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//
// 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_
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