Source code of Windows XP (NT5)
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/*++
Copyright (c) 1996 Microsoft Corporation
All rights reserved.
Module Name:
sharemem.hxx
Abstract:
Simple shared memory object.
Author:
Albert Ting (AlbertT) 17-Dec-1996
Revision History:
--*/
#ifndef SHAREMEM_HXX
#define SHAREMEM_HXX
/********************************************************************
TShareMemLock
Lock a TShareMem for access. If this call succeeds, pGet() will
return the pointer to the object.
TShareMem ShareMem( sizeof( TMyObject ),
TEXT( "MyObject" ),
TShareMem::kCreate | TShareMem::kReadWrite,
NULL,
NULL );
if( ShareMem.bValid( )){
TMyObject *pMyObject;
TShareMemLock<TMyObject> SML( ShareMem, &pMyObject );
//
// Use pMyObject--note it can't have any virtual functions!
//
}
//
// Closing scope of TShareMemLock removes lock.
//
********************************************************************/
class TShareMem;
template<class T>
class TShareMemLock {
public:
TShareMemLock(
TShareMem &ShareMem,
T **ppMem
);
~TShareMemLock(
VOID
);
private:
TShareMem &m_ShareMem;
};
template<class T>
inline
TShareMemLock<T>::
TShareMemLock(
IN TShareMem &ShareMem,
OUT T **ppMem
) : m_ShareMem( ShareMem )
{
m_ShareMem.vEnter();
*ppMem = static_cast<T*>( ShareMem.pGetData() );
}
template<class T>
inline
TShareMemLock<T>::
~TShareMemLock(
VOID
)
{
m_ShareMem.vLeave();
}
class TShareMem {
public:
enum {
kNull = 0,
kCreate = 1,
kReadWrite = 2
};
TShareMem(
UINT uSize,
LPCTSTR pszName,
UINT uFlags,
PSECURITY_ATTRIBUTES psa,
PUINT puSizeDisposition
);
~TShareMem(
VOID
);
BOOL
bValid(
VOID
);
VOID
vEnter(
VOID
);
VOID
vLeave(
VOID
);
PVOID
pGetData(
VOID
);
private:
typedef struct HEADER {
UINT uHeaderSize;
UINT uSize;
} *PHEADER;
HEADER&
GetHeader(
VOID
);
HANDLE m_hFile;
PVOID m_pvBase;
PVOID m_pvUserData;
HANDLE m_hMutex;
};
inline
BOOL
TShareMem::
bValid(
VOID
)
{
return m_pvUserData != NULL;
}
inline
TShareMem::HEADER&
TShareMem::
GetHeader(
VOID
)
{
return *static_cast<PHEADER>( m_pvBase );
}
inline
VOID
TShareMem::
vEnter(
VOID
)
{
WaitForSingleObject( m_hMutex, INFINITE );
}
inline
VOID
TShareMem::
vLeave(
VOID
)
{
ReleaseMutex( m_hMutex );
}
inline
PVOID
TShareMem::
pGetData(
VOID
)
{
return m_pvUserData;
}
#endif // ifdef SHAREMEM_HXX