Add RoundTrip example for XML Streaming API + backport lates libstudxml changes from upstream

XML/samples/RoundTrip/src/RoundTrip.cpp

@@ -0,0 +1,101 @@
+// file      : examples/roundtrip/driver.cxx
+// copyright : not copyrighted - public domain
+
+#include <string>
+#include <fstream>
+#include <iostream>
+
+#include "Poco/XML/XMLStreamParser.h"
+#include "Poco/XML/XMLStreamSerializer.h"
+
+using namespace std;
+using namespace Poco::XML;
+
+int main(int argc, char* argv[])
+{
+	if (argc != 2)
+	{
+		cerr << "usage: " << argv[0] << " <xml-file>" << endl;
+		return 1;
+	}
+
+	try
+	{
+		// Enable stream exceptions so that io failures are reported
+		// as stream rather than as parsing exceptions.
+		//
+		ifstream ifs;
+		ifs.exceptions(ifstream::badbit | ifstream::failbit);
+		ifs.open(argv[1], ifstream::in | ifstream::binary);
+
+		// Configure the parser to receive attributes as events as well
+		// as to receive prefix-namespace mappings (namespace declarations
+		// in XML terminology).
+		//
+		XMLStreamParser p(ifs, argv[1],
+				XMLStreamParser::RECEIVE_DEFAULT | XMLStreamParser::RECEIVE_ATTRIBUTES_EVENT | XMLStreamParser::RECEIVE_NAMESPACE_DECLS);
+
+		// Configure serializer not to perform indentation. Existing
+		// indentation, if any, will be preserved.
+		//
+		XMLStreamSerializer s(cout, "out", 0);
+
+		for (XMLStreamParser::EventType e(p.next()); e != XMLStreamParser::Eof; e = p.next())
+		{
+			switch (e)
+			{
+			case XMLStreamParser::StartElement:
+			{
+				s.startElement(p.getQName());
+				break;
+			}
+			case XMLStreamParser::EndElement:
+			{
+				s.endElement();
+				break;
+			}
+			case XMLStreamParser::StartNamespaceDecl:
+			{
+				s.namespaceDecl(p.namespace_(), p.prefix());
+				break;
+			}
+			case XMLStreamParser::EndNamespaceDecl:
+			{
+				// There is nothing in XML that indicates the end of namespace
+				// declaration since it is scope-based.
+				//
+				break;
+			}
+			case XMLStreamParser::StartAttribute:
+			{
+				s.startAttribute(p.getQName());
+				break;
+			}
+			case XMLStreamParser::EndAttribute:
+			{
+				s.endAttribute();
+				break;
+			}
+			case XMLStreamParser::Characters:
+			{
+				s.characters(p.value());
+				break;
+			}
+			case XMLStreamParser::Eof:
+			{
+				// Handled in the for loop.
+				//
+				break;
+			}
+			}
+		}
+	} catch (const ios_base::failure&)
+	{
+		cerr << "io failure" << endl;
+		return 1;
+	} catch (const Poco::Exception& e)
+	{
+		cerr << e.displayText() << endl;
+		return 1;
+	}
+}