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//------------------------------------------------------------------------------
// File: PStream.cpp
//
// Desc: DirectShow base classes.
//
// Copyright (c) 1992-2001 Microsoft Corporation. All rights reserved.
//------------------------------------------------------------------------------
#include "streams.h"
#include <strsafe.h>
#ifdef PERF
#include <measure.h>
#endif
// #include "pstream.h" in streams.h
//
// Constructor
//
CPersistStream::CPersistStream(IUnknown *punk, __inout HRESULT *phr)
: mPS_fDirty(FALSE)
{
mPS_dwFileVersion = GetSoftwareVersion();
}
//
// Destructor
//
CPersistStream::~CPersistStream() {
// Nothing to do
}
#if 0
SAMPLE CODE TO COPY - not active at the moment
//
// NonDelegatingQueryInterface
//
// This object supports IPersist & IPersistStream
STDMETHODIMP CPersistStream::NonDelegatingQueryInterface(REFIID riid, __deref_out void **ppv)
{
if (riid == IID_IPersist) {
return GetInterface((IPersist *) this, ppv); // ???
}
else if (riid == IID_IPersistStream) {
return GetInterface((IPersistStream *) this, ppv);
}
else {
return CUnknown::NonDelegatingQueryInterface(riid, ppv);
}
}
#endif
//
// WriteToStream
//
// Writes to the stream (default action is to write nothing)
HRESULT CPersistStream::WriteToStream(IStream *pStream)
{
// You can override this to do things like
// hr = pStream->Write(MyStructure, sizeof(MyStructure), NULL);
return NOERROR;
}
HRESULT CPersistStream::ReadFromStream(IStream * pStream)
{
// You can override this to do things like
// hr = pStream->Read(MyStructure, sizeof(MyStructure), NULL);
return NOERROR;
}
//
// Load
//
// Load all the data from the given stream
STDMETHODIMP CPersistStream::Load(LPSTREAM pStm)
{
HRESULT hr;
// Load the version number then the data
mPS_dwFileVersion = ReadInt(pStm, hr);
if (FAILED(hr)) {
return hr;
}
return ReadFromStream(pStm);
} // Load
//
// Save
//
// Save the contents of this Stream.
STDMETHODIMP CPersistStream::Save(LPSTREAM pStm, BOOL fClearDirty)
{
HRESULT hr = WriteInt(pStm, GetSoftwareVersion());
if (FAILED(hr)) {
return hr;
}
hr = WriteToStream(pStm);
if (FAILED(hr)) {
return hr;
}
mPS_fDirty = !fClearDirty;
return hr;
} // Save
// WriteInt
//
// Writes an integer to an IStream as 11 UNICODE characters followed by one space.
// You could use this for shorts or unsigneds or anything (up to 32 bits)
// where the value isn't actually truncated by squeezing it into 32 bits.
// Values such as (unsigned) 0x80000000 would come out as -2147483648
// but would then load as 0x80000000 through ReadInt. Cast as you please.
STDAPI WriteInt(IStream *pIStream, int n)
{
WCHAR Buff[13]; // Allows for trailing null that we don't write
(void)StringCchPrintfW(Buff, NUMELMS(Buff),L"%011d ",n);
return pIStream->Write(&(Buff[0]), 12*sizeof(WCHAR), NULL);
} // WriteInt
// ReadInt
//
// Reads an integer from an IStream.
// Read as 4 bytes. You could use this for shorts or unsigneds or anything
// where the value isn't actually truncated by squeezing it into 32 bits
// Striped down subset of what sscanf can do (without dragging in the C runtime)
STDAPI_(int) ReadInt(IStream *pIStream, __out HRESULT &hr)
{
int Sign = 1;
unsigned int n = 0; // result wil be n*Sign
WCHAR wch;
hr = pIStream->Read( &wch, sizeof(wch), NULL);
if (FAILED(hr)) {
return 0;
}
if (wch==L'-'){
Sign = -1;
hr = pIStream->Read( &wch, sizeof(wch), NULL);
if (FAILED(hr)) {
return 0;
}
}
for( ; ; ) {
if (wch>=L'0' && wch<=L'9') {
n = 10*n+(int)(wch-L'0');
} else if ( wch == L' '
|| wch == L'\t'
|| wch == L'\r'
|| wch == L'\n'
|| wch == L'\0'
) {
break;
} else {
hr = VFW_E_INVALID_FILE_FORMAT;
return 0;
}
hr = pIStream->Read( &wch, sizeof(wch), NULL);
if (FAILED(hr)) {
return 0;
}
}
if (n==0x80000000 && Sign==-1) {
// This is the negative number that has no positive version!
return (int)n;
}
else return (int)n * Sign;
} // ReadInt
// The microsoft C/C++ compile generates level 4 warnings to the effect that
// a particular inline function (from some base class) was not needed.
// This line gets rid of hundreds of such unwanted messages and makes
// -W4 compilation feasible:
#pragma warning(disable: 4514)
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