| // -*- C++ -*- |
| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___FORMAT_FORMAT_CONTEXT_H |
| #define _LIBCPP___FORMAT_FORMAT_CONTEXT_H |
| |
| #include <__availability> |
| #include <__config> |
| #include <__format/format_args.h> |
| #include <__format/format_fwd.h> |
| #include <__iterator/concepts.h> |
| #include <concepts> |
| #include <iterator> |
| #include <string> |
| |
| #ifndef _LIBCPP_HAS_NO_LOCALIZATION |
| #include <locale> |
| #include <optional> |
| #endif |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| #pragma GCC system_header |
| #endif |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER > 17 |
| |
| // TODO FMT Remove this once we require compilers with proper C++20 support. |
| // If the compiler has no concepts support, the format header will be disabled. |
| // Without concepts support enable_if needs to be used and that too much effort |
| // to support compilers with partial C++20 support. |
| #if !defined(_LIBCPP_HAS_NO_CONCEPTS) |
| |
| template <class _OutIt, class _CharT> |
| requires output_iterator<_OutIt, const _CharT&> |
| class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_context; |
| |
| #ifndef _LIBCPP_HAS_NO_LOCALIZATION |
| /** |
| * Helper to create a basic_format_context. |
| * |
| * This is needed since the constructor is private. |
| */ |
| template <class _OutIt, class _CharT> |
| _LIBCPP_HIDE_FROM_ABI basic_format_context<_OutIt, _CharT> |
| __format_context_create( |
| _OutIt __out_it, |
| basic_format_args<basic_format_context<_OutIt, _CharT>> __args, |
| optional<_VSTD::locale>&& __loc = nullopt) { |
| return _VSTD::basic_format_context(_VSTD::move(__out_it), __args, |
| _VSTD::move(__loc)); |
| } |
| #else |
| template <class _OutIt, class _CharT> |
| _LIBCPP_HIDE_FROM_ABI basic_format_context<_OutIt, _CharT> |
| __format_context_create( |
| _OutIt __out_it, |
| basic_format_args<basic_format_context<_OutIt, _CharT>> __args) { |
| return _VSTD::basic_format_context(_VSTD::move(__out_it), __args); |
| } |
| #endif |
| |
| // TODO FMT Implement [format.context]/4 |
| // [Note 1: For a given type charT, implementations are encouraged to provide a |
| // single instantiation of basic_format_context for appending to |
| // basic_string<charT>, vector<charT>, or any other container with contiguous |
| // storage by wrapping those in temporary objects with a uniform interface |
| // (such as a span<charT>) and polymorphic reallocation. - end note] |
| |
| using format_context = basic_format_context<back_insert_iterator<string>, char>; |
| #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS |
| using wformat_context = basic_format_context<back_insert_iterator<wstring>, wchar_t>; |
| #endif |
| |
| template <class _OutIt, class _CharT> |
| requires output_iterator<_OutIt, const _CharT&> |
| class |
| // clang-format off |
| _LIBCPP_TEMPLATE_VIS |
| _LIBCPP_AVAILABILITY_FORMAT |
| _LIBCPP_PREFERRED_NAME(format_context) |
| _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wformat_context)) |
| // clang-format on |
| basic_format_context { |
| public: |
| using iterator = _OutIt; |
| using char_type = _CharT; |
| template <class _Tp> |
| using formatter_type = formatter<_Tp, _CharT>; |
| |
| basic_format_context(const basic_format_context&) = delete; |
| basic_format_context& operator=(const basic_format_context&) = delete; |
| |
| _LIBCPP_HIDE_FROM_ABI basic_format_arg<basic_format_context> |
| arg(size_t __id) const { |
| return __args_.get(__id); |
| } |
| #ifndef _LIBCPP_HAS_NO_LOCALIZATION |
| _LIBCPP_HIDE_FROM_ABI _VSTD::locale locale() { |
| if (!__loc_) |
| __loc_ = _VSTD::locale{}; |
| return *__loc_; |
| } |
| #endif |
| _LIBCPP_HIDE_FROM_ABI iterator out() { return __out_it_; } |
| _LIBCPP_HIDE_FROM_ABI void advance_to(iterator __it) { __out_it_ = __it; } |
| |
| private: |
| iterator __out_it_; |
| basic_format_args<basic_format_context> __args_; |
| #ifndef _LIBCPP_HAS_NO_LOCALIZATION |
| |
| // The Standard doesn't specify how the locale is stored. |
| // [format.context]/6 |
| // std::locale locale(); |
| // Returns: The locale passed to the formatting function if the latter |
| // takes one, and std::locale() otherwise. |
| // This is done by storing the locale of the constructor in this optional. If |
| // locale() is called and the optional has no value the value will be created. |
| // This allows the implementation to lazily create the locale. |
| // TODO FMT Validate whether lazy creation is the best solution. |
| optional<_VSTD::locale> __loc_; |
| |
| template <class __OutIt, class __CharT> |
| friend _LIBCPP_HIDE_FROM_ABI basic_format_context<__OutIt, __CharT> |
| _VSTD::__format_context_create( |
| __OutIt, basic_format_args<basic_format_context<__OutIt, __CharT>>, |
| optional<_VSTD::locale>&&); |
| |
| // Note: the Standard doesn't specify the required constructors. |
| _LIBCPP_HIDE_FROM_ABI |
| explicit basic_format_context(_OutIt __out_it, |
| basic_format_args<basic_format_context> __args, |
| optional<_VSTD::locale>&& __loc) |
| : __out_it_(_VSTD::move(__out_it)), __args_(__args), |
| __loc_(_VSTD::move(__loc)) {} |
| #else |
| template <class __OutIt, class __CharT> |
| friend _LIBCPP_HIDE_FROM_ABI basic_format_context<__OutIt, __CharT> |
| _VSTD::__format_context_create( |
| __OutIt, basic_format_args<basic_format_context<__OutIt, __CharT>>); |
| |
| _LIBCPP_HIDE_FROM_ABI |
| explicit basic_format_context(_OutIt __out_it, |
| basic_format_args<basic_format_context> __args) |
| : __out_it_(_VSTD::move(__out_it)), __args_(__args) {} |
| #endif |
| }; |
| |
| #endif // !defined(_LIBCPP_HAS_NO_CONCEPTS) |
| |
| #endif //_LIBCPP_STD_VER > 17 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP___FORMAT_FORMAT_CONTEXT_H |