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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-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___FORMAT_RANGE_DEFAULT_FORMATTER_H
11#define _LIBCPP___FORMAT_RANGE_DEFAULT_FORMATTER_H
12
13#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
14# pragma GCC system_header
15#endif
16
17#include <__algorithm/ranges_copy.h>
18#include <__chrono/statically_widen.h>
19#include <__concepts/same_as.h>
20#include <__config>
21#include <__format/concepts.h>
22#include <__format/formatter.h>
23#include <__format/range_formatter.h>
24#include <__iterator/back_insert_iterator.h>
25#include <__ranges/concepts.h>
26#include <__ranges/data.h>
27#include <__ranges/from_range.h>
28#include <__ranges/size.h>
29#include <__type_traits/conditional.h>
30#include <__type_traits/remove_cvref.h>
31#include <__utility/pair.h>
32#include <string_view>
33
34_LIBCPP_BEGIN_NAMESPACE_STD
35
36#if _LIBCPP_STD_VER >= 23
37
38template <class _Rp, class _CharT>
39concept __const_formattable_range =
40 ranges::input_range<const _Rp> && formattable<ranges::range_reference_t<const _Rp>, _CharT>;
41
42template <class _Rp, class _CharT>
43using __fmt_maybe_const _LIBCPP_NODEBUG = conditional_t<__const_formattable_range<_Rp, _CharT>, const _Rp, _Rp>;
44
45_LIBCPP_DIAGNOSTIC_PUSH
46_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wshadow")
47_LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wshadow")
48// This shadows map, set, and string.
49enum class range_format { disabled, map, set, sequence, string, debug_string };
50_LIBCPP_DIAGNOSTIC_POP
51
52// There is no definition of this struct, it's purely intended to be used to
53// generate diagnostics.
54template <class _Rp>
55struct __instantiated_the_primary_template_of_format_kind;
56
57template <class _Rp>
58constexpr range_format format_kind = [] {
59 // [format.range.fmtkind]/1
60 // A program that instantiates the primary template of format_kind is ill-formed.
61 static_assert(sizeof(_Rp) != sizeof(_Rp), "create a template specialization of format_kind for your type");
62 return range_format::disabled;
63}();
64
65template <ranges::input_range _Rp>
66 requires same_as<_Rp, remove_cvref_t<_Rp>>
67inline constexpr range_format format_kind<_Rp> = [] {
68 // [format.range.fmtkind]/2
69
70 // 2.1 If same_as<remove_cvref_t<ranges::range_reference_t<R>>, R> is true,
71 // Otherwise format_kind<R> is range_format::disabled.
72 if constexpr (same_as<remove_cvref_t<ranges::range_reference_t<_Rp>>, _Rp>)
73 return range_format::disabled;
74 // 2.2 Otherwise, if the qualified-id R::key_type is valid and denotes a type:
75 else if constexpr (requires { typename _Rp::key_type; }) {
76 // 2.2.1 If the qualified-id R::mapped_type is valid and denotes a type ...
77 if constexpr (requires { typename _Rp::mapped_type; } &&
78 // 2.2.1 ... If either U is a specialization of pair or U is a specialization
79 // of tuple and tuple_size_v<U> == 2
80 __fmt_pair_like<remove_cvref_t<ranges::range_reference_t<_Rp>>>)
81 return range_format::map;
82 else
83 // 2.2.2 Otherwise format_kind<R> is range_format::set.
84 return range_format::set;
85 } else
86 // 2.3 Otherwise, format_kind<R> is range_format::sequence.
87 return range_format::sequence;
88}();
89
90template <range_format _Kp, ranges::input_range _Rp, class _CharT>
91struct __range_default_formatter;
92
93// Required specializations
94
95template <ranges::input_range _Rp, class _CharT>
96struct __range_default_formatter<range_format::sequence, _Rp, _CharT> {
97private:
98 using __maybe_const_r _LIBCPP_NODEBUG = __fmt_maybe_const<_Rp, _CharT>;
99 range_formatter<remove_cvref_t<ranges::range_reference_t<__maybe_const_r>>, _CharT> __underlying_;
100
101public:
102 _LIBCPP_HIDE_FROM_ABI constexpr void set_separator(basic_string_view<_CharT> __separator) noexcept {
103 __underlying_.set_separator(__separator);
104 }
105 _LIBCPP_HIDE_FROM_ABI constexpr void
106 set_brackets(basic_string_view<_CharT> __opening_bracket, basic_string_view<_CharT> __closing_bracket) noexcept {
107 __underlying_.set_brackets(__opening_bracket, __closing_bracket);
108 }
109
110 template <class _ParseContext>
111 _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) {
112 return __underlying_.parse(__ctx);
113 }
114
115 template <class _FormatContext>
116 _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
117 format(__maybe_const_r& __range, _FormatContext& __ctx) const {
118 return __underlying_.format(__range, __ctx);
119 }
120};
121
122template <ranges::input_range _Rp, class _CharT>
123struct __range_default_formatter<range_format::map, _Rp, _CharT> {
124private:
125 using __maybe_const_map _LIBCPP_NODEBUG = __fmt_maybe_const<_Rp, _CharT>;
126 using __element_type _LIBCPP_NODEBUG = remove_cvref_t<ranges::range_reference_t<__maybe_const_map>>;
127 range_formatter<__element_type, _CharT> __underlying_;
128
129public:
130 _LIBCPP_HIDE_FROM_ABI constexpr __range_default_formatter()
131 requires(__fmt_pair_like<__element_type>)
132 {
133 __underlying_.set_brackets(_LIBCPP_STATICALLY_WIDEN(_CharT, "{"), _LIBCPP_STATICALLY_WIDEN(_CharT, "}"));
134 __underlying_.underlying().set_brackets({}, {});
135 __underlying_.underlying().set_separator(_LIBCPP_STATICALLY_WIDEN(_CharT, ": "));
136 }
137
138 template <class _ParseContext>
139 _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) {
140 return __underlying_.parse(__ctx);
141 }
142
143 template <class _FormatContext>
144 _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
145 format(__maybe_const_map& __range, _FormatContext& __ctx) const {
146 return __underlying_.format(__range, __ctx);
147 }
148};
149
150template <ranges::input_range _Rp, class _CharT>
151struct __range_default_formatter<range_format::set, _Rp, _CharT> {
152private:
153 using __maybe_const_set _LIBCPP_NODEBUG = __fmt_maybe_const<_Rp, _CharT>;
154 using __element_type _LIBCPP_NODEBUG = remove_cvref_t<ranges::range_reference_t<__maybe_const_set>>;
155 range_formatter<__element_type, _CharT> __underlying_;
156
157public:
158 _LIBCPP_HIDE_FROM_ABI constexpr __range_default_formatter() {
159 __underlying_.set_brackets(_LIBCPP_STATICALLY_WIDEN(_CharT, "{"), _LIBCPP_STATICALLY_WIDEN(_CharT, "}"));
160 }
161
162 template <class _ParseContext>
163 _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) {
164 return __underlying_.parse(__ctx);
165 }
166
167 template <class _FormatContext>
168 _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
169 format(__maybe_const_set& __range, _FormatContext& __ctx) const {
170 return __underlying_.format(__range, __ctx);
171 }
172};
173
174template <range_format _Kp, ranges::input_range _Rp, class _CharT>
175 requires(_Kp == range_format::string || _Kp == range_format::debug_string)
176struct __range_default_formatter<_Kp, _Rp, _CharT> {
177private:
178 // This deviates from the Standard, there the exposition only type is
179 // formatter<basic_string<charT>, charT> underlying_;
180 // Using a string_view allows the format function to avoid a copy of the
181 // input range when it is a contigious range.
182 formatter<basic_string_view<_CharT>, _CharT> __underlying_;
183
184public:
185 template <class _ParseContext>
186 _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) {
187 typename _ParseContext::iterator __i = __underlying_.parse(__ctx);
188 if constexpr (_Kp == range_format::debug_string)
189 __underlying_.set_debug_format();
190 return __i;
191 }
192
193 template <class _FormatContext>
194 _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
195 format(conditional_t<ranges::input_range<const _Rp>, const _Rp&, _Rp&> __range, _FormatContext& __ctx) const {
196 // When the range is contiguous use a basic_string_view instead to avoid a
197 // copy of the underlying data. The basic_string_view formatter
198 // specialization is the "basic" string formatter in libc++.
199 if constexpr (ranges::contiguous_range<_Rp> && std::ranges::sized_range<_Rp>)
200 return __underlying_.format(basic_string_view<_CharT>{ranges::data(__range), ranges::size(__range)}, __ctx);
201 else
202 return __underlying_.format(basic_string<_CharT>{from_range, __range}, __ctx);
203 }
204};
205
206template <ranges::input_range _Rp, class _CharT>
207 requires(format_kind<_Rp> != range_format::disabled && formattable<ranges::range_reference_t<_Rp>, _CharT>)
208struct formatter<_Rp, _CharT> : __range_default_formatter<format_kind<_Rp>, _Rp, _CharT> {};
209
210#endif // _LIBCPP_STD_VER >= 23
211
212_LIBCPP_END_NAMESPACE_STD
213
214#endif // _LIBCPP___FORMAT_RANGE_DEFAULT_FORMATTER_H