blame: source/misc/embedded_libs/fmt-8.1.1/include/fmt/ostream.h

// 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 <ostream>

#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_same<T, std::basic_string<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 {};

// 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);

  buf.try_resize(buf.size());

}

// 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>>

    : private formatter<basic_string_view<Char>, Char> {

  using formatter<basic_string_view<Char>, Char>::parse;

  template <typename OutputIt>

  auto format(const T& value, basic_format_context<OutputIt, Char>& ctx)

      -> 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);

  }

  // DEPRECATED!

  template <typename OutputIt>

  auto format(const T& value, basic_printf_context<OutputIt, Char>& ctx)

      -> OutputIt {

    auto buffer = basic_memory_buffer<Char>();

    format_value(buffer, value, ctx.locale());

    return std::copy(buffer.begin(), buffer.end(), ctx.out());

  }

};

}  // namespace detail

FMT_MODULE_EXPORT

template <typename Char>

void vprint(std::basic_ostream<Char>& os, basic_string_view<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);

  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 S, typename... Args,

          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>

void print(std::basic_ostream<Char>& os, const S& format_str, Args&&... args) {

  vprint(os, to_string_view(format_str),

         fmt::make_args_checked<Args...>(format_str, args...));

}

FMT_END_NAMESPACE

#endif  // FMT_OSTREAM_H_