v1/__format/range_default_formatter.h

0001 // -*- C++ -*-
0002 //===----------------------------------------------------------------------===//
0003 //
0004 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0005 // See https://llvm.org/LICENSE.txt for license information.
0006 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0007 //
0008 //===----------------------------------------------------------------------===//
0009
0010 #ifndef _LIBCPP___FORMAT_RANGE_DEFAULT_FORMATTER_H
0011 #define _LIBCPP___FORMAT_RANGE_DEFAULT_FORMATTER_H
0012
0013 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0014 #  pragma GCC system_header
0015 #endif
0016
0017 #include <__algorithm/ranges_copy.h>
0018 #include <__chrono/statically_widen.h>
0019 #include <__concepts/same_as.h>
0020 #include <__config>
0021 #include <__format/concepts.h>
0022 #include <__format/formatter.h>
0023 #include <__format/range_formatter.h>
0024 #include <__iterator/back_insert_iterator.h>
0025 #include <__ranges/concepts.h>
0026 #include <__ranges/data.h>
0027 #include <__ranges/from_range.h>
0028 #include <__ranges/size.h>
0029 #include <__type_traits/conditional.h>
0030 #include <__type_traits/remove_cvref.h>
0031 #include <__utility/pair.h>
0032 #include <string_view>
0033
0034 _LIBCPP_BEGIN_NAMESPACE_STD
0035
0036 #if _LIBCPP_STD_VER >= 23
0037
0038 template <class _Rp, class _CharT>
0039 concept __const_formattable_range =
0040     ranges::input_range<const _Rp> && formattable<ranges::range_reference_t<const _Rp>, _CharT>;
0041
0042 template <class _Rp, class _CharT>
0043 using __fmt_maybe_const _LIBCPP_NODEBUG = conditional_t<__const_formattable_range<_Rp, _CharT>, const _Rp, _Rp>;
0044
0045 _LIBCPP_DIAGNOSTIC_PUSH
0046 _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wshadow")
0047 _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wshadow")
0048 // This shadows map, set, and string.
0049 enum class range_format { disabled, map, set, sequence, string, debug_string };
0050 _LIBCPP_DIAGNOSTIC_POP
0051
0052 // There is no definition of this struct, it's purely intended to be used to
0053 // generate diagnostics.
0054 template <class _Rp>
0055 struct _LIBCPP_TEMPLATE_VIS __instantiated_the_primary_template_of_format_kind;
0056
0057 template <class _Rp>
0058 constexpr range_format format_kind = [] {
0059   // [format.range.fmtkind]/1
0060   // A program that instantiates the primary template of format_kind is ill-formed.
0061   static_assert(sizeof(_Rp) != sizeof(_Rp), "create a template specialization of format_kind for your type");
0062   return range_format::disabled;
0063 }();
0064
0065 template <ranges::input_range _Rp>
0066   requires same_as<_Rp, remove_cvref_t<_Rp>>
0067 inline constexpr range_format format_kind<_Rp> = [] {
0068   // [format.range.fmtkind]/2
0069
0070   // 2.1 If same_as<remove_cvref_t<ranges::range_reference_t<R>>, R> is true,
0071   // Otherwise format_kind<R> is range_format::disabled.
0072   if constexpr (same_as<remove_cvref_t<ranges::range_reference_t<_Rp>>, _Rp>)
0073     return range_format::disabled;
0074   // 2.2 Otherwise, if the qualified-id R::key_type is valid and denotes a type:
0075   else if constexpr (requires { typename _Rp::key_type; }) {
0076     // 2.2.1 If the qualified-id R::mapped_type is valid and denotes a type ...
0077     if constexpr (requires { typename _Rp::mapped_type; } &&
0078                   // 2.2.1 ... If either U is a specialization of pair or U is a specialization
0079                   // of tuple and tuple_size_v<U> == 2
0080                   __fmt_pair_like<remove_cvref_t<ranges::range_reference_t<_Rp>>>)
0081       return range_format::map;
0082     else
0083       // 2.2.2 Otherwise format_kind<R> is range_format::set.
0084       return range_format::set;
0085   } else
0086     // 2.3 Otherwise, format_kind<R> is range_format::sequence.
0087     return range_format::sequence;
0088 }();
0089
0090 template <range_format _Kp, ranges::input_range _Rp, class _CharT>
0091 struct _LIBCPP_TEMPLATE_VIS __range_default_formatter;
0092
0093 // Required specializations
0094
0095 template <ranges::input_range _Rp, class _CharT>
0096 struct _LIBCPP_TEMPLATE_VIS __range_default_formatter<range_format::sequence, _Rp, _CharT> {
0097 private:
0098   using __maybe_const_r _LIBCPP_NODEBUG = __fmt_maybe_const<_Rp, _CharT>;
0099   range_formatter<remove_cvref_t<ranges::range_reference_t<__maybe_const_r>>, _CharT> __underlying_;
0100
0101 public:
0102   _LIBCPP_HIDE_FROM_ABI constexpr void set_separator(basic_string_view<_CharT> __separator) noexcept {
0103     __underlying_.set_separator(__separator);
0104   }
0105   _LIBCPP_HIDE_FROM_ABI constexpr void
0106   set_brackets(basic_string_view<_CharT> __opening_bracket, basic_string_view<_CharT> __closing_bracket) noexcept {
0107     __underlying_.set_brackets(__opening_bracket, __closing_bracket);
0108   }
0109
0110   template <class _ParseContext>
0111   _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) {
0112     return __underlying_.parse(__ctx);
0113   }
0114
0115   template <class _FormatContext>
0116   _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
0117   format(__maybe_const_r& __range, _FormatContext& __ctx) const {
0118     return __underlying_.format(__range, __ctx);
0119   }
0120 };
0121
0122 template <ranges::input_range _Rp, class _CharT>
0123 struct _LIBCPP_TEMPLATE_VIS __range_default_formatter<range_format::map, _Rp, _CharT> {
0124 private:
0125   using __maybe_const_map _LIBCPP_NODEBUG = __fmt_maybe_const<_Rp, _CharT>;
0126   using __element_type _LIBCPP_NODEBUG    = remove_cvref_t<ranges::range_reference_t<__maybe_const_map>>;
0127   range_formatter<__element_type, _CharT> __underlying_;
0128
0129 public:
0130   _LIBCPP_HIDE_FROM_ABI constexpr __range_default_formatter()
0131     requires(__fmt_pair_like<__element_type>)
0132   {
0133     __underlying_.set_brackets(_LIBCPP_STATICALLY_WIDEN(_CharT, "{"), _LIBCPP_STATICALLY_WIDEN(_CharT, "}"));
0134     __underlying_.underlying().set_brackets({}, {});
0135     __underlying_.underlying().set_separator(_LIBCPP_STATICALLY_WIDEN(_CharT, ": "));
0136   }
0137
0138   template <class _ParseContext>
0139   _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) {
0140     return __underlying_.parse(__ctx);
0141   }
0142
0143   template <class _FormatContext>
0144   _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
0145   format(__maybe_const_map& __range, _FormatContext& __ctx) const {
0146     return __underlying_.format(__range, __ctx);
0147   }
0148 };
0149
0150 template <ranges::input_range _Rp, class _CharT>
0151 struct _LIBCPP_TEMPLATE_VIS __range_default_formatter<range_format::set, _Rp, _CharT> {
0152 private:
0153   using __maybe_const_set _LIBCPP_NODEBUG = __fmt_maybe_const<_Rp, _CharT>;
0154   using __element_type _LIBCPP_NODEBUG    = remove_cvref_t<ranges::range_reference_t<__maybe_const_set>>;
0155   range_formatter<__element_type, _CharT> __underlying_;
0156
0157 public:
0158   _LIBCPP_HIDE_FROM_ABI constexpr __range_default_formatter() {
0159     __underlying_.set_brackets(_LIBCPP_STATICALLY_WIDEN(_CharT, "{"), _LIBCPP_STATICALLY_WIDEN(_CharT, "}"));
0160   }
0161
0162   template <class _ParseContext>
0163   _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) {
0164     return __underlying_.parse(__ctx);
0165   }
0166
0167   template <class _FormatContext>
0168   _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
0169   format(__maybe_const_set& __range, _FormatContext& __ctx) const {
0170     return __underlying_.format(__range, __ctx);
0171   }
0172 };
0173
0174 template <range_format _Kp, ranges::input_range _Rp, class _CharT>
0175   requires(_Kp == range_format::string || _Kp == range_format::debug_string)
0176 struct _LIBCPP_TEMPLATE_VIS __range_default_formatter<_Kp, _Rp, _CharT> {
0177 private:
0178   // This deviates from the Standard, there the exposition only type is
0179   //   formatter<basic_string<charT>, charT> underlying_;
0180   // Using a string_view allows the format function to avoid a copy of the
0181   // input range when it is a contigious range.
0182   formatter<basic_string_view<_CharT>, _CharT> __underlying_;
0183
0184 public:
0185   template <class _ParseContext>
0186   _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) {
0187     typename _ParseContext::iterator __i = __underlying_.parse(__ctx);
0188     if constexpr (_Kp == range_format::debug_string)
0189       __underlying_.set_debug_format();
0190     return __i;
0191   }
0192
0193   template <class _FormatContext>
0194   _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
0195   format(conditional_t<ranges::input_range<const _Rp>, const _Rp&, _Rp&> __range, _FormatContext& __ctx) const {
0196     // When the range is contiguous use a basic_string_view instead to avoid a
0197     // copy of the underlying data. The basic_string_view formatter
0198     // specialization is the "basic" string formatter in libc++.
0199     if constexpr (ranges::contiguous_range<_Rp> && std::ranges::sized_range<_Rp>)
0200       return __underlying_.format(basic_string_view<_CharT>{ranges::data(__range), ranges::size(__range)}, __ctx);
0201     else
0202       return __underlying_.format(basic_string<_CharT>{from_range, __range}, __ctx);
0203   }
0204 };
0205
0206 template <ranges::input_range _Rp, class _CharT>
0207   requires(format_kind<_Rp> != range_format::disabled && formattable<ranges::range_reference_t<_Rp>, _CharT>)
0208 struct _LIBCPP_TEMPLATE_VIS formatter<_Rp, _CharT> : __range_default_formatter<format_kind<_Rp>, _Rp, _CharT> {};
0209
0210 #endif // _LIBCPP_STD_VER >= 23
0211
0212 _LIBCPP_END_NAMESPACE_STD
0213
0214 #endif // _LIBCPP___FORMAT_RANGE_DEFAULT_FORMATTER_H