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Replace conditional compilation with SFINAE

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This commit is contained in:
Victor Zverovich
2022-04-11 12:16:05 -07:00
parent 8751a03a04
commit ce7ecdb7af
1 changed files with 15 additions and 6 deletions
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21
include/fmt/ostream.h
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@ -55,8 +55,18 @@ template <typename Char> FILE* get_file(std::basic_filebuf<Char>&) {
return nullptr; return nullptr;
} }
#if FMT_MSC_VER struct dummy_filebuf {
FILE* get_file(std::filebuf& buf); 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 // Generate a unique explicit instantion in every translation unit using a tag
// type in an anonymous namespace. // type in an anonymous namespace.
@ -65,12 +75,11 @@ struct filebuf_access_tag {};
} // namespace } // namespace
template <typename Tag, typename FileMemberPtr, FileMemberPtr file> template <typename Tag, typename FileMemberPtr, FileMemberPtr file>
class filebuf_access { 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, template class filebuf_access<filebuf_access_tag,
decltype(&std::filebuf::_Myfile), decltype(&filebuf_type::_Myfile),
&std::filebuf::_Myfile>; &filebuf_type::_Myfile>;
#endif
inline bool write(std::filebuf& buf, fmt::string_view data) { inline bool write(std::filebuf& buf, fmt::string_view data) {
print(get_file(buf), data); print(get_file(buf), data);