libcxx/include/__ostream/print.h

   1 //===---------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===---------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___OSTREAM_PRINT_H
  10 #define _LIBCPP___OSTREAM_PRINT_H
  11
  12 #include <__config>
  13
  14 #if _LIBCPP_HAS_LOCALIZATION
  15
  16 #  include <__fwd/ostream.h>
  17 #  include <__iterator/ostreambuf_iterator.h>
  18 #  include <__ostream/basic_ostream.h>
  19 #  include <format>
  20 #  include <ios>
  21 #  include <locale>
  22 #  include <print>
  23
  24 #  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  25 #    pragma GCC system_header
  26 #  endif
  27
  28 _LIBCPP_BEGIN_NAMESPACE_STD
  29
  30 #  if _LIBCPP_STD_VER >= 23
  31
  32 template <class = void> // TODO PRINT template or availability markup fires too eagerly (http://llvm.org/PR61563).
  33 _LIBCPP_HIDE_FROM_ABI inline void
  34 __vprint_nonunicode(ostream& __os, string_view __fmt, format_args __args, bool __write_nl) {
  35   // [ostream.formatted.print]/3
  36   // Effects: Behaves as a formatted output function
  37   // ([ostream.formatted.reqmts]) of os, except that:
  38   // - failure to generate output is reported as specified below, and
  39   // - any exception thrown by the call to vformat is propagated without regard
  40   //   to the value of os.exceptions() and without turning on ios_base::badbit
  41   //   in the error state of os.
  42   // After constructing a sentry object, the function initializes an automatic
  43   // variable via
  44   //   string out = vformat(os.getloc(), fmt, args);
  45
  46   ostream::sentry __s(__os);
  47   if (__s) {
  48     string __o = std::vformat(__os.getloc(), __fmt, __args);
  49     if (__write_nl)
  50       __o += '\n';
  51
  52     const char* __str = __o.data();
  53     size_t __len      = __o.size();
  54
  55 #    if _LIBCPP_HAS_EXCEPTIONS
  56     try {
  57 #    endif // _LIBCPP_HAS_EXCEPTIONS
  58       typedef ostreambuf_iterator<char> _Ip;
  59       if (std::__pad_and_output(
  60               _Ip(__os),
  61               __str,
  62               (__os.flags() & ios_base::adjustfield) == ios_base::left ? __str + __len : __str,
  63               __str + __len,
  64               __os,
  65               __os.fill())
  66               .failed())
  67         __os.setstate(ios_base::badbit | ios_base::failbit);
  68
  69 #    if _LIBCPP_HAS_EXCEPTIONS
  70     } catch (...) {
  71       __os.__set_badbit_and_consider_rethrow();
  72     }
  73 #    endif // _LIBCPP_HAS_EXCEPTIONS
  74   }
  75 }
  76
  77 template <class = void> // TODO PRINT template or availability markup fires too eagerly (http://llvm.org/PR61563).
  78 _LIBCPP_HIDE_FROM_ABI inline void vprint_nonunicode(ostream& __os, string_view __fmt, format_args __args) {
  79   std::__vprint_nonunicode(__os, __fmt, __args, false);
  80 }
  81
  82 // Returns the FILE* associated with the __os.
  83 // Returns a nullptr when no FILE* is associated with __os.
  84 // This function is in the dylib since the type of the buffer associated
  85 // with std::cout, std::cerr, and std::clog is only known in the dylib.
  86 //
  87 // This function implements part of the implementation-defined behavior
  88 // of [ostream.formatted.print]/3
  89 //   If the function is vprint_unicode and os is a stream that refers to
  90 //   a terminal capable of displaying Unicode which is determined in an
  91 //   implementation-defined manner, writes out to the terminal using the
  92 //   native Unicode API;
  93 // Whether the returned FILE* is "a terminal capable of displaying Unicode"
  94 // is determined in the same way as the print(FILE*, ...) overloads.
  95 _LIBCPP_EXPORTED_FROM_ABI FILE* __get_ostream_file(ostream& __os);
  96
  97 #    if _LIBCPP_HAS_UNICODE
  98 template <class = void> // TODO PRINT template or availability markup fires too eagerly (http://llvm.org/PR61563).
  99 _LIBCPP_HIDE_FROM_ABI void __vprint_unicode(ostream& __os, string_view __fmt, format_args __args, bool __write_nl) {
 100 #      if _LIBCPP_AVAILABILITY_HAS_PRINT == 0
 101   return std::__vprint_nonunicode(__os, __fmt, __args, __write_nl);
 102 #      else
 103   FILE* __file = std::__get_ostream_file(__os);
 104   if (!__file || !__print::__is_terminal(__file))
 105     return std::__vprint_nonunicode(__os, __fmt, __args, __write_nl);
 106
 107   // [ostream.formatted.print]/3
 108   //    If the function is vprint_unicode and os is a stream that refers to a
 109   //    terminal capable of displaying Unicode which is determined in an
 110   //    implementation-defined manner, writes out to the terminal using the
 111   //    native Unicode API; if out contains invalid code units, the behavior is
 112   //    undefined and implementations are encouraged to diagnose it. If the
 113   //    native Unicode API is used, the function flushes os before writing out.
 114   //
 115   // This is the path for the native API, start with flushing.
 116   __os.flush();
 117
 118 #        if _LIBCPP_HAS_EXCEPTIONS
 119   try {
 120 #        endif // _LIBCPP_HAS_EXCEPTIONS
 121     ostream::sentry __s(__os);
 122     if (__s) {
 123 #        ifndef _LIBCPP_WIN32API
 124       __print::__vprint_unicode_posix(__file, __fmt, __args, __write_nl, true);
 125 #        elif _LIBCPP_HAS_WIDE_CHARACTERS
 126     __print::__vprint_unicode_windows(__file, __fmt, __args, __write_nl, true);
 127 #        else
 128 #          error "Windows builds with wchar_t disabled are not supported."
 129 #        endif
 130     }
 131
 132 #        if _LIBCPP_HAS_EXCEPTIONS
 133   } catch (...) {
 134     __os.__set_badbit_and_consider_rethrow();
 135   }
 136 #        endif // _LIBCPP_HAS_EXCEPTIONS
 137 #      endif   // _LIBCPP_AVAILABILITY_HAS_PRINT
 138 }
 139
 140 template <class = void> // TODO PRINT template or availability markup fires too eagerly (http://llvm.org/PR61563).
 141 _LIBCPP_HIDE_FROM_ABI inline void vprint_unicode(ostream& __os, string_view __fmt, format_args __args) {
 142   std::__vprint_unicode(__os, __fmt, __args, false);
 143 }
 144 #    endif // _LIBCPP_HAS_UNICODE
 145
 146 template <class... _Args>
 147 _LIBCPP_HIDE_FROM_ABI void print(ostream& __os, format_string<_Args...> __fmt, _Args&&... __args) {
 148 #    if _LIBCPP_HAS_UNICODE
 149   if constexpr (__print::__use_unicode_execution_charset)
 150     std::__vprint_unicode(__os, __fmt.get(), std::make_format_args(__args...), false);
 151   else
 152     std::__vprint_nonunicode(__os, __fmt.get(), std::make_format_args(__args...), false);
 153 #    else  // _LIBCPP_HAS_UNICODE
 154   std::__vprint_nonunicode(__os, __fmt.get(), std::make_format_args(__args...), false);
 155 #    endif // _LIBCPP_HAS_UNICODE
 156 }
 157
 158 template <class... _Args>
 159 _LIBCPP_HIDE_FROM_ABI void println(ostream& __os, format_string<_Args...> __fmt, _Args&&... __args) {
 160 #    if _LIBCPP_HAS_UNICODE
 161   // Note the wording in the Standard is inefficient. The output of
 162   // std::format is a std::string which is then copied. This solution
 163   // just appends a newline at the end of the output.
 164   if constexpr (__print::__use_unicode_execution_charset)
 165     std::__vprint_unicode(__os, __fmt.get(), std::make_format_args(__args...), true);
 166   else
 167     std::__vprint_nonunicode(__os, __fmt.get(), std::make_format_args(__args...), true);
 168 #    else  // _LIBCPP_HAS_UNICODE
 169   std::__vprint_nonunicode(__os, __fmt.get(), std::make_format_args(__args...), true);
 170 #    endif // _LIBCPP_HAS_UNICODE
 171 }
 172
 173 template <class = void> // TODO PRINT template or availability markup fires too eagerly (http://llvm.org/PR61563).
 174 _LIBCPP_HIDE_FROM_ABI inline void println(ostream& __os) {
 175   std::print(__os, "\n");
 176 }
 177
 178 #  endif // _LIBCPP_STD_VER >= 23
 179
 180 _LIBCPP_END_NAMESPACE_STD
 181
 182 #endif // _LIBCPP_HAS_LOCALIZATION
 183
 184 #endif // _LIBCPP___OSTREAM_PRINT_H