adding back files to be reviewed

include/openmc/xml_interface.h

@@ -0,0 +1,53 @@
+#ifndef OPENMC_XML_INTERFACE_H
+#define OPENMC_XML_INTERFACE_H
+
+#include <cstddef> // for size_t
+#include <sstream> // for stringstream
+#include <string>
+#include <vector>
+
+#include "pugixml.hpp"
+#include "xtensor/xarray.hpp"
+#include "xtensor/xadapt.hpp"
+
+namespace openmc {
+
+inline bool
+check_for_node(pugi::xml_node node, const char *name)
+{
+  return node.attribute(name) || node.child(name);
+}
+
+std::string get_node_value(pugi::xml_node node, const char* name,
+                           bool lowercase=false, bool strip=false);
+
+bool get_node_value_bool(pugi::xml_node node, const char* name);
+
+template <typename T>
+std::vector<T> get_node_array(pugi::xml_node node, const char* name,
+                              bool lowercase=false)
+{
+  // Get value of node attribute/child
+  std::string s {get_node_value(node, name, lowercase)};
+
+  // Read values one by one into vector
+  std::stringstream iss {s};
+  T value;
+  std::vector<T> values;
+  while (iss >> value)
+    values.push_back(value);
+
+  return values;
+}
+
+template <typename T>
+xt::xarray<T> get_node_xarray(pugi::xml_node node, const char* name,
+                              bool lowercase=false)
+{
+  std::vector<T> v = get_node_array<T>(node, name, lowercase);
+  std::vector<std::size_t> shape = {v.size()};
+  return xt::adapt(v, shape);
+}
+
+} // namespace openmc
+#endif // OPENMC_XML_INTERFACE_H