139 lines
4.4 KiB
C++
139 lines
4.4 KiB
C++
#include "priv.h"
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#include "nullstm.h"
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#ifndef UNIX
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// A static empty stream implementation, for back compat & no memory hit
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//
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// Macros copied from cfdefs.h
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//
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#define STDMETHODX(fn) HRESULT STDMETHODCALLTYPE fn
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#define STDMETHODX_(ret,fn) ret STDMETHODCALLTYPE fn
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class CNullStream {
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public:
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IStream *vtable;
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STDMETHODX (QueryInterface)(REFIID riid, void **ppvObj);
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STDMETHODX_(ULONG, AddRef)();
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STDMETHODX_(ULONG, Release)();
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STDMETHODX (Read)(void *pv, ULONG cb, ULONG *pcbRead) { if (pcbRead) *pcbRead = 0; return E_NOTIMPL; }
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STDMETHODX (Write)(void const *pv, ULONG cb, ULONG *pcbWritten) { if (pcbWritten) *pcbWritten = 0; return E_NOTIMPL; }
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STDMETHODX (Seek)(LARGE_INTEGER dlibMove, DWORD dwOrigin, ULARGE_INTEGER *plibNewPosition) { plibNewPosition->HighPart = plibNewPosition->LowPart = 0; return E_NOTIMPL; }
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STDMETHODX (SetSize)(ULARGE_INTEGER libNewSize) { return E_NOTIMPL; }
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STDMETHODX (CopyTo)(IStream *, ULARGE_INTEGER, ULARGE_INTEGER *pcbRead, ULARGE_INTEGER *pcbWritten) { if (pcbRead) pcbRead->LowPart = pcbRead->HighPart = 0; if (pcbWritten) pcbWritten->LowPart = pcbWritten->HighPart = 0; return E_NOTIMPL; }
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STDMETHODX (Commit)(DWORD) { return E_NOTIMPL; }
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STDMETHODX (Revert)() { return E_NOTIMPL; }
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STDMETHODX (LockRegion)(ULARGE_INTEGER, ULARGE_INTEGER, DWORD) { return E_NOTIMPL; }
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STDMETHODX (UnlockRegion)(ULARGE_INTEGER, ULARGE_INTEGER, DWORD) { return E_NOTIMPL; }
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STDMETHODX (Stat)(STATSTG *, DWORD) { return E_NOTIMPL; }
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STDMETHODX (Clone)(IStream **ppstm) { *ppstm = NULL; return E_NOTIMPL; }
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};
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STDMETHODIMP CNullStream::QueryInterface(REFIID riid, void **ppvObj)
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{
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if (IsEqualIID(riid, IID_IStream) || IsEqualIID(riid, IID_IUnknown))
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{
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*ppvObj=this;
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// DllAddRef(); // if this dll supported CoCreateInstance
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return S_OK;
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}
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*ppvObj = NULL;
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return E_NOINTERFACE;
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}
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STDMETHODIMP_(ULONG) CNullStream::AddRef()
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{
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// DllAddRef(); // if this dll supported CoCreateInstance
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return 2;
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}
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STDMETHODIMP_(ULONG) CNullStream::Release()
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{
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// DllRelease(); // if this dll supported CoCreateInstance
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return 1;
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}
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// We need the C vtable declaration, but this is .CPP.
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// Simulate the vtable, swiped from objidl.h and touched up.
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//
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typedef struct IStreamVtbl
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{
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HRESULT ( STDMETHODCALLTYPE CNullStream::*QueryInterface )(REFIID riid, void **ppvObject);
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ULONG ( STDMETHODCALLTYPE CNullStream::*AddRef )( );
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ULONG ( STDMETHODCALLTYPE CNullStream::*Release )( );
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HRESULT ( STDMETHODCALLTYPE CNullStream::*Read )(
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void *pv,
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ULONG cb,
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ULONG *pcbRead);
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HRESULT ( STDMETHODCALLTYPE CNullStream::*Write )(
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const void *pv,
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ULONG cb,
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ULONG *pcbWritten);
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HRESULT ( STDMETHODCALLTYPE CNullStream::*Seek )(
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LARGE_INTEGER dlibMove,
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DWORD dwOrigin,
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ULARGE_INTEGER *plibNewPosition);
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HRESULT ( STDMETHODCALLTYPE CNullStream::*SetSize )(
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ULARGE_INTEGER libNewSize);
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HRESULT ( STDMETHODCALLTYPE CNullStream::*CopyTo )(
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IStream *pstm,
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ULARGE_INTEGER cb,
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ULARGE_INTEGER *pcbRead,
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ULARGE_INTEGER *pcbWritten);
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HRESULT ( STDMETHODCALLTYPE CNullStream::*Commit )(
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DWORD grfCommitFlags);
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HRESULT ( STDMETHODCALLTYPE CNullStream::*Revert )( );
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HRESULT ( STDMETHODCALLTYPE CNullStream::*LockRegion )(
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ULARGE_INTEGER libOffset,
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ULARGE_INTEGER cb,
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DWORD dwLockType);
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HRESULT ( STDMETHODCALLTYPE CNullStream::*UnlockRegion )(
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ULARGE_INTEGER libOffset,
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ULARGE_INTEGER cb,
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DWORD dwLockType);
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HRESULT ( STDMETHODCALLTYPE CNullStream::*Stat )(
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STATSTG *pstatstg,
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DWORD grfStatFlag);
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HRESULT ( STDMETHODCALLTYPE CNullStream::*Clone )(
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IStream **ppstm);
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} IStreamVtbl;
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IStream* SHConstNullStream()
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{
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static const IStreamVtbl c_NullStream = {
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CNullStream::QueryInterface,
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CNullStream::AddRef,
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CNullStream::Release,
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CNullStream::Read,
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CNullStream::Write,
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CNullStream::Seek,
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CNullStream::SetSize,
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CNullStream::CopyTo,
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CNullStream::Commit,
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CNullStream::Revert,
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CNullStream::LockRegion,
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CNullStream::UnlockRegion,
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CNullStream::Stat,
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CNullStream::Clone,
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};
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static const void * vtable = (void*)&c_NullStream;
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return (IStream*)&vtable;
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}
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#endif
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