Replace conditional compilation with SFINAE

This commit is contained in:
Victor Zverovich 2022-04-11 12:16:05 -07:00
parent 8751a03a04
commit ce7ecdb7af

View File

@ -55,8 +55,18 @@ template <typename Char> FILE* get_file(std::basic_filebuf<Char>&) {
return nullptr;
}
#if FMT_MSC_VER
FILE* get_file(std::filebuf& buf);
struct dummy_filebuf {
FILE* _Myfile;
};
template <typename T, typename U = int> struct ms_filebuf {
using type = dummy_filebuf;
};
template <typename T> struct ms_filebuf<T, decltype(T::_Myfile, 0)> {
using type = T;
};
using filebuf_type = ms_filebuf<std::filebuf>::type;
FILE* get_file(filebuf_type& buf);
// Generate a unique explicit instantion in every translation unit using a tag
// type in an anonymous namespace.
@ -65,12 +75,11 @@ struct filebuf_access_tag {};
} // namespace
template <typename Tag, typename FileMemberPtr, FileMemberPtr file>
class filebuf_access {
friend FILE* get_file(std::filebuf& buf) { return buf.*file; }
friend FILE* get_file(filebuf_type& buf) { return buf.*file; }
};
template class filebuf_access<filebuf_access_tag,
decltype(&std::filebuf::_Myfile),
&std::filebuf::_Myfile>;
#endif
decltype(&filebuf_type::_Myfile),
&filebuf_type::_Myfile>;
inline bool write(std::filebuf& buf, fmt::string_view data) {
print(get_file(buf), data);