text: // Formatting library for C++
  //
  // Copyright (c) 2012 - 2016, Victor Zverovich
  // All rights reserved.
  //
  // For the license information refer to format.h.
  
  #ifndef FMT_PRINTF_H_
  #define FMT_PRINTF_H_
  
  #include <algorithm>  // std::fill_n
  #include <limits>     // std::numeric_limits
  
  #include "ostream.h"
  
  FMT_BEGIN_NAMESPACE
  namespace internal {
  
  // Checks if a value fits in int - used to avoid warnings about comparing
  // signed and unsigned integers.
  template <bool IsSigned> struct int_checker {
    template <typename T> static bool fits_in_int(T value) {
      unsigned max = std::numeric_limits<int>::max();
      return value <= max;
    }
    static bool fits_in_int(bool) { return true; }
  };
  
  template <> struct int_checker<true> {
    template <typename T> static bool fits_in_int(T value) {
      return value >= std::numeric_limits<int>::min() &&
             value <= std::numeric_limits<int>::max();
    }
    static bool fits_in_int(int) { return true; }
  };
  
  class printf_precision_handler : public function<int> {
   public:
    template <typename T>
    typename std::enable_if<std::is_integral<T>::value, int>::type operator()(
        T value) {
      if (!int_checker<std::numeric_limits<T>::is_signed>::fits_in_int(value))
        FMT_THROW(format_error("number is too big"));
      return static_cast<int>(value);
    }
  
    template <typename T>
    typename std::enable_if<!std::is_integral<T>::value, int>::type operator()(
        T) {
      FMT_THROW(format_error("precision is not integer"));
      return 0;
    }
  };
  
  // An argument visitor that returns true iff arg is a zero integer.
  class is_zero_int : public function<bool> {
   public:
    template <typename T>
    typename std::enable_if<std::is_integral<T>::value, bool>::type operator()(
        T value) {
      return value == 0;
    }
  
    template <typename T>
    typename std::enable_if<!std::is_integral<T>::value, bool>::type operator()(
        T) {
      return false;
    }
  };
  
  template <typename T> struct make_unsigned_or_bool : std::make_unsigned<T> {};
  
  template <> struct make_unsigned_or_bool<bool> { typedef bool type; };
  
  template <typename T, typename Context>
  class arg_converter : public function<void> {
   private:
    typedef typename Context::char_type Char;
  
    basic_format_arg<Context>& arg_;
    typename Context::char_type type_;
  
   public:
    arg_converter(basic_format_arg<Context>& arg, Char type)
        : arg_(arg), type_(type) {}
  
    void operator()(bool value) {
      if (type_ != 's') operator()<bool>(value);
    }
  
    template <typename U>
    typename std::enable_if<std::is_integral<U>::value>::type operator()(
        U value) {
      bool is_signed = type_ == 'd' || type_ == 'i';
      typedef typename std::conditional<std::is_same<T, void>::value, U, T>::type
          TargetType;
      if (const_check(sizeof(TargetType) <= sizeof(int))) {
        // Extra casts are used to silence warnings.
        if (is_signed) {
          arg_ = internal::make_arg<Context>(
              static_cast<int>(static_cast<TargetType>(value)));
        } else {
          typedef typename make_unsigned_or_bool<TargetType>::type Unsigned;
          arg_ = internal::make_arg<Context>(
              static_cast<unsigned>(static_cast<Unsigned>(value)));
        }
      } else {
        if (is_signed) {
          // glibc's printf doesn't sign extend arguments of smaller types:
          //   std::printf("%lld", -42);  // prints "4294967254"
          // but we don't have to do the same because it's a UB.
          arg_ = internal::make_arg<Context>(static_cast<long long>(value));
        } else {
          arg_ = internal::make_arg<Context>(
              static_cast<typename make_unsigned_or_bool<U>::type>(value));
        }
      }
    }
  
    template <typename U>
    typename std::enable_if<!std::is_integral<U>::value>::type operator()(U) {
      // No coversion needed for non-integral types.
    }
  };
  
  // Converts an integer argument to T for printf, if T is an integral type.
  // If T is void, the argument is converted to corresponding signed or unsigned
  // type depending on the type specifier: 'd' and 'i' - signed, other -
  // unsigned).
  template <typename T, typename Context, typename Char>
  void convert_arg(basic_format_arg<Context>& arg, Char type) {
    visit_format_arg(arg_converter<T, Context>(arg, type), arg);
  }
  
  // Converts an integer argument to char for printf.
  template <typename Context> class char_converter : public function<void> {
   private:
    basic_format_arg<Context>& arg_;
  
   public:
    explicit char_converter(basic_format_arg<Context>& arg) : arg_(arg) {}
  
    template <typename T>
    typename std::enable_if<std::is_integral<T>::value>::type operator()(
        T value) {
      typedef typename Context::char_type Char;
      arg_ = internal::make_arg<Context>(static_cast<Char>(value));
    }
  
    template <typename T>
    typename std::enable_if<!std::is_integral<T>::value>::type operator()(T) {
      // No coversion needed for non-integral types.
    }
  };
  
  // Checks if an argument is a valid printf width specifier and sets
  // left alignment if it is negative.
  template <typename Char>
  class printf_width_handler : public function<unsigned> {
   private:
    typedef basic_format_specs<Char> format_specs;
  
    format_specs& spec_;
  
   public:
    explicit printf_width_handler(format_specs& spec) : spec_(spec) {}
  
    template <typename T>
    typename std::enable_if<std::is_integral<T>::value, unsigned>::type
    operator()(T value) {
      typedef typename internal::int_traits<T>::main_type UnsignedType;
      UnsignedType width = static_cast<UnsignedType>(value);
      if (internal::is_negative(value)) {
        spec_.align_ = ALIGN_LEFT;
        width = 0 - width;
      }
      unsigned int_max = std::numeric_limits<int>::max();
      if (width > int_max) FMT_THROW(format_error("number is too big"));
      return static_cast<unsigned>(width);
    }
  
    template <typename T>
    typename std::enable_if<!std::is_integral<T>::value, unsigned>::type
    operator()(T) {
      FMT_THROW(format_error("width is not integer"));
      return 0;
    }
  };
  
  template <typename Char, typename Context>
  void printf(basic_buffer<Char>& buf, basic_string_view<Char> format,
              basic_format_args<Context> args) {
    Context(std::back_inserter(buf), format, args).format();
  }
  
  template <typename OutputIt, typename Char, typename Context>
  internal::truncating_iterator<OutputIt> printf(
      internal::truncating_iterator<OutputIt> it, basic_string_view<Char> format,
      basic_format_args<Context> args) {
    return Context(it, format, args).format();
  }
  }  // namespace internal
  
  using internal::printf;  // For printing into memory_buffer.
  
  template <typename Range> class printf_arg_formatter;
  
  template <typename OutputIt, typename Char,
            typename ArgFormatter = printf_arg_formatter<
                back_insert_range<internal::basic_buffer<Char>>>>
  class basic_printf_context;
  
  /**
    \rst
    The ``printf`` argument formatter.
    \endrst
   */
  template <typename Range>
  class printf_arg_formatter
      : public internal::function<
            typename internal::arg_formatter_base<Range>::iterator>,
        public internal::arg_formatter_base<Range> {
   private:
    typedef typename Range::value_type char_type;
    typedef decltype(internal::declval<Range>().begin()) iterator;
    typedef internal::arg_formatter_base<Range> base;
    typedef basic_printf_context<iterator, char_type, printf_arg_formatter>
        context_type;
  
    context_type& context_;
  
    void write_null_pointer(char) {
      this->spec()->type = 0;
      this->write("(nil)");
    }
  
    void write_null_pointer(wchar_t) {
      this->spec()->type = 0;
      this->write(L"(nil)");
    }
  
   public:
    typedef typename base::format_specs format_specs;
  
    /**
      \rst
      Constructs an argument formatter object.
      *buffer* is a reference to the output buffer and *spec* contains format
      specifier information for standard argument types.
      \endrst
     */
    printf_arg_formatter(iterator iter, format_specs& spec, context_type& ctx)
        : base(Range(iter), &spec, ctx.locale()), context_(ctx) {}
  
    template <typename T>
    typename std::enable_if<std::is_integral<T>::value, iterator>::type
    operator()(T value) {
      // MSVC2013 fails to compile separate overloads for bool and char_type so
      // use std::is_same instead.
      if (std::is_same<T, bool>::value) {
        format_specs& fmt_spec = *this->spec();
        if (fmt_spec.type != 's') return base::operator()(value ? 1 : 0);
        fmt_spec.type = 0;
        this->write(value != 0);
      } else if (std::is_same<T, char_type>::value) {
        format_specs& fmt_spec = *this->spec();
        if (fmt_spec.type && fmt_spec.type != 'c')
          return (*this)(static_cast<int>(value));
        fmt_spec.flags = 0;
        fmt_spec.align_ = ALIGN_RIGHT;
        return base::operator()(value);
      } else {
        return base::operator()(value);
      }
      return this->out();
    }
  
    template <typename T>
    typename std::enable_if<std::is_floating_point<T>::value, iterator>::type
    operator()(T value) {
      return base::operator()(value);
    }
  
    /** Formats a null-terminated C string. */
    iterator operator()(const char* value) {
      if (value)
        base::operator()(value);
      else if (this->spec()->type == 'p')
        write_null_pointer(char_type());
      else
        this->write("(null)");
      return this->out();
    }
  
    /** Formats a null-terminated wide C string. */
    iterator operator()(const wchar_t* value) {
      if (value)
        base::operator()(value);
      else if (this->spec()->type == 'p')
        write_null_pointer(char_type());
      else
        this->write(L"(null)");
      return this->out();
    }
  
    iterator operator()(basic_string_view<char_type> value) {
      return base::operator()(value);
    }
  
    iterator operator()(monostate value) { return base::operator()(value); }
  
    /** Formats a pointer. */
    iterator operator()(const void* value) {
      if (value) return base::operator()(value);
      this->spec()->type = 0;
      write_null_pointer(char_type());
      return this->out();
    }
  
    /** Formats an argument of a custom (user-defined) type. */
    iterator operator()(typename basic_format_arg<context_type>::handle handle) {
      handle.format(context_);
      return this->out();
    }
  };
  
  template <typename T> struct printf_formatter {
    template <typename ParseContext>
    auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
      return ctx.begin();
    }
  
    template <typename FormatContext>
    auto format(const T& value, FormatContext& ctx) -> decltype(ctx.out()) {
      internal::format_value(internal::get_container(ctx.out()), value);
      return ctx.out();
    }
  };
  
  /** This template formats data and writes the output to a writer. */
  template <typename OutputIt, typename Char, typename ArgFormatter>
  class basic_printf_context :
      // Inherit publicly as a workaround for the icc bug
      // https://software.intel.com/en-us/forums/intel-c-compiler/topic/783476.
      public internal::context_base<
          OutputIt, basic_printf_context<OutputIt, Char, ArgFormatter>, Char> {
   public:
    /** The character type for the output. */
    typedef Char char_type;
  
    template <typename T> struct formatter_type {
      typedef printf_formatter<T> type;
    };
  
   private:
    typedef internal::context_base<OutputIt, basic_printf_context, Char> base;
    typedef typename base::format_arg format_arg;
    typedef basic_format_specs<char_type> format_specs;
  
    static void parse_flags(format_specs& spec, const Char*& it, const Char* end);
  
    // Returns the argument with specified index or, if arg_index is equal
    // to the maximum unsigned value, the next argument.
    format_arg get_arg(unsigned arg_index = std::numeric_limits<unsigned>::max());
  
    // Parses argument index, flags and width and returns the argument index.
    unsigned parse_header(const Char*& it, const Char* end, format_specs& spec);
  
   public:
    /**
     \rst
     Constructs a ``printf_context`` object. References to the arguments and
     the writer are stored in the context object so make sure they have
     appropriate lifetimes.
     \endrst
     */
    basic_printf_context(OutputIt out, basic_string_view<char_type> format_str,
                         basic_format_args<basic_printf_context> args)
        : base(out, format_str, args) {}
  
    using base::advance_to;
    using base::out;
    using base::parse_context;
  
    /** Formats stored arguments and writes the output to the range. */
    OutputIt format();
  };
  
  template <typename OutputIt, typename Char, typename AF>
  void basic_printf_context<OutputIt, Char, AF>::parse_flags(format_specs& spec,
                                                             const Char*& it,
                                                             const Char* end) {
    for (; it != end; ++it) {
      switch (*it) {
      case '-':
        spec.align_ = ALIGN_LEFT;
        break;
      case '+':
        spec.flags |= SIGN_FLAG | PLUS_FLAG;
        break;
      case '0':
        spec.fill_ = '0';
        break;
      case ' ':
        spec.flags |= SIGN_FLAG;
        break;
      case '#':
        spec.flags |= HASH_FLAG;
        break;
      default:
        return;
      }
    }
  }
  
  template <typename OutputIt, typename Char, typename AF>
  typename basic_printf_context<OutputIt, Char, AF>::format_arg
  basic_printf_context<OutputIt, Char, AF>::get_arg(unsigned arg_index) {
    if (arg_index == std::numeric_limits<unsigned>::max())
      return this->do_get_arg(this->parse_context().next_arg_id());
    return base::arg(arg_index - 1);
  }
  
  template <typename OutputIt, typename Char, typename AF>
  unsigned basic_printf_context<OutputIt, Char, AF>::parse_header(
      const Char*& it, const Char* end, format_specs& spec) {
    unsigned arg_index = std::numeric_limits<unsigned>::max();
    char_type c = *it;
    if (c >= '0' && c <= '9') {
      // Parse an argument index (if followed by '$') or a width possibly
      // preceded with '0' flag(s).
      internal::error_handler eh;
      unsigned value = parse_nonnegative_int(it, end, eh);
      if (it != end && *it == '$') {  // value is an argument index
        ++it;
        arg_index = value;
      } else {
        if (c == '0') spec.fill_ = '0';
        if (value != 0) {
          // Nonzero value means that we parsed width and don't need to
          // parse it or flags again, so return now.
          spec.width_ = value;
          return arg_index;
        }
      }
    }
    parse_flags(spec, it, end);
    // Parse width.
    if (it != end) {
      if (*it >= '0' && *it <= '9') {
        internal::error_handler eh;
        spec.width_ = parse_nonnegative_int(it, end, eh);
      } else if (*it == '*') {
        ++it;
        spec.width_ = visit_format_arg(
            internal::printf_width_handler<char_type>(spec), get_arg());
      }
    }
    return arg_index;
  }
  
  template <typename OutputIt, typename Char, typename AF>
  OutputIt basic_printf_context<OutputIt, Char, AF>::format() {
    auto out = this->out();
    const auto range = this->parse_context();
    const Char* const end = range.end();
    const Char* start = range.begin();
    auto it = start;
    while (it != end) {
      char_type c = *it++;
      if (c != '%') continue;
      if (it != end && *it == c) {
        out = std::copy(start, it, out);
        start = ++it;
        continue;
      }
      out = std::copy(start, it - 1, out);
  
      format_specs spec;
      spec.align_ = ALIGN_RIGHT;
  
      // Parse argument index, flags and width.
      unsigned arg_index = parse_header(it, end, spec);
  
      // Parse precision.
      if (it != end && *it == '.') {
        ++it;
        c = it != end ? *it : 0;
        if ('0' <= c && c <= '9') {
          internal::error_handler eh;
          spec.precision = static_cast<int>(parse_nonnegative_int(it, end, eh));
        } else if (c == '*') {
          ++it;
          spec.precision =
              visit_format_arg(internal::printf_precision_handler(), get_arg());
        } else {
          spec.precision = 0;
        }
      }
  
      format_arg arg = get_arg(arg_index);
      if (spec.has(HASH_FLAG) && visit_format_arg(internal::is_zero_int(), arg))
        spec.flags = static_cast<uint_least8_t>(
            spec.flags & (~internal::to_unsigned<int>(HASH_FLAG)));
      if (spec.fill_ == '0') {
        if (arg.is_arithmetic())
          spec.align_ = ALIGN_NUMERIC;
        else
          spec.fill_ = ' ';  // Ignore '0' flag for non-numeric types.
      }
  
      // Parse length and convert the argument to the required type.
      c = it != end ? *it++ : 0;
      char_type t = it != end ? *it : 0;
      using internal::convert_arg;
      switch (c) {
      case 'h':
        if (t == 'h') {
          ++it;
          t = it != end ? *it : 0;
          convert_arg<signed char>(arg, t);
        } else {
          convert_arg<short>(arg, t);
        }
        break;
      case 'l':
        if (t == 'l') {
          ++it;
          t = it != end ? *it : 0;
          convert_arg<long long>(arg, t);
        } else {
          convert_arg<long>(arg, t);
        }
        break;
      case 'j':
        convert_arg<intmax_t>(arg, t);
        break;
      case 'z':
        convert_arg<std::size_t>(arg, t);
        break;
      case 't':
        convert_arg<std::ptrdiff_t>(arg, t);
        break;
      case 'L':
        // printf produces garbage when 'L' is omitted for long double, no
        // need to do the same.
        break;
      default:
        --it;
        convert_arg<void>(arg, c);
      }
  
      // Parse type.
      if (it == end) FMT_THROW(format_error("invalid format string"));
      spec.type = static_cast<char>(*it++);
      if (arg.is_integral()) {
        // Normalize type.
        switch (spec.type) {
        case 'i':
        case 'u':
          spec.type = 'd';
          break;
        case 'c':
          // TODO: handle wchar_t better?
          visit_format_arg(internal::char_converter<basic_printf_context>(arg),
                           arg);
          break;
        }
      }
  
      start = it;
  
      // Format argument.
      visit_format_arg(AF(out, spec, *this), arg);
    }
    return std::copy(start, it, out);
  }
  
  template <typename Buffer> struct basic_printf_context_t {
    typedef basic_printf_context<std::back_insert_iterator<Buffer>,
                                 typename Buffer::value_type>
        type;
  };
  
  typedef basic_printf_context_t<internal::buffer>::type printf_context;
  typedef basic_printf_context_t<internal::wbuffer>::type wprintf_context;
  
  typedef basic_format_args<printf_context> printf_args;
  typedef basic_format_args<wprintf_context> wprintf_args;
  
  template <typename OutputIt, typename Char = typename OutputIt::value_type>
  struct basic_printf_n_context_t {
    typedef fmt::internal::truncating_iterator<OutputIt> OutputIter;
    typedef output_range<OutputIter, Char> Range;
    typedef basic_printf_context<OutputIter, Char, printf_arg_formatter<Range>>
        type;
  };
  
  /**
    \rst
    Constructs an `~fmt::format_arg_store` object that contains references to
    arguments and can be implicitly converted to `~fmt::printf_args`.
    \endrst
   */
  template <typename... Args>
  inline format_arg_store<printf_context, Args...> make_printf_args(
      const Args&... args) {
    return {args...};
  }
  
  /**
    \rst
    Constructs an `~fmt::format_arg_store` object that contains references to
    arguments and can be implicitly converted to `~fmt::wprintf_args`.
    \endrst
   */
  template <typename... Args>
  inline format_arg_store<wprintf_context, Args...> make_wprintf_args(
      const Args&... args) {
    return {args...};
  }
  
  template <typename S, typename Char = FMT_CHAR(S)>
  inline std::basic_string<Char> vsprintf(
      const S& format,
      basic_format_args<
          typename basic_printf_context_t<internal::basic_buffer<Char>>::type>
          args) {
    basic_memory_buffer<Char> buffer;
    printf(buffer, to_string_view(format), args);
    return to_string(buffer);
  }
  
  template <typename OutputIt, typename S, typename Char = FMT_CHAR(S)>
  inline typename std::enable_if<internal::is_output_iterator<OutputIt>::value,
                                 format_to_n_result<OutputIt>>::type
  vsnprintf(
      OutputIt out, std::size_t n, const S& format,
      basic_format_args<typename basic_printf_n_context_t<OutputIt, Char>::type>
          args) {
    typedef internal::truncating_iterator<OutputIt> It;
    auto it = printf(It(out, n), to_string_view(format), args);
    return {it.base(), it.count()};
  }
  
  /**
    \rst
    Formats arguments and returns the result as a string.
  
    **Example**::
  
      std::string message = fmt::sprintf("The answer is %d", 42);
    \endrst
  */
  template <typename S, typename... Args>
  inline FMT_ENABLE_IF_T(internal::is_string<S>::value,
                         std::basic_string<FMT_CHAR(S)>)
      sprintf(const S& format, const Args&... args) {
    internal::check_format_string<Args...>(format);
    typedef internal::basic_buffer<FMT_CHAR(S)> buffer;
    typedef typename basic_printf_context_t<buffer>::type context;
    format_arg_store<context, Args...> as{args...};
    return vsprintf(to_string_view(format), basic_format_args<context>(as));
  }
  
  /**
    \rst
    Formats arguments for up to ``n`` characters stored through output iterator
    ``out``. The function returns the updated iterator and the untruncated amount
    of characters.
  
    **Example**::
      std::vector<char> out;
  
      typedef fmt::format_to_n_result<
        std::back_insert_iterator<std::vector<char>>> res;
      res Res = fmt::snprintf(std::back_inserter(out), 5, "The answer is %d", 42);
    \endrst
  */
  template <typename OutputIt, typename S, typename... Args>
  inline FMT_ENABLE_IF_T(internal::is_string<S>::value&&
                             internal::is_output_iterator<OutputIt>::value,
                         format_to_n_result<OutputIt>)
      snprintf(OutputIt out, std::size_t n, const S& format,
               const Args&... args) {
    internal::check_format_string<Args...>(format);
    typedef FMT_CHAR(S) Char;
    typedef typename basic_printf_n_context_t<OutputIt, Char>::type context;
    format_arg_store<context, Args...> as{args...};
    return vsnprintf(out, n, to_string_view(format),
                     basic_format_args<context>(as));
  }
  
  template <typename S, typename Char = FMT_CHAR(S)>
  inline int vfprintf(
      std::FILE* f, const S& format,
      basic_format_args<
          typename basic_printf_context_t<internal::basic_buffer<Char>>::type>
          args) {
    basic_memory_buffer<Char> buffer;
    printf(buffer, to_string_view(format), args);
    std::size_t size = buffer.size();
    return std::fwrite(buffer.data(), sizeof(Char), size, f) < size
               ? -1
               : static_cast<int>(size);
  }
  
  /**
    \rst
    Prints formatted data to the file *f*.
  
    **Example**::
  
      fmt::fprintf(stderr, "Don't %s!", "panic");
    \endrst
   */
  template <typename S, typename... Args>
  inline FMT_ENABLE_IF_T(internal::is_string<S>::value, int)
      fprintf(std::FILE* f, const S& format, const Args&... args) {
    internal::check_format_string<Args...>(format);
    typedef internal::basic_buffer<FMT_CHAR(S)> buffer;
    typedef typename basic_printf_context_t<buffer>::type context;
    format_arg_store<context, Args...> as{args...};
    return vfprintf(f, to_string_view(format), basic_format_args<context>(as));
  }
  
  template <typename S, typename Char = FMT_CHAR(S)>
  inline int vprintf(
      const S& format,
      basic_format_args<
          typename basic_printf_context_t<internal::basic_buffer<Char>>::type>
          args) {
    return vfprintf(stdout, to_string_view(format), args);
  }
  
  /**
    \rst
    Prints formatted data to ``stdout``.
  
    **Example**::
  
      fmt::printf("Elapsed time: %.2f seconds", 1.23);
    \endrst
   */
  template <typename S, typename... Args>
  inline FMT_ENABLE_IF_T(internal::is_string<S>::value, int)
      printf(const S& format_str, const Args&... args) {
    internal::check_format_string<Args...>(format_str);
    typedef internal::basic_buffer<FMT_CHAR(S)> buffer;
    typedef typename basic_printf_context_t<buffer>::type context;
    format_arg_store<context, Args...> as{args...};
    return vprintf(to_string_view(format_str), basic_format_args<context>(as));
  }
  
  template <typename S, typename Char = FMT_CHAR(S)>
  inline int vfprintf(
      std::basic_ostream<Char>& os, const S& format,
      basic_format_args<
          typename basic_printf_context_t<internal::basic_buffer<Char>>::type>
          args) {
    basic_memory_buffer<Char> buffer;
    printf(buffer, to_string_view(format), args);
    internal::write(os, buffer);
    return static_cast<int>(buffer.size());
  }
  
  /**
    \rst
    Prints formatted data to the stream *os*.
  
    **Example**::
  
      fmt::fprintf(cerr, "Don't %s!", "panic");
    \endrst
   */
  template <typename S, typename... Args>
  inline FMT_ENABLE_IF_T(internal::is_string<S>::value, int)
      fprintf(std::basic_ostream<FMT_CHAR(S)>& os, const S& format_str,
              const Args&... args) {
    internal::check_format_string<Args...>(format_str);
    typedef internal::basic_buffer<FMT_CHAR(S)> buffer;
    typedef typename basic_printf_context_t<buffer>::type context;
    format_arg_store<context, Args...> as{args...};
    return vfprintf(os, to_string_view(format_str),
                    basic_format_args<context>(as));
  }
  FMT_END_NAMESPACE
  
  #endif  // FMT_PRINTF_H_
  