add utility to convert a string to lowercase

doc/src/Developer_utils.rst

@@ -103,6 +103,9 @@ and parsing files or arguments.
 .. doxygenfunction:: strdup
    :project: progguide
 
+.. doxygenfunction:: lowercase
+   :project: progguide
+
 .. doxygenfunction:: trim
    :project: progguide
 

src/utils.cpp

@@ -694,6 +694,17 @@ char *utils::strdup(const std::string &text)
   return tmp;
 }
 
+/* ----------------------------------------------------------------------
+   Return string converted to lowercase
+------------------------------------------------------------------------- */
+
+std::string utils::lowercase(const std::string &text)
+{
+  std::string converted;
+  for (auto c : text) converted += ::tolower(c);
+  return converted;
+}
+
 /* ----------------------------------------------------------------------
    Return string without leading or trailing whitespace
 ------------------------------------------------------------------------- */

src/utils.h

@@ -282,6 +282,13 @@ namespace utils {
 
   char *strdup(const std::string &text);
 
+  /*! Convert string to lowercase
+   *
+   * \param line  string that should be converted
+   * \return new string with all lowercase characters */
+
+  std::string lowercase(const std::string &line);
+
   /*! Trim leading and trailing whitespace. Like TRIM() in Fortran.
    *
    * \param line  string that should be trimmed

unittest/utils/test_utils.cpp

@@ -64,6 +64,12 @@ TEST(Utils, trim)
     ASSERT_THAT(trimmed, StrEq(""));
 }
 
+TEST(Utils, lowercase)
+{
+    ASSERT_THAT(utils::lowercase("Gba35%*zAKgRvr"), StrEq("gba35%*zakgrvr"));
+    ASSERT_THAT(utils::lowercase("A BC DEFG"), StrEq("a bc defg"));
+}
+
 TEST(Utils, trim_comment)
 {
     auto trimmed = utils::trim_comment("some text # comment");