Extract into memory

[Al Hart]

I am having trouble extracting an archiv into a memory buffer.

I have seen hints in a couple of other posts, but just can't get the synta correct.

Here is what I have so far:
(The commented lines are the iines in CLient7z.cpp which I am trying to replace with lines to extract to memory)

        // Get uncompressed size of file
        NCOM::CPropVariant size_prop;
        archive->GetProperty(i, kpidSize, &size_prop);
        ULONGLONG unpackSize = size_prop.uhVal.QuadPart;
        TRACE("SIZE %d\n", unpackSize);

        byte *data = new byte[unpackSize];

        // original code
        // _outFileStreamSpec = new COutFileStream;
        // new code for stream
        CBufPtrSeqOutStream *outStreamSpec = new CBufPtrSeqOutStream;

        // original code
        // CMyComPtr<ISequentialOutStream> outStreamLoc(_outFileStreamSpec);
        // new code for stream
        CMyComPtr<ISequentialOutStream> outStream(outStreamSpec);
        outStreamSpec->Init(data, unpackSize);

        // original code
        // _outFileStream = outStreamLoc;
        // new code for stream
        outStreamSpec = outStream;
        // this line gives this compile error:
        // cannot convert from 'CMyComPtr<T>' to 'CBufPtrSeqOutStream *

        *outStream = outStream.Detach();

        TRACE("DATA: %#x %#x %#x %#x\n", data[0], data[1], data[2], data[3]);
        delete data;

[Igor Pavlov]

you don't need these lines:

outStreamSpec = outStream;
*outStream = outStream.Detach();

[Igor Pavlov]

the problem that you use same name outStream for two different variables. Use outStreamLoc for variable as in Client7z.cpp:

CMyComPtr<ISequentialOutStream> outStreamLoc(outStreamSpec);

[Al Hart]

Thanks for your help on this.

I changed the CMyComPtr line, and commented out the other two lines.

But nothing is being placed in the data array

    // Get name of file in the archive
    NCOM::CPropVariant name_prop;
    archive->GetProperty(i, kpidPath, &name_prop);

    // Get uncompressed size of file
    NCOM::CPropVariant size_prop;
    archive->GetProperty(i, kpidSize, &size_prop);
    ULONGLONG unpackSize = size_prop.uhVal.QuadPart;
    TRACE("FILE NAME w: %ws SIZE: %d\n", name_prop.bstrVal, unpackSize);

    byte *data = new byte[unpackSize];
    memset(data, 0, unpackSize);    // clear to 0s for testing

    CBufPtrSeqOutStream *outStreamSpec = new CBufPtrSeqOutStream;

    CMyComPtr<ISequentialOutStream> outStreamLoc(outStreamSpec);
    outStreamSpec->Init(data, unpackSize);

    //outStreamSpec = outStream;
    //*outStream = outStream.Detach();

    TRACE("DATA: %#x %#x %#x %#x\n", data[0], data[1], data[2], data[3]);
    delete data;

I do not get anything into the data array. I feel like I am missing the line which causes the extract to actualy take place into the data array.

Here is the trace output:showing that I am pointed to a member of the archive, but data is still set to 0s

FILE NAME w: 12in Ceramic.jpg SIZE: 5053
DATA: 0 0 0 0

[Igor Pavlov]

*outStream = outStreamLoc.Detach();

2) also you must call TRACE when data will be decompressed. in SetOperationResult.

[Igor Pavlov]

CMyComPtr<ISequentialOutStream> outStreamLoc;

must be member of
CArchiveExtractCallback

[Al Hart]

I moved the definition of CMyComPtr<ISequentialOutStream> outStreamLoc; into CArchiveExtractCallback

regarding:

*outStream = outStreamLoc.Detach();

I don't have a variable called outStream

Where should I define outStream?

should
CMyComPtr<ISequentialOutStream> outStream;
be in CArchiveExtractCallback as well.

[Igor Pavlov]

original Client7z.cpp:

STDMETHODIMP CArchiveExtractCallback::GetStream(UInt32 index,
    ISequentialOutStream **outStream, Int32 askExtractMode)