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1// -*- C++ -*-2//===----------------------------------------------------------------------===//3//4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.5// See https://llvm.org/LICENSE.txt for license information.6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___FORMAT_FORMATTER_TUPLE_H11#define _LIBCPP___FORMAT_FORMATTER_TUPLE_H12 13#include <__algorithm/ranges_copy.h>14#include <__chrono/statically_widen.h>15#include <__config>16#include <__format/buffer.h>17#include <__format/concepts.h>18#include <__format/format_context.h>19#include <__format/format_error.h>20#include <__format/format_parse_context.h>21#include <__format/formatter.h>22#include <__format/formatter_output.h>23#include <__format/parser_std_format_spec.h>24#include <__type_traits/remove_cvref.h>25#include <__utility/integer_sequence.h>26#include <__utility/pair.h>27#include <string_view>28#include <tuple>29 30#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)31# pragma GCC system_header32#endif33 34_LIBCPP_BEGIN_NAMESPACE_STD35 36#if _LIBCPP_STD_VER >= 2337 38template <__fmt_char_type _CharT, class _Tuple, formattable<_CharT>... _Args>39struct __formatter_tuple {40 _LIBCPP_HIDE_FROM_ABI constexpr void set_separator(basic_string_view<_CharT> __separator) noexcept {41 __separator_ = __separator;42 }43 _LIBCPP_HIDE_FROM_ABI constexpr void44 set_brackets(basic_string_view<_CharT> __opening_bracket, basic_string_view<_CharT> __closing_bracket) noexcept {45 __opening_bracket_ = __opening_bracket;46 __closing_bracket_ = __closing_bracket;47 }48 49 template <class _ParseContext>50 _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) {51 auto __begin = __parser_.__parse(__ctx, __format_spec::__fields_tuple);52 53 auto __end = __ctx.end();54 // Note 'n' is part of the type here55 if (__parser_.__clear_brackets_)56 set_brackets({}, {});57 else if (__begin != __end && *__begin == _CharT('m')) {58 if constexpr (sizeof...(_Args) == 2) {59 set_separator(_LIBCPP_STATICALLY_WIDEN(_CharT, ": "));60 set_brackets({}, {});61 ++__begin;62 } else63 std::__throw_format_error("Type m requires a pair or a tuple with two elements");64 }65 66 if (__begin != __end && *__begin != _CharT('}'))67 std::__throw_format_error("The format specifier should consume the input or end with a '}'");68 69 __ctx.advance_to(__begin);70 71 // [format.tuple]/772 // ... For each element e in underlying_, if e.set_debug_format()73 // is a valid expression, calls e.set_debug_format().74 std::__for_each_index_sequence(make_index_sequence<sizeof...(_Args)>(), [&]<size_t _Index> {75 auto& __formatter = std::get<_Index>(__underlying_);76 __formatter.parse(__ctx);77 // Unlike the range_formatter we don't guard against evil parsers. Since78 // this format-spec never has a format-spec for the underlying type79 // adding the test would give additional overhead.80 std::__set_debug_format(__formatter);81 });82 83 return __begin;84 }85 86 template <class _FormatContext>87 typename _FormatContext::iterator _LIBCPP_HIDE_FROM_ABI88 format(conditional_t<(formattable<const _Args, _CharT> && ...), const _Tuple&, _Tuple&> __tuple,89 _FormatContext& __ctx) const {90 __format_spec::__parsed_specifications<_CharT> __specs = __parser_.__get_parsed_std_specifications(__ctx);91 92 if (!__specs.__has_width())93 return __format_tuple(__tuple, __ctx);94 95 // The size of the buffer needed is:96 // - open bracket characters97 // - close bracket character98 // - n elements where every element may have a different size99 // - (n -1) separators100 // The size of the element is hard to predict, knowing the type helps but101 // it depends on the format-spec. As an initial estimate we guess 6102 // characters.103 // Typically both brackets are 1 character and the separator is 2104 // characters. Which means there will be105 // (n - 1) * 2 + 1 + 1 = n * 2 character106 // So estimate 8 times the range size as buffer.107 __format::__retarget_buffer<_CharT> __buffer{8 * tuple_size_v<_Tuple>};108 basic_format_context<typename __format::__retarget_buffer<_CharT>::__iterator, _CharT> __c{109 __buffer.__make_output_iterator(), __ctx};110 111 __format_tuple(__tuple, __c);112 113 return __formatter::__write_string_no_precision(basic_string_view{__buffer.__view()}, __ctx.out(), __specs);114 }115 116 template <class _FormatContext>117 _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator __format_tuple(auto&& __tuple, _FormatContext& __ctx) const {118 __ctx.advance_to(std::ranges::copy(__opening_bracket_, __ctx.out()).out);119 120 std::__for_each_index_sequence(make_index_sequence<sizeof...(_Args)>(), [&]<size_t _Index> {121 if constexpr (_Index)122 __ctx.advance_to(std::ranges::copy(__separator_, __ctx.out()).out);123 __ctx.advance_to(std::get<_Index>(__underlying_).format(std::get<_Index>(__tuple), __ctx));124 });125 126 return std::ranges::copy(__closing_bracket_, __ctx.out()).out;127 }128 129 __format_spec::__parser<_CharT> __parser_{.__alignment_ = __format_spec::__alignment::__left};130 131private:132 tuple<formatter<remove_cvref_t<_Args>, _CharT>...> __underlying_;133 basic_string_view<_CharT> __separator_ = _LIBCPP_STATICALLY_WIDEN(_CharT, ", ");134 basic_string_view<_CharT> __opening_bracket_ = _LIBCPP_STATICALLY_WIDEN(_CharT, "(");135 basic_string_view<_CharT> __closing_bracket_ = _LIBCPP_STATICALLY_WIDEN(_CharT, ")");136};137 138template <__fmt_char_type _CharT, formattable<_CharT>... _Args>139struct formatter<pair<_Args...>, _CharT> : public __formatter_tuple<_CharT, pair<_Args...>, _Args...> {};140 141template <__fmt_char_type _CharT, formattable<_CharT>... _Args>142struct formatter<tuple<_Args...>, _CharT> : public __formatter_tuple<_CharT, tuple<_Args...>, _Args...> {};143 144#endif // _LIBCPP_STD_VER >= 23145 146_LIBCPP_END_NAMESPACE_STD147 148#endif // _LIBCPP___FORMAT_FORMATTER_TUPLE_H149