src/3rdparty/fmt/ostream.h

   1 // Formatting library for C++ - std::ostream support
   2 //
   3 // Copyright (c) 2012 - present, Victor Zverovich
   4 // All rights reserved.
   5 //
   6 // For the license information refer to format.h.
   7
   8 #ifndef FMT_OSTREAM_H_
   9 #define FMT_OSTREAM_H_
  10
  11 #include <fstream>  // std::filebuf
  12
  13 #ifdef _WIN32
  14 #  ifdef __GLIBCXX__
  15 #    include <ext/stdio_filebuf.h>
  16 #    include <ext/stdio_sync_filebuf.h>
  17 #  endif
  18 #  include <io.h>
  19 #endif
  20
  21 #include "format.h"
  22
  23 FMT_BEGIN_NAMESPACE
  24 namespace detail {
  25
  26 template <typename Streambuf> class formatbuf : public Streambuf {
  27  private:
  28   using char_type = typename Streambuf::char_type;
  29   using streamsize = decltype(std::declval<Streambuf>().sputn(nullptr, 0));
  30   using int_type = typename Streambuf::int_type;
  31   using traits_type = typename Streambuf::traits_type;
  32
  33   buffer<char_type>& buffer_;
  34
  35  public:
  36   explicit formatbuf(buffer<char_type>& buf) : buffer_(buf) {}
  37
  38  protected:
  39   // The put area is always empty. This makes the implementation simpler and has
  40   // the advantage that the streambuf and the buffer are always in sync and
  41   // sputc never writes into uninitialized memory. A disadvantage is that each
  42   // call to sputc always results in a (virtual) call to overflow. There is no
  43   // disadvantage here for sputn since this always results in a call to xsputn.
  44
  45   auto overflow(int_type ch) -> int_type override {
  46     if (!traits_type::eq_int_type(ch, traits_type::eof()))
  47       buffer_.push_back(static_cast<char_type>(ch));
  48     return ch;
  49   }
  50
  51   auto xsputn(const char_type* s, streamsize count) -> streamsize override {
  52     buffer_.append(s, s + count);
  53     return count;
  54   }
  55 };
  56
  57 // Generate a unique explicit instantion in every translation unit using a tag
  58 // type in an anonymous namespace.
  59 namespace {
  60 struct file_access_tag {};
  61 }  // namespace
  62 template <typename Tag, typename BufType, FILE* BufType::*FileMemberPtr>
  63 class file_access {
  64   friend auto get_file(BufType& obj) -> FILE* { return obj.*FileMemberPtr; }
  65 };
  66
  67 #if FMT_MSC_VERSION
  68 template class file_access<file_access_tag, std::filebuf,
  69                            &std::filebuf::_Myfile>;
  70 auto get_file(std::filebuf&) -> FILE*;
  71 #endif
  72
  73 inline auto write_ostream_unicode(std::ostream& os, fmt::string_view data)
  74     -> bool {
  75   FILE* f = nullptr;
  76 #if FMT_MSC_VERSION
  77   if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf()))
  78     f = get_file(*buf);
  79   else
  80     return false;
  81 #elif defined(_WIN32) && defined(__GLIBCXX__)
  82   auto* rdbuf = os.rdbuf();
  83   if (auto* sfbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
  84     f = sfbuf->file();
  85   else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
  86     f = fbuf->file();
  87   else
  88     return false;
  89 #else
  90   ignore_unused(os, data, f);
  91 #endif
  92 #ifdef _WIN32
  93   if (f) {
  94     int fd = _fileno(f);
  95     if (_isatty(fd)) {
  96       os.flush();
  97       return write_console(fd, data);
  98     }
  99   }
 100 #endif
 101   return false;
 102 }
 103 inline auto write_ostream_unicode(std::wostream&,
 104                                   fmt::basic_string_view<wchar_t>) -> bool {
 105   return false;
 106 }
 107
 108 // Write the content of buf to os.
 109 // It is a separate function rather than a part of vprint to simplify testing.
 110 template <typename Char>
 111 void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
 112   const Char* buf_data = buf.data();
 113   using unsigned_streamsize = std::make_unsigned<std::streamsize>::type;
 114   unsigned_streamsize size = buf.size();
 115   unsigned_streamsize max_size = to_unsigned(max_value<std::streamsize>());
 116   do {
 117     unsigned_streamsize n = size <= max_size ? size : max_size;
 118     os.write(buf_data, static_cast<std::streamsize>(n));
 119     buf_data += n;
 120     size -= n;
 121   } while (size != 0);
 122 }
 123
 124 template <typename Char, typename T>
 125 void format_value(buffer<Char>& buf, const T& value) {
 126   auto&& format_buf = formatbuf<std::basic_streambuf<Char>>(buf);
 127   auto&& output = std::basic_ostream<Char>(&format_buf);
 128 #if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
 129   output.imbue(std::locale::classic());  // The default is always unlocalized.
 130 #endif
 131   output << value;
 132   output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
 133 }
 134
 135 template <typename T> struct streamed_view {
 136   const T& value;
 137 };
 138
 139 }  // namespace detail
 140
 141 // Formats an object of type T that has an overloaded ostream operator<<.
 142 template <typename Char>
 143 struct basic_ostream_formatter : formatter<basic_string_view<Char>, Char> {
 144   void set_debug_format() = delete;
 145
 146   template <typename T, typename OutputIt>
 147   auto format(const T& value, basic_format_context<OutputIt, Char>& ctx) const
 148       -> OutputIt {
 149     auto buffer = basic_memory_buffer<Char>();
 150     detail::format_value(buffer, value);
 151     return formatter<basic_string_view<Char>, Char>::format(
 152         {buffer.data(), buffer.size()}, ctx);
 153   }
 154 };
 155
 156 using ostream_formatter = basic_ostream_formatter<char>;
 157
 158 template <typename T, typename Char>
 159 struct formatter<detail::streamed_view<T>, Char>
 160     : basic_ostream_formatter<Char> {
 161   template <typename OutputIt>
 162   auto format(detail::streamed_view<T> view,
 163               basic_format_context<OutputIt, Char>& ctx) const -> OutputIt {
 164     return basic_ostream_formatter<Char>::format(view.value, ctx);
 165   }
 166 };
 167
 168 /**
 169   \rst
 170   Returns a view that formats `value` via an ostream ``operator<<``.
 171
 172   **Example**::
 173
 174     fmt::print("Current thread id: {}\n",
 175                fmt::streamed(std::this_thread::get_id()));
 176   \endrst
 177  */
 178 template <typename T>
 179 constexpr auto streamed(const T& value) -> detail::streamed_view<T> {
 180   return {value};
 181 }
 182
 183 namespace detail {
 184
 185 inline void vprint_directly(std::ostream& os, string_view format_str,
 186                             format_args args) {
 187   auto buffer = memory_buffer();
 188   detail::vformat_to(buffer, format_str, args);
 189   detail::write_buffer(os, buffer);
 190 }
 191
 192 }  // namespace detail
 193
 194 FMT_EXPORT template <typename Char>
 195 void vprint(std::basic_ostream<Char>& os,
 196             basic_string_view<type_identity_t<Char>> format_str,
 197             basic_format_args<buffer_context<type_identity_t<Char>>> args) {
 198   auto buffer = basic_memory_buffer<Char>();
 199   detail::vformat_to(buffer, format_str, args);
 200   if (detail::write_ostream_unicode(os, {buffer.data(), buffer.size()})) return;
 201   detail::write_buffer(os, buffer);
 202 }
 203
 204 /**
 205   \rst
 206   Prints formatted data to the stream *os*.
 207
 208   **Example**::
 209
 210     fmt::print(cerr, "Don't {}!", "panic");
 211   \endrst
 212  */
 213 FMT_EXPORT template <typename... T>
 214 void print(std::ostream& os, format_string<T...> fmt, T&&... args) {
 215   const auto& vargs = fmt::make_format_args(args...);
 216   if (detail::is_utf8())
 217     vprint(os, fmt, vargs);
 218   else
 219     detail::vprint_directly(os, fmt, vargs);
 220 }
 221
 222 FMT_EXPORT
 223 template <typename... Args>
 224 void print(std::wostream& os,
 225            basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
 226            Args&&... args) {
 227   vprint(os, fmt, fmt::make_format_args<buffer_context<wchar_t>>(args...));
 228 }
 229
 230 FMT_EXPORT template <typename... T>
 231 void println(std::ostream& os, format_string<T...> fmt, T&&... args) {
 232   fmt::print(os, "{}\n", fmt::format(fmt, std::forward<T>(args)...));
 233 }
 234
 235 FMT_EXPORT
 236 template <typename... Args>
 237 void println(std::wostream& os,
 238              basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
 239              Args&&... args) {
 240   print(os, L"{}\n", fmt::format(fmt, std::forward<Args>(args)...));
 241 }
 242
 243 FMT_END_NAMESPACE
 244
 245 #endif  // FMT_OSTREAM_H_