text: // Formatting library for C++ - legacy printf implementation
  //
  // 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::max
  #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 = max_value<int>();
      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 <= max_value<int>();
    }
    static bool fits_in_int(int) { return true; }
  };
  
  class printf_precision_handler {
   public:
    template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
    int 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 (std::max)(static_cast<int>(value), 0);
    }
  
    template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
    int 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:
    template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
    bool operator()(T value) {
      return value == 0;
    }
  
    template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
    bool operator()(T) {
      return false;
    }
  };
  
  template <typename T> struct make_unsigned_or_bool : std::make_unsigned<T> {};
  
  template <> struct make_unsigned_or_bool<bool> { using type = bool; };
  
  template <typename T, typename Context> class arg_converter {
   private:
    using char_type = typename Context::char_type;
  
    basic_format_arg<Context>& arg_;
    char_type type_;
  
   public:
    arg_converter(basic_format_arg<Context>& arg, char_type type)
        : arg_(arg), type_(type) {}
  
    void operator()(bool value) {
      if (type_ != 's') operator()<bool>(value);
    }
  
    template <typename U, FMT_ENABLE_IF(std::is_integral<U>::value)>
    void operator()(U value) {
      bool is_signed = type_ == 'd' || type_ == 'i';
      using target_type = conditional_t<std::is_same<T, void>::value, U, T>;
      if (const_check(sizeof(target_type) <= sizeof(int))) {
        // Extra casts are used to silence warnings.
        if (is_signed) {
          arg_ = internal::make_arg<Context>(
              static_cast<int>(static_cast<target_type>(value)));
        } else {
          using unsigned_type = typename make_unsigned_or_bool<target_type>::type;
          arg_ = internal::make_arg<Context>(
              static_cast<unsigned>(static_cast<unsigned_type>(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, FMT_ENABLE_IF(!std::is_integral<U>::value)>
    void operator()(U) {}  // No conversion 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 {
   private:
    basic_format_arg<Context>& arg_;
  
   public:
    explicit char_converter(basic_format_arg<Context>& arg) : arg_(arg) {}
  
    template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
    void operator()(T value) {
      arg_ = internal::make_arg<Context>(
          static_cast<typename Context::char_type>(value));
    }
  
    template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
    void operator()(T) {}  // No conversion 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 {
   private:
    using format_specs = basic_format_specs<Char>;
  
    format_specs& specs_;
  
   public:
    explicit printf_width_handler(format_specs& specs) : specs_(specs) {}
  
    template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
    unsigned operator()(T value) {
      auto width = static_cast<uint32_or_64_or_128_t<T>>(value);
      if (internal::is_negative(value)) {
        specs_.align = align::left;
        width = 0 - width;
      }
      unsigned int_max = max_value<int>();
      if (width > int_max) FMT_THROW(format_error("number is too big"));
      return static_cast<unsigned>(width);
    }
  
    template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
    unsigned operator()(T) {
      FMT_THROW(format_error("width is not integer"));
      return 0;
    }
  };
  
  template <typename Char, typename Context>
  void printf(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> class basic_printf_context;
  
  /**
    \rst
    The ``printf`` argument formatter.
    \endrst
   */
  template <typename Range>
  class printf_arg_formatter : public internal::arg_formatter_base<Range> {
   public:
    using iterator = typename Range::iterator;
  
   private:
    using char_type = typename Range::value_type;
    using base = internal::arg_formatter_base<Range>;
    using context_type = basic_printf_context<iterator, char_type>;
  
    context_type& context_;
  
    void write_null_pointer(char) {
      this->specs()->type = 0;
      this->write("(nil)");
    }
  
    void write_null_pointer(wchar_t) {
      this->specs()->type = 0;
      this->write(L"(nil)");
    }
  
   public:
    using format_specs = typename base::format_specs;
  
    /**
      \rst
      Constructs an argument formatter object.
      *buffer* is a reference to the output buffer and *specs* contains format
      specifier information for standard argument types.
      \endrst
     */
    printf_arg_formatter(iterator iter, format_specs& specs, context_type& ctx)
        : base(Range(iter), &specs, internal::locale_ref()), context_(ctx) {}
  
    template <typename T, FMT_ENABLE_IF(fmt::internal::is_integral<T>::value)>
    iterator 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_specs = *this->specs();
        if (fmt_specs.type != 's') return base::operator()(value ? 1 : 0);
        fmt_specs.type = 0;
        this->write(value != 0);
      } else if (std::is_same<T, char_type>::value) {
        format_specs& fmt_specs = *this->specs();
        if (fmt_specs.type && fmt_specs.type != 'c')
          return (*this)(static_cast<int>(value));
        fmt_specs.sign = sign::none;
        fmt_specs.alt = false;
        fmt_specs.align = align::right;
        return base::operator()(value);
      } else {
        return base::operator()(value);
      }
      return this->out();
    }
  
    template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
    iterator 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->specs()->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->specs()->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->specs()->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_.parse_context(), 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> class basic_printf_context {
   public:
    /** The character type for the output. */
    using char_type = Char;
    using format_arg = basic_format_arg<basic_printf_context>;
    template <typename T> using formatter_type = printf_formatter<T>;
  
   private:
    using format_specs = basic_format_specs<char_type>;
  
    OutputIt out_;
    basic_format_args<basic_printf_context> args_;
    basic_format_parse_context<Char> parse_ctx_;
  
    static void parse_flags(format_specs& specs, 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 = internal::max_value<unsigned>());
  
    // Parses argument index, flags and width and returns the argument index.
    unsigned parse_header(const Char*& it, const Char* end, format_specs& specs);
  
   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)
        : out_(out), args_(args), parse_ctx_(format_str) {}
  
    OutputIt out() { return out_; }
    void advance_to(OutputIt it) { out_ = it; }
  
    format_arg arg(unsigned id) const { return args_.get(id); }
  
    basic_format_parse_context<Char>& parse_context() { return parse_ctx_; }
  
    FMT_CONSTEXPR void on_error(const char* message) {
      parse_ctx_.on_error(message);
    }
  
    /** Formats stored arguments and writes the output to the range. */
    template <typename ArgFormatter = printf_arg_formatter<buffer_range<Char>>>
    OutputIt format();
  };
  
  template <typename OutputIt, typename Char>
  void basic_printf_context<OutputIt, Char>::parse_flags(format_specs& specs,
                                                         const Char*& it,
                                                         const Char* end) {
    for (; it != end; ++it) {
      switch (*it) {
      case '-':
        specs.align = align::left;
        break;
      case '+':
        specs.sign = sign::plus;
        break;
      case '0':
        specs.fill[0] = '0';
        break;
      case ' ':
        specs.sign = sign::space;
        break;
      case '#':
        specs.alt = true;
        break;
      default:
        return;
      }
    }
  }
  
  template <typename OutputIt, typename Char>
  typename basic_printf_context<OutputIt, Char>::format_arg
  basic_printf_context<OutputIt, Char>::get_arg(unsigned arg_index) {
    if (arg_index == internal::max_value<unsigned>())
      arg_index = parse_ctx_.next_arg_id();
    else
      parse_ctx_.check_arg_id(--arg_index);
    return internal::get_arg(*this, arg_index);
  }
  
  template <typename OutputIt, typename Char>
  unsigned basic_printf_context<OutputIt, Char>::parse_header(
      const Char*& it, const Char* end, format_specs& specs) {
    unsigned arg_index = internal::max_value<unsigned>();
    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') specs.fill[0] = '0';
        if (value != 0) {
          // Nonzero value means that we parsed width and don't need to
          // parse it or flags again, so return now.
          specs.width = value;
          return arg_index;
        }
      }
    }
    parse_flags(specs, it, end);
    // Parse width.
    if (it != end) {
      if (*it >= '0' && *it <= '9') {
        internal::error_handler eh;
        specs.width = parse_nonnegative_int(it, end, eh);
      } else if (*it == '*') {
        ++it;
        specs.width = visit_format_arg(
            internal::printf_width_handler<char_type>(specs), get_arg());
      }
    }
    return arg_index;
  }
  
  template <typename OutputIt, typename Char>
  template <typename ArgFormatter>
  OutputIt basic_printf_context<OutputIt, Char>::format() {
    auto out = this->out();
    const Char* start = parse_ctx_.begin();
    const Char* end = parse_ctx_.end();
    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 specs;
      specs.align = align::right;
  
      // Parse argument index, flags and width.
      unsigned arg_index = parse_header(it, end, specs);
      if (arg_index == 0) on_error("argument index out of range");
  
      // Parse precision.
      if (it != end && *it == '.') {
        ++it;
        c = it != end ? *it : 0;
        if ('0' <= c && c <= '9') {
          internal::error_handler eh;
          specs.precision = static_cast<int>(parse_nonnegative_int(it, end, eh));
        } else if (c == '*') {
          ++it;
          specs.precision =
              visit_format_arg(internal::printf_precision_handler(), get_arg());
        } else {
          specs.precision = 0;
        }
      }
  
      format_arg arg = get_arg(arg_index);
      if (specs.alt && visit_format_arg(internal::is_zero_int(), arg))
        specs.alt = false;
      if (specs.fill[0] == '0') {
        if (arg.is_arithmetic())
          specs.align = align::numeric;
        else
          specs.fill[0] = ' ';  // 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"));
      specs.type = static_cast<char>(*it++);
      if (arg.is_integral()) {
        // Normalize type.
        switch (specs.type) {
        case 'i':
        case 'u':
          specs.type = 'd';
          break;
        case 'c':
          visit_format_arg(internal::char_converter<basic_printf_context>(arg),
                           arg);
          break;
        }
      }
  
      start = it;
  
      // Format argument.
      visit_format_arg(ArgFormatter(out, specs, *this), arg);
    }
    return std::copy(start, it, out);
  }
  
  template <typename Char>
  using basic_printf_context_t =
      basic_printf_context<std::back_insert_iterator<internal::buffer<Char>>,
                           Char>;
  
  using printf_context = basic_printf_context_t<char>;
  using wprintf_context = basic_printf_context_t<wchar_t>;
  
  using printf_args = basic_format_args<printf_context>;
  using wprintf_args = basic_format_args<wprintf_context>;
  
  /**
    \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 = char_t<S>>
  inline std::basic_string<Char> vsprintf(
      const S& format, basic_format_args<basic_printf_context_t<Char>> args) {
    basic_memory_buffer<Char> buffer;
    printf(buffer, to_string_view(format), args);
    return to_string(buffer);
  }
  
  /**
    \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,
            typename Char = enable_if_t<internal::is_string<S>::value, char_t<S>>>
  inline std::basic_string<Char> sprintf(const S& format, const Args&... args) {
    using context = basic_printf_context_t<Char>;
    return vsprintf(to_string_view(format), {make_format_args<context>(args...)});
  }
  
  template <typename S, typename Char = char_t<S>>
  inline int vfprintf(std::FILE* f, const S& format,
                      basic_format_args<basic_printf_context_t<Char>> 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,
            typename Char = enable_if_t<internal::is_string<S>::value, char_t<S>>>
  inline int fprintf(std::FILE* f, const S& format, const Args&... args) {
    using context = basic_printf_context_t<Char>;
    return vfprintf(f, to_string_view(format),
                    {make_format_args<context>(args...)});
  }
  
  template <typename S, typename Char = char_t<S>>
  inline int vprintf(const S& format,
                     basic_format_args<basic_printf_context_t<Char>> 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,
            FMT_ENABLE_IF(internal::is_string<S>::value)>
  inline int printf(const S& format_str, const Args&... args) {
    using context = basic_printf_context_t<char_t<S>>;
    return vprintf(to_string_view(format_str),
                   {make_format_args<context>(args...)});
  }
  
  template <typename S, typename Char = char_t<S>>
  inline int vfprintf(std::basic_ostream<Char>& os, const S& format,
                      basic_format_args<basic_printf_context_t<Char>> args) {
    basic_memory_buffer<Char> buffer;
    printf(buffer, to_string_view(format), args);
    internal::write(os, buffer);
    return static_cast<int>(buffer.size());
  }
  
  /** Formats arguments and writes the output to the range. */
  template <typename ArgFormatter, typename Char,
            typename Context =
                basic_printf_context<typename ArgFormatter::iterator, Char>>
  typename ArgFormatter::iterator vprintf(internal::buffer<Char>& out,
                                          basic_string_view<Char> format_str,
                                          basic_format_args<Context> args) {
    typename ArgFormatter::iterator iter(out);
    Context(iter, format_str, args).template format<ArgFormatter>();
    return iter;
  }
  
  /**
    \rst
    Prints formatted data to the stream *os*.
  
    **Example**::
  
      fmt::fprintf(cerr, "Don't %s!", "panic");
    \endrst
   */
  template <typename S, typename... Args, typename Char = char_t<S>>
  inline int fprintf(std::basic_ostream<Char>& os, const S& format_str,
                     const Args&... args) {
    using context = basic_printf_context_t<Char>;
    return vfprintf(os, to_string_view(format_str),
                    {make_format_args<context>(args...)});
  }
  FMT_END_NAMESPACE
  
  #endif  // FMT_PRINTF_H_
  