// -*- C++ -*- //===----------------------------------------------------------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// #ifndef _LIBCPP___FORMAT_FORMATTER_OUTPUT_H #define _LIBCPP___FORMAT_FORMATTER_OUTPUT_H #include <__algorithm/ranges_copy.h> #include <__algorithm/ranges_fill_n.h> #include <__algorithm/ranges_transform.h> #include <__chrono/statically_widen.h> #include <__concepts/same_as.h> #include <__config> #include <__format/buffer.h> #include <__format/concepts.h> #include <__format/escaped_output_table.h> #include <__format/formatter.h> #include <__format/parser_std_format_spec.h> #include <__format/unicode.h> #include <__iterator/back_insert_iterator.h> #include <__type_traits/make_unsigned.h> #include <__utility/move.h> #include <__utility/unreachable.h> #include #include #include #include #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) # pragma GCC system_header #endif _LIBCPP_BEGIN_NAMESPACE_STD #if _LIBCPP_STD_VER > 17 namespace __formatter { _LIBCPP_HIDE_FROM_ABI constexpr char __hex_to_upper(char __c) { switch (__c) { case 'a': return 'A'; case 'b': return 'B'; case 'c': return 'C'; case 'd': return 'D'; case 'e': return 'E'; case 'f': return 'F'; } return __c; } struct _LIBCPP_TYPE_VIS __padding_size_result { size_t __before_; size_t __after_; }; _LIBCPP_HIDE_FROM_ABI constexpr __padding_size_result __padding_size(size_t __size, size_t __width, __format_spec::__alignment __align) { _LIBCPP_ASSERT(__width > __size, "don't call this function when no padding is required"); _LIBCPP_ASSERT( __align != __format_spec::__alignment::__zero_padding, "the caller should have handled the zero-padding"); size_t __fill = __width - __size; switch (__align) { case __format_spec::__alignment::__zero_padding: __libcpp_unreachable(); case __format_spec::__alignment::__left: return {0, __fill}; case __format_spec::__alignment::__center: { // The extra padding is divided per [format.string.std]/3 // __before = floor(__fill, 2); // __after = ceil(__fill, 2); size_t __before = __fill / 2; size_t __after = __fill - __before; return {__before, __after}; } case __format_spec::__alignment::__default: case __format_spec::__alignment::__right: return {__fill, 0}; } __libcpp_unreachable(); } /// Copy wrapper. /// /// This uses a "mass output function" of __format::__output_buffer when possible. template <__fmt_char_type _CharT, __fmt_char_type _OutCharT = _CharT> _LIBCPP_HIDE_FROM_ABI auto __copy(basic_string_view<_CharT> __str, output_iterator auto __out_it) -> decltype(__out_it) { if constexpr (_VSTD::same_as>>) { __out_it.__get_container()->__copy(__str); return __out_it; } else if constexpr (_VSTD::same_as::__iterator>) { __out_it.__buffer_->__copy(__str); return __out_it; } else { return std::ranges::copy(__str, _VSTD::move(__out_it)).out; } } template <__fmt_char_type _CharT, __fmt_char_type _OutCharT = _CharT> _LIBCPP_HIDE_FROM_ABI auto __copy(const _CharT* __first, const _CharT* __last, output_iterator auto __out_it) -> decltype(__out_it) { return __formatter::__copy(basic_string_view{__first, __last}, _VSTD::move(__out_it)); } template <__fmt_char_type _CharT, __fmt_char_type _OutCharT = _CharT> _LIBCPP_HIDE_FROM_ABI auto __copy(const _CharT* __first, size_t __n, output_iterator auto __out_it) -> decltype(__out_it) { return __formatter::__copy(basic_string_view{__first, __n}, _VSTD::move(__out_it)); } /// Transform wrapper. /// /// This uses a "mass output function" of __format::__output_buffer when possible. template <__fmt_char_type _CharT, __fmt_char_type _OutCharT = _CharT, class _UnaryOperation> _LIBCPP_HIDE_FROM_ABI auto __transform(const _CharT* __first, const _CharT* __last, output_iterator auto __out_it, _UnaryOperation __operation) -> decltype(__out_it) { if constexpr (_VSTD::same_as>>) { __out_it.__get_container()->__transform(__first, __last, _VSTD::move(__operation)); return __out_it; } else if constexpr (_VSTD::same_as::__iterator>) { __out_it.__buffer_->__transform(__first, __last, _VSTD::move(__operation)); return __out_it; } else { return std::ranges::transform(__first, __last, _VSTD::move(__out_it), __operation).out; } } /// Fill wrapper. /// /// This uses a "mass output function" of __format::__output_buffer when possible. template <__fmt_char_type _CharT, output_iterator _OutIt> _LIBCPP_HIDE_FROM_ABI _OutIt __fill(_OutIt __out_it, size_t __n, _CharT __value) { if constexpr (_VSTD::same_as>>) { __out_it.__get_container()->__fill(__n, __value); return __out_it; } else if constexpr (_VSTD::same_as::__iterator>) { __out_it.__buffer_->__fill(__n, __value); return __out_it; } else { return std::ranges::fill_n(_VSTD::move(__out_it), __n, __value); } } template _LIBCPP_HIDE_FROM_ABI _OutIt __write_using_decimal_separators(_OutIt __out_it, const char* __begin, const char* __first, const char* __last, string&& __grouping, _CharT __sep, __format_spec::__parsed_specifications<_CharT> __specs) { int __size = (__first - __begin) + // [sign][prefix] (__last - __first) + // data (__grouping.size() - 1); // number of separator characters __padding_size_result __padding = {0, 0}; if (__specs.__alignment_ == __format_spec::__alignment::__zero_padding) { // Write [sign][prefix]. __out_it = __formatter::__copy(__begin, __first, _VSTD::move(__out_it)); if (__specs.__width_ > __size) { // Write zero padding. __padding.__before_ = __specs.__width_ - __size; __out_it = __formatter::__fill(_VSTD::move(__out_it), __specs.__width_ - __size, _CharT('0')); } } else { if (__specs.__width_ > __size) { // Determine padding and write padding. __padding = __formatter::__padding_size(__size, __specs.__width_, __specs.__alignment_); __out_it = __formatter::__fill(_VSTD::move(__out_it), __padding.__before_, __specs.__fill_); } // Write [sign][prefix]. __out_it = __formatter::__copy(__begin, __first, _VSTD::move(__out_it)); } auto __r = __grouping.rbegin(); auto __e = __grouping.rend() - 1; _LIBCPP_ASSERT(__r != __e, "The slow grouping formatting is used while " "there will be no separators written."); // The output is divided in small groups of numbers to write: // - A group before the first separator. // - A separator and a group, repeated for the number of separators. // - A group after the last separator. // This loop achieves that process by testing the termination condition // midway in the loop. // // TODO FMT This loop evaluates the loop invariant `__parser.__type != // _Flags::_Type::__hexadecimal_upper_case` for every iteration. (This test // happens in the __write call.) Benchmark whether making two loops and // hoisting the invariant is worth the effort. while (true) { if (__specs.__std_.__type_ == __format_spec::__type::__hexadecimal_upper_case) { __last = __first + *__r; __out_it = __formatter::__transform(__first, __last, _VSTD::move(__out_it), __hex_to_upper); __first = __last; } else { __out_it = __formatter::__copy(__first, *__r, _VSTD::move(__out_it)); __first += *__r; } if (__r == __e) break; ++__r; *__out_it++ = __sep; } return __formatter::__fill(_VSTD::move(__out_it), __padding.__after_, __specs.__fill_); } /// Writes the input to the output with the required padding. /// /// Since the output column width is specified the function can be used for /// ASCII and Unicode output. /// /// \pre \a __size <= \a __width. Using this function when this pre-condition /// doesn't hold incurs an unwanted overhead. /// /// \param __str The string to write. /// \param __out_it The output iterator to write to. /// \param __specs The parsed formatting specifications. /// \param __size The (estimated) output column width. When the elements /// to be written are ASCII the following condition holds /// \a __size == \a __last - \a __first. /// /// \returns An iterator pointing beyond the last element written. /// /// \note The type of the elements in range [\a __first, \a __last) can differ /// from the type of \a __specs. Integer output uses \c std::to_chars for its /// conversion, which means the [\a __first, \a __last) always contains elements /// of the type \c char. template _LIBCPP_HIDE_FROM_ABI auto __write(basic_string_view<_CharT> __str, output_iterator auto __out_it, __format_spec::__parsed_specifications<_ParserCharT> __specs, ptrdiff_t __size) -> decltype(__out_it) { if (__size >= __specs.__width_) return __formatter::__copy(__str, _VSTD::move(__out_it)); __padding_size_result __padding = __formatter::__padding_size(__size, __specs.__width_, __specs.__std_.__alignment_); __out_it = __formatter::__fill(_VSTD::move(__out_it), __padding.__before_, __specs.__fill_); __out_it = __formatter::__copy(__str, _VSTD::move(__out_it)); return __formatter::__fill(_VSTD::move(__out_it), __padding.__after_, __specs.__fill_); } template _LIBCPP_HIDE_FROM_ABI auto __write(const _CharT* __first, const _CharT* __last, output_iterator auto __out_it, __format_spec::__parsed_specifications<_ParserCharT> __specs, ptrdiff_t __size) -> decltype(__out_it) { _LIBCPP_ASSERT(__first <= __last, "Not a valid range"); return __formatter::__write(basic_string_view{__first, __last}, _VSTD::move(__out_it), __specs, __size); } /// \overload /// /// Calls the function above where \a __size = \a __last - \a __first. template _LIBCPP_HIDE_FROM_ABI auto __write(const _CharT* __first, const _CharT* __last, output_iterator auto __out_it, __format_spec::__parsed_specifications<_ParserCharT> __specs) -> decltype(__out_it) { _LIBCPP_ASSERT(__first <= __last, "Not a valid range"); return __formatter::__write(__first, __last, _VSTD::move(__out_it), __specs, __last - __first); } template _LIBCPP_HIDE_FROM_ABI auto __write_transformed(const _CharT* __first, const _CharT* __last, output_iterator auto __out_it, __format_spec::__parsed_specifications<_ParserCharT> __specs, _UnaryOperation __op) -> decltype(__out_it) { _LIBCPP_ASSERT(__first <= __last, "Not a valid range"); ptrdiff_t __size = __last - __first; if (__size >= __specs.__width_) return __formatter::__transform(__first, __last, _VSTD::move(__out_it), __op); __padding_size_result __padding = __formatter::__padding_size(__size, __specs.__width_, __specs.__alignment_); __out_it = __formatter::__fill(_VSTD::move(__out_it), __padding.__before_, __specs.__fill_); __out_it = __formatter::__transform(__first, __last, _VSTD::move(__out_it), __op); return __formatter::__fill(_VSTD::move(__out_it), __padding.__after_, __specs.__fill_); } /// Writes additional zero's for the precision before the exponent. /// This is used when the precision requested in the format string is larger /// than the maximum precision of the floating-point type. These precision /// digits are always 0. /// /// \param __exponent The location of the exponent character. /// \param __num_trailing_zeros The number of 0's to write before the exponent /// character. template _LIBCPP_HIDE_FROM_ABI auto __write_using_trailing_zeros( const _CharT* __first, const _CharT* __last, output_iterator auto __out_it, __format_spec::__parsed_specifications<_ParserCharT> __specs, size_t __size, const _CharT* __exponent, size_t __num_trailing_zeros) -> decltype(__out_it) { _LIBCPP_ASSERT(__first <= __last, "Not a valid range"); _LIBCPP_ASSERT(__num_trailing_zeros > 0, "The overload not writing trailing zeros should have been used"); __padding_size_result __padding = __formatter::__padding_size(__size + __num_trailing_zeros, __specs.__width_, __specs.__alignment_); __out_it = __formatter::__fill(_VSTD::move(__out_it), __padding.__before_, __specs.__fill_); __out_it = __formatter::__copy(__first, __exponent, _VSTD::move(__out_it)); __out_it = __formatter::__fill(_VSTD::move(__out_it), __num_trailing_zeros, _CharT('0')); __out_it = __formatter::__copy(__exponent, __last, _VSTD::move(__out_it)); return __formatter::__fill(_VSTD::move(__out_it), __padding.__after_, __specs.__fill_); } /// Writes a string using format's width estimation algorithm. /// /// \pre !__specs.__has_precision() /// /// \note When \c _LIBCPP_HAS_NO_UNICODE is defined the function assumes the /// input is ASCII. template _LIBCPP_HIDE_FROM_ABI auto __write_string_no_precision( basic_string_view<_CharT> __str, output_iterator auto __out_it, __format_spec::__parsed_specifications<_CharT> __specs) -> decltype(__out_it) { _LIBCPP_ASSERT(!__specs.__has_precision(), "use __write_string"); // No padding -> copy the string if (!__specs.__has_width()) return __formatter::__copy(__str, _VSTD::move(__out_it)); // Note when the estimated width is larger than size there's no padding. So // there's no reason to get the real size when the estimate is larger than or // equal to the minimum field width. size_t __size = __format_spec::__estimate_column_width(__str, __specs.__width_, __format_spec::__column_width_rounding::__up) .__width_; return __formatter::__write(__str, _VSTD::move(__out_it), __specs, __size); } template _LIBCPP_HIDE_FROM_ABI int __truncate(basic_string_view<_CharT>& __str, int __precision) { __format_spec::__column_width_result<_CharT> __result = __format_spec::__estimate_column_width(__str, __precision, __format_spec::__column_width_rounding::__down); __str = basic_string_view<_CharT>{__str.begin(), __result.__last_}; return __result.__width_; } /// Writes a string using format's width estimation algorithm. /// /// \note When \c _LIBCPP_HAS_NO_UNICODE is defined the function assumes the /// input is ASCII. template _LIBCPP_HIDE_FROM_ABI auto __write_string( basic_string_view<_CharT> __str, output_iterator auto __out_it, __format_spec::__parsed_specifications<_CharT> __specs) -> decltype(__out_it) { if (!__specs.__has_precision()) return __formatter::__write_string_no_precision(__str, _VSTD::move(__out_it), __specs); int __size = __formatter::__truncate(__str, __specs.__precision_); return __formatter::__write(__str.begin(), __str.end(), _VSTD::move(__out_it), __specs, __size); } # if _LIBCPP_STD_VER > 20 struct __nul_terminator {}; template _LIBCPP_HIDE_FROM_ABI bool operator==(const _CharT* __cstr, __nul_terminator) { return *__cstr == _CharT('\0'); } template _LIBCPP_HIDE_FROM_ABI void __write_escaped_code_unit(basic_string<_CharT>& __str, char32_t __value, const _CharT* __prefix) { back_insert_iterator __out_it{__str}; std::ranges::copy(__prefix, __nul_terminator{}, __out_it); char __buffer[8]; to_chars_result __r = std::to_chars(std::begin(__buffer), std::end(__buffer), __value, 16); _LIBCPP_ASSERT(__r.ec == errc(0), "Internal buffer too small"); std::ranges::copy(std::begin(__buffer), __r.ptr, __out_it); __str += _CharT('}'); } // [format.string.escaped]/2.2.1.2 // ... // then the sequence \u{hex-digit-sequence} is appended to E, where // hex-digit-sequence is the shortest hexadecimal representation of C using // lower-case hexadecimal digits. template _LIBCPP_HIDE_FROM_ABI void __write_well_formed_escaped_code_unit(basic_string<_CharT>& __str, char32_t __value) { __formatter::__write_escaped_code_unit(__str, __value, _LIBCPP_STATICALLY_WIDEN(_CharT, "\\u{")); } // [format.string.escaped]/2.2.3 // Otherwise (X is a sequence of ill-formed code units), each code unit U is // appended to E in order as the sequence \x{hex-digit-sequence}, where // hex-digit-sequence is the shortest hexadecimal representation of U using // lower-case hexadecimal digits. template _LIBCPP_HIDE_FROM_ABI void __write_escape_ill_formed_code_unit(basic_string<_CharT>& __str, char32_t __value) { __formatter::__write_escaped_code_unit(__str, __value, _LIBCPP_STATICALLY_WIDEN(_CharT, "\\x{")); } template [[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool __is_escaped_sequence_written(basic_string<_CharT>& __str, char32_t __value) { # ifdef _LIBCPP_HAS_NO_UNICODE // For ASCII assume everything above 127 is printable. if (__value > 127) return false; # endif if (!__escaped_output_table::__needs_escape(__value)) return false; __formatter::__write_well_formed_escaped_code_unit(__str, __value); return true; } template [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr char32_t __to_char32(_CharT __value) { return static_cast>(__value); } enum class _LIBCPP_ENUM_VIS __escape_quotation_mark { __apostrophe, __double_quote }; // [format.string.escaped]/2 template [[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool __is_escaped_sequence_written(basic_string<_CharT>& __str, char32_t __value, __escape_quotation_mark __mark) { // 2.2.1.1 - Mapped character in [tab:format.escape.sequences] switch (__value) { case _CharT('\t'): __str += _LIBCPP_STATICALLY_WIDEN(_CharT, "\\t"); return true; case _CharT('\n'): __str += _LIBCPP_STATICALLY_WIDEN(_CharT, "\\n"); return true; case _CharT('\r'): __str += _LIBCPP_STATICALLY_WIDEN(_CharT, "\\r"); return true; case _CharT('\''): if (__mark == __escape_quotation_mark::__apostrophe) __str += _LIBCPP_STATICALLY_WIDEN(_CharT, R"(\')"); else __str += __value; return true; case _CharT('"'): if (__mark == __escape_quotation_mark::__double_quote) __str += _LIBCPP_STATICALLY_WIDEN(_CharT, R"(\")"); else __str += __value; return true; case _CharT('\\'): __str += _LIBCPP_STATICALLY_WIDEN(_CharT, R"(\\)"); return true; // 2.2.1.2 - Space case _CharT(' '): __str += __value; return true; } // 2.2.2 // Otherwise, if X is a shift sequence, the effect on E and further // decoding of S is unspecified. // For now shift sequences are ignored and treated as Unicode. Other parts // of the format library do the same. It's unknown how ostream treats them. // TODO FMT determine what to do with shift sequences. // 2.2.1.2.1 and 2.2.1.2.2 - Escape return __formatter::__is_escaped_sequence_written(__str, __formatter::__to_char32(__value)); } template _LIBCPP_HIDE_FROM_ABI void __escape(basic_string<_CharT>& __str, basic_string_view<_CharT> __values, __escape_quotation_mark __mark) { __unicode::__code_point_view<_CharT> __view{__values.begin(), __values.end()}; while (!__view.__at_end()) { const _CharT* __first = __view.__position(); typename __unicode::__consume_p2286_result __result = __view.__consume_p2286(); if (__result.__ill_formed_size == 0) { if (!__formatter::__is_escaped_sequence_written(__str, __result.__value, __mark)) // 2.2.1.3 - Add the character ranges::copy(__first, __view.__position(), std::back_insert_iterator(__str)); } else { // 2.2.3 sequence of ill-formed code units // The number of code-units in __result.__value depends on the character type being used. if constexpr (sizeof(_CharT) == 1) { _LIBCPP_ASSERT(__result.__ill_formed_size == 1 || __result.__ill_formed_size == 4, "illegal number of invalid code units."); if (__result.__ill_formed_size == 1) // ill-formed, one code unit __formatter::__write_escape_ill_formed_code_unit(__str, __result.__value & 0xff); else { // out of valid range, four code units // The code point was properly encoded, decode the value. __formatter::__write_escape_ill_formed_code_unit(__str, __result.__value >> 18 | 0xf0); __formatter::__write_escape_ill_formed_code_unit(__str, (__result.__value >> 12 & 0x3f) | 0x80); __formatter::__write_escape_ill_formed_code_unit(__str, (__result.__value >> 6 & 0x3f) | 0x80); __formatter::__write_escape_ill_formed_code_unit(__str, (__result.__value & 0x3f) | 0x80); } } else if constexpr (sizeof(_CharT) == 2) { _LIBCPP_ASSERT(__result.__ill_formed_size == 1, "for UTF-16 at most one invalid code unit"); __formatter::__write_escape_ill_formed_code_unit(__str, __result.__value & 0xffff); } else { static_assert(sizeof(_CharT) == 4, "unsupported character width"); _LIBCPP_ASSERT(__result.__ill_formed_size == 1, "for UTF-32 one code unit is one code point"); __formatter::__write_escape_ill_formed_code_unit(__str, __result.__value); } } } } template _LIBCPP_HIDE_FROM_ABI auto __format_escaped_char(_CharT __value, output_iterator auto __out_it, __format_spec::__parsed_specifications<_CharT> __specs) -> decltype(__out_it) { basic_string<_CharT> __str; __str += _CharT('\''); __formatter::__escape(__str, basic_string_view{std::addressof(__value), 1}, __escape_quotation_mark::__apostrophe); __str += _CharT('\''); return __formatter::__write(__str.data(), __str.data() + __str.size(), _VSTD::move(__out_it), __specs, __str.size()); } template _LIBCPP_HIDE_FROM_ABI auto __format_escaped_string(basic_string_view<_CharT> __values, output_iterator auto __out_it, __format_spec::__parsed_specifications<_CharT> __specs) -> decltype(__out_it) { basic_string<_CharT> __str; __str += _CharT('"'); __formatter::__escape(__str, __values, __escape_quotation_mark::__double_quote); __str += _CharT('"'); return __formatter::__write_string(basic_string_view{__str}, _VSTD::move(__out_it), __specs); } # endif // _LIBCPP_STD_VER > 20 } // namespace __formatter #endif //_LIBCPP_STD_VER > 17 _LIBCPP_END_NAMESPACE_STD #endif // _LIBCPP___FORMAT_FORMATTER_OUTPUT_H