Add wxLZMAInputStream for decompressing data in XZ format

No compression support yet.

include/wx/lzmastream.h

@@ -0,0 +1,54 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        wx/lzmastream.h
+// Purpose:     Filters streams using LZMA(2) compression
+// Author:      Vadim Zeitlin
+// Created:     2018-03-29
+// Copyright:   (c) 2018 Vadim Zeitlin <vadim@wxwidgets.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_LZMASTREAM_H_
+#define _WX_LZMASTREAM_H_
+
+#include "wx/defs.h"
+
+#if wxUSE_LIBLZMA && wxUSE_STREAMS
+
+#include "wx/stream.h"
+#include "wx/versioninfo.h"
+
+struct wxLZMAStream;
+
+// ----------------------------------------------------------------------------
+// Filter for decompressing data compressed using LZMA
+// ----------------------------------------------------------------------------
+
+class WXDLLIMPEXP_BASE wxLZMAInputStream : public wxFilterInputStream
+{
+public:
+    explicit wxLZMAInputStream(wxInputStream& stream);
+    explicit wxLZMAInputStream(wxInputStream* stream);
+    virtual ~wxLZMAInputStream();
+
+    char Peek() wxOVERRIDE { return wxInputStream::Peek(); }
+    wxFileOffset GetLength() const wxOVERRIDE { return wxInputStream::GetLength(); }
+
+protected:
+    size_t OnSysRead(void *buffer, size_t size) wxOVERRIDE;
+    wxFileOffset OnSysTell() const wxOVERRIDE { return m_pos; }
+
+private:
+    void Init();
+
+    wxLZMAStream* m_stream;
+    wxUint8* m_inbuf;
+    wxFileOffset m_pos;
+
+    wxDECLARE_NO_COPY_CLASS(wxLZMAInputStream);
+};
+
+WXDLLIMPEXP_BASE wxVersionInfo wxGetLibLZMAVersionInfo();
+
+#endif // wxUSE_LIBLZMA && wxUSE_STREAMS
+
+#endif // _WX_LZMASTREAM_H_