Leaked source code of windows server 2003
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//+---------------------------------------------------------------------------
//
// Microsoft Windows
// Copyright (C) Microsoft Corporation, 1992 - 1995.
//
// File: MEMLB.CXX
//
// Contents:
//
// Classes: Implements the memory-based ILockBytes class.
//
// Functions:
//
// History: 12-13-95 JoeS (Joe Souza) Created
//
//----------------------------------------------------------------------------
#include <urlint.h>
#include <urlmon.hxx>
#include "clockbyt.hxx"
#include "memlb.hxx"
MemLockBytes::MemLockBytes() : _CRefs()
{
memhandle = NULL;
}
STDMETHODIMP_(ULONG) MemLockBytes::Release(void)
{
VDATETHIS(this);
UrlMkDebugOut((DEB_ILOCKBYTES, "%p IN MemLockBytes::Release\n", this));
UrlMkAssert((_CRefs > 0));
LONG lRet = --_CRefs;
if (_CRefs == 0)
{
if (memhandle)
GlobalFree(memhandle);
delete this;
}
UrlMkDebugOut((DEB_ILOCKBYTES, "%p OUT MemLockBytes::Release\n", this));
return lRet;
}
HRESULT MemLockBytes::ReadAt(THIS_ ULARGE_INTEGER ulOffset, VOID HUGEP *pv,
ULONG cb, ULONG FAR *pcbRead)
{
HRESULT hresult = E_FAIL;
LPVOID memptr;
DWORD memsize;
ULONG count;
UrlMkDebugOut((DEB_ILOCKBYTES, "%p IN MemLockBytes::ReadAt\n", this));
*pcbRead = 0;
if (!cb)
goto ReadAtExit;
if (!memhandle)
goto ReadAtExit;
memsize = GlobalSize(memhandle);
count = cb;
if (ulOffset.QuadPart + cb > memsize)
{
if (ulOffset.QuadPart > memsize)
{
goto ReadAtExit;
}
else
{
count = memsize - (DWORD)ulOffset.QuadPart;
}
}
memptr = GlobalLock(memhandle);
if (!memptr)
goto ReadAtExit;
*(DWORD *)&memptr += (DWORD)ulOffset.QuadPart;
memcpy(pv, memptr, count);
*pcbRead = count;
GlobalUnlock(memhandle);
hresult = NOERROR;
ReadAtExit:
UrlMkDebugOut((DEB_ILOCKBYTES, "%p OUT MemLockBytes::ReadAt\n", this));
return(hresult);
}
HRESULT MemLockBytes::WriteAt(THIS_ ULARGE_INTEGER ulOffset, VOID const HUGEP *pv,
ULONG cb, ULONG FAR *pcbWritten)
{
HRESULT hresult = E_FAIL;
LPVOID memptr;
DWORD memsize;
UrlMkDebugOut((DEB_ILOCKBYTES, "%p IN MemLockBytes::WriteAt\n", this));
*pcbWritten = 0;
if (!cb)
goto WriteAtExit;
if (!memhandle)
{
memhandle = GlobalAlloc(GMEM_MOVEABLE | GMEM_DISCARDABLE,
cb + (DWORD)ulOffset.QuadPart);
}
if (!memhandle)
goto WriteAtExit;
while (1)
{
memsize = GlobalSize(memhandle);
if (ulOffset.QuadPart + cb > memsize)
{
memhandle = GlobalReAlloc(memhandle, cb + (DWORD)ulOffset.QuadPart,
GMEM_MOVEABLE);
}
else
break;
}
memptr = GlobalLock(memhandle);
if (!memptr)
goto WriteAtExit;
*(DWORD *)&memptr += (DWORD)ulOffset.QuadPart;
memcpy(memptr, pv, cb);
GlobalUnlock(memhandle);
*pcbWritten = cb;
hresult = NOERROR;
WriteAtExit:
UrlMkDebugOut((DEB_ILOCKBYTES, "%p OUT MemLockBytes::WriteAt\n", this));
return(hresult);
}
HRESULT MemLockBytes::SetSize(THIS_ ULARGE_INTEGER cb)
{
HRESULT hresult = NOERROR;
UrlMkDebugOut((DEB_ILOCKBYTES, "%p IN MemLockBytes::SetSize\n", this));
if (!memhandle)
{
memhandle = GlobalAlloc(GMEM_MOVEABLE | GMEM_DISCARDABLE,
(DWORD)cb.QuadPart);
}
else
{
memhandle = GlobalReAlloc(memhandle, (DWORD)cb.QuadPart, GMEM_MOVEABLE);
}
if (!memhandle)
hresult = E_FAIL;
UrlMkDebugOut((DEB_ILOCKBYTES, "%p OUT MemLockBytes::SetSize\n", this));
return(hresult);
}