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