Corrected a couple problems in wxStreamBuffer that show up when

reading from a wxMemoryStream


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_4_BRANCH@17977 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/stream.cpp

@@ -58,7 +58,7 @@
 
 void wxStreamBuffer::SetError(wxStreamError err)
 {
-   if ( m_stream->m_lasterror == wxSTREAM_NO_ERROR )
+   if ( m_stream && m_stream->m_lasterror == wxSTREAM_NO_ERROR )
        m_stream->m_lasterror = err;
 }
 
@@ -198,7 +198,9 @@ bool wxStreamBuffer::FillBuffer()
 {
     wxInputStream *inStream = GetInputStream();
 
-    wxCHECK_MSG( inStream, FALSE, _T("should have a stream in wxStreamBuffer") );
+    // It's legal to have no stream, so we shouldn't don't about it just return FALSE
+    if ( !inStream )
+        return FALSE;
 
     size_t count = inStream->OnSysRead(m_buffer_start, m_buffer_size);
     if ( !count )