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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 20:01:36 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 20:01:36 +0000 |
commit | 62e4c68907d8d33709c2c1f92a161dff00b3d5f2 (patch) | |
tree | adbbaf3acf88ea08f6eeec4b75ee98ad3b07fbdc /src/fmtlib/fmt/args.h | |
parent | Initial commit. (diff) | |
download | lnav-28bf0ff1a7ad38ac9ddb1f5864ba0161b0617471.tar.xz lnav-28bf0ff1a7ad38ac9ddb1f5864ba0161b0617471.zip |
Adding upstream version 0.11.2.upstream/0.11.2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/fmtlib/fmt/args.h')
-rw-r--r-- | src/fmtlib/fmt/args.h | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/src/fmtlib/fmt/args.h b/src/fmtlib/fmt/args.h new file mode 100644 index 0000000..a3966d1 --- /dev/null +++ b/src/fmtlib/fmt/args.h @@ -0,0 +1,234 @@ +// 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< + std::is_convertible<T, std::basic_string<char_type>>::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_ |