--- /dev/null
+// 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_
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