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Diffstat (limited to 'contrib/llvm-project/libcxx/include/__charconv/from_chars_integral.h')
| -rw-r--r-- | contrib/llvm-project/libcxx/include/__charconv/from_chars_integral.h | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__charconv/from_chars_integral.h b/contrib/llvm-project/libcxx/include/__charconv/from_chars_integral.h new file mode 100644 index 000000000000..acfdf4b30da7 --- /dev/null +++ b/contrib/llvm-project/libcxx/include/__charconv/from_chars_integral.h @@ -0,0 +1,239 @@ +// -*- 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___CHARCONV_FROM_CHARS_INTEGRAL_H +#define _LIBCPP___CHARCONV_FROM_CHARS_INTEGRAL_H + +#include <__algorithm/copy_n.h> +#include <__charconv/from_chars_result.h> +#include <__charconv/traits.h> +#include <__config> +#include <__memory/addressof.h> +#include <__system_error/errc.h> +#include <__type_traits/enable_if.h> +#include <__type_traits/integral_constant.h> +#include <__type_traits/is_integral.h> +#include <__type_traits/is_unsigned.h> +#include <__type_traits/make_unsigned.h> +#include <limits> + +#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 + +from_chars_result from_chars(const char*, const char*, bool, int = 10) = delete; + +template <typename _It, typename _Tp, typename _Fn, typename... _Ts> +inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI from_chars_result +__sign_combinator(_It __first, _It __last, _Tp& __value, _Fn __f, _Ts... __args) { + using __tl = numeric_limits<_Tp>; + decltype(std::__to_unsigned_like(__value)) __x; + + bool __neg = (__first != __last && *__first == '-'); + auto __r = __f(__neg ? __first + 1 : __first, __last, __x, __args...); + switch (__r.ec) { + case errc::invalid_argument: + return {__first, __r.ec}; + case errc::result_out_of_range: + return __r; + default: + break; + } + + if (__neg) { + if (__x <= std::__complement(std::__to_unsigned_like(__tl::min()))) { + __x = std::__complement(__x); + std::copy_n(std::addressof(__x), 1, std::addressof(__value)); + return __r; + } + } else { + if (__x <= std::__to_unsigned_like(__tl::max())) { + __value = __x; + return __r; + } + } + + return {__r.ptr, errc::result_out_of_range}; +} + +template <typename _Tp> +inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool __in_pattern(_Tp __c) { + return '0' <= __c && __c <= '9'; +} + +struct _LIBCPP_HIDDEN __in_pattern_result { + bool __ok; + int __val; + + explicit _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI operator bool() const { return __ok; } +}; + +template <typename _Tp> +inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI __in_pattern_result __in_pattern(_Tp __c, int __base) { + if (__base <= 10) + return {'0' <= __c && __c < '0' + __base, __c - '0'}; + else if (std::__in_pattern(__c)) + return {true, __c - '0'}; + else if ('a' <= __c && __c < 'a' + __base - 10) + return {true, __c - 'a' + 10}; + else + return {'A' <= __c && __c < 'A' + __base - 10, __c - 'A' + 10}; +} + +template <typename _It, typename _Tp, typename _Fn, typename... _Ts> +inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI from_chars_result +__subject_seq_combinator(_It __first, _It __last, _Tp& __value, _Fn __f, _Ts... __args) { + auto __find_non_zero = [](_It __firstit, _It __lastit) { + for (; __firstit != __lastit; ++__firstit) + if (*__firstit != '0') + break; + return __firstit; + }; + + auto __p = __find_non_zero(__first, __last); + if (__p == __last || !std::__in_pattern(*__p, __args...)) { + if (__p == __first) + return {__first, errc::invalid_argument}; + else { + __value = 0; + return {__p, {}}; + } + } + + auto __r = __f(__p, __last, __value, __args...); + if (__r.ec == errc::result_out_of_range) { + for (; __r.ptr != __last; ++__r.ptr) { + if (!std::__in_pattern(*__r.ptr, __args...)) + break; + } + } + + return __r; +} + +template <typename _Tp, typename enable_if<is_unsigned<_Tp>::value, int>::type = 0> +inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI from_chars_result +__from_chars_atoi(const char* __first, const char* __last, _Tp& __value) { + using __tx = __itoa::__traits<_Tp>; + using __output_type = typename __tx::type; + + return std::__subject_seq_combinator( + __first, __last, __value, [](const char* __f, const char* __l, _Tp& __val) -> from_chars_result { + __output_type __a, __b; + auto __p = __tx::__read(__f, __l, __a, __b); + if (__p == __l || !std::__in_pattern(*__p)) { + __output_type __m = numeric_limits<_Tp>::max(); + if (__m >= __a && __m - __a >= __b) { + __val = __a + __b; + return {__p, {}}; + } + } + return {__p, errc::result_out_of_range}; + }); +} + +template <typename _Tp, typename enable_if<is_signed<_Tp>::value, int>::type = 0> +inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI from_chars_result +__from_chars_atoi(const char* __first, const char* __last, _Tp& __value) { + using __t = decltype(std::__to_unsigned_like(__value)); + return std::__sign_combinator(__first, __last, __value, __from_chars_atoi<__t>); +} + +/* +// Code used to generate __from_chars_log2f_lut. +#include <cmath> +#include <format> +#include <iostream> + +int main() { + for (int i = 2; i <= 36; ++i) + std::cout << std::format("{},\n", log2f(i)); +} +*/ +/// log2f table for bases [2, 36]. +inline constexpr float __from_chars_log2f_lut[35] = { + 1, 1.5849625, 2, 2.321928, 2.5849626, 2.807355, 3, 3.169925, 3.321928, + 3.4594316, 3.5849626, 3.7004397, 3.807355, 3.9068906, 4, 4.087463, 4.169925, 4.2479277, + 4.321928, 4.3923173, 4.4594316, 4.523562, 4.5849624, 4.643856, 4.70044, 4.7548876, 4.807355, + 4.857981, 4.9068904, 4.9541965, 5, 5.044394, 5.087463, 5.129283, 5.169925}; + +template <typename _Tp, typename enable_if<is_unsigned<_Tp>::value, int>::type = 0> +inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI from_chars_result +__from_chars_integral(const char* __first, const char* __last, _Tp& __value, int __base) { + if (__base == 10) + return std::__from_chars_atoi(__first, __last, __value); + + return std::__subject_seq_combinator( + __first, + __last, + __value, + [](const char* __p, const char* __lastp, _Tp& __val, int __b) -> from_chars_result { + using __tl = numeric_limits<_Tp>; + // __base is always between 2 and 36 inclusive. + auto __digits = __tl::digits / __from_chars_log2f_lut[__b - 2]; + _Tp __x = __in_pattern(*__p++, __b).__val, __y = 0; + + for (int __i = 1; __p != __lastp; ++__i, ++__p) { + if (auto __c = __in_pattern(*__p, __b)) { + if (__i < __digits - 1) + __x = __x * __b + __c.__val; + else { + if (!__itoa::__mul_overflowed(__x, __b, __x)) + ++__p; + __y = __c.__val; + break; + } + } else + break; + } + + if (__p == __lastp || !__in_pattern(*__p, __b)) { + if (__tl::max() - __x >= __y) { + __val = __x + __y; + return {__p, {}}; + } + } + return {__p, errc::result_out_of_range}; + }, + __base); +} + +template <typename _Tp, typename enable_if<is_signed<_Tp>::value, int>::type = 0> +inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI from_chars_result +__from_chars_integral(const char* __first, const char* __last, _Tp& __value, int __base) { + using __t = decltype(std::__to_unsigned_like(__value)); + return std::__sign_combinator(__first, __last, __value, __from_chars_integral<__t>, __base); +} + +template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0> +inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI from_chars_result +from_chars(const char* __first, const char* __last, _Tp& __value) { + return std::__from_chars_atoi(__first, __last, __value); +} + +template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0> +inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI from_chars_result +from_chars(const char* __first, const char* __last, _Tp& __value, int __base) { + _LIBCPP_ASSERT_UNCATEGORIZED(2 <= __base && __base <= 36, "base not in [2, 36]"); + return std::__from_chars_integral(__first, __last, __value, __base); +} +#endif // _LIBCPP_STD_VER >= 17 + +_LIBCPP_END_NAMESPACE_STD + +_LIBCPP_POP_MACROS + +#endif // _LIBCPP___CHARCONV_FROM_CHARS_INTEGRAL_H |