text: // Formatting library for C++ - the core API
  //
  // 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 <string>
  #include <type_traits>
  
  // The fmt library version in the form major * 10000 + minor * 100 + patch.
  #define FMT_VERSION 70103
  
  #ifdef __clang__
  #  define FMT_CLANG_VERSION (__clang_major__ * 100 + __clang_minor__)
  #else
  #  define FMT_CLANG_VERSION 0
  #endif
  
  #if defined(__GNUC__) && !defined(__clang__)
  #  define FMT_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
  #else
  #  define FMT_GCC_VERSION 0
  #endif
  
  #if defined(__INTEL_COMPILER)
  #  define FMT_ICC_VERSION __INTEL_COMPILER
  #else
  #  define FMT_ICC_VERSION 0
  #endif
  
  #if __cplusplus >= 201103L || defined(__GXX_EXPERIMENTAL_CXX0X__)
  #  define FMT_HAS_GXX_CXX11 FMT_GCC_VERSION
  #else
  #  define FMT_HAS_GXX_CXX11 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_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
  
  #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_DEPRECATED
  #  if FMT_HAS_CPP14_ATTRIBUTE(deprecated) || FMT_MSC_VER >= 1900
  #    define FMT_DEPRECATED [[deprecated]]
  #  else
  #    if (defined(__GNUC__) && !defined(__LCC__)) || defined(__clang__)
  #      define FMT_DEPRECATED __attribute__((deprecated))
  #    elif FMT_MSC_VER
  #      define FMT_DEPRECATED __declspec(deprecated)
  #    else
  #      define FMT_DEPRECATED /* deprecated */
  #    endif
  #  endif
  #endif
  
  // Workaround broken [[deprecated]] in the Intel, PGI and NVCC compilers.
  #if FMT_ICC_VERSION || defined(__PGI) || FMT_NVCC
  #  define FMT_DEPRECATED_ALIAS
  #else
  #  define FMT_DEPRECATED_ALIAS FMT_DEPRECATED
  #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 v7;     \
        }                       \
        }
  #  endif
  #  define FMT_BEGIN_NAMESPACE \
      namespace axom {          \
      namespace fmt {           \
      FMT_INLINE_NAMESPACE v7 {
  #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)
  #    define FMT_EXTERN_TEMPLATE_API FMT_API
  #    define FMT_EXPORTED
  #  elif defined(FMT_SHARED)
  #    define FMT_API __declspec(dllimport)
  #    define FMT_EXTERN_TEMPLATE_API FMT_API
  #  endif
  #else
  #  define FMT_CLASS_API
  #endif
  #ifndef FMT_API
  #  define FMT_API
  #endif
  #ifndef FMT_EXTERN_TEMPLATE_API
  #  define FMT_EXTERN_TEMPLATE_API
  #endif
  #ifndef FMT_INSTANTIATION_DEF_API
  #  define FMT_INSTANTIATION_DEF_API FMT_API
  #endif
  
  #ifndef FMT_HEADER_ONLY
  #  define FMT_EXTERN extern
  #else
  #  define FMT_EXTERN
  #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_COMPILE_TIME_CHECKS
  #  define FMT_COMPILE_TIME_CHECKS 0
  #endif
  
  FMT_BEGIN_NAMESPACE
  
  // Implementations of enable_if_t and other metafunctions for older systems.
  template <bool B, class T = void>
  using enable_if_t = typename std::enable_if<B, T>::type;
  template <bool B, class T, class 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_const_t = typename std::remove_const<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 {};
  
  // 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
  
  namespace detail {
  
  constexpr bool is_constant_evaluated() FMT_NOEXCEPT {
  #ifdef __cpp_lib_is_constant_evaluated
    return std::is_constant_evaluated();
  #else
    return false;
  #endif
  }
  
  // A helper function to suppress "conditional expression is constant" warnings.
  template <typename T> constexpr T const_check(T value) { 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) ((void)0)
  #  else
  #    define FMT_ASSERT(condition, message)                                    \
        ((condition) /* void() fails with -Winvalid-constexpr on clang 4.0.1 */ \
             ? (void)0                                                          \
             : ::axom::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;
  #else
  #  define FMT_USE_INT128 0
  #endif
  #if !FMT_USE_INT128
  struct int128_t {};
  struct uint128_t {};
  #endif
  
  // Casts a nonnegative integer to unsigned.
  template <typename Int>
  FMT_CONSTEXPR typename std::make_unsigned<Int>::type to_unsigned(Int value) {
    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";
  
  template <typename Char> constexpr bool is_unicode() {
    return FMT_UNICODE || sizeof(Char) != 1 ||
           (sizeof(micro) == 3 && micro[0] == 0xC2 && micro[1] == 0xB5);
  }
  
  #ifdef __cpp_char8_t
  using char8_type = char8_t;
  #else
  enum char8_type : unsigned char {};
  #endif
  }  // namespace detail
  
  #ifdef FMT_USE_INTERNAL
  namespace internal = detail;  // DEPRECATED
  #endif
  
  /**
    An implementation of ``std::basic_string_view`` for pre-C++17. It provides a
    subset of the API. ``axom::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
     */
  #if __cplusplus >= 201703L  // C++17's char_traits::length() is constexpr.
    FMT_CONSTEXPR
  #endif
    basic_string_view(const Char* s)
        : data_(s), 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 const Char* data() const { return data_; }
  
    /** Returns the string size. */
    constexpr size_t size() const { return size_; }
  
    constexpr iterator begin() const { return data_; }
    constexpr iterator end() const { return data_ + size_; }
  
    constexpr const Char& operator[](size_t pos) const { return data_[pos]; }
  
    FMT_CONSTEXPR void remove_prefix(size_t n) {
      data_ += n;
      size_ -= n;
    }
  
    // Lexicographically compare this string reference to other.
    int compare(basic_string_view other) const {
      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;
    }
  
    friend bool operator==(basic_string_view lhs, basic_string_view rhs) {
      return lhs.compare(rhs) == 0;
    }
    friend bool operator!=(basic_string_view lhs, basic_string_view rhs) {
      return lhs.compare(rhs) != 0;
    }
    friend bool operator<(basic_string_view lhs, basic_string_view rhs) {
      return lhs.compare(rhs) < 0;
    }
    friend bool operator<=(basic_string_view lhs, basic_string_view rhs) {
      return lhs.compare(rhs) <= 0;
    }
    friend bool operator>(basic_string_view lhs, basic_string_view rhs) {
      return lhs.compare(rhs) > 0;
    }
    friend bool operator>=(basic_string_view lhs, basic_string_view rhs) {
      return lhs.compare(rhs) >= 0;
    }
  };
  
  using string_view = basic_string_view<char>;
  using wstring_view = basic_string_view<wchar_t>;
  
  /** 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 {};
  template <> struct is_char<wchar_t> : std::true_type {};
  template <> struct is_char<detail::char8_type> : std::true_type {};
  template <> struct is_char<char16_t> : std::true_type {};
  template <> struct is_char<char32_t> : std::true_type {};
  
  /**
    \rst
    Returns a string view of `s`. In order to add custom string type support to
    {fmt} provide an overload of `to_string_view` for it in the same namespace as
    the type for the argument-dependent lookup to work.
  
    **Example**::
  
      namespace my_ns {
      inline string_view to_string_view(const my_string& s) {
        return {s.data(), s.length()};
      }
      }
      std::string message = axom::fmt::format(my_string("The answer is {}"), 42);
    \endrst
   */
  template <typename Char, FMT_ENABLE_IF(is_char<Char>::value)>
  inline basic_string_view<Char> to_string_view(const Char* s) {
    return s;
  }
  
  template <typename Char, typename Traits, typename Alloc>
  inline basic_string_view<Char> to_string_view(
      const std::basic_string<Char, Traits, Alloc>& s) {
    return s;
  }
  
  template <typename Char>
  constexpr basic_string_view<Char> to_string_view(basic_string_view<Char> s) {
    return s;
  }
  
  template <typename Char,
            FMT_ENABLE_IF(!std::is_empty<detail::std_string_view<Char>>::value)>
  inline basic_string_view<Char> to_string_view(detail::std_string_view<Char> s) {
    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 basic_string_view<typename S::char_type> to_string_view(const S& s) {
    return s;
  }
  
  namespace detail {
  void to_string_view(...);
  using axom::fmt::v7::to_string_view;
  
  // Specifies whether S is a string type convertible to axom::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);
  };
  }  // namespace detail
  
  /** 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 one of the following type aliases for common character types:
  
    +-----------------------+-------------------------------------+
    | Type                  | Definition                          |
    +=======================+=====================================+
    | format_parse_context  | basic_format_parse_context<char>    |
    +-----------------------+-------------------------------------+
    | wformat_parse_context | basic_format_parse_context<wchar_t> |
    +-----------------------+-------------------------------------+
    \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 iterator begin() const FMT_NOEXCEPT { return format_str_.begin(); }
  
    /**
      Returns an iterator past the end of the format string range being parsed.
     */
    constexpr iterator end() const FMT_NOEXCEPT { 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 int next_arg_id() {
      // 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 ErrorHandler error_handler() const { return *this; }
  };
  
  using format_parse_context = basic_format_parse_context<char>;
  using wformat_parse_context = basic_format_parse_context<wchar_t>;
  
  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 {};
  
  namespace detail {
  
  // Extracts a reference to the container from back_insert_iterator.
  template <typename Container>
  inline Container& get_container(std::back_insert_iterator<Container> it) {
    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;
  }
  
  /**
    \rst
    A contiguous memory buffer with an optional growing ability. It is an internal
    class and shouldn't be used directly, only via `~axom::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;
  
    /** 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;
  
    T* begin() FMT_NOEXCEPT { return ptr_; }
    T* end() FMT_NOEXCEPT { return ptr_ + size_; }
  
    const T* begin() const FMT_NOEXCEPT { return ptr_; }
    const T* end() const FMT_NOEXCEPT { return ptr_ + size_; }
  
    /** Returns the size of this buffer. */
    size_t size() const FMT_NOEXCEPT { return size_; }
  
    /** Returns the capacity of this buffer. */
    size_t capacity() const FMT_NOEXCEPT { return capacity_; }
  
    /** Returns a pointer to the buffer data. */
    T* data() FMT_NOEXCEPT { return ptr_; }
  
    /** Returns a pointer to the buffer data. */
    const T* data() const FMT_NOEXCEPT { 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> T& operator[](I index) { return ptr_[index]; }
    template <typename I> const T& operator[](I index) const {
      return ptr_[index];
    }
  };
  
  struct buffer_traits {
    explicit buffer_traits(size_t) {}
    size_t count() const { return 0; }
    size_t limit(size_t size) { return size; }
  };
  
  class fixed_buffer_traits {
   private:
    size_t count_ = 0;
    size_t limit_;
  
   public:
    explicit fixed_buffer_traits(size_t limit) : limit_(limit) {}
    size_t count() const { return count_; }
    size_t limit(size_t size) {
      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();
  
   public:
    explicit iterator_buffer(OutputIt out, size_t n = buffer_size)
        : Traits(n), buffer<T>(data_, 0, buffer_size), out_(out) {}
    ~iterator_buffer() { flush(); }
  
    OutputIt out() {
      flush();
      return out_;
    }
    size_t count() const { 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()) {}
  
    T* out() { 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)) {}
    std::back_insert_iterator<Container> out() {
      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) {}
  
    size_t count() { return count_ + this->size(); }
  };
  
  // An output iterator that appends to the buffer.
  // It is used to reduce symbol sizes for the common case.
  template <typename T>
  class buffer_appender : public std::back_insert_iterator<buffer<T>> {
    using base = std::back_insert_iterator<buffer<T>>;
  
   public:
    explicit buffer_appender(buffer<T>& buf) : base(buf) {}
    buffer_appender(base it) : base(it) {}
  
    buffer_appender& operator++() {
      base::operator++();
      return *this;
    }
  
    buffer_appender operator++(int) {
      buffer_appender tmp = *this;
      ++*this;
      return tmp;
    }
  };
  
  // Maps an output iterator into a buffer.
  template <typename T, typename OutputIt>
  iterator_buffer<OutputIt, T> get_buffer(OutputIt);
  template <typename T> buffer<T>& get_buffer(buffer_appender<T>);
  
  template <typename OutputIt> OutputIt get_buffer_init(OutputIt out) {
    return out;
  }
  template <typename T> buffer<T>& get_buffer_init(buffer_appender<T> out) {
    return get_container(out);
  }
  
  template <typename Buffer>
  auto get_iterator(Buffer& buf) -> decltype(buf.out()) {
    return buf.out();
  }
  template <typename T> buffer_appender<T> get_iterator(buffer<T>& buf) {
    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 Context>
  using has_fallback_formatter =
      std::is_constructible<fallback_formatter<T, typename Context::char_type>>;
  
  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;
    const T* args() const { return args_ + 1; }
    named_arg_info<Char>* named_args() { 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 const T* args() const { return args_; }
    FMT_CONSTEXPR FMT_INLINE std::nullptr_t named_args() { return nullptr; }
  };
  
  template <typename Char>
  inline void init_named_args(named_arg_info<Char>*, int, int) {}
  
  template <typename Char, typename T, typename... Tail>
  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>
  void init_named_args(named_arg_info<Char>* named_args, int arg_count,
                       int named_arg_count, const named_arg<Char, 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 <typename T> struct is_named_arg : std::false_type {};
  
  template <typename T, typename Char>
  struct is_named_arg<named_arg<Char, T>> : std::true_type {};
  
  template <bool B = false> constexpr size_t count() { return B ? 1 : 0; }
  template <bool B1, bool B2, bool... Tail> constexpr size_t count() {
    return (B1 ? 1 : 0) + count<B2, Tail...>();
  }
  
  template <typename... Args> constexpr size_t count_named_args() {
    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 {
      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(int val = 0) : 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_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 basic_format_arg<Context> make_arg(const T& value);
  
  // 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 int map(signed char val) { return val; }
    FMT_CONSTEXPR unsigned map(unsigned char val) { return val; }
    FMT_CONSTEXPR int map(short val) { return val; }
    FMT_CONSTEXPR unsigned map(unsigned short val) { return val; }
    FMT_CONSTEXPR int map(int val) { return val; }
    FMT_CONSTEXPR unsigned map(unsigned val) { return val; }
    FMT_CONSTEXPR long_type map(long val) { return val; }
    FMT_CONSTEXPR ulong_type map(unsigned long val) { return val; }
    FMT_CONSTEXPR long long map(long long val) { return val; }
    FMT_CONSTEXPR unsigned long long map(unsigned long long val) { return val; }
    FMT_CONSTEXPR int128_t map(int128_t val) { return val; }
    FMT_CONSTEXPR uint128_t map(uint128_t val) { return val; }
    FMT_CONSTEXPR bool map(bool val) { return val; }
  
    template <typename T, FMT_ENABLE_IF(is_char<T>::value)>
    FMT_CONSTEXPR char_type map(T val) {
      static_assert(
          std::is_same<T, char>::value || std::is_same<T, char_type>::value,
          "mixing character types is disallowed");
      return val;
    }
  
    FMT_CONSTEXPR float map(float val) { return val; }
    FMT_CONSTEXPR double map(double val) { return val; }
    FMT_CONSTEXPR long double map(long double val) { return val; }
  
    FMT_CONSTEXPR const char_type* map(char_type* val) { return val; }
    FMT_CONSTEXPR const char_type* map(const char_type* val) { return val; }
    template <typename T, FMT_ENABLE_IF(is_string<T>::value)>
    FMT_CONSTEXPR basic_string_view<char_type> map(const T& val) {
      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, Context>::value)>
    FMT_CONSTEXPR basic_string_view<char_type> map(const T& val) {
      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, Context>::value)>
    FMT_CONSTEXPR basic_string_view<char_type> map(const T& val) {
      return std_string_view<char_type>(val);
    }
    FMT_CONSTEXPR const char* map(const signed char* val) {
      static_assert(std::is_same<char_type, char>::value, "invalid string type");
      return reinterpret_cast<const char*>(val);
    }
    FMT_CONSTEXPR const char* map(const unsigned char* val) {
      static_assert(std::is_same<char_type, char>::value, "invalid string type");
      return reinterpret_cast<const char*>(val);
    }
    FMT_CONSTEXPR const char* map(signed char* val) {
      const auto* const_val = val;
      return map(const_val);
    }
    FMT_CONSTEXPR const char* map(unsigned char* val) {
      const auto* const_val = val;
      return map(const_val);
    }
  
    FMT_CONSTEXPR const void* map(void* val) { return val; }
    FMT_CONSTEXPR const void* map(const void* val) { return val; }
    FMT_CONSTEXPR const void* map(std::nullptr_t val) { 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 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, Context>::value)>
    FMT_CONSTEXPR 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, Context>::value))>
    FMT_CONSTEXPR const T& map(const T& val) {
      return val;
    }
  
    template <typename T>
    FMT_CONSTEXPR auto map(const named_arg<char_type, T>& val)
        -> decltype(std::declval<arg_mapper>().map(val.value)) {
      return map(val.value);
    }
  
    unformattable map(...) { 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 };
  }  // namespace detail
  
  // 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 basic_format_arg<ContextType> detail::make_arg(
        const T& value);
  
    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;
    }
  
    detail::type type() const { return type_; }
  
    bool is_integral() const { return detail::is_integral_type(type_); }
    bool is_arithmetic() const { 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_DECL FMT_INLINE auto visit_format_arg(
      Visitor&& vis, const basic_format_arg<Context>& arg) -> decltype(vis(0)) {
    using char_type = typename Context::char_type;
    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);
  #if FMT_USE_INT128
    case detail::type::int128_type:
      return vis(arg.value_.int128_value);
    case detail::type::uint128_type:
      return vis(arg.value_.uint128_value);
  #else
    case detail::type::int128_type:
    case detail::type::uint128_type:
      break;
  #endif
    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:
      return vis(basic_string_view<char_type>(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());
  }
  
  template <typename T> struct formattable : std::false_type {};
  
  namespace detail {
  
  #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 <typename Char>
  struct is_contiguous_back_insert_iterator<buffer_appender<Char>>
      : 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> Locale get() const;
  };
  
  template <typename> constexpr unsigned long long encode_types() { return 0; }
  
  template <typename Context, typename Arg, typename... Args>
  constexpr unsigned long long encode_types() {
    return static_cast<unsigned>(mapped_type_constant<Arg, Context>::value) |
           (encode_types<Context, Args...>() << packed_arg_bits);
  }
  
  template <typename Context, typename T>
  FMT_CONSTEXPR basic_format_arg<Context> make_arg(const T& value) {
    basic_format_arg<Context> arg;
    arg.type_ = mapped_type_constant<T, Context>::value;
    arg.value_ = arg_mapper<Context>().map(value);
    return arg;
  }
  
  template <typename T> int check(unformattable) {
    static_assert(
        formattable<T>(),
        "Cannot format an argument. To make type T formattable provide a "
        "formatter<T> specialization: https://fmt.dev/latest/api.html#udt");
    return 0;
  }
  template <typename T, typename U> constexpr const U& check(const U& val) {
    return val;
  }
  
  // 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)>
  constexpr value<Context> make_arg(const T& val) {
    return detail::check<T>(arg_mapper<Context>().map(val));
  }
  
  template <bool IS_PACKED, typename Context, type, typename T,
            FMT_ENABLE_IF(!IS_PACKED)>
  inline basic_format_arg<Context> make_arg(const T& value) {
    return make_arg<Context>(value);
  }
  }  // namespace detail
  
  // 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(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 format_arg arg(int id) const { return args_.get(id); }
    FMT_CONSTEXPR format_arg arg(basic_string_view<char_type> name) {
      return args_.get(name);
    }
    int arg_id(basic_string_view<char_type> name) { return args_.get_id(name); }
    const basic_format_args<basic_format_context>& args() const { return args_; }
  
    FMT_CONSTEXPR detail::error_handler 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 iterator out() { return out_; }
  
    // Advances the begin iterator to ``it``.
    void advance_to(iterator it) {
      if (!detail::is_back_insert_iterator<iterator>()) out_ = it;
    }
  
    FMT_CONSTEXPR detail::locale_ref locale() { return loc_; }
  };
  
  template <typename Char>
  using buffer_context =
      basic_format_context<detail::buffer_appender<Char>, Char>;
  using format_context = buffer_context<char>;
  using wformat_context = buffer_context<wchar_t>;
  
  // 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>;
  
  /**
    \rst
    An array of references to arguments. It can be implicitly converted into
    `~axom::fmt::basic_format_args` for passing into type-erased formatting functions
    such as `~axom::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 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 `~axom::fmt::format_arg_store` object that contains references to
    arguments and can be implicitly converted to `~axom::fmt::format_args`. `Context`
    can be omitted in which case it defaults to `~axom::fmt::context`.
    See `~axom::fmt::arg` for lifetime considerations.
    \endrst
   */
  template <typename Context = format_context, typename... Args>
  constexpr format_arg_store<Context, Args...> make_format_args(
      const Args&... args) {
    return {args...};
  }
  
  /**
    \rst
    Constructs a `~axom::fmt::format_arg_store` object that contains references
    to arguments and can be implicitly converted to `~axom::fmt::format_args`.
    If ``format_str`` is a compile-time string then `make_args_checked` checks
    its validity at compile time.
    \endrst
   */
  template <typename... Args, typename S, typename Char = char_t<S>>
  inline auto make_args_checked(const S& format_str,
                                const remove_reference_t<Args>&... args)
      -> format_arg_store<buffer_context<Char>, remove_reference_t<Args>...> {
    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");
    detail::check_format_string<Args...>(format_str);
    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**::
  
      axom::fmt::print("Elapsed time: {s:.2f} seconds", axom::fmt::arg("s", 1.23));
    \endrst
   */
  template <typename Char, typename T>
  inline detail::named_arg<Char, T> arg(const Char* name, const T& arg) {
    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 bool is_packed() const {
      return (desc_ & detail::is_unpacked_bit) == 0;
    }
    bool has_named_args() const {
      return (desc_ & detail::has_named_args_bit) != 0;
    }
  
    FMT_CONSTEXPR detail::type type(int index) const {
      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 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 `~axom::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
     `~axom::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 format_arg get(int id) const {
      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> format_arg get(basic_string_view<Char> name) const {
      int id = get_id(name);
      return id >= 0 ? get(id) : format_arg();
    }
  
    template <typename Char> int get_id(basic_string_view<Char> name) const {
      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;
    }
  
    int max_size() const {
      unsigned long long max_packed = detail::max_packed_args;
      return static_cast<int>(is_packed() ? max_packed
                                          : desc_ & ~detail::is_unpacked_bit);
    }
  };
  
  #ifdef FMT_ARM_ABI_COMPATIBILITY
  /** An alias to ``basic_format_args<format_context>``. */
  // Separate types would result in shorter symbols but break ABI compatibility
  // between clang and gcc on ARM (#1919).
  using format_args = basic_format_args<format_context>;
  using wformat_args = basic_format_args<wformat_context>;
  #else
  // DEPRECATED! These are kept for ABI compatibility.
  // It is a separate type rather than an alias to make symbols readable.
  struct format_args : basic_format_args<format_context> {
    template <typename... Args>
    FMT_INLINE format_args(const Args&... args) : basic_format_args(args...) {}
  };
  struct wformat_args : basic_format_args<wformat_context> {
    using basic_format_args::basic_format_args;
  };
  #endif
  
  namespace detail {
  
  template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
  std::basic_string<Char> vformat(
      basic_string_view<Char> format_str,
      basic_format_args<buffer_context<type_identity_t<Char>>> args);
  
  FMT_API std::string vformat(string_view format_str, format_args args);
  
  template <typename Char>
  void vformat_to(
      buffer<Char>& buf, basic_string_view<Char> format_str,
      basic_format_args<FMT_BUFFER_CONTEXT(type_identity_t<Char>)> args,
      detail::locale_ref loc = {});
  
  template <typename Char, typename Args,
            FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
  inline void vprint_mojibake(std::FILE*, basic_string_view<Char>, const Args&) {}
  
  FMT_API void vprint_mojibake(std::FILE*, string_view, format_args);
  #ifndef _WIN32
  inline void vprint_mojibake(std::FILE*, string_view, format_args) {}
  #endif
  }  // namespace detail
  
  /** Formats a string and writes the output to ``out``. */
  // GCC 8 and earlier cannot handle std::back_insert_iterator<Container> with
  // vformat_to<ArgFormatter>(...) overload, so SFINAE on iterator type instead.
  template <typename OutputIt, typename S, typename Char = char_t<S>,
            bool enable = detail::is_output_iterator<OutputIt, Char>::value>
  auto vformat_to(OutputIt out, const S& format_str,
                  basic_format_args<buffer_context<type_identity_t<Char>>> args)
      -> typename std::enable_if<enable, OutputIt>::type {
    decltype(detail::get_buffer<Char>(out)) buf(detail::get_buffer_init(out));
    detail::vformat_to(buf, to_string_view(format_str), args);
    return detail::get_iterator(buf);
  }
  
  /**
   \rst
   Formats arguments, writes the result to the output iterator ``out`` and returns
   the iterator past the end of the output range.
  
   **Example**::
  
     std::vector<char> out;
     axom::fmt::format_to(std::back_inserter(out), "{}", 42);
   \endrst
   */
  // We cannot use FMT_ENABLE_IF because of a bug in gcc 8.3.
  template <typename OutputIt, typename S, typename... Args,
            bool enable = detail::is_output_iterator<OutputIt, char_t<S>>::value>
  inline auto format_to(OutputIt out, const S& format_str, Args&&... args) ->
      typename std::enable_if<enable, OutputIt>::type {
    const auto& vargs = axom::fmt::make_args_checked<Args...>(format_str, args...);
    return vformat_to(out, to_string_view(format_str), vargs);
  }
  
  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 Char, typename... Args,
            FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value)>
  inline format_to_n_result<OutputIt> vformat_to_n(
      OutputIt out, size_t n, basic_string_view<Char> format_str,
      basic_format_args<buffer_context<type_identity_t<Char>>> args) {
    detail::iterator_buffer<OutputIt, Char, detail::fixed_buffer_traits> buf(out,
                                                                             n);
    detail::vformat_to(buf, format_str, args);
    return {buf.out(), buf.count()};
  }
  
  /**
   \rst
   Formats arguments, writes up to ``n`` characters of the result to the output
   iterator ``out`` and returns the total output size and the iterator past the
   end of the output range.
   \endrst
   */
  template <typename OutputIt, typename S, typename... Args,
            bool enable = detail::is_output_iterator<OutputIt, char_t<S>>::value>
  inline auto format_to_n(OutputIt out, size_t n, const S& format_str,
                          const Args&... args) ->
      typename std::enable_if<enable, format_to_n_result<OutputIt>>::type {
    const auto& vargs = axom::fmt::make_args_checked<Args...>(format_str, args...);
    return vformat_to_n(out, n, to_string_view(format_str), vargs);
  }
  
  /**
    Returns the number of characters in the output of
    ``format(format_str, args...)``.
   */
  template <typename S, typename... Args, typename Char = char_t<S>>
  inline size_t formatted_size(const S& format_str, Args&&... args) {
    const auto& vargs = axom::fmt::make_args_checked<Args...>(format_str, args...);
    detail::counting_buffer<> buf;
    detail::vformat_to(buf, to_string_view(format_str), vargs);
    return buf.count();
  }
  
  template <typename S, typename Char = char_t<S>>
  FMT_INLINE std::basic_string<Char> vformat(
      const S& format_str,
      basic_format_args<buffer_context<type_identity_t<Char>>> args) {
    return detail::vformat(to_string_view(format_str), args);
  }
  
  /**
    \rst
    Formats arguments and returns the result as a string.
  
    **Example**::
  
      #include <fmt/core.h>
      std::string message = axom::fmt::format("The answer is {}", 42);
    \endrst
  */
  // Pass char_t as a default template parameter instead of using
  // std::basic_string<char_t<S>> to reduce the symbol size.
  template <typename S, typename... Args, typename Char = char_t<S>,
            FMT_ENABLE_IF(!FMT_COMPILE_TIME_CHECKS ||
                          !std::is_same<Char, char>::value)>
  FMT_INLINE std::basic_string<Char> format(const S& format_str, Args&&... args) {
    const auto& vargs = axom::fmt::make_args_checked<Args...>(format_str, args...);
    return detail::vformat(to_string_view(format_str), vargs);
  }
  
  FMT_API void vprint(string_view, format_args);
  FMT_API void vprint(std::FILE*, string_view, format_args);
  
  /**
    \rst
    Formats ``args`` according to specifications in ``format_str`` and writes the
    output to the file ``f``. Strings are assumed to be Unicode-encoded unless the
    ``FMT_UNICODE`` macro is set to 0.
  
    **Example**::
  
      axom::fmt::print(stderr, "Don't {}!", "panic");
    \endrst
   */
  template <typename S, typename... Args, typename Char = char_t<S>>
  inline void print(std::FILE* f, const S& format_str, Args&&... args) {
    const auto& vargs = axom::fmt::make_args_checked<Args...>(format_str, args...);
    return detail::is_unicode<Char>()
               ? vprint(f, to_string_view(format_str), vargs)
               : detail::vprint_mojibake(f, to_string_view(format_str), vargs);
  }
  
  /**
    \rst
    Formats ``args`` according to specifications in ``format_str`` and writes
    the output to ``stdout``. Strings are assumed to be Unicode-encoded unless
    the ``FMT_UNICODE`` macro is set to 0.
  
    **Example**::
  
      axom::fmt::print("Elapsed time: {0:.2f} seconds", 1.23);
    \endrst
   */
  template <typename S, typename... Args, typename Char = char_t<S>>
  inline void print(const S& format_str, Args&&... args) {
    const auto& vargs = axom::fmt::make_args_checked<Args...>(format_str, args...);
    return detail::is_unicode<Char>()
               ? vprint(to_string_view(format_str), vargs)
               : detail::vprint_mojibake(stdout, to_string_view(format_str),
                                         vargs);
  }
  FMT_END_NAMESPACE
  
  #endif  // FMT_CORE_H_
  
  // Define FMT_DYNAMIC_ARGS to make core.h provide dynamic_format_arg_store
  // DEPRECATED! Include fmt/args.h directly instead.
  #ifdef FMT_DYNAMIC_ARGS
  #include "args.h"
  #endif
  