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

// Formatting library for C++ - dynamic format arguments

//

// Copyright (c) 2012 - present, Victor Zverovich

// All rights reserved.

//

// For the license information refer to format.h.

#ifndef FMT_ARGS_H_

#define FMT_ARGS_H_

#include <functional>  // std::reference_wrapper

#include <memory>      // std::unique_ptr

#include <vector>

#include "core.h"

FMT_BEGIN_NAMESPACE

namespace detail {

template <typename T> struct is_reference_wrapper : std::false_type {};

template <typename T>

struct is_reference_wrapper<std::reference_wrapper<T>> : std::true_type {};

template <typename T> const T& unwrap(const T& v) { return v; }

template <typename T> const T& unwrap(const std::reference_wrapper<T>& v) {

  return static_cast<const T&>(v);

}

class dynamic_arg_list {

  // Workaround for clang's -Wweak-vtables. Unlike for regular classes, for

  // templates it doesn't complain about inability to deduce single translation

  // unit for placing vtable. So storage_node_base is made a fake template.

  template <typename = void> struct node {

    virtual ~node() = default;

    std::unique_ptr<node<>> next;

  };

  template <typename T> struct typed_node : node<> {

    T value;

    template <typename Arg>

    FMT_CONSTEXPR typed_node(const Arg& arg) : value(arg) {}

    template <typename Char>

    FMT_CONSTEXPR typed_node(const basic_string_view<Char>& arg)

        : value(arg.data(), arg.size()) {}

  };

  std::unique_ptr<node<>> head_;

 public:

  template <typename T, typename Arg> const T& push(const Arg& arg) {

    auto new_node = std::unique_ptr<typed_node<T>>(new typed_node<T>(arg));

    auto& value = new_node->value;

    new_node->next = std::move(head_);

    head_ = std::move(new_node);

    return value;

  }

};

}  // namespace detail

/**

  \rst

  A dynamic version of `fmt::format_arg_store`.

  It's equipped with a storage to potentially temporary objects which lifetimes

  could be shorter than the format arguments object.

  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>

class dynamic_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:

  using char_type = typename Context::char_type;

  template <typename T> struct need_copy {

    static constexpr detail::type mapped_type =

        detail::mapped_type_constant<T, Context>::value;

    enum {

      value = !(detail::is_reference_wrapper<T>::value ||

                std::is_same<T, basic_string_view<char_type>>::value ||

                std::is_same<T, detail::std_string_view<char_type>>::value ||

                (mapped_type != detail::type::cstring_type &&

                 mapped_type != detail::type::string_type &&

                 mapped_type != detail::type::custom_type))

    };

  };

  template <typename T>

  using stored_type = conditional_t<detail::is_string<T>::value &&

                                        !has_formatter<T, Context>::value &&

                                        !detail::is_reference_wrapper<T>::value,

                                    std::basic_string<char_type>, T>;

  // Storage of basic_format_arg must be contiguous.

  std::vector<basic_format_arg<Context>> data_;

  std::vector<detail::named_arg_info<char_type>> named_info_;

  // Storage of arguments not fitting into basic_format_arg must grow

  // without relocation because items in data_ refer to it.

  detail::dynamic_arg_list dynamic_args_;

  friend class basic_format_args<Context>;

  unsigned long long get_types() const {

    return detail::is_unpacked_bit | data_.size() |

           (named_info_.empty()

                ? 0ULL

                : static_cast<unsigned long long>(detail::has_named_args_bit));

  }

  const basic_format_arg<Context>* data() const {

    return named_info_.empty() ? data_.data() : data_.data() + 1;

  }

  template <typename T> void emplace_arg(const T& arg) {

    data_.emplace_back(detail::make_arg<Context>(arg));

  }

  template <typename T>

  void emplace_arg(const detail::named_arg<char_type, T>& arg) {

    if (named_info_.empty()) {

      constexpr const detail::named_arg_info<char_type>* zero_ptr{nullptr};

      data_.insert(data_.begin(), {zero_ptr, 0});

    }

    data_.emplace_back(detail::make_arg<Context>(detail::unwrap(arg.value)));

    auto pop_one = [](std::vector<basic_format_arg<Context>>* data) {

      data->pop_back();

    };

    std::unique_ptr<std::vector<basic_format_arg<Context>>, decltype(pop_one)>

        guard{&data_, pop_one};

    named_info_.push_back({arg.name, static_cast<int>(data_.size() - 2u)});

    data_[0].value_.named_args = {named_info_.data(), named_info_.size()};

    guard.release();

  }

 public:

  constexpr dynamic_format_arg_store() = default;

  /**

    \rst

    Adds an argument into the dynamic store for later passing to a formatting

    function.

    Note that custom types and string types (but not string views) are copied

    into the store dynamically allocating memory if necessary.

    **Example**::

      fmt::dynamic_format_arg_store<fmt::format_context> store;

      store.push_back(42);

      store.push_back("abc");

      store.push_back(1.5f);

      std::string result = fmt::vformat("{} and {} and {}", store);

    \endrst

  */

  template <typename T> void push_back(const T& arg) {

    if (detail::const_check(need_copy<T>::value))

      emplace_arg(dynamic_args_.push<stored_type<T>>(arg));

    else

      emplace_arg(detail::unwrap(arg));

  }

  /**

    \rst

    Adds a reference to the argument into the dynamic store for later passing to

    a formatting function.

    **Example**::

      fmt::dynamic_format_arg_store<fmt::format_context> store;

      char band[] = "Rolling Stones";

      store.push_back(std::cref(band));

      band[9] = 'c'; // Changing str affects the output.

      std::string result = fmt::vformat("{}", store);

      // result == "Rolling Scones"

    \endrst

  */

  template <typename T> void push_back(std::reference_wrapper<T> arg) {

    static_assert(

        need_copy<T>::value,

        "objects of built-in types and string views are always copied");

    emplace_arg(arg.get());

  }

  /**

    Adds named argument into the dynamic store for later passing to a formatting

    function. ``std::reference_wrapper`` is supported to avoid copying of the

    argument. The name is always copied into the store.

  */

  template <typename T>

  void push_back(const detail::named_arg<char_type, T>& arg) {

    const char_type* arg_name =

        dynamic_args_.push<std::basic_string<char_type>>(arg.name).c_str();

    if (detail::const_check(need_copy<T>::value)) {

      emplace_arg(

          fmt::arg(arg_name, dynamic_args_.push<stored_type<T>>(arg.value)));

    } else {

      emplace_arg(fmt::arg(arg_name, arg.value));

    }

  }

  /** Erase all elements from the store */

  void clear() {

    data_.clear();

    named_info_.clear();

    dynamic_args_ = detail::dynamic_arg_list();

  }

  /**

    \rst

    Reserves space to store at least *new_cap* arguments including

    *new_cap_named* named arguments.

    \endrst

  */

  void reserve(size_t new_cap, size_t new_cap_named) {

    FMT_ASSERT(new_cap >= new_cap_named,

               "Set of arguments includes set of named arguments");

    data_.reserve(new_cap);

    named_info_.reserve(new_cap_named);

  }

};

FMT_END_NAMESPACE

#endif  // FMT_ARGS_H_