1 files changed, 91 insertions, 0 deletions
diff --git a/src/ipcman/ipcheader.inl b/src/ipcman/ipcheader.inl
new file mode 100644
index 0000000000..85aed282c4
--- /dev/null
+++ b/src/ipcman/ipcheader.inl
@@ -0,0 +1,91 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information. 
+//
+
+// ==++==
+//
+ 
+//
+// ==--==
+//*****************************************************************************
+// File: IPCHeader.inl
+//
+// Define the LegacyPrivate header format for COM+ memory mapped files. Everyone
+// outside of IPCMan.lib will use the public header, IPCManagerInterface.h
+//
+//*****************************************************************************
+
+#ifndef _IPCManagerPriv_inl_
+#define _IPCManagerPriv_inl_
+
+#include "ipcheader.h"
+
+//=============================================================================
+// Internal Helpers: Encapsulate any error-prone math / comparisons.
+// The helpers are very streamlined and don't handle error conditions.
+// Also, Table access functions use DWORD instead of typesafe Enums
+// so they can be more flexible (not just for LegacyPrivate blocks).
+//=============================================================================
+
+//-----------------------------------------------------------------------------
+// Returns true if the entry is empty and false if the entry is usable.
+// This is an internal helper that Enforces a formal definition for an 
+// "empty" entry
+//
+// Arguments:
+//   block - IPC block of interest
+//   Id - index of the desired entry in the IPC block's table
+//-----------------------------------------------------------------------------
+inline bool Internal_CheckEntryEmptyLegacyPrivate(
+    const LegacyPrivateIPCControlBlock & block,   
+    DWORD Id                                
+)
+{
+// Directory has offset in bytes of block
+    const DWORD offset = block.m_FullIPCHeader.m_table[Id].m_Offset;
+
+    return (EMPTY_ENTRY_OFFSET == offset);
+}
+
+//-----------------------------------------------------------------------------
+// Returns the base that entry offsets for the specified IPC block
+// are relative to.
+//
+// Arguments:
+//   block - IPC block of interest
+//-----------------------------------------------------------------------------
+inline SIZE_T Internal_GetOffsetBaseLegacyPrivate(const LegacyPrivateIPCControlBlock & block)
+{
+    return LEGACY_IPC_ENTRY_OFFSET_BASE + 
+           block.m_FullIPCHeader.m_header.m_numEntries 
+            * sizeof(IPCEntry);            // skip over directory (variable size)
+}
+
+//-----------------------------------------------------------------------------
+// Returns a BYTE* to a block within a header. This is an internal 
+// helper that encapsulates error-prone math.
+//
+// Arguments:
+//   block - IPC block of interest
+//   Id - index of the desired entry in the IPC block's table
+//-----------------------------------------------------------------------------
+inline BYTE* Internal_GetBlockLegacyPrivate(
+    const LegacyPrivateIPCControlBlock & block,   
+    DWORD Id                                
+)
+{
+
+// Directory has offset in bytes of block
+    const DWORD offset = block.m_FullIPCHeader.m_table[Id].m_Offset;
+
+
+// This block has been removed. Callee should have caught that and not called us.
+    _ASSERTE(!Internal_CheckEntryEmptyLegacyPrivate(block, Id));
+    return
+        ((BYTE*) &block)                    // base pointer to start of block
+        + Internal_GetOffsetBaseLegacyPrivate(block)
+        +offset;                            // jump to block
+}
+
+#endif // _IPCManagerPriv_inl_