[MeL/IO] XDMF: Add XdmfWriter RAII class

MeshLib/IO/XDMF/XdmfWriter.cpp

+#include "XdmfWriter.h"
+
+#include <fstream>
+
+#include "writeXdmf.h"
+#include "BaseLib/RunTime.h"
+#include "BaseLib/Logging.h"
+
+namespace MeshLib::IO
+{
+XdmfWriter::XdmfWriter(std::string const& xdmf_filename,
+                       std::function<std::string(std::vector<double>)>
+                           xdmf_writer_fn)
+    : filename(xdmf_filename), xdmf_writer(xdmf_writer_fn)
+{
+}
+
+XdmfWriter::~XdmfWriter()
+{
+    BaseLib::RunTime time_output;
+    time_output.start();
+    std::ofstream fout;
+    fout.open(this->filename);
+    fout << xdmf_writer(times);
+
+    INFO("[time] Output of XDMF took {:g} s.", time_output.elapsed());
+}
+
+void XdmfWriter::addTimeStep(double const& time_step)
+{
+    times.push_back(time_step);
+}
+
+}  // namespace MeshLib::IO
\ No newline at end of file

MeshLib/IO/XDMF/XdmfWriter.h

+/**
+ * \file
+ * \author Tobias Meisel
+ * \date   2021-06-30
+ * \brief  Collects and holds all metadata for writing XDMF file
+ * \copyright
+ * Copyright (c) 2012-2021, OpenGeoSys Community (http://www.opengeosys.org)
+ *            Distributed under a Modified BSD License.
+ *              See accompanying file LICENSE.txt or
+ *              http://www.opengeosys.org/project/license
+ */
+
+#pragma once
+
+#include <functional>
+#include <string>
+
+namespace MeshLib::IO
+{
+class XdmfWriter final
+{
+public:
+    /**
+     * \brief Writes xdmf string into file on class destruction
+     * @param xdmf_filename absolute or relative filepath to the xdmf file
+     * @param xdmf_writer_fn function that generates xdmf string
+     */
+    XdmfWriter(std::string const& xdmf_filename,
+               std::function<std::string(std::vector<double>)>
+                   xdmf_writer_fn);
+    XdmfWriter(XdmfWriter&&) = default;
+    XdmfWriter& operator=(XdmfWriter&&) = default;
+    XdmfWriter(XdmfWriter const&) = delete;
+    XdmfWriter& operator=(XdmfWriter const&) = delete;
+    ~XdmfWriter();
+
+    /**
+     * \brief Adds data for lazy (xdmf) writing algorithm
+     * @param time_step time value of the current time_step
+     */
+    void addTimeStep(double const& time_step);
+
+private:
+    std::string filename;
+    std::vector<double> times;
+    std::function<std::string(std::vector<double>)> xdmf_writer;
+};
+}  // namespace MeshLib::IO