// Formatting library for C++ - std::ostream support // // Copyright (c) 2012 - present, Victor Zverovich // All rights reserved. // // For the license information refer to format.h. #ifndef FMT_OSTREAM_H_ #define FMT_OSTREAM_H_ #include <fstream> #include <ostream> #if defined(_WIN32) && defined(__GLIBCXX__) # include <ext/stdio_filebuf.h> # include <ext/stdio_sync_filebuf.h> #elif defined(_WIN32) && defined(_LIBCPP_VERSION) # include <__std_stream> #endif #include "format.h" FMT_BEGIN_NAMESPACE template <typename OutputIt, typename Char> class basic_printf_context; namespace detail { // Checks if T has a user-defined operator<<. template <typename T, typename Char, typename Enable = void> class is_streamable { private: template <typename U> static auto test(int) -> bool_constant<sizeof(std::declval<std::basic_ostream<Char>&>() << std::declval<U>()) != 0>; template <typename> static auto test(...) -> std::false_type; using result = decltype(test<T>(0)); public: is_streamable() = default; static const bool value = result::value; }; // Formatting of built-in types and arrays is intentionally disabled because // it's handled by standard (non-ostream) formatters. template <typename T, typename Char> struct is_streamable< T, Char, enable_if_t< std::is_arithmetic<T>::value || std::is_array<T>::value || std::is_pointer<T>::value || std::is_same<T, char8_type>::value || std::is_convertible<T, fmt::basic_string_view<Char>>::value || std::is_same<T, std_string_view<Char>>::value || (std::is_convertible<T, int>::value && !std::is_enum<T>::value)>> : std::false_type {}; // Generate a unique explicit instantion in every translation unit using a tag // type in an anonymous namespace. namespace { struct file_access_tag {}; } // namespace template <class Tag, class BufType, FILE* BufType::*FileMemberPtr> class file_access { friend auto get_file(BufType& obj) -> FILE* { return obj.*FileMemberPtr; } }; #if FMT_MSC_VERSION template class file_access<file_access_tag, std::filebuf, &std::filebuf::_Myfile>; auto get_file(std::filebuf&) -> FILE*; #elif defined(_WIN32) && defined(_LIBCPP_VERSION) template class file_access<file_access_tag, std::__stdoutbuf<char>, &std::__stdoutbuf<char>::__file_>; auto get_file(std::__stdoutbuf<char>&) -> FILE*; #endif inline bool write_ostream_unicode(std::ostream& os, fmt::string_view data) { #if FMT_MSC_VERSION if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf())) if (FILE* f = get_file(*buf)) return write_console(f, data); #elif defined(_WIN32) && defined(__GLIBCXX__) auto* rdbuf = os.rdbuf(); FILE* c_file; if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf)) c_file = fbuf->file(); else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf)) c_file = fbuf->file(); else return false; if (c_file) return write_console(c_file, data); #elif defined(_WIN32) && defined(_LIBCPP_VERSION) if (auto* buf = dynamic_cast<std::__stdoutbuf<char>*>(os.rdbuf())) if (FILE* f = get_file(*buf)) return write_console(f, data); #else ignore_unused(os, data); #endif return false; } inline bool write_ostream_unicode(std::wostream&, fmt::basic_string_view<wchar_t>) { return false; } // Write the content of buf to os. // It is a separate function rather than a part of vprint to simplify testing. template <typename Char> void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) { const Char* buf_data = buf.data(); using unsigned_streamsize = std::make_unsigned<std::streamsize>::type; unsigned_streamsize size = buf.size(); unsigned_streamsize max_size = to_unsigned(max_value<std::streamsize>()); do { unsigned_streamsize n = size <= max_size ? size : max_size; os.write(buf_data, static_cast<std::streamsize>(n)); buf_data += n; size -= n; } while (size != 0); } template <typename Char, typename T> void format_value(buffer<Char>& buf, const T& value, locale_ref loc = locale_ref()) { auto&& format_buf = formatbuf<std::basic_streambuf<Char>>(buf); auto&& output = std::basic_ostream<Char>(&format_buf); #if !defined(FMT_STATIC_THOUSANDS_SEPARATOR) if (loc) output.imbue(loc.get<std::locale>()); #endif output << value; output.exceptions(std::ios_base::failbit | std::ios_base::badbit); } template <typename T> struct streamed_view { const T& value; }; } // namespace detail // Formats an object of type T that has an overloaded ostream operator<<. template <typename Char> struct basic_ostream_formatter : formatter<basic_string_view<Char>, Char> { void set_debug_format() = delete; template <typename T, typename OutputIt> auto format(const T& value, basic_format_context<OutputIt, Char>& ctx) const -> OutputIt { auto buffer = basic_memory_buffer<Char>(); format_value(buffer, value, ctx.locale()); return formatter<basic_string_view<Char>, Char>::format( {buffer.data(), buffer.size()}, ctx); } }; using ostream_formatter = basic_ostream_formatter<char>; template <typename T, typename Char> struct formatter<detail::streamed_view<T>, Char> : basic_ostream_formatter<Char> { template <typename OutputIt> auto format(detail::streamed_view<T> view, basic_format_context<OutputIt, Char>& ctx) const -> OutputIt { return basic_ostream_formatter<Char>::format(view.value, ctx); } }; /** \rst Returns a view that formats `value` via an ostream ``operator<<``. **Example**:: fmt::print("Current thread id: {}\n", fmt::streamed(std::this_thread::get_id())); \endrst */ template <typename T> auto streamed(const T& value) -> detail::streamed_view<T> { return {value}; } namespace detail { // Formats an object of type T that has an overloaded ostream operator<<. template <typename T, typename Char> struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>> : basic_ostream_formatter<Char> { using basic_ostream_formatter<Char>::format; }; inline void vprint_directly(std::ostream& os, string_view format_str, format_args args) { auto buffer = memory_buffer(); detail::vformat_to(buffer, format_str, args); detail::write_buffer(os, buffer); } } // namespace detail FMT_MODULE_EXPORT template <typename Char> void vprint(std::basic_ostream<Char>& os, basic_string_view<type_identity_t<Char>> format_str, basic_format_args<buffer_context<type_identity_t<Char>>> args) { auto buffer = basic_memory_buffer<Char>(); detail::vformat_to(buffer, format_str, args); if (detail::write_ostream_unicode(os, {buffer.data(), buffer.size()})) return; detail::write_buffer(os, buffer); } /** \rst Prints formatted data to the stream *os*. **Example**:: fmt::print(cerr, "Don't {}!", "panic"); \endrst */ FMT_MODULE_EXPORT template <typename... T> void print(std::ostream& os, format_string<T...> fmt, T&&... args) { const auto& vargs = fmt::make_format_args(args...); if (detail::is_utf8()) vprint(os, fmt, vargs); else detail::vprint_directly(os, fmt, vargs); } FMT_MODULE_EXPORT template <typename... Args> void print(std::wostream& os, basic_format_string<wchar_t, type_identity_t<Args>...> fmt, Args&&... args) { vprint(os, fmt, fmt::make_format_args<buffer_context<wchar_t>>(args...)); } FMT_END_NAMESPACE #endif // FMT_OSTREAM_H_