Yi Kong | 8328301 | 2023-12-13 12:57:00 +0900 | [diff] [blame^] | 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_FORMATTER_H |
| 11 | #define _LIBCPP___FORMAT_RANGE_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/buffer.h> |
| 22 | #include <__format/concepts.h> |
| 23 | #include <__format/format_context.h> |
| 24 | #include <__format/format_error.h> |
| 25 | #include <__format/formatter.h> |
| 26 | #include <__format/formatter_output.h> |
| 27 | #include <__format/parser_std_format_spec.h> |
| 28 | #include <__iterator/back_insert_iterator.h> |
| 29 | #include <__ranges/concepts.h> |
| 30 | #include <__ranges/data.h> |
| 31 | #include <__ranges/from_range.h> |
| 32 | #include <__ranges/size.h> |
| 33 | #include <__type_traits/remove_cvref.h> |
| 34 | #include <string_view> |
| 35 | |
| 36 | _LIBCPP_BEGIN_NAMESPACE_STD |
| 37 | |
| 38 | #if _LIBCPP_STD_VER >= 23 |
| 39 | |
| 40 | template <class _Tp, class _CharT = char> |
| 41 | requires same_as<remove_cvref_t<_Tp>, _Tp> && formattable<_Tp, _CharT> |
| 42 | struct _LIBCPP_TEMPLATE_VIS range_formatter { |
| 43 | _LIBCPP_HIDE_FROM_ABI constexpr void set_separator(basic_string_view<_CharT> __separator) noexcept { |
| 44 | __separator_ = __separator; |
| 45 | } |
| 46 | _LIBCPP_HIDE_FROM_ABI constexpr void |
| 47 | set_brackets(basic_string_view<_CharT> __opening_bracket, basic_string_view<_CharT> __closing_bracket) noexcept { |
| 48 | __opening_bracket_ = __opening_bracket; |
| 49 | __closing_bracket_ = __closing_bracket; |
| 50 | } |
| 51 | |
| 52 | _LIBCPP_HIDE_FROM_ABI constexpr formatter<_Tp, _CharT>& underlying() noexcept { return __underlying_; } |
| 53 | _LIBCPP_HIDE_FROM_ABI constexpr const formatter<_Tp, _CharT>& underlying() const noexcept { return __underlying_; } |
| 54 | |
| 55 | template <class _ParseContext> |
| 56 | _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) { |
| 57 | auto __begin = __parser_.__parse(__ctx, __format_spec::__fields_range); |
| 58 | auto __end = __ctx.end(); |
| 59 | // Note the cases where __begin == __end in this code only happens when the |
| 60 | // replacement-field has no terminating }, or when the parse is manually |
| 61 | // called with a format-spec. The former is an error and the latter means |
| 62 | // using a formatter without the format functions or print. |
| 63 | if (__begin == __end) [[unlikely]] |
| 64 | return __parse_empty_range_underlying_spec(__ctx, __begin); |
| 65 | |
| 66 | // The n field overrides a possible m type, therefore delay applying the |
| 67 | // effect of n until the type has been procesed. |
| 68 | __parse_type(__begin, __end); |
| 69 | if (__parser_.__clear_brackets_) |
| 70 | set_brackets({}, {}); |
| 71 | if (__begin == __end) [[unlikely]] |
| 72 | return __parse_empty_range_underlying_spec(__ctx, __begin); |
| 73 | |
| 74 | bool __has_range_underlying_spec = *__begin == _CharT(':'); |
| 75 | if (__has_range_underlying_spec) { |
| 76 | // range-underlying-spec: |
| 77 | // : format-spec |
| 78 | ++__begin; |
| 79 | } else if (__begin != __end && *__begin != _CharT('}')) |
| 80 | // When there is no underlaying range the current parse should have |
| 81 | // consumed the format-spec. If not, the not consumed input will be |
| 82 | // processed by the underlying. For example {:-} for a range in invalid, |
| 83 | // the sign field is not present. Without this check the underlying_ will |
| 84 | // get -} as input which my be valid. |
| 85 | std::__throw_format_error("The format specifier should consume the input or end with a '}'"); |
| 86 | |
| 87 | __ctx.advance_to(__begin); |
| 88 | __begin = __underlying_.parse(__ctx); |
| 89 | |
| 90 | // This test should not be required if __has_range_underlying_spec is false. |
| 91 | // However this test makes sure the underlying formatter left the parser in |
| 92 | // a valid state. (Note this is not a full protection against evil parsers. |
| 93 | // For example |
| 94 | // } this is test for the next argument {} |
| 95 | // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^ |
| 96 | // could consume more than it should. |
| 97 | if (__begin != __end && *__begin != _CharT('}')) |
| 98 | std::__throw_format_error("The format specifier should consume the input or end with a '}'"); |
| 99 | |
| 100 | if (__parser_.__type_ != __format_spec::__type::__default) { |
| 101 | // [format.range.formatter]/6 |
| 102 | // If the range-type is s or ?s, then there shall be no n option and no |
| 103 | // range-underlying-spec. |
| 104 | if (__parser_.__clear_brackets_) { |
| 105 | if (__parser_.__type_ == __format_spec::__type::__string) |
| 106 | std::__throw_format_error("The n option and type s can't be used together"); |
| 107 | std::__throw_format_error("The n option and type ?s can't be used together"); |
| 108 | } |
| 109 | if (__has_range_underlying_spec) { |
| 110 | if (__parser_.__type_ == __format_spec::__type::__string) |
| 111 | std::__throw_format_error("Type s and an underlying format specification can't be used together"); |
| 112 | std::__throw_format_error("Type ?s and an underlying format specification can't be used together"); |
| 113 | } |
| 114 | } else if (!__has_range_underlying_spec) |
| 115 | std::__set_debug_format(__underlying_); |
| 116 | |
| 117 | return __begin; |
| 118 | } |
| 119 | |
| 120 | template <ranges::input_range _Rp, class _FormatContext> |
| 121 | requires formattable<ranges::range_reference_t<_Rp>, _CharT> && |
| 122 | same_as<remove_cvref_t<ranges::range_reference_t<_Rp>>, _Tp> |
| 123 | _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator format(_Rp&& __range, _FormatContext& __ctx) const { |
| 124 | __format_spec::__parsed_specifications<_CharT> __specs = __parser_.__get_parsed_std_specifications(__ctx); |
| 125 | |
| 126 | if (!__specs.__has_width()) |
| 127 | return __format_range(__range, __ctx, __specs); |
| 128 | |
| 129 | // The size of the buffer needed is: |
| 130 | // - open bracket characters |
| 131 | // - close bracket character |
| 132 | // - n elements where every element may have a different size |
| 133 | // - (n -1) separators |
| 134 | // The size of the element is hard to predict, knowing the type helps but |
| 135 | // it depends on the format-spec. As an initial estimate we guess 6 |
| 136 | // characters. |
| 137 | // Typically both brackets are 1 character and the separator is 2 |
| 138 | // characters. Which means there will be |
| 139 | // (n - 1) * 2 + 1 + 1 = n * 2 character |
| 140 | // So estimate 8 times the range size as buffer. |
| 141 | std::size_t __capacity_hint = 0; |
| 142 | if constexpr (std::ranges::sized_range<_Rp>) |
| 143 | __capacity_hint = 8 * ranges::size(__range); |
| 144 | __format::__retarget_buffer<_CharT> __buffer{__capacity_hint}; |
| 145 | basic_format_context<typename __format::__retarget_buffer<_CharT>::__iterator, _CharT> __c{ |
| 146 | __buffer.__make_output_iterator(), __ctx}; |
| 147 | |
| 148 | __format_range(__range, __c, __specs); |
| 149 | |
| 150 | return __formatter::__write_string_no_precision(__buffer.__view(), __ctx.out(), __specs); |
| 151 | } |
| 152 | |
| 153 | template <ranges::input_range _Rp, class _FormatContext> |
| 154 | typename _FormatContext::iterator _LIBCPP_HIDE_FROM_ABI |
| 155 | __format_range(_Rp&& __range, _FormatContext& __ctx, __format_spec::__parsed_specifications<_CharT> __specs) const { |
| 156 | if constexpr (same_as<_Tp, _CharT>) { |
| 157 | switch (__specs.__std_.__type_) { |
| 158 | case __format_spec::__type::__string: |
| 159 | case __format_spec::__type::__debug: |
| 160 | return __format_as_string(__range, __ctx, __specs.__std_.__type_ == __format_spec::__type::__debug); |
| 161 | default: |
| 162 | return __format_as_sequence(__range, __ctx); |
| 163 | } |
| 164 | } else |
| 165 | return __format_as_sequence(__range, __ctx); |
| 166 | } |
| 167 | |
| 168 | template <ranges::input_range _Rp, class _FormatContext> |
| 169 | _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator |
| 170 | __format_as_string(_Rp&& __range, _FormatContext& __ctx, bool __debug_format) const { |
| 171 | // When the range is contiguous use a basic_string_view instead to avoid a |
| 172 | // copy of the underlying data. The basic_string_view formatter |
| 173 | // specialization is the "basic" string formatter in libc++. |
| 174 | if constexpr (ranges::contiguous_range<_Rp> && std::ranges::sized_range<_Rp>) { |
| 175 | std::formatter<basic_string_view<_CharT>, _CharT> __formatter; |
| 176 | if (__debug_format) |
| 177 | __formatter.set_debug_format(); |
| 178 | return __formatter.format( |
| 179 | basic_string_view<_CharT>{ |
| 180 | ranges::data(__range), |
| 181 | ranges::size(__range), |
| 182 | }, |
| 183 | __ctx); |
| 184 | } else { |
| 185 | std::formatter<basic_string<_CharT>, _CharT> __formatter; |
| 186 | if (__debug_format) |
| 187 | __formatter.set_debug_format(); |
| 188 | return __formatter.format(basic_string<_CharT>{from_range, __range}, __ctx); |
| 189 | } |
| 190 | } |
| 191 | |
| 192 | template <ranges::input_range _Rp, class _FormatContext> |
| 193 | _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator |
| 194 | __format_as_sequence(_Rp&& __range, _FormatContext& __ctx) const { |
| 195 | __ctx.advance_to(ranges::copy(__opening_bracket_, __ctx.out()).out); |
| 196 | bool __use_separator = false; |
| 197 | for (auto&& __e : __range) { |
| 198 | if (__use_separator) |
| 199 | __ctx.advance_to(ranges::copy(__separator_, __ctx.out()).out); |
| 200 | else |
| 201 | __use_separator = true; |
| 202 | |
| 203 | __ctx.advance_to(__underlying_.format(__e, __ctx)); |
| 204 | } |
| 205 | |
| 206 | return ranges::copy(__closing_bracket_, __ctx.out()).out; |
| 207 | } |
| 208 | |
| 209 | __format_spec::__parser<_CharT> __parser_{.__alignment_ = __format_spec::__alignment::__left}; |
| 210 | |
| 211 | private: |
| 212 | template <contiguous_iterator _Iterator> |
| 213 | _LIBCPP_HIDE_FROM_ABI constexpr void __parse_type(_Iterator& __begin, _Iterator __end) { |
| 214 | switch (*__begin) { |
| 215 | case _CharT('m'): |
| 216 | if constexpr (__fmt_pair_like<_Tp>) { |
| 217 | set_brackets(_LIBCPP_STATICALLY_WIDEN(_CharT, "{"), _LIBCPP_STATICALLY_WIDEN(_CharT, "}")); |
| 218 | set_separator(_LIBCPP_STATICALLY_WIDEN(_CharT, ", ")); |
| 219 | ++__begin; |
| 220 | } else |
| 221 | std::__throw_format_error("Type m requires a pair or a tuple with two elements"); |
| 222 | break; |
| 223 | |
| 224 | case _CharT('s'): |
| 225 | if constexpr (same_as<_Tp, _CharT>) { |
| 226 | __parser_.__type_ = __format_spec::__type::__string; |
| 227 | ++__begin; |
| 228 | } else |
| 229 | std::__throw_format_error("Type s requires character type as formatting argument"); |
| 230 | break; |
| 231 | |
| 232 | case _CharT('?'): |
| 233 | ++__begin; |
| 234 | if (__begin == __end || *__begin != _CharT('s')) |
| 235 | std::__throw_format_error("The format specifier should consume the input or end with a '}'"); |
| 236 | if constexpr (same_as<_Tp, _CharT>) { |
| 237 | __parser_.__type_ = __format_spec::__type::__debug; |
| 238 | ++__begin; |
| 239 | } else |
| 240 | std::__throw_format_error("Type ?s requires character type as formatting argument"); |
| 241 | } |
| 242 | } |
| 243 | |
| 244 | template <class _ParseContext> |
| 245 | _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator |
| 246 | __parse_empty_range_underlying_spec(_ParseContext& __ctx, typename _ParseContext::iterator __begin) { |
| 247 | __ctx.advance_to(__begin); |
| 248 | [[maybe_unused]] typename _ParseContext::iterator __result = __underlying_.parse(__ctx); |
| 249 | _LIBCPP_ASSERT_UNCATEGORIZED( |
| 250 | __result == __begin, |
| 251 | "the underlying's parse function should not advance the input beyond the end of the input"); |
| 252 | return __begin; |
| 253 | } |
| 254 | |
| 255 | formatter<_Tp, _CharT> __underlying_; |
| 256 | basic_string_view<_CharT> __separator_ = _LIBCPP_STATICALLY_WIDEN(_CharT, ", "); |
| 257 | basic_string_view<_CharT> __opening_bracket_ = _LIBCPP_STATICALLY_WIDEN(_CharT, "["); |
| 258 | basic_string_view<_CharT> __closing_bracket_ = _LIBCPP_STATICALLY_WIDEN(_CharT, "]"); |
| 259 | }; |
| 260 | |
| 261 | #endif //_LIBCPP_STD_VER >= 23 |
| 262 | |
| 263 | _LIBCPP_END_NAMESPACE_STD |
| 264 | |
| 265 | #endif // _LIBCPP___FORMAT_RANGE_FORMATTER_H |