| // -*- 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_FLOATING_POINT_H |
| #define _LIBCPP___FORMAT_FORMATTER_FLOATING_POINT_H |
| |
| #include <__algorithm/copy.h> |
| #include <__algorithm/copy_n.h> |
| #include <__algorithm/fill_n.h> |
| #include <__algorithm/find.h> |
| #include <__algorithm/min.h> |
| #include <__algorithm/rotate.h> |
| #include <__algorithm/transform.h> |
| #include <__assert> |
| #include <__concepts/arithmetic.h> |
| #include <__config> |
| #include <__format/format_error.h> |
| #include <__format/format_fwd.h> |
| #include <__format/format_string.h> |
| #include <__format/formatter.h> |
| #include <__format/formatter_integral.h> |
| #include <__format/parser_std_format_spec.h> |
| #include <__utility/move.h> |
| #include <__utility/unreachable.h> |
| #include <charconv> |
| #include <cmath> |
| |
| #ifndef _LIBCPP_HAS_NO_LOCALIZATION |
| # include <locale> |
| #endif |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER > 17 |
| |
| namespace __format_spec { |
| |
| template <floating_point _Tp> |
| _LIBCPP_HIDE_FROM_ABI char* __to_buffer(char* __first, char* __last, _Tp __value) { |
| to_chars_result __r = _VSTD::to_chars(__first, __last, __value); |
| _LIBCPP_ASSERT(__r.ec == errc(0), "Internal buffer too small"); |
| return __r.ptr; |
| } |
| |
| template <floating_point _Tp> |
| _LIBCPP_HIDE_FROM_ABI char* __to_buffer(char* __first, char* __last, _Tp __value, chars_format __fmt) { |
| to_chars_result __r = _VSTD::to_chars(__first, __last, __value, __fmt); |
| _LIBCPP_ASSERT(__r.ec == errc(0), "Internal buffer too small"); |
| return __r.ptr; |
| } |
| |
| template <floating_point _Tp> |
| _LIBCPP_HIDE_FROM_ABI char* __to_buffer(char* __first, char* __last, _Tp __value, chars_format __fmt, int __precision) { |
| to_chars_result __r = _VSTD::to_chars(__first, __last, __value, __fmt, __precision); |
| _LIBCPP_ASSERT(__r.ec == errc(0), "Internal buffer too small"); |
| return __r.ptr; |
| } |
| |
| // https://en.cppreference.com/w/cpp/language/types#cite_note-1 |
| // float min subnormal: +/-0x1p-149 max: +/- 3.402,823,4 10^38 |
| // double min subnormal: +/-0x1p-1074 max +/- 1.797,693,134,862,315,7 10^308 |
| // long double (x86) min subnormal: +/-0x1p-16446 max: +/- 1.189,731,495,357,231,765,021 10^4932 |
| // |
| // The maximum number of digits required for the integral part is based on the |
| // maximum's value power of 10. Every power of 10 requires one additional |
| // decimal digit. |
| // The maximum number of digits required for the fractional part is based on |
| // the minimal subnormal hexadecimal output's power of 10. Every division of a |
| // fraction's binary 1 by 2, requires one additional decimal digit. |
| // |
| // The maximum size of a formatted value depends on the selected output format. |
| // Ignoring the fact the format string can request a precision larger than the |
| // values maximum required, these values are: |
| // |
| // sign 1 code unit |
| // __max_integral |
| // radix point 1 code unit |
| // __max_fractional |
| // exponent character 1 code unit |
| // sign 1 code unit |
| // __max_fractional_value |
| // ----------------------------------- |
| // total 4 code units extra required. |
| // |
| // TODO FMT Optimize the storage to avoid storing digits that are known to be zero. |
| // https://www.exploringbinary.com/maximum-number-of-decimal-digits-in-binary-floating-point-numbers/ |
| |
| // TODO FMT Add long double specialization when to_chars has proper long double support. |
| template <class _Tp> |
| struct __traits; |
| |
| template <floating_point _Fp> |
| static constexpr size_t __float_buffer_size(int __precision) { |
| using _Traits = __traits<_Fp>; |
| return 4 + _Traits::__max_integral + __precision + _Traits::__max_fractional_value; |
| } |
| |
| template <> |
| struct __traits<float> { |
| static constexpr int __max_integral = 38; |
| static constexpr int __max_fractional = 149; |
| static constexpr int __max_fractional_value = 3; |
| static constexpr size_t __stack_buffer_size = 256; |
| |
| static constexpr int __hex_precision_digits = 3; |
| }; |
| |
| template <> |
| struct __traits<double> { |
| static constexpr int __max_integral = 308; |
| static constexpr int __max_fractional = 1074; |
| static constexpr int __max_fractional_value = 4; |
| static constexpr size_t __stack_buffer_size = 1024; |
| |
| static constexpr int __hex_precision_digits = 4; |
| }; |
| |
| /// Helper class to store the conversion buffer. |
| /// |
| /// Depending on the maxium size required for a value, the buffer is allocated |
| /// on the stack or the heap. |
| template <floating_point _Fp> |
| class _LIBCPP_TEMPLATE_VIS __float_buffer { |
| using _Traits = __traits<_Fp>; |
| |
| public: |
| // TODO FMT Improve this constructor to do a better estimate. |
| // When using a scientific formatting with a precision of 6 a stack buffer |
| // will always suffice. At the moment that isn't important since floats and |
| // doubles use a stack buffer, unless the precision used in the format string |
| // is large. |
| // When supporting long doubles the __max_integral part becomes 4932 which |
| // may be too much for some platforms. For these cases a better estimate is |
| // required. |
| explicit _LIBCPP_HIDE_FROM_ABI __float_buffer(int __precision) |
| : __precision_(__precision != -1 ? __precision : _Traits::__max_fractional) { |
| |
| // When the precision is larger than _Traits::__max_fractional the digits in |
| // the range (_Traits::__max_fractional, precision] will contain the value |
| // zero. There's no need to request to_chars to write these zeros: |
| // - When the value is large a temporary heap buffer needs to be allocated. |
| // - When to_chars writes the values they need to be "copied" to the output: |
| // - char: std::fill on the output iterator is faster than std::copy. |
| // - wchar_t: same argument as char, but additional std::copy won't work. |
| // The input is always a char buffer, so every char in the buffer needs |
| // to be converted from a char to a wchar_t. |
| if (__precision_ > _Traits::__max_fractional) { |
| __num_trailing_zeros_ = __precision_ - _Traits::__max_fractional; |
| __precision_ = _Traits::__max_fractional; |
| } |
| |
| __size_ = __format_spec::__float_buffer_size<_Fp>(__precision_); |
| if (__size_ > _Traits::__stack_buffer_size) |
| // The allocated buffer's contents don't need initialization. |
| __begin_ = allocator<char>{}.allocate(__size_); |
| else |
| __begin_ = __buffer_; |
| } |
| |
| _LIBCPP_HIDE_FROM_ABI ~__float_buffer() { |
| if (__size_ > _Traits::__stack_buffer_size) |
| allocator<char>{}.deallocate(__begin_, __size_); |
| } |
| _LIBCPP_HIDE_FROM_ABI __float_buffer(const __float_buffer&) = delete; |
| _LIBCPP_HIDE_FROM_ABI __float_buffer& operator=(const __float_buffer&) = delete; |
| |
| _LIBCPP_HIDE_FROM_ABI char* begin() const { return __begin_; } |
| _LIBCPP_HIDE_FROM_ABI char* end() const { return __begin_ + __size_; } |
| |
| _LIBCPP_HIDE_FROM_ABI int __precision() const { return __precision_; } |
| _LIBCPP_HIDE_FROM_ABI int __num_trailing_zeros() const { return __num_trailing_zeros_; } |
| _LIBCPP_HIDE_FROM_ABI void __remove_trailing_zeros() { __num_trailing_zeros_ = 0; } |
| |
| private: |
| int __precision_; |
| int __num_trailing_zeros_{0}; |
| size_t __size_; |
| char* __begin_; |
| char __buffer_[_Traits::__stack_buffer_size]; |
| }; |
| |
| struct __float_result { |
| /// Points at the beginning of the integral part in the buffer. |
| /// |
| /// When there's no sign character this points at the start of the buffer. |
| char* __integral; |
| |
| /// Points at the radix point, when not present it's the same as \ref __last. |
| char* __radix_point; |
| |
| /// Points at the exponent character, when not present it's the same as \ref __last. |
| char* __exponent; |
| |
| /// Points beyond the last written element in the buffer. |
| char* __last; |
| }; |
| |
| /// Finds the position of the exponent character 'e' at the end of the buffer. |
| /// |
| /// Assuming there is an exponent the input will terminate with |
| /// eSdd and eSdddd (S = sign, d = digit) |
| /// |
| /// \returns a pointer to the exponent or __last when not found. |
| constexpr inline _LIBCPP_HIDE_FROM_ABI char* __find_exponent(char* __first, char* __last) { |
| ptrdiff_t __size = __last - __first; |
| if (__size > 4) { |
| __first = __last - _VSTD::min(__size, ptrdiff_t(6)); |
| for (; __first != __last - 3; ++__first) { |
| if (*__first == 'e') |
| return __first; |
| } |
| } |
| return __last; |
| } |
| |
| template <class _Fp, class _Tp> |
| _LIBCPP_HIDE_FROM_ABI __float_result __format_buffer_default(const __float_buffer<_Fp>& __buffer, _Tp __value, |
| char* __integral) { |
| __float_result __result; |
| __result.__integral = __integral; |
| __result.__last = __format_spec::__to_buffer(__integral, __buffer.end(), __value); |
| |
| __result.__exponent = __format_spec::__find_exponent(__result.__integral, __result.__last); |
| |
| // Constrains: |
| // - There's at least one decimal digit before the radix point. |
| // - The radix point, when present, is placed before the exponent. |
| __result.__radix_point = _VSTD::find(__result.__integral + 1, __result.__exponent, '.'); |
| |
| // When the radix point isn't found its position is the exponent instead of |
| // __result.__last. |
| if (__result.__radix_point == __result.__exponent) |
| __result.__radix_point = __result.__last; |
| |
| // clang-format off |
| _LIBCPP_ASSERT((__result.__integral != __result.__last) && |
| (__result.__radix_point == __result.__last || *__result.__radix_point == '.') && |
| (__result.__exponent == __result.__last || *__result.__exponent == 'e'), |
| "Post-condition failure."); |
| // clang-format on |
| |
| return __result; |
| } |
| |
| template <class _Fp, class _Tp> |
| _LIBCPP_HIDE_FROM_ABI __float_result __format_buffer_hexadecimal_lower_case(const __float_buffer<_Fp>& __buffer, |
| _Tp __value, int __precision, |
| char* __integral) { |
| __float_result __result; |
| __result.__integral = __integral; |
| if (__precision == -1) |
| __result.__last = __format_spec::__to_buffer(__integral, __buffer.end(), __value, chars_format::hex); |
| else |
| __result.__last = __format_spec::__to_buffer(__integral, __buffer.end(), __value, chars_format::hex, __precision); |
| |
| // H = one or more hex-digits |
| // S = sign |
| // D = one or more decimal-digits |
| // When the fractional part is zero and no precision the output is 0p+0 |
| // else the output is 0.HpSD |
| // So testing the second position can differentiate between these two cases. |
| char* __first = __integral + 1; |
| if (*__first == '.') { |
| __result.__radix_point = __first; |
| // One digit is the minimum |
| // 0.hpSd |
| // ^-- last |
| // ^---- integral = end of search |
| // ^-------- start of search |
| // 0123456 |
| // |
| // Four digits is the maximum |
| // 0.hpSdddd |
| // ^-- last |
| // ^---- integral = end of search |
| // ^-------- start of search |
| // 0123456789 |
| static_assert(__traits<_Fp>::__hex_precision_digits <= 4, "Guard against possible underflow."); |
| |
| char* __last = __result.__last - 2; |
| __first = __last - __traits<_Fp>::__hex_precision_digits; |
| __result.__exponent = _VSTD::find(__first, __last, 'p'); |
| } else { |
| __result.__radix_point = __result.__last; |
| __result.__exponent = __first; |
| } |
| |
| // clang-format off |
| _LIBCPP_ASSERT((__result.__integral != __result.__last) && |
| (__result.__radix_point == __result.__last || *__result.__radix_point == '.') && |
| (__result.__exponent != __result.__last && *__result.__exponent == 'p'), |
| "Post-condition failure."); |
| // clang-format on |
| |
| return __result; |
| } |
| |
| template <class _Fp, class _Tp> |
| _LIBCPP_HIDE_FROM_ABI __float_result __format_buffer_hexadecimal_upper_case(const __float_buffer<_Fp>& __buffer, |
| _Tp __value, int __precision, |
| char* __integral) { |
| __float_result __result = |
| __format_spec::__format_buffer_hexadecimal_lower_case(__buffer, __value, __precision, __integral); |
| _VSTD::transform(__result.__integral, __result.__exponent, __result.__integral, __hex_to_upper); |
| *__result.__exponent = 'P'; |
| return __result; |
| } |
| |
| template <class _Fp, class _Tp> |
| _LIBCPP_HIDE_FROM_ABI __float_result __format_buffer_scientific_lower_case(const __float_buffer<_Fp>& __buffer, |
| _Tp __value, int __precision, |
| char* __integral) { |
| __float_result __result; |
| __result.__integral = __integral; |
| __result.__last = |
| __format_spec::__to_buffer(__integral, __buffer.end(), __value, chars_format::scientific, __precision); |
| |
| char* __first = __integral + 1; |
| _LIBCPP_ASSERT(__first != __result.__last, "No exponent present"); |
| if (*__first == '.') { |
| __result.__radix_point = __first; |
| __result.__exponent = __format_spec::__find_exponent(__first + 1, __result.__last); |
| } else { |
| __result.__radix_point = __result.__last; |
| __result.__exponent = __first; |
| } |
| |
| // clang-format off |
| _LIBCPP_ASSERT((__result.__integral != __result.__last) && |
| (__result.__radix_point == __result.__last || *__result.__radix_point == '.') && |
| (__result.__exponent != __result.__last && *__result.__exponent == 'e'), |
| "Post-condition failure."); |
| // clang-format on |
| return __result; |
| } |
| |
| template <class _Fp, class _Tp> |
| _LIBCPP_HIDE_FROM_ABI __float_result __format_buffer_scientific_upper_case(const __float_buffer<_Fp>& __buffer, |
| _Tp __value, int __precision, |
| char* __integral) { |
| __float_result __result = |
| __format_spec::__format_buffer_scientific_lower_case(__buffer, __value, __precision, __integral); |
| *__result.__exponent = 'E'; |
| return __result; |
| } |
| |
| template <class _Fp, class _Tp> |
| _LIBCPP_HIDE_FROM_ABI __float_result __format_buffer_fixed(const __float_buffer<_Fp>& __buffer, _Tp __value, |
| int __precision, char* __integral) { |
| __float_result __result; |
| __result.__integral = __integral; |
| __result.__last = __format_spec::__to_buffer(__integral, __buffer.end(), __value, chars_format::fixed, __precision); |
| |
| // When there's no precision there's no radix point. |
| // Else the radix point is placed at __precision + 1 from the end. |
| // By converting __precision to a bool the subtraction can be done |
| // unconditionally. |
| __result.__radix_point = __result.__last - (__precision + bool(__precision)); |
| __result.__exponent = __result.__last; |
| |
| // clang-format off |
| _LIBCPP_ASSERT((__result.__integral != __result.__last) && |
| (__result.__radix_point == __result.__last || *__result.__radix_point == '.') && |
| (__result.__exponent == __result.__last), |
| "Post-condition failure."); |
| // clang-format on |
| return __result; |
| } |
| |
| template <class _Fp, class _Tp> |
| _LIBCPP_HIDE_FROM_ABI __float_result __format_buffer_general_lower_case(__float_buffer<_Fp>& __buffer, _Tp __value, |
| int __precision, char* __integral) { |
| |
| __buffer.__remove_trailing_zeros(); |
| |
| __float_result __result; |
| __result.__integral = __integral; |
| __result.__last = __format_spec::__to_buffer(__integral, __buffer.end(), __value, chars_format::general, __precision); |
| |
| char* __first = __integral + 1; |
| if (__first == __result.__last) { |
| __result.__radix_point = __result.__last; |
| __result.__exponent = __result.__last; |
| } else { |
| __result.__exponent = __format_spec::__find_exponent(__first, __result.__last); |
| if (__result.__exponent != __result.__last) |
| // In scientific mode if there's a radix point it will always be after |
| // the first digit. (This is the position __first points at). |
| __result.__radix_point = *__first == '.' ? __first : __result.__last; |
| else { |
| // In fixed mode the algorithm truncates trailing spaces and possibly the |
| // radix point. There's no good guess for the position of the radix point |
| // therefore scan the output after the first digit. |
| __result.__radix_point = _VSTD::find(__first, __result.__last, '.'); |
| } |
| } |
| |
| // clang-format off |
| _LIBCPP_ASSERT((__result.__integral != __result.__last) && |
| (__result.__radix_point == __result.__last || *__result.__radix_point == '.') && |
| (__result.__exponent == __result.__last || *__result.__exponent == 'e'), |
| "Post-condition failure."); |
| // clang-format on |
| |
| return __result; |
| } |
| |
| template <class _Fp, class _Tp> |
| _LIBCPP_HIDE_FROM_ABI __float_result __format_buffer_general_upper_case(__float_buffer<_Fp>& __buffer, _Tp __value, |
| int __precision, char* __integral) { |
| __float_result __result = |
| __format_spec::__format_buffer_general_lower_case(__buffer, __value, __precision, __integral); |
| if (__result.__exponent != __result.__last) |
| *__result.__exponent = 'E'; |
| return __result; |
| } |
| |
| # ifndef _LIBCPP_HAS_NO_LOCALIZATION |
| template <class _OutIt, class _Fp, class _CharT> |
| _LIBCPP_HIDE_FROM_ABI _OutIt __format_locale_specific_form(_OutIt __out_it, const __float_buffer<_Fp>& __buffer, |
| const __float_result& __result, _VSTD::locale __loc, |
| size_t __width, _Flags::_Alignment __alignment, |
| _CharT __fill) { |
| const auto& __np = use_facet<numpunct<_CharT>>(__loc); |
| string __grouping = __np.grouping(); |
| char* __first = __result.__integral; |
| // When no radix point or exponent are present __last will be __result.__last. |
| char* __last = _VSTD::min(__result.__radix_point, __result.__exponent); |
| |
| ptrdiff_t __digits = __last - __first; |
| if (!__grouping.empty()) { |
| if (__digits <= __grouping[0]) |
| __grouping.clear(); |
| else |
| __grouping = __determine_grouping(__digits, __grouping); |
| } |
| |
| size_t __size = __result.__last - __buffer.begin() + // Formatted string |
| __buffer.__num_trailing_zeros() + // Not yet rendered zeros |
| __grouping.size() - // Grouping contains one |
| !__grouping.empty(); // additional character |
| |
| __formatter::__padding_size_result __padding = {0, 0}; |
| bool __zero_padding = __alignment == _Flags::_Alignment::__default; |
| if (__size < __width) { |
| if (__zero_padding) { |
| __alignment = _Flags::_Alignment::__right; |
| __fill = _CharT('0'); |
| } |
| |
| __padding = __formatter::__padding_size(__size, __width, __alignment); |
| } |
| |
| // sign and (zero padding or alignment) |
| if (__zero_padding && __first != __buffer.begin()) |
| *__out_it++ = *__buffer.begin(); |
| __out_it = _VSTD::fill_n(_VSTD::move(__out_it), __padding.__before, __fill); |
| if (!__zero_padding && __first != __buffer.begin()) |
| *__out_it++ = *__buffer.begin(); |
| |
| // integral part |
| if (__grouping.empty()) { |
| __out_it = _VSTD::copy_n(__first, __digits, _VSTD::move(__out_it)); |
| } else { |
| auto __r = __grouping.rbegin(); |
| auto __e = __grouping.rend() - 1; |
| _CharT __sep = __np.thousands_sep(); |
| // 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. |
| while (true) { |
| __out_it = _VSTD::copy_n(__first, *__r, _VSTD::move(__out_it)); |
| __first += *__r; |
| |
| if (__r == __e) |
| break; |
| |
| ++__r; |
| *__out_it++ = __sep; |
| } |
| } |
| |
| // fractional part |
| if (__result.__radix_point != __result.__last) { |
| *__out_it++ = __np.decimal_point(); |
| __out_it = _VSTD::copy(__result.__radix_point + 1, __result.__exponent, _VSTD::move(__out_it)); |
| __out_it = _VSTD::fill_n(_VSTD::move(__out_it), __buffer.__num_trailing_zeros(), _CharT('0')); |
| } |
| |
| // exponent |
| if (__result.__exponent != __result.__last) |
| __out_it = _VSTD::copy(__result.__exponent, __result.__last, _VSTD::move(__out_it)); |
| |
| // alignment |
| return _VSTD::fill_n(_VSTD::move(__out_it), __padding.__after, __fill); |
| } |
| |
| # endif // _LIBCPP_HAS_NO_LOCALIZATION |
| |
| template <__formatter::__char_type _CharT> |
| class _LIBCPP_TEMPLATE_VIS __formatter_floating_point : public __parser_floating_point<_CharT> { |
| public: |
| template <floating_point _Tp> |
| _LIBCPP_HIDE_FROM_ABI auto format(_Tp __value, auto& __ctx) -> decltype(__ctx.out()) { |
| if (this->__width_needs_substitution()) |
| this->__substitute_width_arg_id(__ctx.arg(this->__width)); |
| |
| bool __negative = _VSTD::signbit(__value); |
| |
| if (!_VSTD::isfinite(__value)) [[unlikely]] |
| return __format_non_finite(__ctx.out(), __negative, _VSTD::isnan(__value)); |
| |
| bool __has_precision = this->__has_precision_field(); |
| if (this->__precision_needs_substitution()) |
| this->__substitute_precision_arg_id(__ctx.arg(this->__precision)); |
| |
| // Depending on the std-format-spec string the sign and the value |
| // might not be outputted together: |
| // - zero-padding may insert additional '0' characters. |
| // Therefore the value is processed as a non negative value. |
| // The function @ref __insert_sign will insert a '-' when the value was |
| // negative. |
| |
| if (__negative) |
| __value = _VSTD::copysign(__value, +1.0); |
| |
| // TODO FMT _Fp should just be _Tp when to_chars has proper long double support. |
| using _Fp = conditional_t<same_as<_Tp, long double>, double, _Tp>; |
| // Force the type of the precision to avoid -1 to become an unsigned value. |
| __float_buffer<_Fp> __buffer(__has_precision ? int(this->__precision) : -1); |
| __float_result __result = __format_buffer(__buffer, __value, __negative, __has_precision); |
| |
| if (this->__alternate_form && __result.__radix_point == __result.__last) { |
| *__result.__last++ = '.'; |
| |
| // When there is an exponent the point needs to be moved before the |
| // exponent. When there's no exponent the rotate does nothing. Since |
| // rotate tests whether the operation is a nop, call it unconditionally. |
| _VSTD::rotate(__result.__exponent, __result.__last - 1, __result.__last); |
| __result.__radix_point = __result.__exponent; |
| |
| // The radix point is always placed before the exponent. |
| // - No exponent needs to point to the new last. |
| // - An exponent needs to move one position to the right. |
| // So it's safe to increment the value unconditionally. |
| ++__result.__exponent; |
| } |
| |
| # ifndef _LIBCPP_HAS_NO_LOCALIZATION |
| if (this->__locale_specific_form) |
| return __format_spec::__format_locale_specific_form(__ctx.out(), __buffer, __result, __ctx.locale(), |
| this->__width, this->__alignment, this->__fill); |
| # endif |
| |
| ptrdiff_t __size = __result.__last - __buffer.begin(); |
| int __num_trailing_zeros = __buffer.__num_trailing_zeros(); |
| if (__size + __num_trailing_zeros >= this->__width) { |
| if (__num_trailing_zeros && __result.__exponent != __result.__last) |
| // Insert trailing zeros before exponent character. |
| return _VSTD::copy(__result.__exponent, __result.__last, |
| _VSTD::fill_n(_VSTD::copy(__buffer.begin(), __result.__exponent, __ctx.out()), |
| __num_trailing_zeros, _CharT('0'))); |
| |
| return _VSTD::fill_n(_VSTD::copy(__buffer.begin(), __result.__last, __ctx.out()), __num_trailing_zeros, |
| _CharT('0')); |
| } |
| |
| auto __out_it = __ctx.out(); |
| char* __first = __buffer.begin(); |
| if (this->__alignment == _Flags::_Alignment::__default) { |
| // When there is a sign output it before the padding. Note the __size |
| // doesn't need any adjustment, regardless whether the sign is written |
| // here or in __formatter::__write. |
| if (__first != __result.__integral) |
| *__out_it++ = *__first++; |
| // After the sign is written, zero padding is the same a right alignment |
| // with '0'. |
| this->__alignment = _Flags::_Alignment::__right; |
| this->__fill = _CharT('0'); |
| } |
| |
| if (__num_trailing_zeros) |
| return __formatter::__write(_VSTD::move(__out_it), __first, __result.__last, __size, this->__width, this->__fill, |
| this->__alignment, __result.__exponent, __num_trailing_zeros); |
| |
| return __formatter::__write(_VSTD::move(__out_it), __first, __result.__last, __size, this->__width, this->__fill, |
| this->__alignment); |
| } |
| |
| private: |
| template <class _OutIt> |
| _LIBCPP_HIDE_FROM_ABI _OutIt __format_non_finite(_OutIt __out_it, bool __negative, bool __isnan) { |
| char __buffer[4]; |
| char* __last = __insert_sign(__buffer, __negative, this->__sign); |
| |
| // to_char can return inf, infinity, nan, and nan(n-char-sequence). |
| // The format library requires inf and nan. |
| // All in one expression to avoid dangling references. |
| __last = _VSTD::copy_n(&("infnanINFNAN"[6 * (this->__type == _Flags::_Type::__float_hexadecimal_upper_case || |
| this->__type == _Flags::_Type::__scientific_upper_case || |
| this->__type == _Flags::_Type::__fixed_upper_case || |
| this->__type == _Flags::_Type::__general_upper_case) + |
| 3 * __isnan]), |
| 3, __last); |
| |
| // [format.string.std]/13 |
| // A zero (0) character preceding the width field pads the field with |
| // leading zeros (following any indication of sign or base) to the field |
| // width, except when applied to an infinity or NaN. |
| if (this->__alignment == _Flags::_Alignment::__default) |
| this->__alignment = _Flags::_Alignment::__right; |
| |
| ptrdiff_t __size = __last - __buffer; |
| if (__size >= this->__width) |
| return _VSTD::copy_n(__buffer, __size, _VSTD::move(__out_it)); |
| |
| return __formatter::__write(_VSTD::move(__out_it), __buffer, __last, __size, this->__width, this->__fill, |
| this->__alignment); |
| } |
| |
| /// Fills the buffer with the data based on the requested formatting. |
| /// |
| /// This function, when needed, turns the characters to upper case and |
| /// determines the "interesting" locations which are returned to the caller. |
| /// |
| /// This means the caller never has to convert the contents of the buffer to |
| /// upper case or search for radix points and the location of the exponent. |
| /// This gives a bit of overhead. The original code didn't do that, but due |
| /// to the number of possible additional work needed to turn this number to |
| /// the proper output the code was littered with tests for upper cases and |
| /// searches for radix points and exponents. |
| /// - When a precision larger than the type's precision is selected |
| /// additional zero characters need to be written before the exponent. |
| /// - alternate form needs to add a radix point when not present. |
| /// - localization needs to do grouping in the integral part. |
| template <class _Fp, class _Tp> |
| // TODO FMT _Fp should just be _Tp when to_chars has proper long double support. |
| _LIBCPP_HIDE_FROM_ABI __float_result __format_buffer(__float_buffer<_Fp>& __buffer, _Tp __value, bool __negative, |
| bool __has_precision) { |
| char* __first = __insert_sign(__buffer.begin(), __negative, this->__sign); |
| switch (this->__type) { |
| case _Flags::_Type::__default: |
| return __format_spec::__format_buffer_default(__buffer, __value, __first); |
| |
| case _Flags::_Type::__float_hexadecimal_lower_case: |
| return __format_spec::__format_buffer_hexadecimal_lower_case( |
| __buffer, __value, __has_precision ? __buffer.__precision() : -1, __first); |
| |
| case _Flags::_Type::__float_hexadecimal_upper_case: |
| return __format_spec::__format_buffer_hexadecimal_upper_case( |
| __buffer, __value, __has_precision ? __buffer.__precision() : -1, __first); |
| |
| case _Flags::_Type::__scientific_lower_case: |
| return __format_spec::__format_buffer_scientific_lower_case(__buffer, __value, __buffer.__precision(), __first); |
| |
| case _Flags::_Type::__scientific_upper_case: |
| return __format_spec::__format_buffer_scientific_upper_case(__buffer, __value, __buffer.__precision(), __first); |
| |
| case _Flags::_Type::__fixed_lower_case: |
| case _Flags::_Type::__fixed_upper_case: |
| return __format_spec::__format_buffer_fixed(__buffer, __value, __buffer.__precision(), __first); |
| |
| case _Flags::_Type::__general_lower_case: |
| return __format_spec::__format_buffer_general_lower_case(__buffer, __value, __buffer.__precision(), __first); |
| |
| case _Flags::_Type::__general_upper_case: |
| return __format_spec::__format_buffer_general_upper_case(__buffer, __value, __buffer.__precision(), __first); |
| |
| default: |
| _LIBCPP_ASSERT(false, "The parser should have validated the type"); |
| __libcpp_unreachable(); |
| } |
| } |
| }; |
| |
| } //namespace __format_spec |
| |
| template <__formatter::__char_type _CharT> |
| struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<float, _CharT> |
| : public __format_spec::__formatter_floating_point<_CharT> {}; |
| template <__formatter::__char_type _CharT> |
| struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<double, _CharT> |
| : public __format_spec::__formatter_floating_point<_CharT> {}; |
| template <__formatter::__char_type _CharT> |
| struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<long double, _CharT> |
| : public __format_spec::__formatter_floating_point<_CharT> {}; |
| |
| #endif //_LIBCPP_STD_VER > 17 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP___FORMAT_FORMATTER_FLOATING_POINT_H |
