fmt-11.0.2/include/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 #ifndef FMT_MODULE
  12 #  include <fstream>  // std::filebuf
  13 #endif
  14
  15 #ifdef _WIN32
  16 #  ifdef __GLIBCXX__
  17 #    include <ext/stdio_filebuf.h>
  18 #    include <ext/stdio_sync_filebuf.h>
  19 #  endif
  20 #  include <io.h>
  21 #endif
  22
  23 #include "chrono.h"  // formatbuf
  24
  25 FMT_BEGIN_NAMESPACE
  26 namespace detail {
  27
  28 // Generate a unique explicit instantion in every translation unit using a tag
  29 // type in an anonymous namespace.
  30 namespace {
  31 struct file_access_tag {};
  32 }  // namespace
  33 template <typename Tag, typename BufType, FILE* BufType::*FileMemberPtr>
  34 class file_access {
  35   friend auto get_file(BufType& obj) -> FILE* { return obj.*FileMemberPtr; }
  36 };
  37
  38 #if FMT_MSC_VERSION
  39 template class file_access<file_access_tag, std::filebuf,
  40                            &std::filebuf::_Myfile>;
  41 auto get_file(std::filebuf&) -> FILE*;
  42 #endif
  43
  44 inline auto write_ostream_unicode(std::ostream& os, fmt::string_view data)
  45     -> bool {
  46   FILE* f = nullptr;
  47 #if FMT_MSC_VERSION && FMT_USE_RTTI
  48   if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf()))
  49     f = get_file(*buf);
  50   else
  51     return false;
  52 #elif defined(_WIN32) && defined(__GLIBCXX__) && FMT_USE_RTTI
  53   auto* rdbuf = os.rdbuf();
  54   if (auto* sfbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
  55     f = sfbuf->file();
  56   else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
  57     f = fbuf->file();
  58   else
  59     return false;
  60 #else
  61   ignore_unused(os, data, f);
  62 #endif
  63 #ifdef _WIN32
  64   if (f) {
  65     int fd = _fileno(f);
  66     if (_isatty(fd)) {
  67       os.flush();
  68       return write_console(fd, data);
  69     }
  70   }
  71 #endif
  72   return false;
  73 }
  74 inline auto write_ostream_unicode(std::wostream&,
  75                                   fmt::basic_string_view<wchar_t>) -> bool {
  76   return false;
  77 }
  78
  79 // Write the content of buf to os.
  80 // It is a separate function rather than a part of vprint to simplify testing.
  81 template <typename Char>
  82 void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
  83   const Char* buf_data = buf.data();
  84   using unsigned_streamsize = std::make_unsigned<std::streamsize>::type;
  85   unsigned_streamsize size = buf.size();
  86   unsigned_streamsize max_size = to_unsigned(max_value<std::streamsize>());
  87   do {
  88     unsigned_streamsize n = size <= max_size ? size : max_size;
  89     os.write(buf_data, static_cast<std::streamsize>(n));
  90     buf_data += n;
  91     size -= n;
  92   } while (size != 0);
  93 }
  94
  95 template <typename Char, typename T>
  96 void format_value(buffer<Char>& buf, const T& value) {
  97   auto&& format_buf = formatbuf<std::basic_streambuf<Char>>(buf);
  98   auto&& output = std::basic_ostream<Char>(&format_buf);
  99 #if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
 100   output.imbue(std::locale::classic());  // The default is always unlocalized.
 101 #endif
 102   output << value;
 103   output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
 104 }
 105
 106 template <typename T> struct streamed_view {
 107   const T& value;
 108 };
 109
 110 }  // namespace detail
 111
 112 // Formats an object of type T that has an overloaded ostream operator<<.
 113 template <typename Char>
 114 struct basic_ostream_formatter : formatter<basic_string_view<Char>, Char> {
 115   void set_debug_format() = delete;
 116
 117   template <typename T, typename Context>
 118   auto format(const T& value, Context& ctx) const -> decltype(ctx.out()) {
 119     auto buffer = basic_memory_buffer<Char>();
 120     detail::format_value(buffer, value);
 121     return formatter<basic_string_view<Char>, Char>::format(
 122         {buffer.data(), buffer.size()}, ctx);
 123   }
 124 };
 125
 126 using ostream_formatter = basic_ostream_formatter<char>;
 127
 128 template <typename T, typename Char>
 129 struct formatter<detail::streamed_view<T>, Char>
 130     : basic_ostream_formatter<Char> {
 131   template <typename Context>
 132   auto format(detail::streamed_view<T> view, Context& ctx) const
 133       -> decltype(ctx.out()) {
 134     return basic_ostream_formatter<Char>::format(view.value, ctx);
 135   }
 136 };
 137
 138 /**
 139  * Returns a view that formats `value` via an ostream `operator<<`.
 140  *
 141  * **Example**:
 142  *
 143  *     fmt::print("Current thread id: {}\n",
 144  *                fmt::streamed(std::this_thread::get_id()));
 145  */
 146 template <typename T>
 147 constexpr auto streamed(const T& value) -> detail::streamed_view<T> {
 148   return {value};
 149 }
 150
 151 namespace detail {
 152
 153 inline void vprint_directly(std::ostream& os, string_view format_str,
 154                             format_args args) {
 155   auto buffer = memory_buffer();
 156   detail::vformat_to(buffer, format_str, args);
 157   detail::write_buffer(os, buffer);
 158 }
 159
 160 }  // namespace detail
 161
 162 FMT_EXPORT template <typename Char>
 163 void vprint(std::basic_ostream<Char>& os,
 164             basic_string_view<type_identity_t<Char>> format_str,
 165             typename detail::vformat_args<Char>::type args) {
 166   auto buffer = basic_memory_buffer<Char>();
 167   detail::vformat_to(buffer, format_str, args);
 168   if (detail::write_ostream_unicode(os, {buffer.data(), buffer.size()})) return;
 169   detail::write_buffer(os, buffer);
 170 }
 171
 172 /**
 173  * Prints formatted data to the stream `os`.
 174  *
 175  * **Example**:
 176  *
 177  *     fmt::print(cerr, "Don't {}!", "panic");
 178  */
 179 FMT_EXPORT template <typename... T>
 180 void print(std::ostream& os, format_string<T...> fmt, T&&... args) {
 181   const auto& vargs = fmt::make_format_args(args...);
 182   if (detail::use_utf8())
 183     vprint(os, fmt, vargs);
 184   else
 185     detail::vprint_directly(os, fmt, vargs);
 186 }
 187
 188 FMT_EXPORT
 189 template <typename... Args>
 190 void print(std::wostream& os,
 191            basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
 192            Args&&... args) {
 193   vprint(os, fmt, fmt::make_format_args<buffered_context<wchar_t>>(args...));
 194 }
 195
 196 FMT_EXPORT template <typename... T>
 197 void println(std::ostream& os, format_string<T...> fmt, T&&... args) {
 198   fmt::print(os, "{}\n", fmt::format(fmt, std::forward<T>(args)...));
 199 }
 200
 201 FMT_EXPORT
 202 template <typename... Args>
 203 void println(std::wostream& os,
 204              basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
 205              Args&&... args) {
 206   print(os, L"{}\n", fmt::format(fmt, std::forward<Args>(args)...));
 207 }
 208
 209 FMT_END_NAMESPACE
 210
 211 #endif  // FMT_OSTREAM_H_