Re: [1/5] windowscodecs: Implement IWICStream::InitializeFromIStream. (try 2)

[Dmitry Timoshkov]

Józef Kucia  wrote:
> - offset.QuadPart = 0;
> - size.u.LowPart = 0xffffffff;
> - size.u.HighPart = 0xffffffff;
> - return IWICStream_InitializeFromIStreamRegion(iface, pIStream, offset, size);

What prevents you from discovering correct stream size?

[1/5] windowscodecs: Implement IWICStream::InitializeFromIStream. (try 2)

[Józef Kucia]

On Tue, May 29, 2012 at 12:07 PM, Dmitry Timoshkov  wrote:
> What prevents you from discovering correct stream size?

A stream can grow its memory. For example, IStream returned by
CreateStreamOnHGlobal do this.

[1/5] windowscodecs: Implement IWICStream::InitializeFromIStream. (try 2)

[Dmitry Timoshkov]

Józef Kucia  wrote:
> > What prevents you from discovering correct stream size?
>
> A stream can grow its memory. For example, IStream returned by
> CreateStreamOnHGlobal do this.

I don't think you need to worry about that unless you have a test case
or an app that depends on this.

[1/5] windowscodecs: Implement IWICStream::InitializeFromIStream. (try 2)

[Józef Kucia]

On Tue, May 29, 2012 at 12:29 PM, Dmitry Timoshkov  wrote:
> Józef Kucia  wrote:
> > A stream can grow its memory. For example, IStream returned by
> > CreateStreamOnHGlobal do this.
>
> I don't think you need to worry about that unless you have a test case
> or an app that depends on this.

That's what native does. See the attached unit tests.

[1/5] windowscodecs: Implement IWICStream::InitializeFromIStream. (try 2)

[Vincent Povirk]

> > - offset.QuadPart = 0;
> > - size.u.LowPart = 0xffffffff;
> > - size.u.HighPart = 0xffffffff;
> > - return IWICStream_InitializeFromIStreamRegion(iface, pIStream, offset, size);
>
> What prevents you from discovering correct stream size?

The size passed to InitializeFromIStreamRegion is an upper limit. If
the underlying stream is smaller, the appropriate size will still be
reported from Read, Stat, and Seek.

[1/5] windowscodecs: Implement IWICStream::InitializeFromIStream. (try 2)

[Vincent Povirk]

BTW, the patch looks good to me.

On Tue, May 29, 2012 at 8:07 AM, Vincent Povirk  wrote:
> > > - offset.QuadPart = 0;
> > > - size.u.LowPart = 0xffffffff;
> > > - size.u.HighPart = 0xffffffff;
> > > - return IWICStream_InitializeFromIStreamRegion(iface, pIStream, offset, size);
> >
> > What prevents you from discovering correct stream size?
>
> The size passed to InitializeFromIStreamRegion is an upper limit. If
> the underlying stream is smaller, the appropriate size will still be
> reported from Read, Stat, and Seek.