fixup! Add builtin class for string_to_upper_case

Author: romainbrenguier

src/solvers/refinement/string_builtin_function.cpp

@@ -187,6 +187,12 @@ exprt string_set_char_builtin_functiont::length_constraint() const
     equal_exprt(return_code, return_value));
 }
 
+static bool eval_is_upper_case(const mp_integer &c)
+{
+  return ('A' <= c && c <= 'Z') || (0xc0 <= c && c <= 0xd6) ||
+         (0xd8 <= c && c <= 0xde);
+}
+
 optionalt<exprt> string_to_lower_case_builtin_functiont::eval(
   const std::function<exprt(const exprt &)> &get_value) const
 {
@@ -195,9 +201,7 @@ optionalt<exprt> string_to_lower_case_builtin_functiont::eval(
     return {};
   for(mp_integer &c : input_opt.value())
   {
-    if(
-      ('A' <= c && c <= 'Z') || (0xc0 <= c && c <= 0xd6) ||
-      (0xd8 <= c && c <= 0xde))
+    if(eval_is_upper_case(c))
       c += 0x20;
   }
   const auto length =
@@ -214,7 +218,7 @@ optionalt<exprt> string_to_upper_case_builtin_functiont::eval(
     return {};
   for(mp_integer &c : input_opt.value())
   {
-    if('a' <= c && c <= 'z')
+    if(eval_is_upper_case(c - 0x20))
       c -= 0x20;
   }
   const auto length =