Don't hang in ReadLine when there's no input left

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@48162 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/txtstrm.cpp

@@ -77,6 +77,9 @@ wxChar wxTextInputStream::NextChar()
     memset((void*)m_lastBytes, 0, 10);
     for(size_t inlen = 0; inlen < 9; inlen++)
     {
+        if (!m_input.CanRead())
+            return wxEOT;
+
         // actually read the next character
         m_lastBytes[inlen] = m_input.GetC();
 
@@ -90,6 +93,9 @@ wxChar wxTextInputStream::NextChar()
     // there should be no encoding which requires more than nine bytes for one character...
     return wxEOT;
 #else
+    if (!m_input.CanRead())
+        return wxEOT;
+
     m_lastBytes[0] = m_input.GetC();
 
     if(m_input.LastRead() <= 0)