Utility::contains(), Utility::ends_with()

You'd think these would be easy enough to implement ourselves, but we
had a bug in our idiom for ends_with(), so let's just consolidate
everything.

I'll give these names to match C++20/23 standard names, both for an
easier transition in the future and to reassure myself that I'm not the
only one who was bad enough with string utilities to benefit from these
helper functions.

Author: roystgnr

include/utils/utility.h

@@ -386,6 +386,20 @@ void deallocate (std::vector<T> & vec)
 std::string_view basename_of(const std::string & fullname);
 
 
+/**
+ * Look for a substring within a string.
+ */
+bool contains(std::string_view superstring,
+              std::string_view substring);
+
+
+/**
+ * Look for a substring at the very end of a string.
+ */
+bool ends_with(std::string_view superstring,
+               std::string_view suffix);
+
+
 // Utility functions useful when dealing with complex numbers.
 
 #ifdef LIBMESH_USE_COMPLEX_NUMBERS

src/utils/utility.C

@@ -202,5 +202,27 @@ std::string Utility::unzip_file (std::string_view name)
 
 
 
+bool Utility::contains(std::string_view superstring, std::string_view substring)
+{
+  // This can just be C++23 contains() someday
+  return superstring.find(substring) != std::string::npos;
+}
+
+
+
+bool Utility::ends_with(std::string_view superstring,
+                        std::string_view suffix)
+{
+  // This can just be C++20 ends_with() someday
+  const auto sufsize = suffix.size();
+  const auto supsize = superstring.size();
+  if (sufsize > supsize)
+    return false;
+
+  return superstring.compare(supsize - sufsize, std::string::npos,
+                             suffix) == 0;
+}
+
+
 
 } // namespace libMesh