Use utf8cpp conversion (#376)

Author: andiwand

scripts/conan

@@ -1,8 +1,7 @@
 #include <odr/internal/pdf/pdf_cmap.hpp>
 
 #include <odr/internal/util/map_util.hpp>
-
-#include <utf8cpp/utf8/cpp17.h>
+#include <odr/internal/util/string_util.hpp>
 
 namespace odr::internal::pdf {
 
@@ -23,7 +22,7 @@ std::string CMap::translate_string(const std::string &glyphs) const {
     result += translate_glyph(glyph);
   }
 
-  return utf8::utf16to8(result);
+  return util::string::u16string_to_string(result);
 }
 
 } // namespace odr::internal::pdf

src/odr/internal/pdf/pdf_cmap.cpp

@@ -2,11 +2,12 @@
 
 #include <algorithm>
 #include <cctype>
-#include <codecvt>
 #include <iomanip>
 #include <locale>
 #include <sstream>
 
+#include <utf8cpp/utf8/cpp17.h>
+
 namespace odr::internal::util {
 
 bool string::starts_with(const std::string &string, const std::string &with) {
@@ -72,15 +73,11 @@ std::string string::to_string(const double d, const int precision) {
 }
 
 std::string string::u16string_to_string(const std::u16string &string) {
-  static std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t>
-      convert;
-  return convert.to_bytes(string);
+  return utf8::utf16to8(string);
 }
 
 std::u16string string::string_to_u16string(const std::string &string) {
-  static std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t>
-      convert;
-  return convert.from_bytes(string);
+  return utf8::utf8to16(string);
 }
 
 std::string string::c16str_to_string(const char16_t *c16str,