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 #include <wchar.h>

 namespace base {

 bool IsWprintfFormatPortable(const wchar_t* format) {

   for (const wchar_t* position = format; *position != '\0'; ++position) {

     if (*position == '%') {

       bool in_specification = true;

       bool modifier_l = false;

       while (in_specification) {

         // Eat up characters until reaching a known specifier.

         if (*++position == '\0') {

           // The format string ended in the middle of a specification.  Call

           // it portable because no unportable specifications were found.  The

           // string is equally broken on all platforms.

           return true;

         }

         if (*position == 'l') {

           // 'l' is the only thing that can save the 's' and 'c' specifiers.

           modifier_l = true;

         } else if (((*position == 's' || *position == 'c') && !modifier_l) ||

                    *position == 'S' || *position == 'C' || *position == 'F' ||

                    *position == 'D' || *position == 'O' || *position == 'U') {

           // Not portable.

           return false;

         }

         if (wcschr(L"diouxXeEfgGaAcspn%", *position)) {

           // Portable, keep scanning the rest of the format string.

           in_specification = false;

         }

       }

     }

   }

   return true;

 }

 }  // namespace base