharacter.FC_IGNORE:
                         return new NdrIgnoreTypeReference();
                     case NdrFormatCharacter.FC_SYSTEM_HANDLE:
diff --git a/NtApiDotNet/Ndr/NdrStructureTypes.cs b/NtApiDotNet/Ndr/NdrStructureTypes.cs
index 9d6f815c..4575e75f 100644
--- a/NtApiDotNet/Ndr/NdrStructureTypes.cs
+++ b/NtApiDotNet/Ndr/NdrStructureTypes.cs
@@ -81,11 +81,18 @@ protected virtual List<NdrStructureMember> PopulateMembers()
             int current_offset = 0;
             foreach (var type in _base_members)
             {
-                if (!(type is NdrStructurePaddingTypeReference))
+                if (type is NdrStructureAlignTypeReference align)
                 {
-                    members.Add(new NdrStructureMember(type, current_offset, $"Member{current_offset:X}"));
+                    current_offset = align.Align(current_offset);
+                }
+                else
+                {
+                    if (!(type is NdrStructurePaddingTypeReference))
+                    {
+                        members.Add(new NdrStructureMember(type, current_offset, $"Member{current_offset:X}"));
+                    }
+                    current_offset += type.GetSize();
                 }
-                current_offset += type.GetSize();
             }
             return members;
         }
@@ -311,6 +318,34 @@ public override int GetSize()
         }
     }
 
+    [Serializable]
+    public sealed class NdrStructureAlignTypeReference : NdrBaseTypeReference
+    {
+        internal NdrStructureAlignTypeReference(NdrFormatCharacter format) : base(format)
+        {
+        }
+
+        internal int Align(int offset)
+        {
+            switch (Format)
+            {
+                case NdrFormatCharacter.FC_ALIGNM2:
+                    return (offset + 1) & ~1;
+                case NdrFormatCharacter.FC_ALIGNM4:
+                    return (offset + 3) & ~3;
+                case NdrFormatCharacter.FC_ALIGNM8:
+                    return (offset + 7) & ~7;
+                default:
+                    throw new InvalidOperationException("Format must be an alignment.");
+            }
+        }
+
+        public override int GetSize()
+        {
+            return 0;
+        }
+    }
+
     [Serializable]
     public sealed class NdrPointerInfoInstance
     {