text: // Formatting library for C++ - the core API for char/UTF-8
  //
  // Copyright (c) 2012 - present, Victor Zverovich
  // All rights reserved.
  //
  // For the license information refer to format.h.
  
  #ifndef FMT_CORE_H_
  #define FMT_CORE_H_
  
  #include <cstdio>  // std::FILE
  #include <cstring>
  #include <iterator>
  #include <limits>
  #include <string>
  #include <type_traits>
  
  // The fmt library version in the form major * 10000 + minor * 100 + patch.
  #define FMT_VERSION 80001
  
  #ifdef __clang__
  #  define FMT_CLANG_VERSION (__clang_major__ * 100 + __clang_minor__)
  #else
  #  define FMT_CLANG_VERSION 0
  #endif
  
  #if defined(__GNUC__) && !defined(__clang__) && !defined(__INTEL_COMPILER)
  #  define FMT_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
  #  define FMT_GCC_PRAGMA(arg) _Pragma(arg)
  #else
  #  define FMT_GCC_VERSION 0
  #  define FMT_GCC_PRAGMA(arg)
  #endif
  
  #if __cplusplus >= 201103L || defined(__GXX_EXPERIMENTAL_CXX0X__)
  #  define FMT_HAS_GXX_CXX11 FMT_GCC_VERSION
  #else
  #  define FMT_HAS_GXX_CXX11 0
  #endif
  
  #if defined(__INTEL_COMPILER)
  #  define FMT_ICC_VERSION __INTEL_COMPILER
  #else
  #  define FMT_ICC_VERSION 0
  #endif
  
  #ifdef __NVCC__
  #  define FMT_NVCC __NVCC__
  #else
  #  define FMT_NVCC 0
  #endif
  
  #ifdef _MSC_VER
  #  define FMT_MSC_VER _MSC_VER
  #  define FMT_MSC_WARNING(...) __pragma(warning(__VA_ARGS__))
  #else
  #  define FMT_MSC_VER 0
  #  define FMT_MSC_WARNING(...)
  #endif
  
  #ifdef __has_feature
  #  define FMT_HAS_FEATURE(x) __has_feature(x)
  #else
  #  define FMT_HAS_FEATURE(x) 0
  #endif
  
  #if defined(__has_include) &&                             \
      (!defined(__INTELLISENSE__) || FMT_MSC_VER > 1900) && \
      (!FMT_ICC_VERSION || FMT_ICC_VERSION >= 1600)
  #  define FMT_HAS_INCLUDE(x) __has_include(x)
  #else
  #  define FMT_HAS_INCLUDE(x) 0
  #endif
  
  #ifdef __has_cpp_attribute
  #  define FMT_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
  #else
  #  define FMT_HAS_CPP_ATTRIBUTE(x) 0
  #endif
  
  #define FMT_HAS_CPP14_ATTRIBUTE(attribute) \
    (__cplusplus >= 201402L && FMT_HAS_CPP_ATTRIBUTE(attribute))
  
  #define FMT_HAS_CPP17_ATTRIBUTE(attribute) \
    (__cplusplus >= 201703L && FMT_HAS_CPP_ATTRIBUTE(attribute))
  
  // Check if relaxed C++14 constexpr is supported.
  // GCC doesn't allow throw in constexpr until version 6 (bug 67371).
  #ifndef FMT_USE_CONSTEXPR
  #  define FMT_USE_CONSTEXPR                                           \
      (FMT_HAS_FEATURE(cxx_relaxed_constexpr) || FMT_MSC_VER >= 1910 || \
       (FMT_GCC_VERSION >= 600 && __cplusplus >= 201402L)) &&           \
          !FMT_NVCC && !FMT_ICC_VERSION
  #endif
  #if FMT_USE_CONSTEXPR
  #  define FMT_CONSTEXPR constexpr
  #  define FMT_CONSTEXPR_DECL constexpr
  #else
  #  define FMT_CONSTEXPR
  #  define FMT_CONSTEXPR_DECL
  #endif
  
  // Check if constexpr std::char_traits<>::compare,length is supported.
  #if defined(__GLIBCXX__)
  #  if __cplusplus >= 201703L && defined(_GLIBCXX_RELEASE) && \
        _GLIBCXX_RELEASE >= 7  // GCC 7+ libstdc++ has _GLIBCXX_RELEASE.
  #    define FMT_CONSTEXPR_CHAR_TRAITS constexpr
  #  endif
  #elif defined(_LIBCPP_VERSION) && __cplusplus >= 201703L && \
      _LIBCPP_VERSION >= 4000
  #  define FMT_CONSTEXPR_CHAR_TRAITS constexpr
  #elif FMT_MSC_VER >= 1914 && _MSVC_LANG >= 201703L
  #  define FMT_CONSTEXPR_CHAR_TRAITS constexpr
  #endif
  #ifndef FMT_CONSTEXPR_CHAR_TRAITS
  #  define FMT_CONSTEXPR_CHAR_TRAITS
  #endif
  
  #ifndef FMT_OVERRIDE
  #  if FMT_HAS_FEATURE(cxx_override_control) || \
        (FMT_GCC_VERSION >= 408 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1900
  #    define FMT_OVERRIDE override
  #  else
  #    define FMT_OVERRIDE
  #  endif
  #endif
  
  // Check if exceptions are disabled.
  #ifndef FMT_EXCEPTIONS
  #  if (defined(__GNUC__) && !defined(__EXCEPTIONS)) || \
        FMT_MSC_VER && !_HAS_EXCEPTIONS
  #    define FMT_EXCEPTIONS 0
  #  else
  #    define FMT_EXCEPTIONS 1
  #  endif
  #endif
  
  // Define FMT_USE_NOEXCEPT to make fmt use noexcept (C++11 feature).
  #ifndef FMT_USE_NOEXCEPT
  #  define FMT_USE_NOEXCEPT 0
  #endif
  
  #if FMT_USE_NOEXCEPT || FMT_HAS_FEATURE(cxx_noexcept) || \
      (FMT_GCC_VERSION >= 408 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1900
  #  define FMT_DETECTED_NOEXCEPT noexcept
  #  define FMT_HAS_CXX11_NOEXCEPT 1
  #else
  #  define FMT_DETECTED_NOEXCEPT throw()
  #  define FMT_HAS_CXX11_NOEXCEPT 0
  #endif
  
  #ifndef FMT_NOEXCEPT
  #  if FMT_EXCEPTIONS || FMT_HAS_CXX11_NOEXCEPT
  #    define FMT_NOEXCEPT FMT_DETECTED_NOEXCEPT
  #  else
  #    define FMT_NOEXCEPT
  #  endif
  #endif
  
  // [[noreturn]] is disabled on MSVC and NVCC because of bogus unreachable code
  // warnings.
  #if FMT_EXCEPTIONS && FMT_HAS_CPP_ATTRIBUTE(noreturn) && !FMT_MSC_VER && \
      !FMT_NVCC
  #  define FMT_NORETURN [[noreturn]]
  #else
  #  define FMT_NORETURN
  #endif
  
  #ifndef FMT_MAYBE_UNUSED
  #  if FMT_HAS_CPP17_ATTRIBUTE(maybe_unused)
  #    define FMT_MAYBE_UNUSED [[maybe_unused]]
  #  else
  #    define FMT_MAYBE_UNUSED
  #  endif
  #endif
  
  #if __cplusplus == 201103L || __cplusplus == 201402L
  #  if defined(__INTEL_COMPILER) || defined(__PGI)
  #    define FMT_FALLTHROUGH
  #  elif defined(__clang__)
  #    define FMT_FALLTHROUGH [[clang::fallthrough]]
  #  elif FMT_GCC_VERSION >= 700 && \
        (!defined(__EDG_VERSION__) || __EDG_VERSION__ >= 520)
  #    define FMT_FALLTHROUGH [[gnu::fallthrough]]
  #  else
  #    define FMT_FALLTHROUGH
  #  endif
  #elif FMT_HAS_CPP17_ATTRIBUTE(fallthrough) || \
      (defined(_MSVC_LANG) && _MSVC_LANG >= 201703L)
  #  define FMT_FALLTHROUGH [[fallthrough]]
  #else
  #  define FMT_FALLTHROUGH
  #endif
  
  #ifndef FMT_USE_FLOAT
  #  define FMT_USE_FLOAT 1
  #endif
  #ifndef FMT_USE_DOUBLE
  #  define FMT_USE_DOUBLE 1
  #endif
  #ifndef FMT_USE_LONG_DOUBLE
  #  define FMT_USE_LONG_DOUBLE 1
  #endif
  
  #ifndef FMT_INLINE
  #  if FMT_GCC_VERSION || FMT_CLANG_VERSION
  #    define FMT_INLINE inline __attribute__((always_inline))
  #  else
  #    define FMT_INLINE inline
  #  endif
  #endif
  
  #ifndef FMT_USE_INLINE_NAMESPACES
  #  if FMT_HAS_FEATURE(cxx_inline_namespaces) || FMT_GCC_VERSION >= 404 || \
        (FMT_MSC_VER >= 1900 && (!defined(_MANAGED) || !_MANAGED))
  #    define FMT_USE_INLINE_NAMESPACES 1
  #  else
  #    define FMT_USE_INLINE_NAMESPACES 0
  #  endif
  #endif
  
  #ifndef FMT_BEGIN_NAMESPACE
  #  if FMT_USE_INLINE_NAMESPACES
  #    define FMT_INLINE_NAMESPACE inline namespace
  #    define FMT_END_NAMESPACE \
        }                       \
        }
  #  else
  #    define FMT_INLINE_NAMESPACE namespace
  #    define FMT_END_NAMESPACE \
        }                       \
        using namespace v8;     \
        }
  #  endif
  #  define FMT_BEGIN_NAMESPACE \
      namespace fmt {           \
      FMT_INLINE_NAMESPACE v8 {
  #endif
  
  #ifndef FMT_MODULE_EXPORT
  #  define FMT_MODULE_EXPORT
  #  define FMT_MODULE_EXPORT_BEGIN
  #  define FMT_MODULE_EXPORT_END
  #  define FMT_BEGIN_DETAIL_NAMESPACE namespace detail {
  #  define FMT_END_DETAIL_NAMESPACE }
  #endif
  
  #if !defined(FMT_HEADER_ONLY) && defined(_WIN32)
  #  define FMT_CLASS_API FMT_MSC_WARNING(suppress : 4275)
  #  ifdef FMT_EXPORT
  #    define FMT_API __declspec(dllexport)
  #  elif defined(FMT_SHARED)
  #    define FMT_API __declspec(dllimport)
  #  endif
  #else
  #  define FMT_CLASS_API
  #  if defined(FMT_EXPORT) || defined(FMT_SHARED)
  #    if defined(__GNUC__) || defined(__clang__)
  #      define FMT_API __attribute__((visibility("default")))
  #    endif
  #  endif
  #endif
  #ifndef FMT_API
  #  define FMT_API
  #endif
  
  #if FMT_GCC_VERSION
  #  define FMT_GCC_VISIBILITY_HIDDEN __attribute__((visibility("hidden")))
  #else
  #  define FMT_GCC_VISIBILITY_HIDDEN
  #endif
  
  // libc++ supports string_view in pre-c++17.
  #if (FMT_HAS_INCLUDE(<string_view>) &&                       \
       (__cplusplus > 201402L || defined(_LIBCPP_VERSION))) || \
      (defined(_MSVC_LANG) && _MSVC_LANG > 201402L && _MSC_VER >= 1910)
  #  include <string_view>
  #  define FMT_USE_STRING_VIEW
  #elif FMT_HAS_INCLUDE("experimental/string_view") && __cplusplus >= 201402L
  #  include <experimental/string_view>
  #  define FMT_USE_EXPERIMENTAL_STRING_VIEW
  #endif
  
  #ifndef FMT_UNICODE
  #  define FMT_UNICODE !FMT_MSC_VER
  #endif
  
  #ifndef FMT_CONSTEVAL
  #  if ((FMT_GCC_VERSION >= 1000 || FMT_CLANG_VERSION >= 1101) && \
         __cplusplus > 201703L) ||                                 \
        (defined(__cpp_consteval) &&                               \
         !FMT_MSC_VER)  // consteval is broken in MSVC.
  #    define FMT_CONSTEVAL consteval
  #    define FMT_HAS_CONSTEVAL
  #  else
  #    define FMT_CONSTEVAL
  #  endif
  #endif
  
  #ifndef FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
  #  if defined(__cpp_nontype_template_args) &&                \
        ((FMT_GCC_VERSION >= 903 && __cplusplus >= 201709L) || \
         __cpp_nontype_template_args >= 201911L)
  #    define FMT_USE_NONTYPE_TEMPLATE_PARAMETERS 1
  #  else
  #    define FMT_USE_NONTYPE_TEMPLATE_PARAMETERS 0
  #  endif
  #endif
  
  // Enable minimal optimizations for more compact code in debug mode.
  FMT_GCC_PRAGMA("GCC push_options")
  #ifndef __OPTIMIZE__
  FMT_GCC_PRAGMA("GCC optimize(\"Og\")")
  #endif
  
  FMT_BEGIN_NAMESPACE
  FMT_MODULE_EXPORT_BEGIN
  
  // Implementations of enable_if_t and other metafunctions for older systems.
  template <bool B, typename T = void>
  using enable_if_t = typename std::enable_if<B, T>::type;
  template <bool B, typename T, typename F>
  using conditional_t = typename std::conditional<B, T, F>::type;
  template <bool B> using bool_constant = std::integral_constant<bool, B>;
  template <typename T>
  using remove_reference_t = typename std::remove_reference<T>::type;
  template <typename T>
  using remove_cvref_t = typename std::remove_cv<remove_reference_t<T>>::type;
  template <typename T> struct type_identity { using type = T; };
  template <typename T> using type_identity_t = typename type_identity<T>::type;
  
  struct monostate {
    constexpr monostate() {}
  };
  
  // Suppress "unused variable" warnings with the method described in
  // https://herbsutter.com/2009/10/18/mailbag-shutting-up-compiler-warnings/.
  // (void)var does not work on many Intel compilers.
  template <typename... T> FMT_CONSTEXPR void ignore_unused(const T&...) {}
  
  // An enable_if helper to be used in template parameters which results in much
  // shorter symbols: https://godbolt.org/z/sWw4vP. Extra parentheses are needed
  // to workaround a bug in MSVC 2019 (see #1140 and #1186).
  #ifdef FMT_DOC
  #  define FMT_ENABLE_IF(...)
  #else
  #  define FMT_ENABLE_IF(...) enable_if_t<(__VA_ARGS__), int> = 0
  #endif
  
  FMT_BEGIN_DETAIL_NAMESPACE
  
  constexpr FMT_INLINE auto is_constant_evaluated() FMT_NOEXCEPT -> bool {
  #ifdef __cpp_lib_is_constant_evaluated
    return std::is_constant_evaluated();
  #else
    return false;
  #endif
  }
  
  // A function to suppress "conditional expression is constant" warnings.
  template <typename T> constexpr auto const_check(T value) -> T { return value; }
  
  FMT_NORETURN FMT_API void assert_fail(const char* file, int line,
                                        const char* message);
  
  #ifndef FMT_ASSERT
  #  ifdef NDEBUG
  // FMT_ASSERT is not empty to avoid -Werror=empty-body.
  #    define FMT_ASSERT(condition, message) \
        ::fmt::ignore_unused((condition), (message))
  #  else
  #    define FMT_ASSERT(condition, message)                                    \
        ((condition) /* void() fails with -Winvalid-constexpr on clang 4.0.1 */ \
             ? (void)0                                                          \
             : ::fmt::detail::assert_fail(__FILE__, __LINE__, (message)))
  #  endif
  #endif
  
  #if defined(FMT_USE_STRING_VIEW)
  template <typename Char> using std_string_view = std::basic_string_view<Char>;
  #elif defined(FMT_USE_EXPERIMENTAL_STRING_VIEW)
  template <typename Char>
  using std_string_view = std::experimental::basic_string_view<Char>;
  #else
  template <typename T> struct std_string_view {};
  #endif
  
  #ifdef FMT_USE_INT128
  // Do nothing.
  #elif defined(__SIZEOF_INT128__) && !FMT_NVCC && \
      !(FMT_CLANG_VERSION && FMT_MSC_VER)
  #  define FMT_USE_INT128 1
  using int128_t = __int128_t;
  using uint128_t = __uint128_t;
  template <typename T> inline auto convert_for_visit(T value) -> T {
    return value;
  }
  #else
  #  define FMT_USE_INT128 0
  #endif
  #if !FMT_USE_INT128
  enum class int128_t {};
  enum class uint128_t {};
  // Reduce template instantiations.
  template <typename T> inline auto convert_for_visit(T) -> monostate {
    return {};
  }
  #endif
  
  // Casts a nonnegative integer to unsigned.
  template <typename Int>
  FMT_CONSTEXPR auto to_unsigned(Int value) ->
      typename std::make_unsigned<Int>::type {
    FMT_ASSERT(value >= 0, "negative value");
    return static_cast<typename std::make_unsigned<Int>::type>(value);
  }
  
  FMT_MSC_WARNING(suppress : 4566) constexpr unsigned char micro[] = "\u00B5";
  
  constexpr auto is_utf8() -> bool {
    // Avoid buggy sign extensions in MSVC's constant evaluation mode.
    // https://developercommunity.visualstudio.com/t/C-difference-in-behavior-for-unsigned/1233612
    using uchar = unsigned char;
    return FMT_UNICODE || (sizeof(micro) == 3 && uchar(micro[0]) == 0xC2 &&
                           uchar(micro[1]) == 0xB5);
  }
  FMT_END_DETAIL_NAMESPACE
  
  /**
    An implementation of ``std::basic_string_view`` for pre-C++17. It provides a
    subset of the API. ``fmt::basic_string_view`` is used for format strings even
    if ``std::string_view`` is available to prevent issues when a library is
    compiled with a different ``-std`` option than the client code (which is not
    recommended).
   */
  template <typename Char> class basic_string_view {
   private:
    const Char* data_;
    size_t size_;
  
   public:
    using value_type = Char;
    using iterator = const Char*;
  
    constexpr basic_string_view() FMT_NOEXCEPT : data_(nullptr), size_(0) {}
  
    /** Constructs a string reference object from a C string and a size. */
    constexpr basic_string_view(const Char* s, size_t count) FMT_NOEXCEPT
        : data_(s),
          size_(count) {}
  
    /**
      \rst
      Constructs a string reference object from a C string computing
      the size with ``std::char_traits<Char>::length``.
      \endrst
     */
    FMT_CONSTEXPR_CHAR_TRAITS
    FMT_INLINE
    basic_string_view(const Char* s) : data_(s) {
      if (detail::const_check(std::is_same<Char, char>::value &&
                              !detail::is_constant_evaluated()))
        size_ = std::strlen(reinterpret_cast<const char*>(s));
      else
        size_ = std::char_traits<Char>::length(s);
    }
  
    /** Constructs a string reference from a ``std::basic_string`` object. */
    template <typename Traits, typename Alloc>
    FMT_CONSTEXPR basic_string_view(
        const std::basic_string<Char, Traits, Alloc>& s) FMT_NOEXCEPT
        : data_(s.data()),
          size_(s.size()) {}
  
    template <typename S, FMT_ENABLE_IF(std::is_same<
                                        S, detail::std_string_view<Char>>::value)>
    FMT_CONSTEXPR basic_string_view(S s) FMT_NOEXCEPT : data_(s.data()),
                                                        size_(s.size()) {}
  
    /** Returns a pointer to the string data. */
    constexpr auto data() const -> const Char* { return data_; }
  
    /** Returns the string size. */
    constexpr auto size() const -> size_t { return size_; }
  
    constexpr auto begin() const -> iterator { return data_; }
    constexpr auto end() const -> iterator { return data_ + size_; }
  
    constexpr auto operator[](size_t pos) const -> const Char& {
      return data_[pos];
    }
  
    FMT_CONSTEXPR void remove_prefix(size_t n) {
      data_ += n;
      size_ -= n;
    }
  
    // Lexicographically compare this string reference to other.
    FMT_CONSTEXPR_CHAR_TRAITS auto compare(basic_string_view other) const -> int {
      size_t str_size = size_ < other.size_ ? size_ : other.size_;
      int result = std::char_traits<Char>::compare(data_, other.data_, str_size);
      if (result == 0)
        result = size_ == other.size_ ? 0 : (size_ < other.size_ ? -1 : 1);
      return result;
    }
  
    FMT_CONSTEXPR_CHAR_TRAITS friend auto operator==(basic_string_view lhs,
                                                     basic_string_view rhs)
        -> bool {
      return lhs.compare(rhs) == 0;
    }
    friend auto operator!=(basic_string_view lhs, basic_string_view rhs) -> bool {
      return lhs.compare(rhs) != 0;
    }
    friend auto operator<(basic_string_view lhs, basic_string_view rhs) -> bool {
      return lhs.compare(rhs) < 0;
    }
    friend auto operator<=(basic_string_view lhs, basic_string_view rhs) -> bool {
      return lhs.compare(rhs) <= 0;
    }
    friend auto operator>(basic_string_view lhs, basic_string_view rhs) -> bool {
      return lhs.compare(rhs) > 0;
    }
    friend auto operator>=(basic_string_view lhs, basic_string_view rhs) -> bool {
      return lhs.compare(rhs) >= 0;
    }
  };
  
  using string_view = basic_string_view<char>;
  
  /** Specifies if ``T`` is a character type. Can be specialized by users. */
  template <typename T> struct is_char : std::false_type {};
  template <> struct is_char<char> : std::true_type {};
  
  // Returns a string view of `s`.
  template <typename Char, FMT_ENABLE_IF(is_char<Char>::value)>
  FMT_INLINE auto to_string_view(const Char* s) -> basic_string_view<Char> {
    return s;
  }
  template <typename Char, typename Traits, typename Alloc>
  inline auto to_string_view(const std::basic_string<Char, Traits, Alloc>& s)
      -> basic_string_view<Char> {
    return s;
  }
  template <typename Char>
  constexpr auto to_string_view(basic_string_view<Char> s)
      -> basic_string_view<Char> {
    return s;
  }
  template <typename Char,
            FMT_ENABLE_IF(!std::is_empty<detail::std_string_view<Char>>::value)>
  inline auto to_string_view(detail::std_string_view<Char> s)
      -> basic_string_view<Char> {
    return s;
  }
  
  // A base class for compile-time strings. It is defined in the fmt namespace to
  // make formatting functions visible via ADL, e.g. format(FMT_STRING("{}"), 42).
  struct compile_string {};
  
  template <typename S>
  struct is_compile_string : std::is_base_of<compile_string, S> {};
  
  template <typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
  constexpr auto to_string_view(const S& s)
      -> basic_string_view<typename S::char_type> {
    return basic_string_view<typename S::char_type>(s);
  }
  
  FMT_BEGIN_DETAIL_NAMESPACE
  
  void to_string_view(...);
  using fmt::v8::to_string_view;
  
  // Specifies whether S is a string type convertible to fmt::basic_string_view.
  // It should be a constexpr function but MSVC 2017 fails to compile it in
  // enable_if and MSVC 2015 fails to compile it as an alias template.
  template <typename S>
  struct is_string : std::is_class<decltype(to_string_view(std::declval<S>()))> {
  };
  
  template <typename S, typename = void> struct char_t_impl {};
  template <typename S> struct char_t_impl<S, enable_if_t<is_string<S>::value>> {
    using result = decltype(to_string_view(std::declval<S>()));
    using type = typename result::value_type;
  };
  
  // Reports a compile-time error if S is not a valid format string.
  template <typename..., typename S, FMT_ENABLE_IF(!is_compile_string<S>::value)>
  FMT_INLINE void check_format_string(const S&) {
  #ifdef FMT_ENFORCE_COMPILE_STRING
    static_assert(is_compile_string<S>::value,
                  "FMT_ENFORCE_COMPILE_STRING requires all format strings to use "
                  "FMT_STRING.");
  #endif
  }
  template <typename..., typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
  void check_format_string(S);
  
  struct error_handler {
    constexpr error_handler() = default;
    constexpr error_handler(const error_handler&) = default;
  
    // This function is intentionally not constexpr to give a compile-time error.
    FMT_NORETURN FMT_API void on_error(const char* message);
  };
  FMT_END_DETAIL_NAMESPACE
  
  /** String's character type. */
  template <typename S> using char_t = typename detail::char_t_impl<S>::type;
  
  /**
    \rst
    Parsing context consisting of a format string range being parsed and an
    argument counter for automatic indexing.
    You can use the ``format_parse_context`` type alias for ``char`` instead.
    \endrst
   */
  template <typename Char, typename ErrorHandler = detail::error_handler>
  class basic_format_parse_context : private ErrorHandler {
   private:
    basic_string_view<Char> format_str_;
    int next_arg_id_;
  
   public:
    using char_type = Char;
    using iterator = typename basic_string_view<Char>::iterator;
  
    explicit constexpr basic_format_parse_context(
        basic_string_view<Char> format_str, ErrorHandler eh = {},
        int next_arg_id = 0)
        : ErrorHandler(eh), format_str_(format_str), next_arg_id_(next_arg_id) {}
  
    /**
      Returns an iterator to the beginning of the format string range being
      parsed.
     */
    constexpr auto begin() const FMT_NOEXCEPT -> iterator {
      return format_str_.begin();
    }
  
    /**
      Returns an iterator past the end of the format string range being parsed.
     */
    constexpr auto end() const FMT_NOEXCEPT -> iterator {
      return format_str_.end();
    }
  
    /** Advances the begin iterator to ``it``. */
    FMT_CONSTEXPR void advance_to(iterator it) {
      format_str_.remove_prefix(detail::to_unsigned(it - begin()));
    }
  
    /**
      Reports an error if using the manual argument indexing; otherwise returns
      the next argument index and switches to the automatic indexing.
     */
    FMT_CONSTEXPR auto next_arg_id() -> int {
      // Don't check if the argument id is valid to avoid overhead and because it
      // will be checked during formatting anyway.
      if (next_arg_id_ >= 0) return next_arg_id_++;
      on_error("cannot switch from manual to automatic argument indexing");
      return 0;
    }
  
    /**
      Reports an error if using the automatic argument indexing; otherwise
      switches to the manual indexing.
     */
    FMT_CONSTEXPR void check_arg_id(int) {
      if (next_arg_id_ > 0)
        on_error("cannot switch from automatic to manual argument indexing");
      else
        next_arg_id_ = -1;
    }
  
    FMT_CONSTEXPR void check_arg_id(basic_string_view<Char>) {}
  
    FMT_CONSTEXPR void on_error(const char* message) {
      ErrorHandler::on_error(message);
    }
  
    constexpr auto error_handler() const -> ErrorHandler { return *this; }
  };
  
  using format_parse_context = basic_format_parse_context<char>;
  
  template <typename Context> class basic_format_arg;
  template <typename Context> class basic_format_args;
  template <typename Context> class dynamic_format_arg_store;
  
  // A formatter for objects of type T.
  template <typename T, typename Char = char, typename Enable = void>
  struct formatter {
    // A deleted default constructor indicates a disabled formatter.
    formatter() = delete;
  };
  
  // Specifies if T has an enabled formatter specialization. A type can be
  // formattable even if it doesn't have a formatter e.g. via a conversion.
  template <typename T, typename Context>
  using has_formatter =
      std::is_constructible<typename Context::template formatter_type<T>>;
  
  // Checks whether T is a container with contiguous storage.
  template <typename T> struct is_contiguous : std::false_type {};
  template <typename Char>
  struct is_contiguous<std::basic_string<Char>> : std::true_type {};
  
  class appender;
  
  FMT_BEGIN_DETAIL_NAMESPACE
  
  // Extracts a reference to the container from back_insert_iterator.
  template <typename Container>
  inline auto get_container(std::back_insert_iterator<Container> it)
      -> Container& {
    using bi_iterator = std::back_insert_iterator<Container>;
    struct accessor : bi_iterator {
      accessor(bi_iterator iter) : bi_iterator(iter) {}
      using bi_iterator::container;
    };
    return *accessor(it).container;
  }
  
  template <typename Char, typename InputIt, typename OutputIt>
  FMT_CONSTEXPR auto copy_str(InputIt begin, InputIt end, OutputIt out)
      -> OutputIt {
    while (begin != end) *out++ = static_cast<Char>(*begin++);
    return out;
  }
  
  template <typename Char, FMT_ENABLE_IF(std::is_same<Char, char>::value)>
  FMT_CONSTEXPR auto copy_str(const Char* begin, const Char* end, Char* out)
      -> Char* {
    if (is_constant_evaluated())
      return copy_str<Char, const Char*, Char*>(begin, end, out);
    auto size = to_unsigned(end - begin);
    memcpy(out, begin, size);
    return out + size;
  }
  
  /**
    \rst
    A contiguous memory buffer with an optional growing ability. It is an internal
    class and shouldn't be used directly, only via `~fmt::basic_memory_buffer`.
    \endrst
   */
  template <typename T> class buffer {
   private:
    T* ptr_;
    size_t size_;
    size_t capacity_;
  
   protected:
    // Don't initialize ptr_ since it is not accessed to save a few cycles.
    FMT_MSC_WARNING(suppress : 26495)
    buffer(size_t sz) FMT_NOEXCEPT : size_(sz), capacity_(sz) {}
  
    buffer(T* p = nullptr, size_t sz = 0, size_t cap = 0) FMT_NOEXCEPT
        : ptr_(p),
          size_(sz),
          capacity_(cap) {}
  
    ~buffer() = default;
    buffer(buffer&&) = default;
  
    /** Sets the buffer data and capacity. */
    void set(T* buf_data, size_t buf_capacity) FMT_NOEXCEPT {
      ptr_ = buf_data;
      capacity_ = buf_capacity;
    }
  
    /** Increases the buffer capacity to hold at least *capacity* elements. */
    virtual void grow(size_t capacity) = 0;
  
   public:
    using value_type = T;
    using const_reference = const T&;
  
    buffer(const buffer&) = delete;
    void operator=(const buffer&) = delete;
  
    auto begin() FMT_NOEXCEPT -> T* { return ptr_; }
    auto end() FMT_NOEXCEPT -> T* { return ptr_ + size_; }
  
    auto begin() const FMT_NOEXCEPT -> const T* { return ptr_; }
    auto end() const FMT_NOEXCEPT -> const T* { return ptr_ + size_; }
  
    /** Returns the size of this buffer. */
    auto size() const FMT_NOEXCEPT -> size_t { return size_; }
  
    /** Returns the capacity of this buffer. */
    auto capacity() const FMT_NOEXCEPT -> size_t { return capacity_; }
  
    /** Returns a pointer to the buffer data. */
    auto data() FMT_NOEXCEPT -> T* { return ptr_; }
  
    /** Returns a pointer to the buffer data. */
    auto data() const FMT_NOEXCEPT -> const T* { return ptr_; }
  
    /** Clears this buffer. */
    void clear() { size_ = 0; }
  
    // Tries resizing the buffer to contain *count* elements. If T is a POD type
    // the new elements may not be initialized.
    void try_resize(size_t count) {
      try_reserve(count);
      size_ = count <= capacity_ ? count : capacity_;
    }
  
    // Tries increasing the buffer capacity to *new_capacity*. It can increase the
    // capacity by a smaller amount than requested but guarantees there is space
    // for at least one additional element either by increasing the capacity or by
    // flushing the buffer if it is full.
    void try_reserve(size_t new_capacity) {
      if (new_capacity > capacity_) grow(new_capacity);
    }
  
    void push_back(const T& value) {
      try_reserve(size_ + 1);
      ptr_[size_++] = value;
    }
  
    /** Appends data to the end of the buffer. */
    template <typename U> void append(const U* begin, const U* end);
  
    template <typename I> auto operator[](I index) -> T& { return ptr_[index]; }
    template <typename I> auto operator[](I index) const -> const T& {
      return ptr_[index];
    }
  };
  
  struct buffer_traits {
    explicit buffer_traits(size_t) {}
    auto count() const -> size_t { return 0; }
    auto limit(size_t size) -> size_t { return size; }
  };
  
  class fixed_buffer_traits {
   private:
    size_t count_ = 0;
    size_t limit_;
  
   public:
    explicit fixed_buffer_traits(size_t limit) : limit_(limit) {}
    auto count() const -> size_t { return count_; }
    auto limit(size_t size) -> size_t {
      size_t n = limit_ > count_ ? limit_ - count_ : 0;
      count_ += size;
      return size < n ? size : n;
    }
  };
  
  // A buffer that writes to an output iterator when flushed.
  template <typename OutputIt, typename T, typename Traits = buffer_traits>
  class iterator_buffer final : public Traits, public buffer<T> {
   private:
    OutputIt out_;
    enum { buffer_size = 256 };
    T data_[buffer_size];
  
   protected:
    void grow(size_t) final FMT_OVERRIDE {
      if (this->size() == buffer_size) flush();
    }
  
    void flush() {
      auto size = this->size();
      this->clear();
      out_ = copy_str<T>(data_, data_ + this->limit(size), out_);
    }
  
   public:
    explicit iterator_buffer(OutputIt out, size_t n = buffer_size)
        : Traits(n), buffer<T>(data_, 0, buffer_size), out_(out) {}
    iterator_buffer(iterator_buffer&& other)
        : Traits(other), buffer<T>(data_, 0, buffer_size), out_(other.out_) {}
    ~iterator_buffer() { flush(); }
  
    auto out() -> OutputIt {
      flush();
      return out_;
    }
    auto count() const -> size_t { return Traits::count() + this->size(); }
  };
  
  template <typename T> class iterator_buffer<T*, T> final : public buffer<T> {
   protected:
    void grow(size_t) final FMT_OVERRIDE {}
  
   public:
    explicit iterator_buffer(T* out, size_t = 0) : buffer<T>(out, 0, ~size_t()) {}
  
    auto out() -> T* { return &*this->end(); }
  };
  
  // A buffer that writes to a container with the contiguous storage.
  template <typename Container>
  class iterator_buffer<std::back_insert_iterator<Container>,
                        enable_if_t<is_contiguous<Container>::value,
                                    typename Container::value_type>>
      final : public buffer<typename Container::value_type> {
   private:
    Container& container_;
  
   protected:
    void grow(size_t capacity) final FMT_OVERRIDE {
      container_.resize(capacity);
      this->set(&container_[0], capacity);
    }
  
   public:
    explicit iterator_buffer(Container& c)
        : buffer<typename Container::value_type>(c.size()), container_(c) {}
    explicit iterator_buffer(std::back_insert_iterator<Container> out, size_t = 0)
        : iterator_buffer(get_container(out)) {}
    auto out() -> std::back_insert_iterator<Container> {
      return std::back_inserter(container_);
    }
  };
  
  // A buffer that counts the number of code units written discarding the output.
  template <typename T = char> class counting_buffer final : public buffer<T> {
   private:
    enum { buffer_size = 256 };
    T data_[buffer_size];
    size_t count_ = 0;
  
   protected:
    void grow(size_t) final FMT_OVERRIDE {
      if (this->size() != buffer_size) return;
      count_ += this->size();
      this->clear();
    }
  
   public:
    counting_buffer() : buffer<T>(data_, 0, buffer_size) {}
  
    auto count() -> size_t { return count_ + this->size(); }
  };
  
  template <typename T>
  using buffer_appender = conditional_t<std::is_same<T, char>::value, appender,
                                        std::back_insert_iterator<buffer<T>>>;
  
  // Maps an output iterator to a buffer.
  template <typename T, typename OutputIt>
  auto get_buffer(OutputIt out) -> iterator_buffer<OutputIt, T> {
    return iterator_buffer<OutputIt, T>(out);
  }
  
  template <typename Buffer>
  auto get_iterator(Buffer& buf) -> decltype(buf.out()) {
    return buf.out();
  }
  template <typename T> auto get_iterator(buffer<T>& buf) -> buffer_appender<T> {
    return buffer_appender<T>(buf);
  }
  
  template <typename T, typename Char = char, typename Enable = void>
  struct fallback_formatter {
    fallback_formatter() = delete;
  };
  
  // Specifies if T has an enabled fallback_formatter specialization.
  template <typename T, typename Char>
  using has_fallback_formatter =
      std::is_constructible<fallback_formatter<T, Char>>;
  
  struct view {};
  
  template <typename Char, typename T> struct named_arg : view {
    const Char* name;
    const T& value;
    named_arg(const Char* n, const T& v) : name(n), value(v) {}
  };
  
  template <typename Char> struct named_arg_info {
    const Char* name;
    int id;
  };
  
  template <typename T, typename Char, size_t NUM_ARGS, size_t NUM_NAMED_ARGS>
  struct arg_data {
    // args_[0].named_args points to named_args_ to avoid bloating format_args.
    // +1 to workaround a bug in gcc 7.5 that causes duplicated-branches warning.
    T args_[1 + (NUM_ARGS != 0 ? NUM_ARGS : +1)];
    named_arg_info<Char> named_args_[NUM_NAMED_ARGS];
  
    template <typename... U>
    arg_data(const U&... init) : args_{T(named_args_, NUM_NAMED_ARGS), init...} {}
    arg_data(const arg_data& other) = delete;
    auto args() const -> const T* { return args_ + 1; }
    auto named_args() -> named_arg_info<Char>* { return named_args_; }
  };
  
  template <typename T, typename Char, size_t NUM_ARGS>
  struct arg_data<T, Char, NUM_ARGS, 0> {
    // +1 to workaround a bug in gcc 7.5 that causes duplicated-branches warning.
    T args_[NUM_ARGS != 0 ? NUM_ARGS : +1];
  
    template <typename... U>
    FMT_CONSTEXPR FMT_INLINE arg_data(const U&... init) : args_{init...} {}
    FMT_CONSTEXPR FMT_INLINE auto args() const -> const T* { return args_; }
    FMT_CONSTEXPR FMT_INLINE auto named_args() -> std::nullptr_t {
      return nullptr;
    }
  };
  
  template <typename Char>
  inline void init_named_args(named_arg_info<Char>*, int, int) {}
  
  template <typename T> struct is_named_arg : std::false_type {};
  template <typename T> struct is_statically_named_arg : std::false_type {};
  
  template <typename T, typename Char>
  struct is_named_arg<named_arg<Char, T>> : std::true_type {};
  
  template <typename Char, typename T, typename... Tail,
            FMT_ENABLE_IF(!is_named_arg<T>::value)>
  void init_named_args(named_arg_info<Char>* named_args, int arg_count,
                       int named_arg_count, const T&, const Tail&... args) {
    init_named_args(named_args, arg_count + 1, named_arg_count, args...);
  }
  
  template <typename Char, typename T, typename... Tail,
            FMT_ENABLE_IF(is_named_arg<T>::value)>
  void init_named_args(named_arg_info<Char>* named_args, int arg_count,
                       int named_arg_count, const T& arg, const Tail&... args) {
    named_args[named_arg_count++] = {arg.name, arg_count};
    init_named_args(named_args, arg_count + 1, named_arg_count, args...);
  }
  
  template <typename... Args>
  FMT_CONSTEXPR FMT_INLINE void init_named_args(std::nullptr_t, int, int,
                                                const Args&...) {}
  
  template <bool B = false> constexpr auto count() -> size_t { return B ? 1 : 0; }
  template <bool B1, bool B2, bool... Tail> constexpr auto count() -> size_t {
    return (B1 ? 1 : 0) + count<B2, Tail...>();
  }
  
  template <typename... Args> constexpr auto count_named_args() -> size_t {
    return count<is_named_arg<Args>::value...>();
  }
  
  enum class type {
    none_type,
    // Integer types should go first,
    int_type,
    uint_type,
    long_long_type,
    ulong_long_type,
    int128_type,
    uint128_type,
    bool_type,
    char_type,
    last_integer_type = char_type,
    // followed by floating-point types.
    float_type,
    double_type,
    long_double_type,
    last_numeric_type = long_double_type,
    cstring_type,
    string_type,
    pointer_type,
    custom_type
  };
  
  // Maps core type T to the corresponding type enum constant.
  template <typename T, typename Char>
  struct type_constant : std::integral_constant<type, type::custom_type> {};
  
  #define FMT_TYPE_CONSTANT(Type, constant) \
    template <typename Char>                \
    struct type_constant<Type, Char>        \
        : std::integral_constant<type, type::constant> {}
  
  FMT_TYPE_CONSTANT(int, int_type);
  FMT_TYPE_CONSTANT(unsigned, uint_type);
  FMT_TYPE_CONSTANT(long long, long_long_type);
  FMT_TYPE_CONSTANT(unsigned long long, ulong_long_type);
  FMT_TYPE_CONSTANT(int128_t, int128_type);
  FMT_TYPE_CONSTANT(uint128_t, uint128_type);
  FMT_TYPE_CONSTANT(bool, bool_type);
  FMT_TYPE_CONSTANT(Char, char_type);
  FMT_TYPE_CONSTANT(float, float_type);
  FMT_TYPE_CONSTANT(double, double_type);
  FMT_TYPE_CONSTANT(long double, long_double_type);
  FMT_TYPE_CONSTANT(const Char*, cstring_type);
  FMT_TYPE_CONSTANT(basic_string_view<Char>, string_type);
  FMT_TYPE_CONSTANT(const void*, pointer_type);
  
  constexpr bool is_integral_type(type t) {
    return t > type::none_type && t <= type::last_integer_type;
  }
  
  constexpr bool is_arithmetic_type(type t) {
    return t > type::none_type && t <= type::last_numeric_type;
  }
  
  template <typename Char> struct string_value {
    const Char* data;
    size_t size;
  };
  
  template <typename Char> struct named_arg_value {
    const named_arg_info<Char>* data;
    size_t size;
  };
  
  template <typename Context> struct custom_value {
    using parse_context = typename Context::parse_context_type;
    const void* value;
    void (*format)(const void* arg, parse_context& parse_ctx, Context& ctx);
  };
  
  // A formatting argument value.
  template <typename Context> class value {
   public:
    using char_type = typename Context::char_type;
  
    union {
      monostate no_value;
      int int_value;
      unsigned uint_value;
      long long long_long_value;
      unsigned long long ulong_long_value;
      int128_t int128_value;
      uint128_t uint128_value;
      bool bool_value;
      char_type char_value;
      float float_value;
      double double_value;
      long double long_double_value;
      const void* pointer;
      string_value<char_type> string;
      custom_value<Context> custom;
      named_arg_value<char_type> named_args;
    };
  
    constexpr FMT_INLINE value() : no_value() {}
    constexpr FMT_INLINE value(int val) : int_value(val) {}
    constexpr FMT_INLINE value(unsigned val) : uint_value(val) {}
    constexpr FMT_INLINE value(long long val) : long_long_value(val) {}
    constexpr FMT_INLINE value(unsigned long long val) : ulong_long_value(val) {}
    FMT_INLINE value(int128_t val) : int128_value(val) {}
    FMT_INLINE value(uint128_t val) : uint128_value(val) {}
    FMT_INLINE value(float val) : float_value(val) {}
    FMT_INLINE value(double val) : double_value(val) {}
    FMT_INLINE value(long double val) : long_double_value(val) {}
    constexpr FMT_INLINE value(bool val) : bool_value(val) {}
    constexpr FMT_INLINE value(char_type val) : char_value(val) {}
    FMT_CONSTEXPR FMT_INLINE value(const char_type* val) {
      string.data = val;
      if (is_constant_evaluated()) string.size = {};
    }
    FMT_CONSTEXPR FMT_INLINE value(basic_string_view<char_type> val) {
      string.data = val.data();
      string.size = val.size();
    }
    FMT_INLINE value(const void* val) : pointer(val) {}
    FMT_INLINE value(const named_arg_info<char_type>* args, size_t size)
        : named_args{args, size} {}
  
    template <typename T> FMT_CONSTEXPR FMT_INLINE value(const T& val) {
      custom.value = &val;
      // Get the formatter type through the context to allow different contexts
      // have different extension points, e.g. `formatter<T>` for `format` and
      // `printf_formatter<T>` for `printf`.
      custom.format = format_custom_arg<
          T, conditional_t<has_formatter<T, Context>::value,
                           typename Context::template formatter_type<T>,
                           fallback_formatter<T, char_type>>>;
    }
  
   private:
    // Formats an argument of a custom type, such as a user-defined class.
    template <typename T, typename Formatter>
    static void format_custom_arg(const void* arg,
                                  typename Context::parse_context_type& parse_ctx,
                                  Context& ctx) {
      Formatter f;
      parse_ctx.advance_to(f.parse(parse_ctx));
      ctx.advance_to(f.format(*static_cast<const T*>(arg), ctx));
    }
  };
  
  template <typename Context, typename T>
  FMT_CONSTEXPR auto make_arg(const T& value) -> basic_format_arg<Context>;
  
  // To minimize the number of types we need to deal with, long is translated
  // either to int or to long long depending on its size.
  enum { long_short = sizeof(long) == sizeof(int) };
  using long_type = conditional_t<long_short, int, long long>;
  using ulong_type = conditional_t<long_short, unsigned, unsigned long long>;
  
  struct unformattable {};
  
  // Maps formatting arguments to core types.
  template <typename Context> struct arg_mapper {
    using char_type = typename Context::char_type;
  
    FMT_CONSTEXPR FMT_INLINE auto map(signed char val) -> int { return val; }
    FMT_CONSTEXPR FMT_INLINE auto map(unsigned char val) -> unsigned {
      return val;
    }
    FMT_CONSTEXPR FMT_INLINE auto map(short val) -> int { return val; }
    FMT_CONSTEXPR FMT_INLINE auto map(unsigned short val) -> unsigned {
      return val;
    }
    FMT_CONSTEXPR FMT_INLINE auto map(int val) -> int { return val; }
    FMT_CONSTEXPR FMT_INLINE auto map(unsigned val) -> unsigned { return val; }
    FMT_CONSTEXPR FMT_INLINE auto map(long val) -> long_type { return val; }
    FMT_CONSTEXPR FMT_INLINE auto map(unsigned long val) -> ulong_type {
      return val;
    }
    FMT_CONSTEXPR FMT_INLINE auto map(long long val) -> long long { return val; }
    FMT_CONSTEXPR FMT_INLINE auto map(unsigned long long val)
        -> unsigned long long {
      return val;
    }
    FMT_CONSTEXPR FMT_INLINE auto map(int128_t val) -> int128_t { return val; }
    FMT_CONSTEXPR FMT_INLINE auto map(uint128_t val) -> uint128_t { return val; }
    FMT_CONSTEXPR FMT_INLINE auto map(bool val) -> bool { return val; }
  
    template <typename T, FMT_ENABLE_IF(is_char<T>::value)>
    FMT_CONSTEXPR FMT_INLINE auto map(T val) -> char_type {
      static_assert(
          std::is_same<T, char>::value || std::is_same<T, char_type>::value,
          "mixing character types is disallowed");
      return val;
    }
  
    FMT_CONSTEXPR FMT_INLINE auto map(float val) -> float { return val; }
    FMT_CONSTEXPR FMT_INLINE auto map(double val) -> double { return val; }
    FMT_CONSTEXPR FMT_INLINE auto map(long double val) -> long double {
      return val;
    }
  
    FMT_CONSTEXPR FMT_INLINE auto map(char_type* val) -> const char_type* {
      return val;
    }
    FMT_CONSTEXPR FMT_INLINE auto map(const char_type* val) -> const char_type* {
      return val;
    }
    template <typename T, FMT_ENABLE_IF(is_string<T>::value)>
    FMT_CONSTEXPR FMT_INLINE auto map(const T& val)
        -> basic_string_view<char_type> {
      static_assert(std::is_same<char_type, char_t<T>>::value,
                    "mixing character types is disallowed");
      return to_string_view(val);
    }
    template <typename T,
              FMT_ENABLE_IF(
                  std::is_constructible<basic_string_view<char_type>, T>::value &&
                  !is_string<T>::value && !has_formatter<T, Context>::value &&
                  !has_fallback_formatter<T, char_type>::value)>
    FMT_CONSTEXPR FMT_INLINE auto map(const T& val)
        -> basic_string_view<char_type> {
      return basic_string_view<char_type>(val);
    }
    template <
        typename T,
        FMT_ENABLE_IF(
            std::is_constructible<std_string_view<char_type>, T>::value &&
            !std::is_constructible<basic_string_view<char_type>, T>::value &&
            !is_string<T>::value && !has_formatter<T, Context>::value &&
            !has_fallback_formatter<T, char_type>::value)>
    FMT_CONSTEXPR FMT_INLINE auto map(const T& val)
        -> basic_string_view<char_type> {
      return std_string_view<char_type>(val);
    }
    FMT_CONSTEXPR FMT_INLINE auto map(const signed char* val) -> const char* {
      static_assert(std::is_same<char_type, char>::value, "invalid string type");
      return reinterpret_cast<const char*>(val);
    }
    FMT_CONSTEXPR FMT_INLINE auto map(const unsigned char* val) -> const char* {
      static_assert(std::is_same<char_type, char>::value, "invalid string type");
      return reinterpret_cast<const char*>(val);
    }
    FMT_CONSTEXPR FMT_INLINE auto map(signed char* val) -> const char* {
      const auto* const_val = val;
      return map(const_val);
    }
    FMT_CONSTEXPR FMT_INLINE auto map(unsigned char* val) -> const char* {
      const auto* const_val = val;
      return map(const_val);
    }
  
    FMT_CONSTEXPR FMT_INLINE auto map(void* val) -> const void* { return val; }
    FMT_CONSTEXPR FMT_INLINE auto map(const void* val) -> const void* {
      return val;
    }
    FMT_CONSTEXPR FMT_INLINE auto map(std::nullptr_t val) -> const void* {
      return val;
    }
  
    // We use SFINAE instead of a const T* parameter to avoid conflicting with
    // the C array overload.
    template <typename T>
    FMT_CONSTEXPR auto map(T) -> enable_if_t<std::is_pointer<T>::value, int> {
      // Formatting of arbitrary pointers is disallowed. If you want to output
      // a pointer cast it to "void *" or "const void *". In particular, this
      // forbids formatting of "[const] volatile char *" which is printed as bool
      // by iostreams.
      static_assert(!sizeof(T), "formatting of non-void pointers is disallowed");
      return 0;
    }
  
    template <typename T, std::size_t N>
    FMT_CONSTEXPR FMT_INLINE auto map(const T (&values)[N]) -> const T (&)[N] {
      return values;
    }
  
    template <typename T,
              FMT_ENABLE_IF(std::is_enum<T>::value &&
                            !has_formatter<T, Context>::value &&
                            !has_fallback_formatter<T, char_type>::value)>
    FMT_CONSTEXPR FMT_INLINE auto map(const T& val)
        -> decltype(std::declval<arg_mapper>().map(
            static_cast<typename std::underlying_type<T>::type>(val))) {
      return map(static_cast<typename std::underlying_type<T>::type>(val));
    }
    template <typename T,
              FMT_ENABLE_IF(!is_string<T>::value && !is_char<T>::value &&
                            (has_formatter<T, Context>::value ||
                             has_fallback_formatter<T, char_type>::value))>
    FMT_CONSTEXPR FMT_INLINE auto map(const T& val) -> const T& {
      return val;
    }
  
    template <typename T, FMT_ENABLE_IF(is_named_arg<T>::value)>
    FMT_CONSTEXPR FMT_INLINE auto map(const T& named_arg)
        -> decltype(std::declval<arg_mapper>().map(named_arg.value)) {
      return map(named_arg.value);
    }
  
    auto map(...) -> unformattable { return {}; }
  };
  
  // A type constant after applying arg_mapper<Context>.
  template <typename T, typename Context>
  using mapped_type_constant =
      type_constant<decltype(arg_mapper<Context>().map(std::declval<const T&>())),
                    typename Context::char_type>;
  
  enum { packed_arg_bits = 4 };
  // Maximum number of arguments with packed types.
  enum { max_packed_args = 62 / packed_arg_bits };
  enum : unsigned long long { is_unpacked_bit = 1ULL << 63 };
  enum : unsigned long long { has_named_args_bit = 1ULL << 62 };
  
  FMT_END_DETAIL_NAMESPACE
  
  // An output iterator that appends to a buffer.
  // It is used to reduce symbol sizes for the common case.
  class appender : public std::back_insert_iterator<detail::buffer<char>> {
    using base = std::back_insert_iterator<detail::buffer<char>>;
  
    template <typename T>
    friend auto get_buffer(appender out) -> detail::buffer<char>& {
      return detail::get_container(out);
    }
  
   public:
    using std::back_insert_iterator<detail::buffer<char>>::back_insert_iterator;
    appender(base it) : base(it) {}
    using _Unchecked_type = appender;  // Mark iterator as checked.
  
    auto operator++() -> appender& {
      base::operator++();
      return *this;
    }
  
    auto operator++(int) -> appender {
      auto tmp = *this;
      ++*this;
      return tmp;
    }
  };
  
  // A formatting argument. It is a trivially copyable/constructible type to
  // allow storage in basic_memory_buffer.
  template <typename Context> class basic_format_arg {
   private:
    detail::value<Context> value_;
    detail::type type_;
  
    template <typename ContextType, typename T>
    friend FMT_CONSTEXPR auto detail::make_arg(const T& value)
        -> basic_format_arg<ContextType>;
  
    template <typename Visitor, typename Ctx>
    friend FMT_CONSTEXPR auto visit_format_arg(Visitor&& vis,
                                               const basic_format_arg<Ctx>& arg)
        -> decltype(vis(0));
  
    friend class basic_format_args<Context>;
    friend class dynamic_format_arg_store<Context>;
  
    using char_type = typename Context::char_type;
  
    template <typename T, typename Char, size_t NUM_ARGS, size_t NUM_NAMED_ARGS>
    friend struct detail::arg_data;
  
    basic_format_arg(const detail::named_arg_info<char_type>* args, size_t size)
        : value_(args, size) {}
  
   public:
    class handle {
     public:
      explicit handle(detail::custom_value<Context> custom) : custom_(custom) {}
  
      void format(typename Context::parse_context_type& parse_ctx,
                  Context& ctx) const {
        custom_.format(custom_.value, parse_ctx, ctx);
      }
  
     private:
      detail::custom_value<Context> custom_;
    };
  
    constexpr basic_format_arg() : type_(detail::type::none_type) {}
  
    constexpr explicit operator bool() const FMT_NOEXCEPT {
      return type_ != detail::type::none_type;
    }
  
    auto type() const -> detail::type { return type_; }
  
    auto is_integral() const -> bool { return detail::is_integral_type(type_); }
    auto is_arithmetic() const -> bool {
      return detail::is_arithmetic_type(type_);
    }
  };
  
  /**
    \rst
    Visits an argument dispatching to the appropriate visit method based on
    the argument type. For example, if the argument type is ``double`` then
    ``vis(value)`` will be called with the value of type ``double``.
    \endrst
   */
  template <typename Visitor, typename Context>
  FMT_CONSTEXPR FMT_INLINE auto visit_format_arg(
      Visitor&& vis, const basic_format_arg<Context>& arg) -> decltype(vis(0)) {
    switch (arg.type_) {
    case detail::type::none_type:
      break;
    case detail::type::int_type:
      return vis(arg.value_.int_value);
    case detail::type::uint_type:
      return vis(arg.value_.uint_value);
    case detail::type::long_long_type:
      return vis(arg.value_.long_long_value);
    case detail::type::ulong_long_type:
      return vis(arg.value_.ulong_long_value);
    case detail::type::int128_type:
      return vis(detail::convert_for_visit(arg.value_.int128_value));
    case detail::type::uint128_type:
      return vis(detail::convert_for_visit(arg.value_.uint128_value));
    case detail::type::bool_type:
      return vis(arg.value_.bool_value);
    case detail::type::char_type:
      return vis(arg.value_.char_value);
    case detail::type::float_type:
      return vis(arg.value_.float_value);
    case detail::type::double_type:
      return vis(arg.value_.double_value);
    case detail::type::long_double_type:
      return vis(arg.value_.long_double_value);
    case detail::type::cstring_type:
      return vis(arg.value_.string.data);
    case detail::type::string_type:
      using sv = basic_string_view<typename Context::char_type>;
      return vis(sv(arg.value_.string.data, arg.value_.string.size));
    case detail::type::pointer_type:
      return vis(arg.value_.pointer);
    case detail::type::custom_type:
      return vis(typename basic_format_arg<Context>::handle(arg.value_.custom));
    }
    return vis(monostate());
  }
  
  FMT_BEGIN_DETAIL_NAMESPACE
  
  template <typename Char, typename InputIt>
  auto copy_str(InputIt begin, InputIt end, appender out) -> appender {
    get_container(out).append(begin, end);
    return out;
  }
  
  #if FMT_GCC_VERSION && FMT_GCC_VERSION < 500
  // A workaround for gcc 4.8 to make void_t work in a SFINAE context.
  template <typename... Ts> struct void_t_impl { using type = void; };
  template <typename... Ts>
  using void_t = typename detail::void_t_impl<Ts...>::type;
  #else
  template <typename...> using void_t = void;
  #endif
  
  template <typename It, typename T, typename Enable = void>
  struct is_output_iterator : std::false_type {};
  
  template <typename It, typename T>
  struct is_output_iterator<
      It, T,
      void_t<typename std::iterator_traits<It>::iterator_category,
             decltype(*std::declval<It>() = std::declval<T>())>>
      : std::true_type {};
  
  template <typename OutputIt>
  struct is_back_insert_iterator : std::false_type {};
  template <typename Container>
  struct is_back_insert_iterator<std::back_insert_iterator<Container>>
      : std::true_type {};
  
  template <typename OutputIt>
  struct is_contiguous_back_insert_iterator : std::false_type {};
  template <typename Container>
  struct is_contiguous_back_insert_iterator<std::back_insert_iterator<Container>>
      : is_contiguous<Container> {};
  template <>
  struct is_contiguous_back_insert_iterator<appender> : std::true_type {};
  
  // A type-erased reference to an std::locale to avoid heavy <locale> include.
  class locale_ref {
   private:
    const void* locale_;  // A type-erased pointer to std::locale.
  
   public:
    constexpr locale_ref() : locale_(nullptr) {}
    template <typename Locale> explicit locale_ref(const Locale& loc);
  
    explicit operator bool() const FMT_NOEXCEPT { return locale_ != nullptr; }
  
    template <typename Locale> auto get() const -> Locale;
  };
  
  template <typename> constexpr auto encode_types() -> unsigned long long {
    return 0;
  }
  
  template <typename Context, typename Arg, typename... Args>
  constexpr auto encode_types() -> unsigned long long {
    return static_cast<unsigned>(mapped_type_constant<Arg, Context>::value) |
           (encode_types<Context, Args...>() << packed_arg_bits);
  }
  
  template <typename Context, typename T>
  FMT_CONSTEXPR auto make_arg(const T& value) -> basic_format_arg<Context> {
    basic_format_arg<Context> arg;
    arg.type_ = mapped_type_constant<T, Context>::value;
    arg.value_ = arg_mapper<Context>().map(value);
    return arg;
  }
  
  // The type template parameter is there to avoid an ODR violation when using
  // a fallback formatter in one translation unit and an implicit conversion in
  // another (not recommended).
  template <bool IS_PACKED, typename Context, type, typename T,
            FMT_ENABLE_IF(IS_PACKED)>
  FMT_CONSTEXPR FMT_INLINE auto make_arg(const T& val) -> value<Context> {
    const auto& arg = arg_mapper<Context>().map(val);
    static_assert(
        !std::is_same<decltype(arg), const unformattable&>::value,
        "Cannot format an argument. To make type T formattable provide a "
        "formatter<T> specialization: https://fmt.dev/latest/api.html#udt");
    return {arg};
  }
  
  template <bool IS_PACKED, typename Context, type, typename T,
            FMT_ENABLE_IF(!IS_PACKED)>
  inline auto make_arg(const T& value) -> basic_format_arg<Context> {
    return make_arg<Context>(value);
  }
  FMT_END_DETAIL_NAMESPACE
  
  // Formatting context.
  template <typename OutputIt, typename Char> class basic_format_context {
   public:
    /** The character type for the output. */
    using char_type = Char;
  
   private:
    OutputIt out_;
    basic_format_args<basic_format_context> args_;
    detail::locale_ref loc_;
  
   public:
    using iterator = OutputIt;
    using format_arg = basic_format_arg<basic_format_context>;
    using parse_context_type = basic_format_parse_context<Char>;
    template <typename T> using formatter_type = formatter<T, char_type>;
  
    basic_format_context(basic_format_context&&) = default;
    basic_format_context(const basic_format_context&) = delete;
    void operator=(const basic_format_context&) = delete;
    /**
     Constructs a ``basic_format_context`` object. References to the arguments are
     stored in the object so make sure they have appropriate lifetimes.
     */
    constexpr basic_format_context(
        OutputIt out, basic_format_args<basic_format_context> ctx_args,
        detail::locale_ref loc = detail::locale_ref())
        : out_(out), args_(ctx_args), loc_(loc) {}
  
    constexpr auto arg(int id) const -> format_arg { return args_.get(id); }
    FMT_CONSTEXPR auto arg(basic_string_view<char_type> name) -> format_arg {
      return args_.get(name);
    }
    FMT_CONSTEXPR auto arg_id(basic_string_view<char_type> name) -> int {
      return args_.get_id(name);
    }
    auto args() const -> const basic_format_args<basic_format_context>& {
      return args_;
    }
  
    FMT_CONSTEXPR auto error_handler() -> detail::error_handler { return {}; }
    void on_error(const char* message) { error_handler().on_error(message); }
  
    // Returns an iterator to the beginning of the output range.
    FMT_CONSTEXPR auto out() -> iterator { return out_; }
  
    // Advances the begin iterator to ``it``.
    void advance_to(iterator it) {
      if (!detail::is_back_insert_iterator<iterator>()) out_ = it;
    }
  
    FMT_CONSTEXPR auto locale() -> detail::locale_ref { return loc_; }
  };
  
  template <typename Char>
  using buffer_context =
      basic_format_context<detail::buffer_appender<Char>, Char>;
  using format_context = buffer_context<char>;
  
  // Workaround an alias issue: https://stackoverflow.com/q/62767544/471164.
  #define FMT_BUFFER_CONTEXT(Char) \
    basic_format_context<detail::buffer_appender<Char>, Char>
  
  template <typename T, typename Char = char>
  using is_formattable = bool_constant<
      !std::is_same<decltype(detail::arg_mapper<buffer_context<Char>>().map(
                        std::declval<T>())),
                    detail::unformattable>::value &&
      !detail::has_fallback_formatter<T, Char>::value>;
  
  /**
    \rst
    An array of references to arguments. It can be implicitly converted into
    `~fmt::basic_format_args` for passing into type-erased formatting functions
    such as `~fmt::vformat`.
    \endrst
   */
  template <typename Context, typename... Args>
  class format_arg_store
  #if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
      // Workaround a GCC template argument substitution bug.
      : public basic_format_args<Context>
  #endif
  {
   private:
    static const size_t num_args = sizeof...(Args);
    static const size_t num_named_args = detail::count_named_args<Args...>();
    static const bool is_packed = num_args <= detail::max_packed_args;
  
    using value_type = conditional_t<is_packed, detail::value<Context>,
                                     basic_format_arg<Context>>;
  
    detail::arg_data<value_type, typename Context::char_type, num_args,
                     num_named_args>
        data_;
  
    friend class basic_format_args<Context>;
  
    static constexpr unsigned long long desc =
        (is_packed ? detail::encode_types<Context, Args...>()
                   : detail::is_unpacked_bit | num_args) |
        (num_named_args != 0
             ? static_cast<unsigned long long>(detail::has_named_args_bit)
             : 0);
  
   public:
    FMT_CONSTEXPR FMT_INLINE format_arg_store(const Args&... args)
        :
  #if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
          basic_format_args<Context>(*this),
  #endif
          data_{detail::make_arg<
              is_packed, Context,
              detail::mapped_type_constant<Args, Context>::value>(args)...} {
      detail::init_named_args(data_.named_args(), 0, 0, args...);
    }
  };
  
  /**
    \rst
    Constructs a `~fmt::format_arg_store` object that contains references to
    arguments and can be implicitly converted to `~fmt::format_args`. `Context`
    can be omitted in which case it defaults to `~fmt::context`.
    See `~fmt::arg` for lifetime considerations.
    \endrst
   */
  template <typename Context = format_context, typename... Args>
  constexpr auto make_format_args(const Args&... args)
      -> format_arg_store<Context, Args...> {
    return {args...};
  }
  
  /**
    \rst
    Returns a named argument to be used in a formatting function.
    It should only be used in a call to a formatting function or
    `dynamic_format_arg_store::push_back`.
  
    **Example**::
  
      fmt::print("Elapsed time: {s:.2f} seconds", fmt::arg("s", 1.23));
    \endrst
   */
  template <typename Char, typename T>
  inline auto arg(const Char* name, const T& arg) -> detail::named_arg<Char, T> {
    static_assert(!detail::is_named_arg<T>(), "nested named arguments");
    return {name, arg};
  }
  
  /**
    \rst
    A view of a collection of formatting arguments. To avoid lifetime issues it
    should only be used as a parameter type in type-erased functions such as
    ``vformat``::
  
      void vlog(string_view format_str, format_args args);  // OK
      format_args args = make_format_args(42);  // Error: dangling reference
    \endrst
   */
  template <typename Context> class basic_format_args {
   public:
    using size_type = int;
    using format_arg = basic_format_arg<Context>;
  
   private:
    // A descriptor that contains information about formatting arguments.
    // If the number of arguments is less or equal to max_packed_args then
    // argument types are passed in the descriptor. This reduces binary code size
    // per formatting function call.
    unsigned long long desc_;
    union {
      // If is_packed() returns true then argument values are stored in values_;
      // otherwise they are stored in args_. This is done to improve cache
      // locality and reduce compiled code size since storing larger objects
      // may require more code (at least on x86-64) even if the same amount of
      // data is actually copied to stack. It saves ~10% on the bloat test.
      const detail::value<Context>* values_;
      const format_arg* args_;
    };
  
    constexpr auto is_packed() const -> bool {
      return (desc_ & detail::is_unpacked_bit) == 0;
    }
    auto has_named_args() const -> bool {
      return (desc_ & detail::has_named_args_bit) != 0;
    }
  
    FMT_CONSTEXPR auto type(int index) const -> detail::type {
      int shift = index * detail::packed_arg_bits;
      unsigned int mask = (1 << detail::packed_arg_bits) - 1;
      return static_cast<detail::type>((desc_ >> shift) & mask);
    }
  
    constexpr FMT_INLINE basic_format_args(unsigned long long desc,
                                           const detail::value<Context>* values)
        : desc_(desc), values_(values) {}
    constexpr basic_format_args(unsigned long long desc, const format_arg* args)
        : desc_(desc), args_(args) {}
  
   public:
    constexpr basic_format_args() : desc_(0), args_(nullptr) {}
  
    /**
     \rst
     Constructs a `basic_format_args` object from `~fmt::format_arg_store`.
     \endrst
     */
    template <typename... Args>
    constexpr FMT_INLINE basic_format_args(
        const format_arg_store<Context, Args...>& store)
        : basic_format_args(format_arg_store<Context, Args...>::desc,
                            store.data_.args()) {}
  
    /**
     \rst
     Constructs a `basic_format_args` object from
     `~fmt::dynamic_format_arg_store`.
     \endrst
     */
    constexpr FMT_INLINE basic_format_args(
        const dynamic_format_arg_store<Context>& store)
        : basic_format_args(store.get_types(), store.data()) {}
  
    /**
     \rst
     Constructs a `basic_format_args` object from a dynamic set of arguments.
     \endrst
     */
    constexpr basic_format_args(const format_arg* args, int count)
        : basic_format_args(detail::is_unpacked_bit | detail::to_unsigned(count),
                            args) {}
  
    /** Returns the argument with the specified id. */
    FMT_CONSTEXPR auto get(int id) const -> format_arg {
      format_arg arg;
      if (!is_packed()) {
        if (id < max_size()) arg = args_[id];
        return arg;
      }
      if (id >= detail::max_packed_args) return arg;
      arg.type_ = type(id);
      if (arg.type_ == detail::type::none_type) return arg;
      arg.value_ = values_[id];
      return arg;
    }
  
    template <typename Char>
    auto get(basic_string_view<Char> name) const -> format_arg {
      int id = get_id(name);
      return id >= 0 ? get(id) : format_arg();
    }
  
    template <typename Char>
    auto get_id(basic_string_view<Char> name) const -> int {
      if (!has_named_args()) return -1;
      const auto& named_args =
          (is_packed() ? values_[-1] : args_[-1].value_).named_args;
      for (size_t i = 0; i < named_args.size; ++i) {
        if (named_args.data[i].name == name) return named_args.data[i].id;
      }
      return -1;
    }
  
    auto max_size() const -> int {
      unsigned long long max_packed = detail::max_packed_args;
      return static_cast<int>(is_packed() ? max_packed
                                          : desc_ & ~detail::is_unpacked_bit);
    }
  };
  
  /** An alias to ``basic_format_args<format_context>``. */
  // A separate type would result in shorter symbols but break ABI compatibility
  // between clang and gcc on ARM (#1919).
  using format_args = basic_format_args<format_context>;
  
  // We cannot use enum classes as bit fields because of a gcc bug
  // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61414.
  namespace align {
  enum type { none, left, right, center, numeric };
  }
  using align_t = align::type;
  namespace sign {
  enum type { none, minus, plus, space };
  }
  using sign_t = sign::type;
  
  FMT_BEGIN_DETAIL_NAMESPACE
  
  void throw_format_error(const char* message);
  
  // Workaround an array initialization issue in gcc 4.8.
  template <typename Char> struct fill_t {
   private:
    enum { max_size = 4 };
    Char data_[max_size] = {Char(' '), Char(0), Char(0), Char(0)};
    unsigned char size_ = 1;
  
   public:
    FMT_CONSTEXPR void operator=(basic_string_view<Char> s) {
      auto size = s.size();
      if (size > max_size) return throw_format_error("invalid fill");
      for (size_t i = 0; i < size; ++i) data_[i] = s[i];
      size_ = static_cast<unsigned char>(size);
    }
  
    constexpr auto size() const -> size_t { return size_; }
    constexpr auto data() const -> const Char* { return data_; }
  
    FMT_CONSTEXPR auto operator[](size_t index) -> Char& { return data_[index]; }
    FMT_CONSTEXPR auto operator[](size_t index) const -> const Char& {
      return data_[index];
    }
  };
  FMT_END_DETAIL_NAMESPACE
  
  // Format specifiers for built-in and string types.
  template <typename Char> struct basic_format_specs {
    int width;
    int precision;
    char type;
    align_t align : 4;
    sign_t sign : 3;
    bool alt : 1;  // Alternate form ('#').
    bool localized : 1;
    detail::fill_t<Char> fill;
  
    constexpr basic_format_specs()
        : width(0),
          precision(-1),
          type(0),
          align(align::none),
          sign(sign::none),
          alt(false),
          localized(false) {}
  };
  
  using format_specs = basic_format_specs<char>;
  
  FMT_BEGIN_DETAIL_NAMESPACE
  
  enum class arg_id_kind { none, index, name };
  
  // An argument reference.
  template <typename Char> struct arg_ref {
    FMT_CONSTEXPR arg_ref() : kind(arg_id_kind::none), val() {}
  
    FMT_CONSTEXPR explicit arg_ref(int index)
        : kind(arg_id_kind::index), val(index) {}
    FMT_CONSTEXPR explicit arg_ref(basic_string_view<Char> name)
        : kind(arg_id_kind::name), val(name) {}
  
    FMT_CONSTEXPR auto operator=(int idx) -> arg_ref& {
      kind = arg_id_kind::index;
      val.index = idx;
      return *this;
    }
  
    arg_id_kind kind;
    union value {
      FMT_CONSTEXPR value(int id = 0) : index{id} {}
      FMT_CONSTEXPR value(basic_string_view<Char> n) : name(n) {}
  
      int index;
      basic_string_view<Char> name;
    } val;
  };
  
  // Format specifiers with mWidth and precision resolved at formatting rather
  // than parsing time to allow re-using the same parsed specifiers with
  // different sets of arguments (precompilation of format strings).
  template <typename Char>
  struct dynamic_format_specs : basic_format_specs<Char> {
    arg_ref<Char> width_ref;
    arg_ref<Char> precision_ref;
  };
  
  struct auto_id {};
  
  // A format specifier handler that sets fields in basic_format_specs.
  template <typename Char> class specs_setter {
   protected:
    basic_format_specs<Char>& specs_;
  
   public:
    explicit FMT_CONSTEXPR specs_setter(basic_format_specs<Char>& specs)
        : specs_(specs) {}
  
    FMT_CONSTEXPR specs_setter(const specs_setter& other)
        : specs_(other.specs_) {}
  
    FMT_CONSTEXPR void on_align(align_t align) { specs_.align = align; }
    FMT_CONSTEXPR void on_fill(basic_string_view<Char> fill) {
      specs_.fill = fill;
    }
    FMT_CONSTEXPR void on_sign(sign_t s) { specs_.sign = s; }
    FMT_CONSTEXPR void on_hash() { specs_.alt = true; }
    FMT_CONSTEXPR void on_localized() { specs_.localized = true; }
  
    FMT_CONSTEXPR void on_zero() {
      if (specs_.align == align::none) specs_.align = align::numeric;
      specs_.fill[0] = Char('0');
    }
  
    FMT_CONSTEXPR void on_width(int width) { specs_.width = width; }
    FMT_CONSTEXPR void on_precision(int precision) {
      specs_.precision = precision;
    }
    FMT_CONSTEXPR void end_precision() {}
  
    FMT_CONSTEXPR void on_type(Char type) {
      specs_.type = static_cast<char>(type);
    }
  };
  
  // Format spec handler that saves references to arguments representing dynamic
  // mWidth and precision to be resolved at formatting time.
  template <typename ParseContext>
  class dynamic_specs_handler
      : public specs_setter<typename ParseContext::char_type> {
   public:
    using char_type = typename ParseContext::char_type;
  
    FMT_CONSTEXPR dynamic_specs_handler(dynamic_format_specs<char_type>& specs,
                                        ParseContext& ctx)
        : specs_setter<char_type>(specs), specs_(specs), context_(ctx) {}
  
    FMT_CONSTEXPR dynamic_specs_handler(const dynamic_specs_handler& other)
        : specs_setter<char_type>(other),
          specs_(other.specs_),
          context_(other.context_) {}
  
    template <typename Id> FMT_CONSTEXPR void on_dynamic_width(Id arg_id) {
      specs_.width_ref = make_arg_ref(arg_id);
    }
  
    template <typename Id> FMT_CONSTEXPR void on_dynamic_precision(Id arg_id) {
      specs_.precision_ref = make_arg_ref(arg_id);
    }
  
    FMT_CONSTEXPR void on_error(const char* message) {
      context_.on_error(message);
    }
  
   private:
    dynamic_format_specs<char_type>& specs_;
    ParseContext& context_;
  
    using arg_ref_type = arg_ref<char_type>;
  
    FMT_CONSTEXPR auto make_arg_ref(int arg_id) -> arg_ref_type {
      context_.check_arg_id(arg_id);
      return arg_ref_type(arg_id);
    }
  
    FMT_CONSTEXPR auto make_arg_ref(auto_id) -> arg_ref_type {
      return arg_ref_type(context_.next_arg_id());
    }
  
    FMT_CONSTEXPR auto make_arg_ref(basic_string_view<char_type> arg_id)
        -> arg_ref_type {
      context_.check_arg_id(arg_id);
      basic_string_view<char_type> format_str(
          context_.begin(), to_unsigned(context_.end() - context_.begin()));
      return arg_ref_type(arg_id);
    }
  };
  
  template <typename Char> constexpr bool is_ascii_letter(Char c) {
    return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
  }
  
  // Converts a character to ASCII. Returns a number > 127 on conversion failure.
  template <typename Char, FMT_ENABLE_IF(std::is_integral<Char>::value)>
  constexpr auto to_ascii(Char value) -> Char {
    return value;
  }
  template <typename Char, FMT_ENABLE_IF(std::is_enum<Char>::value)>
  constexpr auto to_ascii(Char value) ->
      typename std::underlying_type<Char>::type {
    return value;
  }
  
  template <typename Char>
  FMT_CONSTEXPR auto code_point_length(const Char* begin) -> int {
    if (const_check(sizeof(Char) != 1)) return 1;
    constexpr char lengths[] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
                                0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 3, 3, 4, 0};
    int len = lengths[static_cast<unsigned char>(*begin) >> 3];
  
    // Compute the pointer to the next character early so that the next
    // iteration can start working on the next character. Neither Clang
    // nor GCC figure out this reordering on their own.
    return len + !len;
  }
  
  // Return the result via the out param to workaround gcc bug 77539.
  template <bool IS_CONSTEXPR, typename T, typename Ptr = const T*>
  FMT_CONSTEXPR auto find(Ptr first, Ptr last, T value, Ptr& out) -> bool {
    for (out = first; out != last; ++out) {
      if (*out == value) return true;
    }
    return false;
  }
  
  template <>
  inline auto find<false, char>(const char* first, const char* last, char value,
                                const char*& out) -> bool {
    out = static_cast<const char*>(
        std::memchr(first, value, to_unsigned(last - first)));
    return out != nullptr;
  }
  
  // Parses the range [begin, end) as an unsigned integer. This function assumes
  // that the range is non-empty and the first character is a digit.
  template <typename Char>
  FMT_CONSTEXPR auto parse_nonnegative_int(const Char*& begin, const Char* end,
                                           int error_value) noexcept -> int {
    FMT_ASSERT(begin != end && '0' <= *begin && *begin <= '9', "");
    unsigned value = 0, prev = 0;
    auto p = begin;
    do {
      prev = value;
      value = value * 10 + unsigned(*p - '0');
      ++p;
    } while (p != end && '0' <= *p && *p <= '9');
    auto num_digits = p - begin;
    begin = p;
    if (num_digits <= std::numeric_limits<int>::digits10)
      return static_cast<int>(value);
    // Check for overflow.
    const unsigned max = to_unsigned((std::numeric_limits<int>::max)());
    return num_digits == std::numeric_limits<int>::digits10 + 1 &&
                   prev * 10ull + unsigned(p[-1] - '0') <= max
               ? static_cast<int>(value)
               : error_value;
  }
  
  // Parses fill and alignment.
  template <typename Char, typename Handler>
  FMT_CONSTEXPR auto parse_align(const Char* begin, const Char* end,
                                 Handler&& handler) -> const Char* {
    FMT_ASSERT(begin != end, "");
    auto align = align::none;
    auto p = begin + code_point_length(begin);
    if (p >= end) p = begin;
    for (;;) {
      switch (to_ascii(*p)) {
      case '<':
        align = align::left;
        break;
      case '>':
        align = align::right;
        break;
      case '^':
        align = align::center;
        break;
      default:
        break;
      }
      if (align != align::none) {
        if (p != begin) {
          auto c = *begin;
          if (c == '{')
            return handler.on_error("invalid fill character '{'"), begin;
          handler.on_fill(basic_string_view<Char>(begin, to_unsigned(p - begin)));
          begin = p + 1;
        } else
          ++begin;
        handler.on_align(align);
        break;
      } else if (p == begin) {
        break;
      }
      p = begin;
    }
    return begin;
  }
  
  template <typename Char> FMT_CONSTEXPR bool is_name_start(Char c) {
    return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || '_' == c;
  }
  
  template <typename Char, typename IDHandler>
  FMT_CONSTEXPR auto do_parse_arg_id(const Char* begin, const Char* end,
                                     IDHandler&& handler) -> const Char* {
    FMT_ASSERT(begin != end, "");
    Char c = *begin;
    if (c >= '0' && c <= '9') {
      int index = 0;
      if (c != '0')
        index =
            parse_nonnegative_int(begin, end, (std::numeric_limits<int>::max)());
      else
        ++begin;
      if (begin == end || (*begin != '}' && *begin != ':'))
        handler.on_error("invalid format string");
      else
        handler(index);
      return begin;
    }
    if (!is_name_start(c)) {
      handler.on_error("invalid format string");
      return begin;
    }
    auto it = begin;
    do {
      ++it;
    } while (it != end && (is_name_start(c = *it) || ('0' <= c && c <= '9')));
    handler(basic_string_view<Char>(begin, to_unsigned(it - begin)));
    return it;
  }
  
  template <typename Char, typename IDHandler>
  FMT_CONSTEXPR FMT_INLINE auto parse_arg_id(const Char* begin, const Char* end,
                                             IDHandler&& handler) -> const Char* {
    Char c = *begin;
    if (c != '}' && c != ':') return do_parse_arg_id(begin, end, handler);
    handler();
    return begin;
  }
  
  template <typename Char, typename Handler>
  FMT_CONSTEXPR auto parse_width(const Char* begin, const Char* end,
                                 Handler&& handler) -> const Char* {
    using detail::auto_id;
    struct width_adapter {
      Handler& handler;
  
      FMT_CONSTEXPR void operator()() { handler.on_dynamic_width(auto_id()); }
      FMT_CONSTEXPR void operator()(int id) { handler.on_dynamic_width(id); }
      FMT_CONSTEXPR void operator()(basic_string_view<Char> id) {
        handler.on_dynamic_width(id);
      }
      FMT_CONSTEXPR void on_error(const char* message) {
        if (message) handler.on_error(message);
      }
    };
  
    FMT_ASSERT(begin != end, "");
    if ('0' <= *begin && *begin <= '9') {
      int width = parse_nonnegative_int(begin, end, -1);
      if (width != -1)
        handler.on_width(width);
      else
        handler.on_error("number is too big");
    } else if (*begin == '{') {
      ++begin;
      if (begin != end) begin = parse_arg_id(begin, end, width_adapter{handler});
      if (begin == end || *begin != '}')
        return handler.on_error("invalid format string"), begin;
      ++begin;
    }
    return begin;
  }
  
  template <typename Char, typename Handler>
  FMT_CONSTEXPR auto parse_precision(const Char* begin, const Char* end,
                                     Handler&& handler) -> const Char* {
    using detail::auto_id;
    struct precision_adapter {
      Handler& handler;
  
      FMT_CONSTEXPR void operator()() { handler.on_dynamic_precision(auto_id()); }
      FMT_CONSTEXPR void operator()(int id) { handler.on_dynamic_precision(id); }
      FMT_CONSTEXPR void operator()(basic_string_view<Char> id) {
        handler.on_dynamic_precision(id);
      }
      FMT_CONSTEXPR void on_error(const char* message) {
        if (message) handler.on_error(message);
      }
    };
  
    ++begin;
    auto c = begin != end ? *begin : Char();
    if ('0' <= c && c <= '9') {
      auto precision = parse_nonnegative_int(begin, end, -1);
      if (precision != -1)
        handler.on_precision(precision);
      else
        handler.on_error("number is too big");
    } else if (c == '{') {
      ++begin;
      if (begin != end)
        begin = parse_arg_id(begin, end, precision_adapter{handler});
      if (begin == end || *begin++ != '}')
        return handler.on_error("invalid format string"), begin;
    } else {
      return handler.on_error("missing precision specifier"), begin;
    }
    handler.end_precision();
    return begin;
  }
  
  // Parses standard format specifiers and sends notifications about parsed
  // components to handler.
  template <typename Char, typename SpecHandler>
  FMT_CONSTEXPR FMT_INLINE auto parse_format_specs(const Char* begin,
                                                   const Char* end,
                                                   SpecHandler&& handler)
      -> const Char* {
    if (begin + 1 < end && begin[1] == '}' && is_ascii_letter(*begin) &&
        *begin != 'L') {
      handler.on_type(*begin++);
      return begin;
    }
  
    if (begin == end) return begin;
  
    begin = parse_align(begin, end, handler);
    if (begin == end) return begin;
  
    // Parse sign.
    switch (to_ascii(*begin)) {
    case '+':
      handler.on_sign(sign::plus);
      ++begin;
      break;
    case '-':
      handler.on_sign(sign::minus);
      ++begin;
      break;
    case ' ':
      handler.on_sign(sign::space);
      ++begin;
      break;
    default:
      break;
    }
    if (begin == end) return begin;
  
    if (*begin == '#') {
      handler.on_hash();
      if (++begin == end) return begin;
    }
  
    // Parse zero flag.
    if (*begin == '0') {
      handler.on_zero();
      if (++begin == end) return begin;
    }
  
    begin = parse_width(begin, end, handler);
    if (begin == end) return begin;
  
    // Parse precision.
    if (*begin == '.') {
      begin = parse_precision(begin, end, handler);
      if (begin == end) return begin;
    }
  
    if (*begin == 'L') {
      handler.on_localized();
      ++begin;
    }
  
    // Parse type.
    if (begin != end && *begin != '}') handler.on_type(*begin++);
    return begin;
  }
  
  template <typename Char, typename Handler>
  FMT_CONSTEXPR auto parse_replacement_field(const Char* begin, const Char* end,
                                             Handler&& handler) -> const Char* {
    struct id_adapter {
      Handler& handler;
      int arg_id;
  
      FMT_CONSTEXPR void operator()() { arg_id = handler.on_arg_id(); }
      FMT_CONSTEXPR void operator()(int id) { arg_id = handler.on_arg_id(id); }
      FMT_CONSTEXPR void operator()(basic_string_view<Char> id) {
        arg_id = handler.on_arg_id(id);
      }
      FMT_CONSTEXPR void on_error(const char* message) {
        if (message) handler.on_error(message);
      }
    };
  
    ++begin;
    if (begin == end) return handler.on_error("invalid format string"), end;
    if (*begin == '}') {
      handler.on_replacement_field(handler.on_arg_id(), begin);
    } else if (*begin == '{') {
      handler.on_text(begin, begin + 1);
    } else {
      auto adapter = id_adapter{handler, 0};
      begin = parse_arg_id(begin, end, adapter);
      Char c = begin != end ? *begin : Char();
      if (c == '}') {
        handler.on_replacement_field(adapter.arg_id, begin);
      } else if (c == ':') {
        begin = handler.on_format_specs(adapter.arg_id, begin + 1, end);
        if (begin == end || *begin != '}')
          return handler.on_error("unknown format specifier"), end;
      } else {
        return handler.on_error("missing '}' in format string"), end;
      }
    }
    return begin + 1;
  }
  
  template <bool IS_CONSTEXPR, typename Char, typename Handler>
  FMT_CONSTEXPR FMT_INLINE void parse_format_string(
      basic_string_view<Char> format_str, Handler&& handler) {
    // this is most likely a name-lookup defect in msvc's modules implementation
    using detail::find;
  
    auto begin = format_str.data();
    auto end = begin + format_str.size();
    if (end - begin < 32) {
      // Use a simple loop instead of memchr for small strings.
      const Char* p = begin;
      while (p != end) {
        auto c = *p++;
        if (c == '{') {
          handler.on_text(begin, p - 1);
          begin = p = parse_replacement_field(p - 1, end, handler);
        } else if (c == '}') {
          if (p == end || *p != '}')
            return handler.on_error("unmatched '}' in format string");
          handler.on_text(begin, p);
          begin = ++p;
        }
      }
      handler.on_text(begin, end);
      return;
    }
    struct writer {
      FMT_CONSTEXPR void operator()(const Char* pbegin, const Char* pend) {
        if (pbegin == pend) return;
        for (;;) {
          const Char* p = nullptr;
          if (!find<IS_CONSTEXPR>(pbegin, pend, Char('}'), p))
            return handler_.on_text(pbegin, pend);
          ++p;
          if (p == pend || *p != '}')
            return handler_.on_error("unmatched '}' in format string");
          handler_.on_text(pbegin, p);
          pbegin = p + 1;
        }
      }
      Handler& handler_;
    } write{handler};
    while (begin != end) {
      // Doing two passes with memchr (one for '{' and another for '}') is up to
      // 2.5x faster than the naive one-pass implementation on big format strings.
      const Char* p = begin;
      if (*begin != '{' && !find<IS_CONSTEXPR>(begin + 1, end, Char('{'), p))
        return write(begin, end);
      write(begin, p);
      begin = parse_replacement_field(p, end, handler);
    }
  }
  
  template <typename T, typename ParseContext>
  FMT_CONSTEXPR auto parse_format_specs(ParseContext& ctx)
      -> decltype(ctx.begin()) {
    using char_type = typename ParseContext::char_type;
    using context = buffer_context<char_type>;
    using mapped_type = conditional_t<
        mapped_type_constant<T, context>::value != type::custom_type,
        decltype(arg_mapper<context>().map(std::declval<const T&>())), T>;
    auto f = conditional_t<has_formatter<mapped_type, context>::value,
                           formatter<mapped_type, char_type>,
                           fallback_formatter<T, char_type>>();
    return f.parse(ctx);
  }
  
  // A parse context with extra argument id checks. It is only used at compile
  // time because adding checks at runtime would introduce substantial overhead
  // and would be redundant since argument ids are checked when arguments are
  // retrieved anyway.
  template <typename Char, typename ErrorHandler = error_handler>
  class compile_parse_context
      : public basic_format_parse_context<Char, ErrorHandler> {
   private:
    int num_args_;
    using base = basic_format_parse_context<Char, ErrorHandler>;
  
   public:
    explicit FMT_CONSTEXPR compile_parse_context(
        basic_string_view<Char> format_str,
        int num_args = (std::numeric_limits<int>::max)(), ErrorHandler eh = {})
        : base(format_str, eh), num_args_(num_args) {}
  
    FMT_CONSTEXPR auto next_arg_id() -> int {
      int id = base::next_arg_id();
      if (id >= num_args_) this->on_error("argument not found");
      return id;
    }
  
    FMT_CONSTEXPR void check_arg_id(int id) {
      base::check_arg_id(id);
      if (id >= num_args_) this->on_error("argument not found");
    }
    using base::check_arg_id;
  };
  
  template <typename ErrorHandler>
  FMT_CONSTEXPR void check_int_type_spec(char spec, ErrorHandler&& eh) {
    switch (spec) {
    case 0:
    case 'd':
    case 'x':
    case 'X':
    case 'b':
    case 'B':
    case 'o':
    case 'c':
      break;
    default:
      eh.on_error("invalid type specifier");
      break;
    }
  }
  
  // Checks char specs and returns true if the type spec is char (and not int).
  template <typename Char, typename ErrorHandler = error_handler>
  FMT_CONSTEXPR auto check_char_specs(const basic_format_specs<Char>& specs,
                                      ErrorHandler&& eh = {}) -> bool {
    if (specs.type && specs.type != 'c') {
      check_int_type_spec(specs.type, eh);
      return false;
    }
    if (specs.align == align::numeric || specs.sign != sign::none || specs.alt)
      eh.on_error("invalid format specifier for char");
    return true;
  }
  
  // A floating-point presentation format.
  enum class float_format : unsigned char {
    general,  // General: exponent notation or fixed point based on magnitude.
    exp,      // Exponent notation with the default precision of 6, e.g. 1.2e-3.
    fixed,    // Fixed point with the default precision of 6, e.g. 0.0012.
    hex
  };
  
  struct float_specs {
    int precision;
    float_format format : 8;
    sign_t sign : 8;
    bool upper : 1;
    bool locale : 1;
    bool binary32 : 1;
    bool use_grisu : 1;
    bool showpoint : 1;
  };
  
  template <typename ErrorHandler = error_handler, typename Char>
  FMT_CONSTEXPR auto parse_float_type_spec(const basic_format_specs<Char>& specs,
                                           ErrorHandler&& eh = {})
      -> float_specs {
    auto result = float_specs();
    result.showpoint = specs.alt;
    result.locale = specs.localized;
    switch (specs.type) {
    case 0:
      result.format = float_format::general;
      break;
    case 'G':
      result.upper = true;
      FMT_FALLTHROUGH;
    case 'g':
      result.format = float_format::general;
      break;
    case 'E':
      result.upper = true;
      FMT_FALLTHROUGH;
    case 'e':
      result.format = float_format::exp;
      result.showpoint |= specs.precision != 0;
      break;
    case 'F':
      result.upper = true;
      FMT_FALLTHROUGH;
    case 'f':
      result.format = float_format::fixed;
      result.showpoint |= specs.precision != 0;
      break;
    case 'A':
      result.upper = true;
      FMT_FALLTHROUGH;
    case 'a':
      result.format = float_format::hex;
      break;
    default:
      eh.on_error("invalid type specifier");
      break;
    }
    return result;
  }
  
  template <typename Char, typename ErrorHandler = error_handler>
  FMT_CONSTEXPR auto check_cstring_type_spec(Char spec, ErrorHandler&& eh = {})
      -> bool {
    if (spec == 0 || spec == 's') return true;
    if (spec != 'p') eh.on_error("invalid type specifier");
    return false;
  }
  
  template <typename Char, typename ErrorHandler = error_handler>
  FMT_CONSTEXPR void check_string_type_spec(Char spec, ErrorHandler&& eh = {}) {
    if (spec != 0 && spec != 's') eh.on_error("invalid type specifier");
  }
  
  template <typename Char, typename ErrorHandler>
  FMT_CONSTEXPR void check_pointer_type_spec(Char spec, ErrorHandler&& eh) {
    if (spec != 0 && spec != 'p') eh.on_error("invalid type specifier");
  }
  
  // A parse_format_specs handler that checks if specifiers are consistent with
  // the argument type.
  template <typename Handler> class specs_checker : public Handler {
   private:
    detail::type arg_type_;
  
    FMT_CONSTEXPR void require_numeric_argument() {
      if (!is_arithmetic_type(arg_type_))
        this->on_error("format specifier requires numeric argument");
    }
  
   public:
    FMT_CONSTEXPR specs_checker(const Handler& handler, detail::type arg_type)
        : Handler(handler), arg_type_(arg_type) {}
  
    FMT_CONSTEXPR void on_align(align_t align) {
      if (align == align::numeric) require_numeric_argument();
      Handler::on_align(align);
    }
  
    FMT_CONSTEXPR void on_sign(sign_t s) {
      require_numeric_argument();
      if (is_integral_type(arg_type_) && arg_type_ != type::int_type &&
          arg_type_ != type::long_long_type && arg_type_ != type::char_type) {
        this->on_error("format specifier requires signed argument");
      }
      Handler::on_sign(s);
    }
  
    FMT_CONSTEXPR void on_hash() {
      require_numeric_argument();
      Handler::on_hash();
    }
  
    FMT_CONSTEXPR void on_localized() {
      require_numeric_argument();
      Handler::on_localized();
    }
  
    FMT_CONSTEXPR void on_zero() {
      require_numeric_argument();
      Handler::on_zero();
    }
  
    FMT_CONSTEXPR void end_precision() {
      if (is_integral_type(arg_type_) || arg_type_ == type::pointer_type)
        this->on_error("precision not allowed for this argument type");
    }
  };
  
  constexpr int invalid_arg_index = -1;
  
  #if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
  template <int N, typename T, typename... Args, typename Char>
  constexpr auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
    if constexpr (detail::is_statically_named_arg<T>()) {
      if (name == T::name) return N;
    }
    if constexpr (sizeof...(Args) > 0) {
      return get_arg_index_by_name<N + 1, Args...>(name);
    } else {
      (void)name;  // Workaround an MSVC bug about "unused" parameter.
      return invalid_arg_index;
    }
  }
  #endif
  
  template <typename... Args, typename Char>
  FMT_CONSTEXPR auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
  #if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
    if constexpr (sizeof...(Args) > 0) {
      return get_arg_index_by_name<0, Args...>(name);
    } else {
      (void)name;
      return invalid_arg_index;
    }
  #else
    (void)name;
    return invalid_arg_index;
  #endif
  }
  
  template <typename Char, typename ErrorHandler, typename... Args>
  class format_string_checker {
   private:
    using parse_context_type = compile_parse_context<Char, ErrorHandler>;
    enum { num_args = sizeof...(Args) };
  
    // Format specifier parsing function.
    using parse_func = const Char* (*)(parse_context_type&);
  
    parse_context_type context_;
    parse_func parse_funcs_[num_args > 0 ? num_args : 1];
  
   public:
    explicit FMT_CONSTEXPR format_string_checker(
        basic_string_view<Char> format_str, ErrorHandler eh)
        : context_(format_str, num_args, eh),
          parse_funcs_{&parse_format_specs<Args, parse_context_type>...} {}
  
    FMT_CONSTEXPR void on_text(const Char*, const Char*) {}
  
    FMT_CONSTEXPR auto on_arg_id() -> int { return context_.next_arg_id(); }
    FMT_CONSTEXPR auto on_arg_id(int id) -> int {
      return context_.check_arg_id(id), id;
    }
    FMT_CONSTEXPR auto on_arg_id(basic_string_view<Char> id) -> int {
  #if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
      auto index = get_arg_index_by_name<Args...>(id);
      if (index == invalid_arg_index) on_error("named argument is not found");
      return context_.check_arg_id(index), index;
  #else
      (void)id;
      on_error("compile-time checks for named arguments require C++20 support");
      return 0;
  #endif
    }
  
    FMT_CONSTEXPR void on_replacement_field(int, const Char*) {}
  
    FMT_CONSTEXPR auto on_format_specs(int id, const Char* begin, const Char*)
        -> const Char* {
      context_.advance_to(context_.begin() + (begin - &*context_.begin()));
      // id >= 0 check is a workaround for gcc 10 bug (#2065).
      return id >= 0 && id < num_args ? parse_funcs_[id](context_) : begin;
    }
  
    FMT_CONSTEXPR void on_error(const char* message) {
      context_.on_error(message);
    }
  };
  
  template <typename... Args, typename S,
            enable_if_t<(is_compile_string<S>::value), int>>
  void check_format_string(S format_str) {
    FMT_CONSTEXPR auto s = to_string_view(format_str);
    using checker = format_string_checker<typename S::char_type, error_handler,
                                          remove_cvref_t<Args>...>;
    FMT_CONSTEXPR bool invalid_format =
        (parse_format_string<true>(s, checker(s, {})), true);
    ignore_unused(invalid_format);
  }
  
  template <typename Char>
  void vformat_to(
      buffer<Char>& buf, basic_string_view<Char> fmt,
      basic_format_args<FMT_BUFFER_CONTEXT(type_identity_t<Char>)> args,
      locale_ref loc = {});
  
  FMT_API void vprint_mojibake(std::FILE*, string_view, format_args);
  #ifndef _WIN32
  inline void vprint_mojibake(std::FILE*, string_view, format_args) {}
  #endif
  FMT_END_DETAIL_NAMESPACE
  
  // A formatter specialization for the core types corresponding to detail::type
  // constants.
  template <typename T, typename Char>
  struct formatter<T, Char,
                   enable_if_t<detail::type_constant<T, Char>::value !=
                               detail::type::custom_type>> {
   private:
    detail::dynamic_format_specs<Char> specs_;
  
   public:
    // Parses format specifiers stopping either at the end of the range or at the
    // terminating '}'.
    template <typename ParseContext>
    FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
      auto begin = ctx.begin(), end = ctx.end();
      if (begin == end) return begin;
      using handler_type = detail::dynamic_specs_handler<ParseContext>;
      auto type = detail::type_constant<T, Char>::value;
      auto checker =
          detail::specs_checker<handler_type>(handler_type(specs_, ctx), type);
      auto it = detail::parse_format_specs(begin, end, checker);
      auto eh = ctx.error_handler();
      switch (type) {
      case detail::type::none_type:
        FMT_ASSERT(false, "invalid argument type");
        break;
      case detail::type::bool_type:
        if (!specs_.type || specs_.type == 's') break;
        FMT_FALLTHROUGH;
      case detail::type::int_type:
      case detail::type::uint_type:
      case detail::type::long_long_type:
      case detail::type::ulong_long_type:
      case detail::type::int128_type:
      case detail::type::uint128_type:
        detail::check_int_type_spec(specs_.type, eh);
        break;
      case detail::type::char_type:
        detail::check_char_specs(specs_, eh);
        break;
      case detail::type::float_type:
        if (detail::const_check(FMT_USE_FLOAT))
          detail::parse_float_type_spec(specs_, eh);
        else
          FMT_ASSERT(false, "float support disabled");
        break;
      case detail::type::double_type:
        if (detail::const_check(FMT_USE_DOUBLE))
          detail::parse_float_type_spec(specs_, eh);
        else
          FMT_ASSERT(false, "double support disabled");
        break;
      case detail::type::long_double_type:
        if (detail::const_check(FMT_USE_LONG_DOUBLE))
          detail::parse_float_type_spec(specs_, eh);
        else
          FMT_ASSERT(false, "long double support disabled");
        break;
      case detail::type::cstring_type:
        detail::check_cstring_type_spec(specs_.type, eh);
        break;
      case detail::type::string_type:
        detail::check_string_type_spec(specs_.type, eh);
        break;
      case detail::type::pointer_type:
        detail::check_pointer_type_spec(specs_.type, eh);
        break;
      case detail::type::custom_type:
        // Custom format specifiers are checked in parse functions of
        // formatter specializations.
        break;
      }
      return it;
    }
  
    template <typename FormatContext>
    FMT_CONSTEXPR auto format(const T& val, FormatContext& ctx) const
        -> decltype(ctx.out());
  };
  
  template <typename Char> struct basic_runtime { basic_string_view<Char> str; };
  
  template <typename Char, typename... Args> class basic_format_string {
   private:
    basic_string_view<Char> str_;
  
   public:
    template <typename S,
              FMT_ENABLE_IF(
                  std::is_convertible<const S&, basic_string_view<Char>>::value)>
    FMT_CONSTEVAL basic_format_string(const S& s) : str_(s) {
      static_assert(
          detail::count<
              (std::is_base_of<detail::view, remove_reference_t<Args>>::value &&
               std::is_reference<Args>::value)...>() == 0,
          "passing views as lvalues is disallowed");
  #ifdef FMT_HAS_CONSTEVAL
      if constexpr (detail::count_named_args<Args...>() == 0) {
        using checker = detail::format_string_checker<Char, detail::error_handler,
                                                      remove_cvref_t<Args>...>;
        detail::parse_format_string<true>(str_, checker(s, {}));
      }
  #else
      detail::check_format_string<Args...>(s);
  #endif
    }
    basic_format_string(basic_runtime<Char> r) : str_(r.str) {}
  
    FMT_INLINE operator basic_string_view<Char>() const { return str_; }
  };
  
  #if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
  // Workaround broken conversion on older gcc.
  template <typename... Args> using format_string = string_view;
  template <typename S> auto runtime(const S& s) -> basic_string_view<char_t<S>> {
    return s;
  }
  #else
  template <typename... Args>
  using format_string = basic_format_string<char, type_identity_t<Args>...>;
  // Creates a runtime format string.
  template <typename S> auto runtime(const S& s) -> basic_runtime<char_t<S>> {
    return {{s}};
  }
  #endif
  
  FMT_API auto vformat(string_view fmt, format_args args) -> std::string;
  
  /**
    \rst
    Formats ``args`` according to specifications in ``fmt`` and returns the result
    as a string.
  
    **Example**::
  
      #include <fmt/core.h>
      std::string message = fmt::format("The answer is {}", 42);
    \endrst
  */
  template <typename... T>
  FMT_INLINE auto format(format_string<T...> fmt, T&&... args) -> std::string {
    return vformat(fmt, fmt::make_format_args(args...));
  }
  
  /** Formats a string and writes the output to ``out``. */
  template <typename OutputIt,
            FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
  auto vformat_to(OutputIt out, string_view fmt, format_args args) -> OutputIt {
    using detail::get_buffer;
    auto&& buf = get_buffer<char>(out);
    detail::vformat_to(buf, string_view(fmt), args, {});
    return detail::get_iterator(buf);
  }
  
  /**
   \rst
   Formats ``args`` according to specifications in ``fmt``, writes the result to
   the output iterator ``out`` and returns the iterator past the end of the output
   range.
  
   **Example**::
  
     auto out = std::vector<char>();
     fmt::format_to(std::back_inserter(out), "{}", 42);
   \endrst
   */
  template <typename OutputIt, typename... T,
            FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
  FMT_INLINE auto format_to(OutputIt out, format_string<T...> fmt, T&&... args)
      -> OutputIt {
    return vformat_to(out, fmt, fmt::make_format_args(args...));
  }
  
  template <typename OutputIt> struct format_to_n_result {
    /** Iterator past the end of the output range. */
    OutputIt out;
    /** Total (not truncated) output size. */
    size_t size;
  };
  
  template <typename OutputIt, typename... T,
            FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
  auto vformat_to_n(OutputIt out, size_t n, string_view fmt, format_args args)
      -> format_to_n_result<OutputIt> {
    using buffer =
        detail::iterator_buffer<OutputIt, char, detail::fixed_buffer_traits>;
    auto buf = buffer(out, n);
    detail::vformat_to(buf, fmt, args, {});
    return {buf.out(), buf.count()};
  }
  
  /**
    \rst
    Formats ``args`` according to specifications in ``fmt``, writes up to ``n``
    characters of the result to the output iterator ``out`` and returns the total
    (not truncated) output size and the iterator past the end of the output range.
    \endrst
   */
  template <typename OutputIt, typename... T,
            FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
  FMT_INLINE auto format_to_n(OutputIt out, size_t n, format_string<T...> fmt,
                              const T&... args) -> format_to_n_result<OutputIt> {
    return vformat_to_n(out, n, fmt, fmt::make_format_args(args...));
  }
  
  /** Returns the number of chars in the output of ``format(fmt, args...)``. */
  template <typename... T>
  FMT_INLINE auto formatted_size(format_string<T...> fmt, T&&... args) -> size_t {
    auto buf = detail::counting_buffer<>();
    detail::vformat_to(buf, string_view(fmt), fmt::make_format_args(args...), {});
    return buf.count();
  }
  
  FMT_API void vprint(string_view fmt, format_args args);
  FMT_API void vprint(std::FILE* f, string_view fmt, format_args args);
  
  /**
    \rst
    Formats ``args`` according to specifications in ``fmt`` and writes the output
    to ``stdout``.
  
    **Example**::
  
      fmt::print("Elapsed time: {0:.2f} seconds", 1.23);
    \endrst
   */
  template <typename... T>
  FMT_INLINE void print(format_string<T...> fmt, T&&... args) {
    const auto& vargs = fmt::make_format_args(args...);
    return detail::is_utf8() ? vprint(fmt, vargs)
                             : detail::vprint_mojibake(stdout, fmt, vargs);
  }
  
  /**
    \rst
    Formats ``args`` according to specifications in ``fmt`` and writes the
    output to the file ``f``.
  
    **Example**::
  
      fmt::print(stderr, "Don't {}!", "panic");
    \endrst
   */
  template <typename... T>
  FMT_INLINE void print(std::FILE* f, format_string<T...> fmt, T&&... args) {
    const auto& vargs = fmt::make_format_args(args...);
    return detail::is_utf8() ? vprint(f, fmt, vargs)
                             : detail::vprint_mojibake(f, fmt, vargs);
  }
  
  FMT_MODULE_EXPORT_END
  FMT_GCC_PRAGMA("GCC pop_options")
  FMT_END_NAMESPACE
  
  #ifdef FMT_HEADER_ONLY
  #  include "format.h"
  #endif
  #endif  // FMT_CORE_H_
  