windows-nt/Source/XPSP1/NT/multimedia/media/sndrec32/o2base/stgutils.cxx

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2020-09-26 03:20:57 -05:00
//+---------------------------------------------------------------------
//
// File: stgutils.hxx
//
// Contents: IStorage and IStream Helper functions
//
//----------------------------------------------------------------------
#include "headers.hxx"
#pragma hdrstop
//+---------------------------------------------------------------
//
// Function: GetMonikerDisplayName
//
// Synopsis: Retrieves the display name of a moniker
//
// Arguments: [pmk] -- the moniker for which the display name is requested
// [ppstr] -- the place where the display name is returned
//
// Returns: Success iff the display name could be retrieved
//
// Notes: The display name string is allocated using the task allocator
// and should be freed by the same.
//
//----------------------------------------------------------------
HRESULT
GetMonikerDisplayName(LPMONIKER pmk, LPOLESTR FAR* ppstr)
{
HRESULT r;
LPBC pbc;
if (OK(r = CreateBindCtx(0, &pbc)))
{
r = pmk->GetDisplayName(pbc, NULL, ppstr);
pbc->Release();
}
return r;
}
//+---------------------------------------------------------------
//
// Function: CreateStorageOnHGlobal
//
// Synopsis: Creates an IStorage on a global memory handle
//
// Arguments: [hgbl] -- memory handle to create storage on
// [ppStg] -- where the storage is returned
//
// Returns: Success iff the storage could be successfully created
// on the memory handle.
//
// Notes: This helper function combines CreateILockBytesOnHGlobal
// and StgCreateDocfileOnILockBytes. hgbl may be NULL in
// which case a global memory handle will be automatically
// allocated.
//
//----------------------------------------------------------------
HRESULT
CreateStorageOnHGlobal(HGLOBAL hgbl, LPSTORAGE FAR* ppStg)
{
HRESULT r;
LPLOCKBYTES pLockBytes;
if (OK(r = CreateILockBytesOnHGlobal(hgbl, TRUE, &pLockBytes)))
{
//REVIEW: should be use STGM_DELETEONRELEASE when hgbl == NULL?
r = StgCreateDocfileOnILockBytes(pLockBytes,
STGM_CREATE|STGM_READWRITE|STGM_SHARE_EXCLUSIVE, 0, ppStg);
pLockBytes->Release();
}
return r;
}
//+---------------------------------------------------------------
//
// Function: ConvertToMemoryStream
//
// Synopsis: Takes a stream and produces an equivalent stream
// stored in memory for faster individual reads
//
// Arguments: [pStrmFrom] -- the stream to convert
//
// Returns: An equivalent stream
//
// Notes: Any failure in creating the memory stream will result in
// the original stream, pStrmFrom, being returned.
// Hence the caller should assume the stream passed in has
// been released and should release the stream returned
// after it has finished using it.
//
//----------------------------------------------------------------
LPSTREAM
ConvertToMemoryStream(LPSTREAM pStrmFrom)
{
//REVIEW: perhaps we should use the IStream::CopyTo function
// instead of doing the read manually!
HRESULT r;
LPSTREAM pStrm = NULL;
STATSTG statstg;
if (OK(r = pStrmFrom->Stat(&statstg, STATFLAG_NONAME)))
{
if (statstg.cbSize.HighPart != 0)
{
DOUT(TEXT("o2base/stdils/ConvertToMemoryStream E_FAIL\r\n"));
r = E_FAIL;
}
else
{
HGLOBAL hgbl = GlobalAlloc(GMEM_SHARE, statstg.cbSize.LowPart);
if (hgbl == NULL)
{
DOUT(TEXT("o2base/stgutils/ConvertToMemoryStream failed\r\n"));
r = E_OUTOFMEMORY;
}
else
{
LPVOID pv = GlobalLock(hgbl);
if (pv == NULL)
{
DOUT(TEXT("o2base/stdils/ConvertToMemoryStream E_FAIL(2)\r\n"));
r = E_FAIL;
}
else
{
r = pStrmFrom->Read(pv, statstg.cbSize.LowPart, NULL);
GlobalUnlock(hgbl);
if (OK(r))
{
if (OK(r = CreateStreamOnHGlobal(hgbl, TRUE, &pStrm)))
{
pStrm->SetSize(statstg.cbSize);
pStrmFrom->Release();
}
else
{
DOUT(TEXT("o2base/stdils/ConvertToMemoryStream CreateStreamOnHGlobal Failed!\r\n"));
}
}
}
if (!OK(r))
{
GlobalFree(hgbl);
}
}
}
}
if (!OK(r))
{
pStrm = pStrmFrom;
}
return pStrm;
}