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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_OUTPUT_H11#define _LIBCPP___FORMAT_FORMATTER_OUTPUT_H12 13#include <__algorithm/ranges_copy.h>14#include <__algorithm/ranges_fill_n.h>15#include <__algorithm/ranges_transform.h>16#include <__bit/countl.h>17#include <__concepts/same_as.h>18#include <__config>19#include <__cstddef/ptrdiff_t.h>20#include <__cstddef/size_t.h>21#include <__format/buffer.h>22#include <__format/concepts.h>23#include <__format/formatter.h>24#include <__format/parser_std_format_spec.h>25#include <__format/unicode.h>26#include <__iterator/back_insert_iterator.h>27#include <__iterator/concepts.h>28#include <__iterator/iterator_traits.h>29#include <__memory/addressof.h>30#include <__memory/pointer_traits.h>31#include <__utility/move.h>32#include <__utility/unreachable.h>33#include <string_view>34 35#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)36# pragma GCC system_header37#endif38 39_LIBCPP_PUSH_MACROS40#include <__undef_macros>41 42_LIBCPP_BEGIN_NAMESPACE_STD43 44#if _LIBCPP_STD_VER >= 2045 46namespace __formatter {47 48struct __padding_size_result {49 size_t __before_;50 size_t __after_;51};52 53_LIBCPP_HIDE_FROM_ABI constexpr __padding_size_result54__padding_size(size_t __size, size_t __width, __format_spec::__alignment __align) {55 _LIBCPP_ASSERT_INTERNAL(__width > __size, "don't call this function when no padding is required");56 _LIBCPP_ASSERT_INTERNAL(57 __align != __format_spec::__alignment::__zero_padding, "the caller should have handled the zero-padding");58 59 size_t __fill = __width - __size;60 switch (__align) {61 case __format_spec::__alignment::__zero_padding:62 __libcpp_unreachable();63 64 case __format_spec::__alignment::__left:65 return {0, __fill};66 67 case __format_spec::__alignment::__center: {68 // The extra padding is divided per [format.string.std]/369 // __before = floor(__fill, 2);70 // __after = ceil(__fill, 2);71 size_t __before = __fill / 2;72 size_t __after = __fill - __before;73 return {__before, __after};74 }75 case __format_spec::__alignment::__default:76 case __format_spec::__alignment::__right:77 return {__fill, 0};78 }79 __libcpp_unreachable();80}81 82/// Copy wrapper.83///84/// This uses a "mass output function" of __format::__output_buffer when possible.85template <__fmt_char_type _CharT, __fmt_char_type _OutCharT = _CharT>86_LIBCPP_HIDE_FROM_ABI auto87__copy(basic_string_view<_CharT> __str, output_iterator<const _OutCharT&> auto __out_it) -> decltype(__out_it) {88 if constexpr (std::same_as<decltype(__out_it), std::back_insert_iterator<__format::__output_buffer<_OutCharT>>>) {89 __out_it.__get_container()->__copy(__str);90 return __out_it;91 } else if constexpr (std::same_as<decltype(__out_it), typename __format::__retarget_buffer<_OutCharT>::__iterator>) {92 __out_it.__buffer_->__copy(__str);93 return __out_it;94 } else {95 return std::ranges::copy(__str, std::move(__out_it)).out;96 }97}98 99template <contiguous_iterator _Iterator,100 __fmt_char_type _CharT = typename iterator_traits<_Iterator>::value_type,101 __fmt_char_type _OutCharT = _CharT>102_LIBCPP_HIDE_FROM_ABI auto103__copy(_Iterator __first, _Iterator __last, output_iterator<const _OutCharT&> auto __out_it) -> decltype(__out_it) {104 return __formatter::__copy(basic_string_view{__first, __last}, std::move(__out_it));105}106 107template <contiguous_iterator _Iterator,108 __fmt_char_type _CharT = typename iterator_traits<_Iterator>::value_type,109 __fmt_char_type _OutCharT = _CharT>110_LIBCPP_HIDE_FROM_ABI auto111__copy(_Iterator __first, size_t __n, output_iterator<const _OutCharT&> auto __out_it) -> decltype(__out_it) {112 return __formatter::__copy(basic_string_view{std::to_address(__first), __n}, std::move(__out_it));113}114 115/// Transform wrapper.116///117/// This uses a "mass output function" of __format::__output_buffer when possible.118template <contiguous_iterator _Iterator,119 __fmt_char_type _CharT = typename iterator_traits<_Iterator>::value_type,120 __fmt_char_type _OutCharT = _CharT,121 class _UnaryOperation>122_LIBCPP_HIDE_FROM_ABI auto123__transform(_Iterator __first,124 _Iterator __last,125 output_iterator<const _OutCharT&> auto __out_it,126 _UnaryOperation __operation) -> decltype(__out_it) {127 if constexpr (std::same_as<decltype(__out_it), std::back_insert_iterator<__format::__output_buffer<_OutCharT>>>) {128 __out_it.__get_container()->__transform(__first, __last, std::move(__operation));129 return __out_it;130 } else if constexpr (std::same_as<decltype(__out_it), typename __format::__retarget_buffer<_OutCharT>::__iterator>) {131 __out_it.__buffer_->__transform(__first, __last, std::move(__operation));132 return __out_it;133 } else {134 return std::ranges::transform(__first, __last, std::move(__out_it), __operation).out;135 }136}137 138/// Fill wrapper.139///140/// This uses a "mass output function" of __format::__output_buffer when possible.141template <__fmt_char_type _CharT, output_iterator<const _CharT&> _OutIt>142_LIBCPP_HIDE_FROM_ABI _OutIt __fill(_OutIt __out_it, size_t __n, _CharT __value) {143 if constexpr (std::same_as<decltype(__out_it), std::back_insert_iterator<__format::__output_buffer<_CharT>>>) {144 __out_it.__get_container()->__fill(__n, __value);145 return __out_it;146 } else if constexpr (std::same_as<decltype(__out_it), typename __format::__retarget_buffer<_CharT>::__iterator>) {147 __out_it.__buffer_->__fill(__n, __value);148 return __out_it;149 } else {150 return std::ranges::fill_n(std::move(__out_it), __n, __value);151 }152}153 154template <__fmt_char_type _CharT, output_iterator<const _CharT&> _OutIt>155_LIBCPP_HIDE_FROM_ABI _OutIt __fill(_OutIt __out_it, size_t __n, __format_spec::__code_point<_CharT> __value) {156# if _LIBCPP_HAS_UNICODE157 if constexpr (same_as<_CharT, char>) {158 std::size_t __bytes = std::countl_one(static_cast<unsigned char>(__value.__data[0]));159 if (__bytes == 0)160 return __formatter::__fill(std::move(__out_it), __n, __value.__data[0]);161 162 for (size_t __i = 0; __i < __n; ++__i)163 __out_it = __formatter::__copy(164 std::addressof(__value.__data[0]), std::addressof(__value.__data[0]) + __bytes, std::move(__out_it));165 return __out_it;166# if _LIBCPP_HAS_WIDE_CHARACTERS167 } else if constexpr (same_as<_CharT, wchar_t>) {168 if constexpr (sizeof(wchar_t) == 2) {169 if (!__unicode::__is_high_surrogate(__value.__data[0]))170 return __formatter::__fill(std::move(__out_it), __n, __value.__data[0]);171 172 for (size_t __i = 0; __i < __n; ++__i)173 __out_it = __formatter::__copy(174 std::addressof(__value.__data[0]), std::addressof(__value.__data[0]) + 2, std::move(__out_it));175 return __out_it;176 } else if constexpr (sizeof(wchar_t) == 4) {177 return __formatter::__fill(std::move(__out_it), __n, __value.__data[0]);178 } else {179 static_assert(false, "expected sizeof(wchar_t) to be 2 or 4");180 }181# endif // _LIBCPP_HAS_WIDE_CHARACTERS182 } else {183 static_assert(false, "Unexpected CharT");184 }185# else // _LIBCPP_HAS_UNICODE186 return __formatter::__fill(std::move(__out_it), __n, __value.__data[0]);187# endif // _LIBCPP_HAS_UNICODE188}189 190/// Writes the input to the output with the required padding.191///192/// Since the output column width is specified the function can be used for193/// ASCII and Unicode output.194///195/// \pre \a __size <= \a __width. Using this function when this pre-condition196/// doesn't hold incurs an unwanted overhead.197///198/// \param __str The string to write.199/// \param __out_it The output iterator to write to.200/// \param __specs The parsed formatting specifications.201/// \param __size The (estimated) output column width. When the elements202/// to be written are ASCII the following condition holds203/// \a __size == \a __last - \a __first.204///205/// \returns An iterator pointing beyond the last element written.206///207/// \note The type of the elements in range [\a __first, \a __last) can differ208/// from the type of \a __specs. Integer output uses \c std::to_chars for its209/// conversion, which means the [\a __first, \a __last) always contains elements210/// of the type \c char.211template <class _CharT, class _ParserCharT>212_LIBCPP_HIDE_FROM_ABI auto213__write(basic_string_view<_CharT> __str,214 output_iterator<const _CharT&> auto __out_it,215 __format_spec::__parsed_specifications<_ParserCharT> __specs,216 ptrdiff_t __size) -> decltype(__out_it) {217 if (__size >= __specs.__width_)218 return __formatter::__copy(__str, std::move(__out_it));219 220 __padding_size_result __padding = __formatter::__padding_size(__size, __specs.__width_, __specs.__std_.__alignment_);221 __out_it = __formatter::__fill(std::move(__out_it), __padding.__before_, __specs.__fill_);222 __out_it = __formatter::__copy(__str, std::move(__out_it));223 return __formatter::__fill(std::move(__out_it), __padding.__after_, __specs.__fill_);224}225 226template <contiguous_iterator _Iterator, class _ParserCharT>227_LIBCPP_HIDE_FROM_ABI auto228__write(_Iterator __first,229 _Iterator __last,230 output_iterator<const iter_value_t<_Iterator>&> auto __out_it,231 __format_spec::__parsed_specifications<_ParserCharT> __specs,232 ptrdiff_t __size) -> decltype(__out_it) {233 _LIBCPP_ASSERT_VALID_INPUT_RANGE(__first <= __last, "Not a valid range");234 return __formatter::__write(basic_string_view{__first, __last}, std::move(__out_it), __specs, __size);235}236 237/// \overload238///239/// Calls the function above where \a __size = \a __last - \a __first.240template <contiguous_iterator _Iterator, class _ParserCharT>241_LIBCPP_HIDE_FROM_ABI auto242__write(_Iterator __first,243 _Iterator __last,244 output_iterator<const iter_value_t<_Iterator>&> auto __out_it,245 __format_spec::__parsed_specifications<_ParserCharT> __specs) -> decltype(__out_it) {246 _LIBCPP_ASSERT_VALID_INPUT_RANGE(__first <= __last, "Not a valid range");247 return __formatter::__write(__first, __last, std::move(__out_it), __specs, __last - __first);248}249 250template <contiguous_iterator _Iterator,251 class _CharT = typename iterator_traits<_Iterator>::value_type,252 class _ParserCharT,253 class _UnaryOperation>254_LIBCPP_HIDE_FROM_ABI auto __write_transformed(255 _Iterator __first,256 _Iterator __last,257 output_iterator<const _CharT&> auto __out_it,258 __format_spec::__parsed_specifications<_ParserCharT> __specs,259 _UnaryOperation __op) -> decltype(__out_it) {260 _LIBCPP_ASSERT_VALID_INPUT_RANGE(__first <= __last, "Not a valid range");261 262 ptrdiff_t __size = __last - __first;263 if (__size >= __specs.__width_)264 return __formatter::__transform(__first, __last, std::move(__out_it), __op);265 266 __padding_size_result __padding = __formatter::__padding_size(__size, __specs.__width_, __specs.__alignment_);267 __out_it = __formatter::__fill(std::move(__out_it), __padding.__before_, __specs.__fill_);268 __out_it = __formatter::__transform(__first, __last, std::move(__out_it), __op);269 return __formatter::__fill(std::move(__out_it), __padding.__after_, __specs.__fill_);270}271 272/// Writes a string using format's width estimation algorithm.273///274/// \pre !__specs.__has_precision()275///276/// \note When \c _LIBCPP_HAS_UNICODE is false the function assumes the input is ASCII.277template <class _CharT>278_LIBCPP_HIDE_FROM_ABI auto __write_string_no_precision(279 basic_string_view<_CharT> __str,280 output_iterator<const _CharT&> auto __out_it,281 __format_spec::__parsed_specifications<_CharT> __specs) -> decltype(__out_it) {282 _LIBCPP_ASSERT_INTERNAL(!__specs.__has_precision(), "use __write_string");283 284 // No padding -> copy the string285 if (!__specs.__has_width())286 return __formatter::__copy(__str, std::move(__out_it));287 288 // Note when the estimated width is larger than size there's no padding. So289 // there's no reason to get the real size when the estimate is larger than or290 // equal to the minimum field width.291 size_t __size =292 __format_spec::__estimate_column_width(__str, __specs.__width_, __format_spec::__column_width_rounding::__up)293 .__width_;294 return __formatter::__write(__str, std::move(__out_it), __specs, __size);295}296 297template <class _CharT>298_LIBCPP_HIDE_FROM_ABI int __truncate(basic_string_view<_CharT>& __str, int __precision) {299 __format_spec::__column_width_result __result =300 __format_spec::__estimate_column_width(__str, __precision, __format_spec::__column_width_rounding::__down);301 __str = basic_string_view<_CharT>{__str.begin(), __result.__last_};302 return __result.__width_;303}304 305} // namespace __formatter306 307#endif // _LIBCPP_STD_VER >= 20308 309_LIBCPP_END_NAMESPACE_STD310 311_LIBCPP_POP_MACROS312 313#endif // _LIBCPP___FORMAT_FORMATTER_OUTPUT_H314