// xcharconv_ryu.h internal header


// Copyright 2018 Ulf Adams
// Copyright (c) Microsoft Corporation. All rights reserved.

// Boost Software License - Version 1.0 - August 17th, 2003

// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:

// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.


#pragma once
#ifndef _XCHARCONV_RYU_H
#define _XCHARCONV_RYU_H
#ifndef RC_INVOKED

#include <string.h>
#include <xcharconv.h>

#ifdef _M_X64
 #include <intrin0.h> // for _umul128() and __shiftright128()
#endif // _M_X64

#if !_HAS_CXX17
 #error The contents of <charconv> are only available with C++17. (Also, you should not include this internal header.)
#endif /* !_HAS_CXX17 */

#pragma pack(push,_CRT_PACKING)
#pragma warning(push,_STL_WARNING_LEVEL)
#pragma warning(disable: _STL_DISABLED_WARNINGS)
_STL_DISABLE_CLANG_WARNINGS
#pragma push_macro("new")
#undef new

#pragma warning(disable: 4793) // function compiled as native

_STD_BEGIN

// https://github.com/ulfjack/ryu/tree/955142e/ryu

// vvvvvvvvvv DERIVED FROM common.h vvvvvvvvvv

// Returns __e == 0 ? 1 : ceil(log_2(5^__e)).
_NODISCARD inline int32_t __pow5bits(const int32_t __e) {
	// This approximation works up to the point that the multiplication overflows at __e = 3529.
	// If the multiplication were done in 64 bits, it would fail at 5^4004 which is just greater
	// than 2^9297.
	_STL_INTERNAL_CHECK(__e >= 0, "__e >= 0");
	_STL_INTERNAL_CHECK(__e <= 3528, "__e <= 3528");
	return static_cast<int32_t>(((static_cast<uint32_t>(__e) * 1217359) >> 19) + 1);
}

// Returns floor(log_10(2^__e)).
_NODISCARD inline uint32_t __log10Pow2(const int32_t __e) {
	// The first value this approximation fails for is 2^1651 which is just greater than 10^297.
	_STL_INTERNAL_CHECK(__e >= 0, "__e >= 0");
	_STL_INTERNAL_CHECK(__e <= 1650, "__e <= 1650");
	return (static_cast<uint32_t>(__e) * 78913) >> 18;
}

// Returns floor(log_10(5^__e)).
_NODISCARD inline uint32_t __log10Pow5(const int32_t __e) {
	// The first value this approximation fails for is 5^2621 which is just greater than 10^1832.
	_STL_INTERNAL_CHECK(__e >= 0, "__e >= 0");
	_STL_INTERNAL_CHECK(__e <= 2620, "__e <= 2620");
	return (static_cast<uint32_t>(__e) * 732923) >> 20;
}

_NODISCARD inline uint32_t __float_to_bits(const float __f) {
	uint32_t __bits = 0;
	_CSTD memcpy(&__bits, &__f, sizeof(float));
	return __bits;
}

_NODISCARD inline uint64_t __double_to_bits(const double __d) {
	uint64_t __bits = 0;
	_CSTD memcpy(&__bits, &__d, sizeof(double));
	return __bits;
}

// ^^^^^^^^^^ DERIVED FROM common.h ^^^^^^^^^^

// vvvvvvvvvv DERIVED FROM digit_table.h vvvvvvvvvv

// A table of all two-digit numbers. This is used to speed up decimal digit
// generation by copying pairs of digits into the final output.
inline constexpr char __DIGIT_TABLE[200] = {
	'0','0','0','1','0','2','0','3','0','4','0','5','0','6','0','7','0','8','0','9',
	'1','0','1','1','1','2','1','3','1','4','1','5','1','6','1','7','1','8','1','9',
	'2','0','2','1','2','2','2','3','2','4','2','5','2','6','2','7','2','8','2','9',
	'3','0','3','1','3','2','3','3','3','4','3','5','3','6','3','7','3','8','3','9',
	'4','0','4','1','4','2','4','3','4','4','4','5','4','6','4','7','4','8','4','9',
	'5','0','5','1','5','2','5','3','5','4','5','5','5','6','5','7','5','8','5','9',
	'6','0','6','1','6','2','6','3','6','4','6','5','6','6','6','7','6','8','6','9',
	'7','0','7','1','7','2','7','3','7','4','7','5','7','6','7','7','7','8','7','9',
	'8','0','8','1','8','2','8','3','8','4','8','5','8','6','8','7','8','8','8','9',
	'9','0','9','1','9','2','9','3','9','4','9','5','9','6','9','7','9','8','9','9'
};

// ^^^^^^^^^^ DERIVED FROM digit_table.h ^^^^^^^^^^

// vvvvvvvvvv DERIVED FROM f2s.c vvvvvvvvvv

inline constexpr int __FLOAT_MANTISSA_BITS = 23;
inline constexpr int __FLOAT_EXPONENT_BITS = 8;

// This table is generated by PrintFloatLookupTable.
inline constexpr int __FLOAT_POW5_INV_BITCOUNT = 59;
inline constexpr uint64_t __FLOAT_POW5_INV_SPLIT[31] = {
	576460752303423489u, 461168601842738791u, 368934881474191033u, 295147905179352826u,
	472236648286964522u, 377789318629571618u, 302231454903657294u, 483570327845851670u,
	386856262276681336u, 309485009821345069u, 495176015714152110u, 396140812571321688u,
	316912650057057351u, 507060240091291761u, 405648192073033409u, 324518553658426727u,
	519229685853482763u, 415383748682786211u, 332306998946228969u, 531691198313966350u,
	425352958651173080u, 340282366920938464u, 544451787073501542u, 435561429658801234u,
	348449143727040987u, 557518629963265579u, 446014903970612463u, 356811923176489971u,
	570899077082383953u, 456719261665907162u, 365375409332725730u
};
inline constexpr int __FLOAT_POW5_BITCOUNT = 61;
inline constexpr uint64_t __FLOAT_POW5_SPLIT[47] = {
	1152921504606846976u, 1441151880758558720u, 1801439850948198400u, 2251799813685248000u,
	1407374883553280000u, 1759218604441600000u, 2199023255552000000u, 1374389534720000000u,
	1717986918400000000u, 2147483648000000000u, 1342177280000000000u, 1677721600000000000u,
	2097152000000000000u, 1310720000000000000u, 1638400000000000000u, 2048000000000000000u,
	1280000000000000000u, 1600000000000000000u, 2000000000000000000u, 1250000000000000000u,
	1562500000000000000u, 1953125000000000000u, 1220703125000000000u, 1525878906250000000u,
	1907348632812500000u, 1192092895507812500u, 1490116119384765625u, 1862645149230957031u,
	1164153218269348144u, 1455191522836685180u, 1818989403545856475u, 2273736754432320594u,
	1421085471520200371u, 1776356839400250464u, 2220446049250313080u, 1387778780781445675u,
	1734723475976807094u, 2168404344971008868u, 1355252715606880542u, 1694065894508600678u,
	2117582368135750847u, 1323488980084844279u, 1654361225106055349u, 2067951531382569187u,
	1292469707114105741u, 1615587133892632177u, 2019483917365790221u
};

_NODISCARD inline uint32_t __pow5Factor(uint32_t __value) {
	uint32_t __count = 0;
	for (;;) {
		_STL_INTERNAL_CHECK(__value != 0, "__value != 0");
		const uint32_t __q = __value / 5;
		const uint32_t __r = __value % 5;
		if (__r != 0) {
			break;
		}
		__value = __q;
		++__count;
	}
	return __count;
}

// Returns true if __value is divisible by 5^__p.
_NODISCARD inline bool __multipleOfPowerOf5(const uint32_t __value, const uint32_t __p) {
	return __pow5Factor(__value) >= __p;
}

// Returns true if __value is divisible by 2^__p.
_NODISCARD inline bool __multipleOfPowerOf2(const uint32_t __value, const uint32_t __p) {
	// return __builtin_ctz(__value) >= __p;
	return (__value & ((1u << __p) - 1)) == 0;
}

_NODISCARD inline uint32_t __mulShift(const uint32_t __m, const uint64_t __factor, const int32_t __shift) {
	_STL_INTERNAL_CHECK(__shift > 32, "__shift > 32");

	// The casts here help MSVC to avoid calls to the __allmul library
	// function.
	const uint32_t __factorLo = static_cast<uint32_t>(__factor);
	const uint32_t __factorHi = static_cast<uint32_t>(__factor >> 32);
	const uint64_t __bits0 = static_cast<uint64_t>(__m) * __factorLo;
	const uint64_t __bits1 = static_cast<uint64_t>(__m) * __factorHi;

#ifndef _WIN64
	// On 32-bit platforms we can avoid a 64-bit shift-right since we only
	// need the upper 32 bits of the result and the shift value is > 32.
	const uint32_t __bits0Hi = static_cast<uint32_t>(__bits0 >> 32);
	uint32_t __bits1Lo = static_cast<uint32_t>(__bits1);
	uint32_t __bits1Hi = static_cast<uint32_t>(__bits1 >> 32);
	__bits1Lo += __bits0Hi;
	__bits1Hi += (__bits1Lo < __bits0Hi);
	const int32_t __s = __shift - 32;
	return (__bits1Hi << (32 - __s)) | (__bits1Lo >> __s);
#else // ^^^ 32-bit ^^^ / vvv 64-bit vvv
	const uint64_t __sum = (__bits0 >> 32) + __bits1;
	const uint64_t __shiftedSum = __sum >> (__shift - 32);
	_STL_INTERNAL_CHECK(__shiftedSum <= UINT32_MAX, "__shiftedSum <= UINT32_MAX");
	return static_cast<uint32_t>(__shiftedSum);
#endif // ^^^ 64-bit ^^^
}

_NODISCARD inline uint32_t __mulPow5InvDivPow2(const uint32_t __m, const uint32_t __q, const int32_t __j) {
	return __mulShift(__m, __FLOAT_POW5_INV_SPLIT[__q], __j);
}

_NODISCARD inline uint32_t __mulPow5divPow2(const uint32_t __m, const uint32_t __i, const int32_t __j) {
	return __mulShift(__m, __FLOAT_POW5_SPLIT[__i], __j);
}

_NODISCARD inline uint32_t __decimalLength(const uint32_t __v) {
	// Function precondition: __v is not a 10-digit number.
	// (9 digits are sufficient for round-tripping.)
	_STL_INTERNAL_CHECK(__v < 1000000000, "__v < 1000000000");
	if (__v >= 100000000) { return 9; }
	if (__v >= 10000000) { return 8; }
	if (__v >= 1000000) { return 7; }
	if (__v >= 100000) { return 6; }
	if (__v >= 10000) { return 5; }
	if (__v >= 1000) { return 4; }
	if (__v >= 100) { return 3; }
	if (__v >= 10) { return 2; }
	return 1;
}

// A floating decimal representing m * 10^e.
struct __floating_decimal_32 {
	uint32_t __mantissa;
	int32_t __exponent;
};

_NODISCARD inline __floating_decimal_32 __f2d(const uint32_t __ieeeMantissa, const uint32_t __ieeeExponent) {
	constexpr int32_t __bias = (1u << (__FLOAT_EXPONENT_BITS - 1)) - 1;

	int32_t __e2;
	uint32_t __m2;
	if (__ieeeExponent == 0) {
		// We subtract 2 so that the bounds computation has 2 additional bits.
		__e2 = 1 - __bias - __FLOAT_MANTISSA_BITS - 2;
		__m2 = __ieeeMantissa;
	} else {
		__e2 = static_cast<int32_t>(__ieeeExponent) - __bias - __FLOAT_MANTISSA_BITS - 2;
		__m2 = (1u << __FLOAT_MANTISSA_BITS) | __ieeeMantissa;
	}
	const bool __even = (__m2 & 1) == 0;
	const bool __acceptBounds = __even;

	// Step 2: Determine the interval of valid decimal representations.
	const uint32_t __mv = 4 * __m2;
	const uint32_t __mp = 4 * __m2 + 2;
	// Implicit bool -> int conversion. True is 1, false is 0.
	const uint32_t __mmShift = __ieeeMantissa != 0 || __ieeeExponent <= 1;
	const uint32_t __mm = 4 * __m2 - 1 - __mmShift;

	// Step 3: Convert to a decimal power base using 64-bit arithmetic.
	uint32_t __vr, __vp, __vm;
	int32_t __e10;
	bool __vmIsTrailingZeros = false;
	bool __vrIsTrailingZeros = false;
	uint8_t __lastRemovedDigit = 0;
	if (__e2 >= 0) {
		const uint32_t __q = __log10Pow2(__e2);
		__e10 = static_cast<int32_t>(__q);
		const int32_t __k = __FLOAT_POW5_INV_BITCOUNT + __pow5bits(static_cast<int32_t>(__q)) - 1;
		const int32_t __i = -__e2 + static_cast<int32_t>(__q) + __k;
		__vr = __mulPow5InvDivPow2(__mv, __q, __i);
		__vp = __mulPow5InvDivPow2(__mp, __q, __i);
		__vm = __mulPow5InvDivPow2(__mm, __q, __i);
		if (__q != 0 && (__vp - 1) / 10 <= __vm / 10) {
			// We need to know one removed digit even if we are not going to loop below. We could use
			// __q = X - 1 above, except that would require 33 bits for the result, and we've found that
			// 32-bit arithmetic is faster even on 64-bit machines.
			const int32_t __l = __FLOAT_POW5_INV_BITCOUNT + __pow5bits(static_cast<int32_t>(__q - 1)) - 1;
			__lastRemovedDigit = static_cast<uint8_t>(__mulPow5InvDivPow2(__mv, __q - 1,
				-__e2 + static_cast<int32_t>(__q) - 1 + __l) % 10);
		}
		if (__q <= 9) {
			// The largest power of 5 that fits in 24 bits is 5^10, but __q <= 9 seems to be safe as well.
			// Only one of __mp, __mv, and __mm can be a multiple of 5, if any.
			if (__mv % 5 == 0) {
				__vrIsTrailingZeros = __multipleOfPowerOf5(__mv, __q);
			} else if (__acceptBounds) {
				__vmIsTrailingZeros = __multipleOfPowerOf5(__mm, __q);
			} else {
				__vp -= __multipleOfPowerOf5(__mp, __q);
			}
		}
	} else {
		const uint32_t __q = __log10Pow5(-__e2);
		__e10 = static_cast<int32_t>(__q) + __e2;
		const int32_t __i = -__e2 - static_cast<int32_t>(__q);
		const int32_t __k = __pow5bits(__i) - __FLOAT_POW5_BITCOUNT;
		int32_t __j = static_cast<int32_t>(__q) - __k;
		__vr = __mulPow5divPow2(__mv, static_cast<uint32_t>(__i), __j);
		__vp = __mulPow5divPow2(__mp, static_cast<uint32_t>(__i), __j);
		__vm = __mulPow5divPow2(__mm, static_cast<uint32_t>(__i), __j);
		if (__q != 0 && (__vp - 1) / 10 <= __vm / 10) {
			__j = static_cast<int32_t>(__q) - 1 - (__pow5bits(__i + 1) - __FLOAT_POW5_BITCOUNT);
			__lastRemovedDigit = static_cast<uint8_t>(__mulPow5divPow2(__mv, static_cast<uint32_t>(__i + 1), __j) % 10);
		}
		if (__q <= 1) {
			// {__vr,__vp,__vm} is trailing zeros if {__mv,__mp,__mm} has at least __q trailing 0 bits.
			// __mv = 4 * __m2, so it always has at least two trailing 0 bits.
			__vrIsTrailingZeros = true;
			if (__acceptBounds) {
				// __mm = __mv - 1 - __mmShift, so it has 1 trailing 0 bit iff __mmShift == 1.
				__vmIsTrailingZeros = __mmShift == 1;
			} else {
				// __mp = __mv + 2, so it always has at least one trailing 0 bit.
				--__vp;
			}
		} else if (__q < 31) { // TODO(ulfjack): Use a tighter bound here.
			__vrIsTrailingZeros = __multipleOfPowerOf2(__mv, __q - 1);
		}
	}

	// Step 4: Find the shortest decimal representation in the interval of valid representations.
	int32_t __removed = 0;
	uint32_t __output;
	if (__vmIsTrailingZeros || __vrIsTrailingZeros) {
		// General case, which happens rarely (~4.0%).
		while (__vp / 10 > __vm / 10) {
#ifdef __clang__ // TRANSITION, LLVM#23106
			__vmIsTrailingZeros &= __vm - (__vm / 10) * 10 == 0;
#else
			__vmIsTrailingZeros &= __vm % 10 == 0;
#endif
			__vrIsTrailingZeros &= __lastRemovedDigit == 0;
			__lastRemovedDigit = static_cast<uint8_t>(__vr % 10);
			__vr /= 10;
			__vp /= 10;
			__vm /= 10;
			++__removed;
		}
		if (__vmIsTrailingZeros) {
			while (__vm % 10 == 0) {
				__vrIsTrailingZeros &= __lastRemovedDigit == 0;
				__lastRemovedDigit = static_cast<uint8_t>(__vr % 10);
				__vr /= 10;
				__vp /= 10;
				__vm /= 10;
				++__removed;
			}
		}
		if (__vrIsTrailingZeros && __lastRemovedDigit == 5 && __vr % 2 == 0) {
			// Round even if the exact number is .....50..0.
			__lastRemovedDigit = 4;
		}
		// We need to take __vr + 1 if __vr is outside bounds or we need to round up.
		__output = __vr + ((__vr == __vm && (!__acceptBounds || !__vmIsTrailingZeros)) || __lastRemovedDigit >= 5);
	} else {
		// Specialized for the common case (~96.0%). Percentages below are relative to this.
		// Loop iterations below (approximately):
		// 0: 13.6%, 1: 70.7%, 2: 14.1%, 3: 1.39%, 4: 0.14%, 5+: 0.01%
		while (__vp / 10 > __vm / 10) {
			__lastRemovedDigit = static_cast<uint8_t>(__vr % 10);
			__vr /= 10;
			__vp /= 10;
			__vm /= 10;
			++__removed;
		}
		// We need to take __vr + 1 if __vr is outside bounds or we need to round up.
		__output = __vr + (__vr == __vm || __lastRemovedDigit >= 5);
	}
	const int32_t __exp = __e10 + __removed;

	__floating_decimal_32 __fd;
	__fd.__exponent = __exp;
	__fd.__mantissa = __output;
	return __fd;
}

_NODISCARD inline to_chars_result __to_chars(char * const _First, char * const _Last, const __floating_decimal_32 __v,
	chars_format _Fmt, const uint32_t __ieeeMantissa, const uint32_t __ieeeExponent) {
	// Step 5: Print the decimal representation.
	uint32_t __output = __v.__mantissa;
	const uint32_t __olength = __decimalLength(__output);
	int32_t _Scientific_exponent = __v.__exponent + static_cast<int32_t>(__olength) - 1;

	if (_Fmt == chars_format{}) {
		int32_t _Lower;
		int32_t _Upper;

		if (__olength == 1) {
			// Value | Fixed   | Scientific
			// 1e-3  | "0.001" | "1e-03"
			// 1e4   | "10000" | "1e+04"
			_Lower = -3;
			_Upper = 4;
		} else {
			// Value   | Fixed       | Scientific
			// 1234e-7 | "0.0001234" | "1.234e-04"
			// 1234e5  | "123400000" | "1.234e+08"
			_Lower = -static_cast<int32_t>(__olength + 3);
			_Upper = 5;
		}

		if (_Lower <= __v.__exponent && __v.__exponent <= _Upper) {
			_Fmt = chars_format::fixed;
		} else {
			_Fmt = chars_format::scientific;
		}
	} else if (_Fmt == chars_format::general) {
		// C11 7.21.6.1 "The fprintf function"/8:
		// "Let P equal [...] 6 if the precision is omitted [...].
		// Then, if a conversion with style E would have an exponent of X:
		// - if P > X >= -4, the conversion is with style f [...].
		// - otherwise, the conversion is with style e [...]."
		if (-4 <= _Scientific_exponent && _Scientific_exponent < 6) {
			_Fmt = chars_format::fixed;
		} else {
			_Fmt = chars_format::scientific;
		}
	}

	if (_Fmt == chars_format::fixed) {
		// Example: __output == 1729, __olength == 4

		// __v.__exponent | Printed  | _Whole_digits | _Total_fixed_length  | Notes
		// ---------------|----------|---------------|----------------------|---------------------------------------
		//              2 | 172900   |  6            | _Whole_digits        | Ryu can't be used for printing
		//              1 | 17290    |  5            | (sometimes adjusted) | when the trimmed digits are nonzero.
		// ---------------|----------|---------------|----------------------|---------------------------------------
		//              0 | 1729     |  4            | _Whole_digits        | Unified length cases.
		// ---------------|----------|---------------|----------------------|---------------------------------------
		//             -1 | 172.9    |  3            | __olength + 1        | This case can't happen for
		//             -2 | 17.29    |  2            |                      | __olength == 1, but no additional
		//             -3 | 1.729    |  1            |                      | code is needed to avoid it.
		// ---------------|----------|---------------|----------------------|---------------------------------------
		//             -4 | 0.1729   |  0            | 2 - __v.__exponent   | C11 7.21.6.1 "The fprintf function"/8:
		//             -5 | 0.01729  | -1            |                      | "If a decimal-point character appears,
		//             -6 | 0.001729 | -2            |                      | at least one digit appears before it."

		const int32_t _Whole_digits = static_cast<int32_t>(__olength) + __v.__exponent;

		uint32_t _Total_fixed_length;
		if (__v.__exponent >= 0) { // cases "172900" and "1729"
			_Total_fixed_length = static_cast<uint32_t>(_Whole_digits);
			if (__output == 1) {
				// Rounding can affect the number of digits.
				// For example, 1e11f is exactly "99999997952" which is 11 digits instead of 12.
				// We can use a lookup table to detect this and adjust the total length.
				static constexpr uint8_t _Adjustment[39] = {
					0,0,0,0,0,0,0,0,0,0,0,1,1,1,0,1,0,1,1,1,0,0,1,1,0,1,0,1,1,0,0,1,0,1,1,0,1,1,1 };
				_Total_fixed_length -= _Adjustment[__v.__exponent];
				// _Whole_digits doesn't need to be adjusted because these cases won't refer to it later.
			}
		} else if (_Whole_digits > 0) { // case "17.29"
			_Total_fixed_length = __olength + 1;
		} else { // case "0.001729"
			_Total_fixed_length = static_cast<uint32_t>(2 - __v.__exponent);
		}

		if (_Last - _First < static_cast<ptrdiff_t>(_Total_fixed_length)) {
			return { _Last, errc::value_too_large };
		}

		char * _Mid;
		if (__v.__exponent > 0) { // case "172900"
			bool _Can_use_ryu;

			if (__v.__exponent > 10) { // 10^10 is the largest power of 10
				_Can_use_ryu = false; // that's exactly representable as a float
			} else {
				// Ryu generated X: __v.__mantissa * 10^__v.__exponent
				// __v.__mantissa == 2^_Trailing_zero_bits * (__v.__mantissa >> _Trailing_zero_bits)
				// 10^__v.__exponent == 2^__v.__exponent * 5^__v.__exponent

				// _Trailing_zero_bits is [0, 29] (aside: because 2^29 is the largest power of 2
				// with 9 decimal digits, which is float's round-trip limit.)
				// __v.__exponent is [1, 10].
				// Normalization adds [2, 23] (aside: at least 2 because the pre-normalized mantissa is at least 5).
				// This adds up to [3, 62], which is well below float's maximum binary exponent 127.

				// Therefore, we just need to consider (__v.__mantissa >> _Trailing_zero_bits) * 5^__v.__exponent.

				// If that product would exceed 24 bits, then X can't be exactly represented as a float.
				// (That's not a problem for round-tripping, because X is close enough to the original float,
				// but X isn't mathematically equal to the original float.) This requires a high-precision fallback.

				// If the product is 24 bits or smaller, then X can be exactly represented as a float (and we don't
				// need to re-synthesize it; the original float must have been X, because Ryu wouldn't produce the
				// same output for two different floats X and Y). This allows Ryu's output to be used (zero-filled).

				// (2^24 - 1) / 5^0 (for indexing), (2^24 - 1) / 5^1, ..., (2^24 - 1) / 5^10
				static constexpr uint32_t _Max_shifted_mantissa[11] = {
					16777215, 3355443, 671088, 134217, 26843, 5368, 1073, 214, 42, 8, 1 };

				unsigned long _Trailing_zero_bits;
				(void) _BitScanForward(&_Trailing_zero_bits, __v.__mantissa); // __v.__mantissa is guaranteed nonzero
				const uint32_t _Shifted_mantissa = __v.__mantissa >> _Trailing_zero_bits;
				_Can_use_ryu = _Shifted_mantissa <= _Max_shifted_mantissa[__v.__exponent];
			}

			if (!_Can_use_ryu) {
				_Print_exact_integer_from_float(_First, __ieeeMantissa, __ieeeExponent, _Total_fixed_length);
				return { _First + _Total_fixed_length, errc{} };
			}

			// Print the decimal digits, left-aligned within [_First, _First + _Total_fixed_length).
			_Mid = _First + __olength;
		} else { // cases "1729", "17.29", and "0.001729"
			// Print the decimal digits, right-aligned within [_First, _First + _Total_fixed_length).
			_Mid = _First + _Total_fixed_length;
		}

		while (__output >= 10000) {
#ifdef __clang__ // TRANSITION, LLVM#38217
			const uint32_t __c = __output - 10000 * (__output / 10000);
#else
			const uint32_t __c = __output % 10000;
#endif
			__output /= 10000;
			const uint32_t __c0 = (__c % 100) << 1;
			const uint32_t __c1 = (__c / 100) << 1;
			_CSTD memcpy(_Mid -= 2, __DIGIT_TABLE + __c0, 2);
			_CSTD memcpy(_Mid -= 2, __DIGIT_TABLE + __c1, 2);
		}
		if (__output >= 100) {
			const uint32_t __c = (__output % 100) << 1;
			__output /= 100;
			_CSTD memcpy(_Mid -= 2, __DIGIT_TABLE + __c, 2);
		}
		if (__output >= 10) {
			const uint32_t __c = __output << 1;
			_CSTD memcpy(_Mid -= 2, __DIGIT_TABLE + __c, 2);
		} else {
			*--_Mid = static_cast<char>('0' + __output);
		}

		if (__v.__exponent > 0) { // case "172900"
			// Performance note: it might be more efficient to do this immediately after setting _Mid.
			_CSTD memset(_First + __olength, '0', static_cast<size_t>(__v.__exponent));
		} else if (__v.__exponent == 0) { // case "1729"
			// Done!
		} else if (_Whole_digits > 0) { // case "17.29"
			// Performance note: moving digits might not be optimal.
			_CSTD memmove(_First, _First + 1, static_cast<size_t>(_Whole_digits));
			_First[_Whole_digits] = '.';
		} else { // case "0.001729"
			// Performance note: a larger memset() followed by overwriting '.' might be more efficient.
			_First[0] = '0';
			_First[1] = '.';
			_CSTD memset(_First + 2, '0', static_cast<size_t>(-_Whole_digits));
		}

		return { _First + _Total_fixed_length, errc{} };
	}

	const uint32_t _Total_scientific_length =
		__olength + (__olength > 1) + 4; // digits + possible decimal point + scientific exponent
	if (_Last - _First < static_cast<ptrdiff_t>(_Total_scientific_length)) {
		return { _Last, errc::value_too_large };
	}
	char * const __result = _First;

	// Print the decimal digits.
	uint32_t __i = 0;
	while (__output >= 10000) {
#ifdef __clang__ // TRANSITION, LLVM#38217
		const uint32_t __c = __output - 10000 * (__output / 10000);
#else
		const uint32_t __c = __output % 10000;
#endif
		__output /= 10000;
		const uint32_t __c0 = (__c % 100) << 1;
		const uint32_t __c1 = (__c / 100) << 1;
		_CSTD memcpy(__result + __olength - __i - 1, __DIGIT_TABLE + __c0, 2);
		_CSTD memcpy(__result + __olength - __i - 3, __DIGIT_TABLE + __c1, 2);
		__i += 4;
	}
	if (__output >= 100) {
		const uint32_t __c = (__output % 100) << 1;
		__output /= 100;
		_CSTD memcpy(__result + __olength - __i - 1, __DIGIT_TABLE + __c, 2);
		__i += 2;
	}
	if (__output >= 10) {
		const uint32_t __c = __output << 1;
		// We can't use memcpy here: the decimal dot goes between these two digits.
		__result[__olength - __i] = __DIGIT_TABLE[__c + 1];
		__result[0] = __DIGIT_TABLE[__c];
	} else {
		__result[0] = static_cast<char>('0' + __output);
	}

	// Print decimal point if needed.
	uint32_t __index;
	if (__olength > 1) {
		__result[1] = '.';
		__index = __olength + 1;
	} else {
		__index = 1;
	}

	// Print the exponent.
	__result[__index++] = 'e';
	if (_Scientific_exponent < 0) {
		__result[__index++] = '-';
		_Scientific_exponent = -_Scientific_exponent;
	} else {
		__result[__index++] = '+';
	}

	_CSTD memcpy(__result + __index, __DIGIT_TABLE + 2 * _Scientific_exponent, 2);
	__index += 2;

	return { _First + _Total_scientific_length, errc{} };
}

_NODISCARD inline to_chars_result __f2s_buffered_n(char * const _First, char * const _Last, const float __f,
	const chars_format _Fmt) {

	// Step 1: Decode the floating-point number, and unify normalized and subnormal cases.
	const uint32_t __bits = __float_to_bits(__f);

	// Case distinction; exit early for the easy cases.
	if (__bits == 0) {
		if (_Fmt == chars_format::scientific) {
			if (_Last - _First < 5) {
				return { _Last, errc::value_too_large };
			}

			_CSTD memcpy(_First, "0e+00", 5);

			return { _First + 5, errc{} };
		}

		// Print "0" for chars_format::fixed, chars_format::general, and chars_format{}.
		if (_First == _Last) {
			return { _Last, errc::value_too_large };
		}

		*_First = '0';

		return { _First + 1, errc{} };
	}

	// Decode __bits into mantissa and exponent.
	const uint32_t __ieeeMantissa = __bits & ((1u << __FLOAT_MANTISSA_BITS) - 1);
	const uint32_t __ieeeExponent = __bits >> __FLOAT_MANTISSA_BITS;

	const __floating_decimal_32 __v = __f2d(__ieeeMantissa, __ieeeExponent);
	return __to_chars(_First, _Last, __v, _Fmt, __ieeeMantissa, __ieeeExponent);
}

// ^^^^^^^^^^ DERIVED FROM f2s.c ^^^^^^^^^^

// vvvvvvvvvv DERIVED FROM d2s.h vvvvvvvvvv

inline constexpr int __DOUBLE_MANTISSA_BITS = 52;
inline constexpr int __DOUBLE_EXPONENT_BITS = 11;

inline constexpr int __DOUBLE_POW5_INV_BITCOUNT = 122;
inline constexpr int __DOUBLE_POW5_BITCOUNT = 121;

// ^^^^^^^^^^ DERIVED FROM d2s.h ^^^^^^^^^^

// vvvvvvvvvv DERIVED FROM d2s_full_table.h vvvvvvvvvv

// These tables are generated by PrintDoubleLookupTable.
inline constexpr uint64_t __DOUBLE_POW5_INV_SPLIT[292][2] = {
	{                    1u, 288230376151711744u }, {  3689348814741910324u, 230584300921369395u },
	{  2951479051793528259u, 184467440737095516u }, { 17118578500402463900u, 147573952589676412u },
	{ 12632330341676300947u, 236118324143482260u }, { 10105864273341040758u, 188894659314785808u },
	{ 15463389048156653253u, 151115727451828646u }, { 17362724847566824558u, 241785163922925834u },
	{ 17579528692795369969u, 193428131138340667u }, {  6684925324752475329u, 154742504910672534u },
	{ 18074578149087781173u, 247588007857076054u }, { 18149011334012135262u, 198070406285660843u },
	{  3451162622983977240u, 158456325028528675u }, {  5521860196774363583u, 253530120045645880u },
	{  4417488157419490867u, 202824096036516704u }, {  7223339340677503017u, 162259276829213363u },
	{  7867994130342094503u, 259614842926741381u }, {  2605046489531765280u, 207691874341393105u },
	{  2084037191625412224u, 166153499473114484u }, { 10713157136084480204u, 265845599156983174u },
	{ 12259874523609494487u, 212676479325586539u }, { 13497248433629505913u, 170141183460469231u },
	{ 14216899864323388813u, 272225893536750770u }, { 11373519891458711051u, 217780714829400616u },
	{  5409467098425058518u, 174224571863520493u }, {  4965798542738183305u, 278759314981632789u },
	{  7661987648932456967u, 223007451985306231u }, {  2440241304404055250u, 178405961588244985u },
	{  3904386087046488400u, 285449538541191976u }, { 17880904128604832013u, 228359630832953580u },
	{ 14304723302883865611u, 182687704666362864u }, { 15133127457049002812u, 146150163733090291u },
	{ 16834306301794583852u, 233840261972944466u }, {  9778096226693756759u, 187072209578355573u },
	{ 15201174610838826053u, 149657767662684458u }, {  2185786488890659746u, 239452428260295134u },
	{  5437978005854438120u, 191561942608236107u }, { 15418428848909281466u, 153249554086588885u },
	{  6222742084545298729u, 245199286538542217u }, { 16046240111861969953u, 196159429230833773u },
	{  1768945645263844993u, 156927543384667019u }, { 10209010661905972635u, 251084069415467230u },
	{  8167208529524778108u, 200867255532373784u }, { 10223115638361732810u, 160693804425899027u },
	{  1599589762411131202u, 257110087081438444u }, {  4969020624670815285u, 205688069665150755u },
	{  3975216499736652228u, 164550455732120604u }, { 13739044029062464211u, 263280729171392966u },
	{  7301886408508061046u, 210624583337114373u }, { 13220206756290269483u, 168499666669691498u },
	{ 17462981995322520850u, 269599466671506397u }, {  6591687966774196033u, 215679573337205118u },
	{ 12652048002903177473u, 172543658669764094u }, {  9175230360419352987u, 276069853871622551u },
	{  3650835473593572067u, 220855883097298041u }, { 17678063637842498946u, 176684706477838432u },
	{ 13527506561580357021u, 282695530364541492u }, {  3443307619780464970u, 226156424291633194u },
	{  6443994910566282300u, 180925139433306555u }, {  5155195928453025840u, 144740111546645244u },
	{ 15627011115008661990u, 231584178474632390u }, { 12501608892006929592u, 185267342779705912u },
	{  2622589484121723027u, 148213874223764730u }, {  4196143174594756843u, 237142198758023568u },
	{ 10735612169159626121u, 189713759006418854u }, { 12277838550069611220u, 151771007205135083u },
	{ 15955192865369467629u, 242833611528216133u }, {  1696107848069843133u, 194266889222572907u },
	{ 12424932722681605476u, 155413511378058325u }, {  1433148282581017146u, 248661618204893321u },
	{ 15903913885032455010u, 198929294563914656u }, {  9033782293284053685u, 159143435651131725u },
	{ 14454051669254485895u, 254629497041810760u }, { 11563241335403588716u, 203703597633448608u },
	{ 16629290697806691620u, 162962878106758886u }, {   781423413297334329u, 260740604970814219u },
	{  4314487545379777786u, 208592483976651375u }, {  3451590036303822229u, 166873987181321100u },
	{  5522544058086115566u, 266998379490113760u }, {  4418035246468892453u, 213598703592091008u },
	{ 10913125826658934609u, 170878962873672806u }, { 10082303693170474728u, 273406340597876490u },
	{  8065842954536379782u, 218725072478301192u }, { 17520720807854834795u, 174980057982640953u },
	{  5897060404116273733u, 279968092772225526u }, {  1028299508551108663u, 223974474217780421u },
	{ 15580034865808528224u, 179179579374224336u }, { 17549358155809824511u, 286687326998758938u },
	{  2971440080422128639u, 229349861599007151u }, { 17134547323305344204u, 183479889279205720u },
	{ 13707637858644275364u, 146783911423364576u }, { 14553522944347019935u, 234854258277383322u },
	{  4264120725993795302u, 187883406621906658u }, { 10789994210278856888u, 150306725297525326u },
	{  9885293106962350374u, 240490760476040522u }, {   529536856086059653u, 192392608380832418u },
	{  7802327114352668369u, 153914086704665934u }, {  1415676938738538420u, 246262538727465495u },
	{  1132541550990830736u, 197010030981972396u }, { 15663428499760305882u, 157608024785577916u },
	{ 17682787970132668764u, 252172839656924666u }, { 10456881561364224688u, 201738271725539733u },
	{ 15744202878575200397u, 161390617380431786u }, { 17812026976236499989u, 258224987808690858u },
	{  3181575136763469022u, 206579990246952687u }, { 13613306553636506187u, 165263992197562149u },
	{ 10713244041592678929u, 264422387516099439u }, { 12259944048016053467u, 211537910012879551u },
	{  6118606423670932450u, 169230328010303641u }, {  2411072648389671274u, 270768524816485826u },
	{ 16686253377679378312u, 216614819853188660u }, { 13349002702143502650u, 173291855882550928u },
	{ 17669055508687693916u, 277266969412081485u }, { 14135244406950155133u, 221813575529665188u },
	{   240149081334393137u, 177450860423732151u }, { 11452284974360759988u, 283921376677971441u },
	{  5472479164746697667u, 227137101342377153u }, { 11756680961281178780u, 181709681073901722u },
	{  2026647139541122378u, 145367744859121378u }, { 18000030682233437097u, 232588391774594204u },
	{ 18089373360528660001u, 186070713419675363u }, {  3403452244197197031u, 148856570735740291u },
	{ 16513570034941246220u, 238170513177184465u }, { 13210856027952996976u, 190536410541747572u },
	{  3189987192878576934u, 152429128433398058u }, {  1414630693863812771u, 243886605493436893u },
	{  8510402184574870864u, 195109284394749514u }, { 10497670562401807014u, 156087427515799611u },
	{  9417575270359070576u, 249739884025279378u }, { 14912757845771077107u, 199791907220223502u },
	{  4551508647133041040u, 159833525776178802u }, { 10971762650154775986u, 255733641241886083u },
	{ 16156107749607641435u, 204586912993508866u }, {  9235537384944202825u, 163669530394807093u },
	{ 11087511001168814197u, 261871248631691349u }, { 12559357615676961681u, 209496998905353079u },
	{ 13736834907283479668u, 167597599124282463u }, { 18289587036911657145u, 268156158598851941u },
	{ 10942320814787415393u, 214524926879081553u }, { 16132554281313752961u, 171619941503265242u },
	{ 11054691591134363444u, 274591906405224388u }, { 16222450902391311402u, 219673525124179510u },
	{ 12977960721913049122u, 175738820099343608u }, { 17075388340318968271u, 281182112158949773u },
	{  2592264228029443648u, 224945689727159819u }, {  5763160197165465241u, 179956551781727855u },
	{  9221056315464744386u, 287930482850764568u }, { 14755542681855616155u, 230344386280611654u },
	{ 15493782960226403247u, 184275509024489323u }, {  1326979923955391628u, 147420407219591459u },
	{  9501865507812447252u, 235872651551346334u }, { 11290841220991868125u, 188698121241077067u },
	{  1653975347309673853u, 150958496992861654u }, { 10025058185179298811u, 241533595188578646u },
	{  4330697733401528726u, 193226876150862917u }, { 14532604630946953951u, 154581500920690333u },
	{  1116074521063664381u, 247330401473104534u }, {  4582208431592841828u, 197864321178483627u },
	{ 14733813189500004432u, 158291456942786901u }, { 16195403473716186445u, 253266331108459042u },
	{  5577625149489128510u, 202613064886767234u }, {  8151448934333213131u, 162090451909413787u },
	{ 16731667109675051333u, 259344723055062059u }, { 17074682502481951390u, 207475778444049647u },
	{  6281048372501740465u, 165980622755239718u }, {  6360328581260874421u, 265568996408383549u },
	{  8777611679750609860u, 212455197126706839u }, { 10711438158542398211u, 169964157701365471u },
	{  9759603424184016492u, 271942652322184754u }, { 11497031554089123517u, 217554121857747803u },
	{ 16576322872755119460u, 174043297486198242u }, { 11764721337440549842u, 278469275977917188u },
	{ 16790474699436260520u, 222775420782333750u }, { 13432379759549008416u, 178220336625867000u },
	{  3045063541568861850u, 285152538601387201u }, { 17193446092222730773u, 228122030881109760u },
	{ 13754756873778184618u, 182497624704887808u }, { 18382503128506368341u, 145998099763910246u },
	{  3586563302416817083u, 233596959622256395u }, {  2869250641933453667u, 186877567697805116u },
	{ 17052795772514404226u, 149502054158244092u }, { 12527077977055405469u, 239203286653190548u },
	{ 17400360011128145022u, 191362629322552438u }, {  2852241564676785048u, 153090103458041951u },
	{ 15631632947708587046u, 244944165532867121u }, {  8815957543424959314u, 195955332426293697u },
	{ 18120812478965698421u, 156764265941034957u }, { 14235904707377476180u, 250822825505655932u },
	{  4010026136418160298u, 200658260404524746u }, { 17965416168102169531u, 160526608323619796u },
	{  2919224165770098987u, 256842573317791675u }, {  2335379332616079190u, 205474058654233340u },
	{  1868303466092863352u, 164379246923386672u }, {  6678634360490491686u, 263006795077418675u },
	{  5342907488392393349u, 210405436061934940u }, {  4274325990713914679u, 168324348849547952u },
	{ 10528270399884173809u, 269318958159276723u }, { 15801313949391159694u, 215455166527421378u },
	{  1573004715287196786u, 172364133221937103u }, { 17274202803427156150u, 275782613155099364u },
	{ 17508711057483635243u, 220626090524079491u }, { 10317620031244997871u, 176500872419263593u },
	{ 12818843235250086271u, 282401395870821749u }, { 13944423402941979340u, 225921116696657399u },
	{ 14844887537095493795u, 180736893357325919u }, { 15565258844418305359u, 144589514685860735u },
	{  6457670077359736959u, 231343223497377177u }, { 16234182506113520537u, 185074578797901741u },
	{  9297997190148906106u, 148059663038321393u }, { 11187446689496339446u, 236895460861314229u },
	{ 12639306166338981880u, 189516368689051383u }, { 17490142562555006151u, 151613094951241106u },
	{  2158786396894637579u, 242580951921985771u }, { 16484424376483351356u, 194064761537588616u },
	{  9498190686444770762u, 155251809230070893u }, { 11507756283569722895u, 248402894768113429u },
	{ 12895553841597688639u, 198722315814490743u }, { 17695140702761971558u, 158977852651592594u },
	{ 17244178680193423523u, 254364564242548151u }, { 10105994129412828495u, 203491651394038521u },
	{  4395446488788352473u, 162793321115230817u }, { 10722063196803274280u, 260469313784369307u },
	{  1198952927958798777u, 208375451027495446u }, { 15716557601334680315u, 166700360821996356u },
	{ 17767794532651667857u, 266720577315194170u }, { 14214235626121334286u, 213376461852155336u },
	{  7682039686155157106u, 170701169481724269u }, {  1223217053622520399u, 273121871170758831u },
	{ 15735968901865657612u, 218497496936607064u }, { 16278123936234436413u, 174797997549285651u },
	{   219556594781725998u, 279676796078857043u }, {  7554342905309201445u, 223741436863085634u },
	{  9732823138989271479u, 178993149490468507u }, {   815121763415193074u, 286389039184749612u },
	{ 11720143854957885429u, 229111231347799689u }, { 13065463898708218666u, 183288985078239751u },
	{  6763022304224664610u, 146631188062591801u }, {  3442138057275642729u, 234609900900146882u },
	{ 13821756890046245153u, 187687920720117505u }, { 11057405512036996122u, 150150336576094004u },
	{  6623802375033462826u, 240240538521750407u }, { 16367088344252501231u, 192192430817400325u },
	{ 13093670675402000985u, 153753944653920260u }, {  2503129006933649959u, 246006311446272417u },
	{ 13070549649772650937u, 196805049157017933u }, { 17835137349301941396u, 157444039325614346u },
	{  2710778055689733971u, 251910462920982955u }, {  2168622444551787177u, 201528370336786364u },
	{  5424246770383340065u, 161222696269429091u }, {  1300097203129523457u, 257956314031086546u },
	{ 15797473021471260058u, 206365051224869236u }, {  8948629602435097724u, 165092040979895389u },
	{  3249760919670425388u, 264147265567832623u }, {  9978506365220160957u, 211317812454266098u },
	{ 15361502721659949412u, 169054249963412878u }, {  2442311466204457120u, 270486799941460606u },
	{ 16711244431931206989u, 216389439953168484u }, { 17058344360286875914u, 173111551962534787u },
	{ 12535955717491360170u, 276978483140055660u }, { 10028764573993088136u, 221582786512044528u },
	{ 15401709288678291155u, 177266229209635622u }, {  9885339602917624555u, 283625966735416996u },
	{  4218922867592189321u, 226900773388333597u }, { 14443184738299482427u, 181520618710666877u },
	{  4175850161155765295u, 145216494968533502u }, { 10370709072591134795u, 232346391949653603u },
	{ 15675264887556728482u, 185877113559722882u }, {  5161514280561562140u, 148701690847778306u },
	{   879725219414678777u, 237922705356445290u }, {   703780175531743021u, 190338164285156232u },
	{ 11631070584651125387u, 152270531428124985u }, {   162968861732249003u, 243632850284999977u },
	{ 11198421533611530172u, 194906280227999981u }, {  5269388412147313814u, 155925024182399985u },
	{  8431021459435702103u, 249480038691839976u }, {  3055468352806651359u, 199584030953471981u },
	{ 17201769941212962380u, 159667224762777584u }, { 16454785461715008838u, 255467559620444135u },
	{ 13163828369372007071u, 204374047696355308u }, { 17909760324981426303u, 163499238157084246u },
	{  2830174816776909822u, 261598781051334795u }, {  2264139853421527858u, 209279024841067836u },
	{ 16568707141704863579u, 167423219872854268u }, {  4373838538276319787u, 267877151796566830u },
	{  3499070830621055830u, 214301721437253464u }, {  6488605479238754987u, 171441377149802771u },
	{  3003071137298187333u, 274306203439684434u }, {  6091805724580460189u, 219444962751747547u },
	{ 15941491023890099121u, 175555970201398037u }, { 10748990379256517301u, 280889552322236860u },
	{  8599192303405213841u, 224711641857789488u }, { 14258051472207991719u, 179769313486231590u }
};

inline constexpr uint64_t __DOUBLE_POW5_SPLIT[326][2] = {
	{                    0u,  72057594037927936u }, {                    0u,  90071992547409920u },
	{                    0u, 112589990684262400u }, {                    0u, 140737488355328000u },
	{                    0u,  87960930222080000u }, {                    0u, 109951162777600000u },
	{                    0u, 137438953472000000u }, {                    0u,  85899345920000000u },
	{                    0u, 107374182400000000u }, {                    0u, 134217728000000000u },
	{                    0u,  83886080000000000u }, {                    0u, 104857600000000000u },
	{                    0u, 131072000000000000u }, {                    0u,  81920000000000000u },
	{                    0u, 102400000000000000u }, {                    0u, 128000000000000000u },
	{                    0u,  80000000000000000u }, {                    0u, 100000000000000000u },
	{                    0u, 125000000000000000u }, {                    0u,  78125000000000000u },
	{                    0u,  97656250000000000u }, {                    0u, 122070312500000000u },
	{                    0u,  76293945312500000u }, {                    0u,  95367431640625000u },
	{                    0u, 119209289550781250u }, {  4611686018427387904u,  74505805969238281u },
	{ 10376293541461622784u,  93132257461547851u }, {  8358680908399640576u, 116415321826934814u },
	{   612489549322387456u,  72759576141834259u }, { 14600669991935148032u,  90949470177292823u },
	{ 13639151471491547136u, 113686837721616029u }, {  3213881284082270208u, 142108547152020037u },
	{  4314518811765112832u,  88817841970012523u }, {   781462496279003136u, 111022302462515654u },
	{ 10200200157203529728u, 138777878078144567u }, { 13292654125893287936u,  86736173798840354u },
	{  7392445620511834112u, 108420217248550443u }, {  4628871007212404736u, 135525271560688054u },
	{ 16728102434789916672u,  84703294725430033u }, {  7075069988205232128u, 105879118406787542u },
	{ 18067209522111315968u, 132348898008484427u }, {  8986162942105878528u,  82718061255302767u },
	{  6621017659204960256u, 103397576569128459u }, {  3664586055578812416u, 129246970711410574u },
	{ 16125424340018921472u,  80779356694631608u }, {  1710036351314100224u, 100974195868289511u },
	{ 15972603494424788992u, 126217744835361888u }, {  9982877184015493120u,  78886090522101180u },
	{ 12478596480019366400u,  98607613152626475u }, { 10986559581596820096u, 123259516440783094u },
	{  2254913720070624656u,  77037197775489434u }, { 12042014186943056628u,  96296497219361792u },
	{ 15052517733678820785u, 120370621524202240u }, {  9407823583549262990u,  75231638452626400u },
	{ 11759779479436578738u,  94039548065783000u }, { 14699724349295723422u, 117549435082228750u },
	{  4575641699882439235u,  73468396926392969u }, { 10331238143280436948u,  91835496157991211u },
	{  8302361660673158281u, 114794370197489014u }, {  1154580038986672043u, 143492962746861268u },
	{  9944984561221445835u,  89683101716788292u }, { 12431230701526807293u, 112103877145985365u },
	{  1703980321626345405u, 140129846432481707u }, { 17205888765512323542u,  87581154020301066u },
	{ 12283988920035628619u, 109476442525376333u }, {  1519928094762372062u, 136845553156720417u },
	{ 12479170105294952299u,  85528470722950260u }, { 15598962631618690374u, 106910588403687825u },
	{  5663645234241199255u, 133638235504609782u }, { 17374836326682913246u,  83523897190381113u },
	{  7883487353071477846u, 104404871487976392u }, {  9854359191339347308u, 130506089359970490u },
	{ 10770660513014479971u,  81566305849981556u }, { 13463325641268099964u, 101957882312476945u },
	{  2994098996302961243u, 127447352890596182u }, { 15706369927971514489u,  79654595556622613u },
	{  5797904354682229399u,  99568244445778267u }, {  2635694424925398845u, 124460305557222834u },
	{  6258995034005762182u,  77787690973264271u }, {  3212057774079814824u,  97234613716580339u },
	{ 17850130272881932242u, 121543267145725423u }, { 18073860448192289507u,  75964541966078389u },
	{  8757267504958198172u,  94955677457597987u }, {  6334898362770359811u, 118694596821997484u },
	{ 13182683513586250689u,  74184123013748427u }, { 11866668373555425458u,  92730153767185534u },
	{  5609963430089506015u, 115912692208981918u }, { 17341285199088104971u,  72445432630613698u },
	{ 12453234462005355406u,  90556790788267123u }, { 10954857059079306353u, 113195988485333904u },
	{ 13693571323849132942u, 141494985606667380u }, { 17781854114260483896u,  88434366004167112u },
	{  3780573569116053255u, 110542957505208891u }, {   114030942967678664u, 138178696881511114u },
	{  4682955357782187069u,  86361685550944446u }, { 15077066234082509644u, 107952106938680557u },
	{  5011274737320973344u, 134940133673350697u }, { 14661261756894078100u,  84337583545844185u },
	{  4491519140835433913u, 105421979432305232u }, {  5614398926044292391u, 131777474290381540u },
	{ 12732371365632458552u,  82360921431488462u }, {  6692092170185797382u, 102951151789360578u },
	{ 17588487249587022536u, 128688939736700722u }, { 15604490549419276989u,  80430587335437951u },
	{ 14893927168346708332u, 100538234169297439u }, { 14005722942005997511u, 125672792711621799u },
	{ 15671105866394830300u,  78545495444763624u }, {  1142138259283986260u,  98181869305954531u },
	{ 15262730879387146537u, 122727336632443163u }, {  7233363790403272633u,  76704585395276977u },
	{ 13653390756431478696u,  95880731744096221u }, {  3231680390257184658u, 119850914680120277u },
	{  4325643253124434363u,  74906821675075173u }, { 10018740084832930858u,  93633527093843966u },
	{  3300053069186387764u, 117041908867304958u }, { 15897591223523656064u,  73151193042065598u },
	{ 10648616992549794273u,  91438991302581998u }, {  4087399203832467033u, 114298739128227498u },
	{ 14332621041645359599u, 142873423910284372u }, { 18181260187883125557u,  89295889943927732u },
	{  4279831161144355331u, 111619862429909666u }, { 14573160988285219972u, 139524828037387082u },
	{ 13719911636105650386u,  87203017523366926u }, {  7926517508277287175u, 109003771904208658u },
	{   684774848491833161u, 136254714880260823u }, {  7345513307948477581u,  85159196800163014u },
	{ 18405263671790372785u, 106448996000203767u }, { 18394893571310578077u, 133061245000254709u },
	{ 13802651491282805250u,  83163278125159193u }, {  3418256308821342851u, 103954097656448992u },
	{  4272820386026678563u, 129942622070561240u }, {  2670512741266674102u,  81214138794100775u },
	{ 17173198981865506339u, 101517673492625968u }, {  3019754653622331308u, 126897091865782461u },
	{  4193189667727651020u,  79310682416114038u }, { 14464859121514339583u,  99138353020142547u },
	{ 13469387883465536574u, 123922941275178184u }, {  8418367427165960359u,  77451838296986365u },
	{ 15134645302384838353u,  96814797871232956u }, {   471562554271496325u, 121018497339041196u },
	{  9518098633274461011u,  75636560836900747u }, {  7285937273165688360u,  94545701046125934u },
	{ 18330793628311886258u, 118182126307657417u }, {  4539216990053847055u,  73863828942285886u },
	{ 14897393274422084627u,  92329786177857357u }, {  4786683537745442072u, 115412232722321697u },
	{ 14520892257159371055u,  72132645451451060u }, { 18151115321449213818u,  90165806814313825u },
	{  8853836096529353561u, 112707258517892282u }, {  1843923083806916143u, 140884073147365353u },
	{ 12681666973447792349u,  88052545717103345u }, {  2017025661527576725u, 110065682146379182u },
	{ 11744654113764246714u, 137582102682973977u }, {   422879793461572340u,  85988814176858736u },
	{   528599741826965425u, 107486017721073420u }, {   660749677283706782u, 134357522151341775u },
	{  7330497575943398595u,  83973451344588609u }, { 13774807988356636147u, 104966814180735761u },
	{  3383451930163631472u, 131208517725919702u }, { 15949715511634433382u,  82005323578699813u },
	{  6102086334260878016u, 102506654473374767u }, {  3015921899398709616u, 128133318091718459u },
	{ 18025852251620051174u,  80083323807324036u }, {  4085571240815512351u, 100104154759155046u },
	{ 14330336087874166247u, 125130193448943807u }, { 15873989082562435760u,  78206370905589879u },
	{ 15230800334775656796u,  97757963631987349u }, {  5203442363187407284u, 122197454539984187u },
	{   946308467778435600u,  76373409087490117u }, {  5794571603150432404u,  95466761359362646u },
	{ 16466586540792816313u, 119333451699203307u }, {  7985773578781816244u,  74583407312002067u },
	{  5370530955049882401u,  93229259140002584u }, {  6713163693812353001u, 116536573925003230u },
	{ 18030785363914884337u,  72835358703127018u }, { 13315109668038829614u,  91044198378908773u },
	{  2808829029766373305u, 113805247973635967u }, { 17346094342490130344u, 142256559967044958u },
	{  6229622945628943561u,  88910349979403099u }, {  3175342663608791547u, 111137937474253874u },
	{ 13192550366365765242u, 138922421842817342u }, {  3633657960551215372u,  86826513651760839u },
	{ 18377130505971182927u, 108533142064701048u }, {  4524669058754427043u, 135666427580876311u },
	{  9745447189362598758u,  84791517238047694u }, {  2958436949848472639u, 105989396547559618u },
	{ 12921418224165366607u, 132486745684449522u }, { 12687572408530742033u,  82804216052780951u },
	{ 11247779492236039638u, 103505270065976189u }, {   224666310012885835u, 129381587582470237u },
	{  2446259452971747599u,  80863492239043898u }, { 12281196353069460307u, 101079365298804872u },
	{ 15351495441336825384u, 126349206623506090u }, { 14206370669262903769u,  78968254139691306u },
	{  8534591299723853903u,  98710317674614133u }, { 15279925143082205283u, 123387897093267666u },
	{ 14161639232853766206u,  77117435683292291u }, { 13090363022639819853u,  96396794604115364u },
	{ 16362953778299774816u, 120495993255144205u }, { 12532689120651053212u,  75309995784465128u },
	{ 15665861400813816515u,  94137494730581410u }, { 10358954714162494836u, 117671868413226763u },
	{  4168503687137865320u,  73544917758266727u }, {   598943590494943747u,  91931147197833409u },
	{  5360365506546067587u, 114913933997291761u }, { 11312142901609972388u, 143642417496614701u },
	{  9375932322719926695u,  89776510935384188u }, { 11719915403399908368u, 112220638669230235u },
	{ 10038208235822497557u, 140275798336537794u }, { 10885566165816448877u,  87672373960336121u },
	{ 18218643725697949000u, 109590467450420151u }, { 18161618638695048346u, 136988084313025189u },
	{ 13656854658398099168u,  85617552695640743u }, { 12459382304570236056u, 107021940869550929u },
	{  1739169825430631358u, 133777426086938662u }, { 14922039196176308311u,  83610891304336663u },
	{ 14040862976792997485u, 104513614130420829u }, {  3716020665709083144u, 130642017663026037u },
	{  4628355925281870917u,  81651261039391273u }, { 10397130925029726550u, 102064076299239091u },
	{  8384727637859770284u, 127580095374048864u }, {  5240454773662356427u,  79737559608780540u },
	{  6550568467077945534u,  99671949510975675u }, {  3576524565420044014u, 124589936888719594u },
	{  6847013871814915412u,  77868710555449746u }, { 17782139376623420074u,  97335888194312182u },
	{ 13004302183924499284u, 121669860242890228u }, { 17351060901807587860u,  76043662651806392u },
	{  3242082053549933210u,  95054578314757991u }, { 17887660622219580224u, 118818222893447488u },
	{ 11179787888887237640u,  74261389308404680u }, { 13974734861109047050u,  92826736635505850u },
	{  8245046539531533005u, 116033420794382313u }, { 16682369133275677888u,  72520887996488945u },
	{  7017903361312433648u,  90651109995611182u }, { 17995751238495317868u, 113313887494513977u },
	{  8659630992836983623u, 141642359368142472u }, {  5412269370523114764u,  88526474605089045u },
	{ 11377022731581281359u, 110658093256361306u }, {  4997906377621825891u, 138322616570451633u },
	{ 14652906532082110942u,  86451635356532270u }, {  9092761128247862869u, 108064544195665338u },
	{  2142579373455052779u, 135080680244581673u }, { 12868327154477877747u,  84425425152863545u },
	{  2250350887815183471u, 105531781441079432u }, {  2812938609768979339u, 131914726801349290u },
	{  6369772649532999991u,  82446704250843306u }, { 17185587848771025797u, 103058380313554132u },
	{  3035240737254230630u, 128822975391942666u }, {  6508711479211282048u,  80514359619964166u },
	{ 17359261385868878368u, 100642949524955207u }, { 17087390713908710056u, 125803686906194009u },
	{  3762090168551861929u,  78627304316371256u }, {  4702612710689827411u,  98284130395464070u },
	{ 15101637925217060072u, 122855162994330087u }, { 16356052730901744401u,  76784476871456304u },
	{  1998321839917628885u,  95980596089320381u }, {  7109588318324424010u, 119975745111650476u },
	{ 13666864735807540814u,  74984840694781547u }, { 12471894901332038114u,  93731050868476934u },
	{  6366496589810271835u, 117163813585596168u }, {  3979060368631419896u,  73227383490997605u },
	{  9585511479216662775u,  91534229363747006u }, {  2758517312166052660u, 114417786704683758u },
	{ 12671518677062341634u, 143022233380854697u }, {  1002170145522881665u,  89388895863034186u },
	{ 10476084718758377889u, 111736119828792732u }, { 13095105898447972362u, 139670149785990915u },
	{  5878598177316288774u,  87293843616244322u }, { 16571619758500136775u, 109117304520305402u },
	{ 11491152661270395161u, 136396630650381753u }, {   264441385652915120u,  85247894156488596u },
	{   330551732066143900u, 106559867695610745u }, {  5024875683510067779u, 133199834619513431u },
	{ 10058076329834874218u,  83249896637195894u }, {  3349223375438816964u, 104062370796494868u },
	{  4186529219298521205u, 130077963495618585u }, { 14145795808130045513u,  81298727184761615u },
	{ 13070558741735168987u, 101623408980952019u }, { 11726512408741573330u, 127029261226190024u },
	{  7329070255463483331u,  79393288266368765u }, { 13773023837756742068u,  99241610332960956u },
	{ 17216279797195927585u, 124052012916201195u }, {  8454331864033760789u,  77532508072625747u },
	{  5956228811614813082u,  96915635090782184u }, {  7445286014518516353u, 121144543863477730u },
	{  9264989777501460624u,  75715339914673581u }, { 16192923240304213684u,  94644174893341976u },
	{  1794409976670715490u, 118305218616677471u }, {  8039035263060279037u,  73940761635423419u },
	{  5437108060397960892u,  92425952044279274u }, { 16019757112352226923u, 115532440055349092u },
	{   788976158365366019u,  72207775034593183u }, { 14821278253238871236u,  90259718793241478u },
	{  9303225779693813237u, 112824648491551848u }, { 11629032224617266546u, 141030810614439810u },
	{ 11879831158813179495u,  88144256634024881u }, {  1014730893234310657u, 110180320792531102u },
	{ 10491785653397664129u, 137725400990663877u }, {  8863209042587234033u,  86078375619164923u },
	{  6467325284806654637u, 107597969523956154u }, { 17307528642863094104u, 134497461904945192u },
	{ 10817205401789433815u,  84060913690590745u }, { 18133192770664180173u, 105076142113238431u },
	{ 18054804944902837312u, 131345177641548039u }, { 18201782118205355176u,  82090736025967524u },
	{  4305483574047142354u, 102613420032459406u }, { 14605226504413703751u, 128266775040574257u },
	{  2210737537617482988u,  80166734400358911u }, { 16598479977304017447u, 100208418000448638u },
	{ 11524727934775246001u, 125260522500560798u }, {  2591268940807140847u,  78287826562850499u },
	{ 17074144231291089770u,  97859783203563123u }, { 16730994270686474309u, 122324729004453904u },
	{ 10456871419179046443u,  76452955627783690u }, {  3847717237119032246u,  95566194534729613u },
	{  9421332564826178211u, 119457743168412016u }, {  5888332853016361382u,  74661089480257510u },
	{ 16583788103125227536u,  93326361850321887u }, { 16118049110479146516u, 116657952312902359u },
	{ 16991309721690548428u,  72911220195563974u }, { 12015765115258409727u,  91139025244454968u },
	{ 15019706394073012159u, 113923781555568710u }, {  9551260955736489391u, 142404726944460888u },
	{  5969538097335305869u,  89002954340288055u }, {  2850236603241744433u, 111253692925360069u }
};

// ^^^^^^^^^^ DERIVED FROM d2s_full_table.h ^^^^^^^^^^

// vvvvvvvvvv DERIVED FROM d2s_intrinsics.h vvvvvvvvvv

#ifndef _M_X64

_NODISCARD __forceinline uint64_t __ryu_umul128(const uint64_t __a, const uint64_t __b,
	uint64_t * const __productHi) { // TRANSITION, VSO#634761
	// The casts here help MSVC to avoid calls to the __allmul library function.
	const uint32_t __aLo = static_cast<uint32_t>(__a);
	const uint32_t __aHi = static_cast<uint32_t>(__a >> 32);
	const uint32_t __bLo = static_cast<uint32_t>(__b);
	const uint32_t __bHi = static_cast<uint32_t>(__b >> 32);

	const uint64_t __b00 = static_cast<uint64_t>(__aLo) * __bLo;
	const uint64_t __b01 = static_cast<uint64_t>(__aLo) * __bHi;
	const uint64_t __b10 = static_cast<uint64_t>(__aHi) * __bLo;
	const uint64_t __b11 = static_cast<uint64_t>(__aHi) * __bHi;

	const uint32_t __b00Lo = static_cast<uint32_t>(__b00);
	const uint32_t __b00Hi = static_cast<uint32_t>(__b00 >> 32);

	const uint64_t __mid1 = __b10 + __b00Hi;
	const uint32_t __mid1Lo = static_cast<uint32_t>(__mid1);
	const uint32_t __mid1Hi = static_cast<uint32_t>(__mid1 >> 32);

	const uint64_t __mid2 = __b01 + __mid1Lo;
	const uint32_t __mid2Lo = static_cast<uint32_t>(__mid2);
	const uint32_t __mid2Hi = static_cast<uint32_t>(__mid2 >> 32);

	const uint64_t __pHi = __b11 + __mid1Hi + __mid2Hi;
	const uint64_t __pLo = (static_cast<uint64_t>(__mid2Lo) << 32) + __b00Lo;

	*__productHi = __pHi;
	return __pLo;
}

_NODISCARD inline uint64_t __ryu_shiftright128(const uint64_t __lo, const uint64_t __hi, const uint32_t __dist) {
	// For the __shiftright128 intrinsic, the shift value is always
	// modulo 64.
	// In the current implementation of the double-precision version
	// of Ryu, the shift value is always < 64.
	// (The shift value is in the range [49, 58].)
	// Check this here in case a future change requires larger shift
	// values. In this case this function needs to be adjusted.
	_STL_INTERNAL_CHECK(__dist < 64, "__dist < 64");
#ifdef _WIN64
	_STL_INTERNAL_CHECK(__dist > 0, "__dist > 0");
	return (__hi << (64 - __dist)) | (__lo >> __dist);
#else // ^^^ 64-bit ^^^ / vvv 32-bit vvv
	// Avoid a 64-bit shift by taking advantage of the range of shift values.
	_STL_INTERNAL_CHECK(__dist >= 32, "__dist >= 32");
	return (__hi << (64 - __dist)) | (static_cast<uint32_t>(__lo >> 32) >> (__dist - 32));
#endif // ^^^ 32-bit ^^^
}

#endif // ^^^ intrinsics unavailable ^^^

#ifndef _WIN64

// Returns the high 64 bits of the 128-bit product of __a and __b.
_NODISCARD inline uint64_t __umulh(const uint64_t __a, const uint64_t __b) {
	// Reuse the __ryu_umul128 implementation.
	// Optimizers will likely eliminate the instructions used to compute the
	// low part of the product.
	uint64_t __hi;
	(void) __ryu_umul128(__a, __b, &__hi);
	return __hi;
}

// On 32-bit platforms, compilers typically generate calls to library
// functions for 64-bit divisions, even if the divisor is a constant.
//
// TRANSITION, VSO#664754, LLVM#37932
//
// The functions here perform division-by-constant using multiplications
// in the same way as 64-bit compilers would do.
//
// NB:
// The multipliers and shift values are the ones generated by clang x64
// for expressions like x/5, x/10, etc.

_NODISCARD inline uint64_t __div5(const uint64_t __x) {
	return __umulh(__x, 0xCCCCCCCCCCCCCCCDu) >> 2;
}

_NODISCARD inline uint64_t __div10(const uint64_t __x) {
	return __umulh(__x, 0xCCCCCCCCCCCCCCCDu) >> 3;
}

_NODISCARD inline uint64_t __div100(const uint64_t __x) {
	return __umulh(__x >> 2, 0x28F5C28F5C28F5C3u) >> 2;
}

_NODISCARD inline uint64_t __div100000000(const uint64_t __x) {
	return __umulh(__x, 0xABCC77118461CEFDu) >> 26;
}

#else // ^^^ 32-bit ^^^ / vvv 64-bit vvv

_NODISCARD inline uint64_t __div5(const uint64_t __x) {
	return __x / 5;
}

_NODISCARD inline uint64_t __div10(const uint64_t __x) {
	return __x / 10;
}

_NODISCARD inline uint64_t __div100(const uint64_t __x) {
	return __x / 100;
}

_NODISCARD inline uint64_t __div100000000(const uint64_t __x) {
	return __x / 100000000;
}

#endif // ^^^ 64-bit ^^^

// ^^^^^^^^^^ DERIVED FROM d2s_intrinsics.h ^^^^^^^^^^

// vvvvvvvvvv DERIVED FROM d2s.c vvvvvvvvvv

_NODISCARD inline uint32_t __pow5Factor(uint64_t __value) {
	uint32_t __count = 0;
	for (;;) {
		_STL_INTERNAL_CHECK(__value != 0, "__value != 0");
		const uint64_t __q = __div5(__value);
		const uint32_t __r = static_cast<uint32_t>(__value - 5 * __q);
		if (__r != 0) {
			break;
		}
		__value = __q;
		++__count;
	}
	return __count;
}

// Returns true if __value is divisible by 5^__p.
_NODISCARD inline bool __multipleOfPowerOf5(const uint64_t __value, const uint32_t __p) {
	// I tried a case distinction on __p, but there was no performance difference.
	return __pow5Factor(__value) >= __p;
}

// Returns true if __value is divisible by 2^__p.
_NODISCARD inline bool __multipleOfPowerOf2(const uint64_t __value, const uint32_t __p) {
	// return __builtin_ctzll(__value) >= __p;
	return (__value & ((1ull << __p) - 1)) == 0;
}

// We need a 64x128-bit multiplication and a subsequent 128-bit shift.
// Multiplication:
//   The 64-bit factor is variable and passed in, the 128-bit factor comes
//   from a lookup table. We know that the 64-bit factor only has 55
//   significant bits (i.e., the 9 topmost bits are zeros). The 128-bit
//   factor only has 124 significant bits (i.e., the 4 topmost bits are
//   zeros).
// Shift:
//   In principle, the multiplication result requires 55 + 124 = 179 bits to
//   represent. However, we then shift this value to the right by __j, which is
//   at least __j >= 115, so the result is guaranteed to fit into 179 - 115 = 64
//   bits. This means that we only need the topmost 64 significant bits of
//   the 64x128-bit multiplication.
//
// There are several ways to do this:
// 1. Best case: the compiler exposes a 128-bit type.
//    We perform two 64x64-bit multiplications, add the higher 64 bits of the
//    lower result to the higher result, and shift by __j - 64 bits.
//
//    We explicitly cast from 64-bit to 128-bit, so the compiler can tell
//    that these are only 64-bit inputs, and can map these to the best
//    possible sequence of assembly instructions.
//    x64 machines happen to have matching assembly instructions for
//    64x64-bit multiplications and 128-bit shifts.
//
// 2. Second best case: the compiler exposes intrinsics for the x64 assembly
//    instructions mentioned in 1.
//
// 3. We only have 64x64 bit instructions that return the lower 64 bits of
//    the result, i.e., we have to use plain C.
//    Our inputs are less than the full width, so we have three options:
//    a. Ignore this fact and just implement the intrinsics manually.
//    b. Split both into 31-bit pieces, which guarantees no internal overflow,
//       but requires extra work upfront (unless we change the lookup table).
//    c. Split only the first factor into 31-bit pieces, which also guarantees
//       no internal overflow, but requires extra work since the intermediate
//       results are not perfectly aligned.
#ifdef _M_X64

_NODISCARD inline uint64_t __mulShift(const uint64_t __m, const uint64_t * const __mul, const int32_t __j) {
	// __m is maximum 55 bits
	uint64_t __high1;                                          // 128
	const uint64_t __low1 = _umul128(__m, __mul[1], &__high1); // 64
	uint64_t __high0;                                          // 64
	(void) _umul128(__m, __mul[0], &__high0);                  // 0
	const uint64_t __sum = __high0 + __low1;
	if (__sum < __high0) {
		++__high1; // overflow into __high1
	}
	return __shiftright128(__sum, __high1, static_cast<unsigned char>(__j - 64));
}

_NODISCARD inline uint64_t __mulShiftAll(const uint64_t __m, const uint64_t * const __mul, const int32_t __j,
	uint64_t * const __vp, uint64_t * const __vm, const uint32_t __mmShift) {
	*__vp = __mulShift(4 * __m + 2, __mul, __j);
	*__vm = __mulShift(4 * __m - 1 - __mmShift, __mul, __j);
	return __mulShift(4 * __m, __mul, __j);
}

#else // ^^^ intrinsics available ^^^ / vvv intrinsics unavailable vvv

_NODISCARD __forceinline uint64_t __mulShiftAll(uint64_t __m, const uint64_t * const __mul, const int32_t __j,
	uint64_t * const __vp, uint64_t * const __vm, const uint32_t __mmShift) { // TRANSITION, VSO#634761
	__m <<= 1;
	// __m is maximum 55 bits
	uint64_t __tmp;
	const uint64_t __lo = __ryu_umul128(__m, __mul[0], &__tmp);
	uint64_t __hi;
	const uint64_t __mid = __tmp + __ryu_umul128(__m, __mul[1], &__hi);
	__hi += __mid < __tmp; // overflow into __hi

	const uint64_t __lo2 = __lo + __mul[0];
	const uint64_t __mid2 = __mid + __mul[1] + (__lo2 < __lo);
	const uint64_t __hi2 = __hi + (__mid2 < __mid);
	*__vp = __ryu_shiftright128(__mid2, __hi2, static_cast<uint32_t>(__j - 64 - 1));

	if (__mmShift == 1) {
		const uint64_t __lo3 = __lo - __mul[0];
		const uint64_t __mid3 = __mid - __mul[1] - (__lo3 > __lo);
		const uint64_t __hi3 = __hi - (__mid3 > __mid);
		*__vm = __ryu_shiftright128(__mid3, __hi3, static_cast<uint32_t>(__j - 64 - 1));
	} else {
		const uint64_t __lo3 = __lo + __lo;
		const uint64_t __mid3 = __mid + __mid + (__lo3 < __lo);
		const uint64_t __hi3 = __hi + __hi + (__mid3 < __mid);
		const uint64_t __lo4 = __lo3 - __mul[0];
		const uint64_t __mid4 = __mid3 - __mul[1] - (__lo4 > __lo3);
		const uint64_t __hi4 = __hi3 - (__mid4 > __mid3);
		*__vm = __ryu_shiftright128(__mid4, __hi4, static_cast<uint32_t>(__j - 64));
	}

	return __ryu_shiftright128(__mid, __hi, static_cast<uint32_t>(__j - 64 - 1));
}

#endif // ^^^ intrinsics unavailable ^^^

_NODISCARD inline uint32_t __decimalLength(const uint64_t __v) {
	// This is slightly faster than a loop.
	// The average output length is 16.38 digits, so we check high-to-low.
	// Function precondition: __v is not an 18, 19, or 20-digit number.
	// (17 digits are sufficient for round-tripping.)
	_STL_INTERNAL_CHECK(__v < 100000000000000000L, "__v < 100000000000000000L");
	if (__v >= 10000000000000000L) { return 17; }
	if (__v >= 1000000000000000L) { return 16; }
	if (__v >= 100000000000000L) { return 15; }
	if (__v >= 10000000000000L) { return 14; }
	if (__v >= 1000000000000L) { return 13; }
	if (__v >= 100000000000L) { return 12; }
	if (__v >= 10000000000L) { return 11; }
	if (__v >= 1000000000L) { return 10; }
	if (__v >= 100000000L) { return 9; }
	if (__v >= 10000000L) { return 8; }
	if (__v >= 1000000L) { return 7; }
	if (__v >= 100000L) { return 6; }
	if (__v >= 10000L) { return 5; }
	if (__v >= 1000L) { return 4; }
	if (__v >= 100L) { return 3; }
	if (__v >= 10L) { return 2; }
	return 1;
}

// A floating decimal representing m * 10^e.
struct __floating_decimal_64 {
	uint64_t __mantissa;
	int32_t __exponent;
};

_NODISCARD inline __floating_decimal_64 __d2d(const uint64_t __ieeeMantissa, const uint32_t __ieeeExponent) {
	constexpr int32_t __bias = (1u << (__DOUBLE_EXPONENT_BITS - 1)) - 1;

	int32_t __e2;
	uint64_t __m2;
	if (__ieeeExponent == 0) {
		// We subtract 2 so that the bounds computation has 2 additional bits.
		__e2 = 1 - __bias - __DOUBLE_MANTISSA_BITS - 2;
		__m2 = __ieeeMantissa;
	} else {
		__e2 = static_cast<int32_t>(__ieeeExponent) - __bias - __DOUBLE_MANTISSA_BITS - 2;
		__m2 = (1ull << __DOUBLE_MANTISSA_BITS) | __ieeeMantissa;
	}
	const bool __even = (__m2 & 1) == 0;
	const bool __acceptBounds = __even;

	// Step 2: Determine the interval of valid decimal representations.
	const uint64_t __mv = 4 * __m2;
	// Implicit bool -> int conversion. True is 1, false is 0.
	const uint32_t __mmShift = __ieeeMantissa != 0 || __ieeeExponent <= 1;
	// We would compute __mp and __mm like this:
	// uint64_t __mp = 4 * __m2 + 2;
	// uint64_t __mm = __mv - 1 - __mmShift;

	// Step 3: Convert to a decimal power base using 128-bit arithmetic.
	uint64_t __vr, __vp, __vm;
	int32_t __e10;
	bool __vmIsTrailingZeros = false;
	bool __vrIsTrailingZeros = false;
	if (__e2 >= 0) {
		// I tried special-casing __q == 0, but there was no effect on performance.
		// This expression is slightly faster than max(0, __log10Pow2(__e2) - 1).
		const uint32_t __q = __log10Pow2(__e2) - (__e2 > 3);
		__e10 = static_cast<int32_t>(__q);
		const int32_t __k = __DOUBLE_POW5_INV_BITCOUNT + __pow5bits(static_cast<int32_t>(__q)) - 1;
		const int32_t __i = -__e2 + static_cast<int32_t>(__q) + __k;
		__vr = __mulShiftAll(__m2, __DOUBLE_POW5_INV_SPLIT[__q], __i, &__vp, &__vm, __mmShift);
		if (__q <= 21) {
			// This should use __q <= 22, but I think 21 is also safe. Smaller values
			// may still be safe, but it's more difficult to reason about them.
			// Only one of __mp, __mv, and __mm can be a multiple of 5, if any.
			const uint32_t __mvMod5 = static_cast<uint32_t>(__mv - 5 * __div5(__mv));
			if (__mvMod5 == 0) {
				__vrIsTrailingZeros = __multipleOfPowerOf5(__mv, __q);
			} else if (__acceptBounds) {
				// Same as min(__e2 + (~__mm & 1), __pow5Factor(__mm)) >= __q
				// <=> __e2 + (~__mm & 1) >= __q && __pow5Factor(__mm) >= __q
				// <=> true && __pow5Factor(__mm) >= __q, since __e2 >= __q.
				__vmIsTrailingZeros = __multipleOfPowerOf5(__mv - 1 - __mmShift, __q);
			} else {
				// Same as min(__e2 + 1, __pow5Factor(__mp)) >= __q.
				__vp -= __multipleOfPowerOf5(__mv + 2, __q);
			}
		}
	} else {
		// This expression is slightly faster than max(0, __log10Pow5(-__e2) - 1).
		const uint32_t __q = __log10Pow5(-__e2) - (-__e2 > 1);
		__e10 = static_cast<int32_t>(__q) + __e2;
		const int32_t __i = -__e2 - static_cast<int32_t>(__q);
		const int32_t __k = __pow5bits(__i) - __DOUBLE_POW5_BITCOUNT;
		const int32_t __j = static_cast<int32_t>(__q) - __k;
		__vr = __mulShiftAll(__m2, __DOUBLE_POW5_SPLIT[__i], __j, &__vp, &__vm, __mmShift);
		if (__q <= 1) {
			// {__vr,__vp,__vm} is trailing zeros if {__mv,__mp,__mm} has at least __q trailing 0 bits.
			// __mv = 4 * __m2, so it always has at least two trailing 0 bits.
			__vrIsTrailingZeros = true;
			if (__acceptBounds) {
				// __mm = __mv - 1 - __mmShift, so it has 1 trailing 0 bit iff __mmShift == 1.
				__vmIsTrailingZeros = __mmShift == 1;
			} else {
				// __mp = __mv + 2, so it always has at least one trailing 0 bit.
				--__vp;
			}
		} else if (__q < 63) { // TODO(ulfjack): Use a tighter bound here.
			// We need to compute min(ntz(__mv), __pow5Factor(__mv) - __e2) >= __q - 1
			// <=> ntz(__mv) >= __q - 1 && __pow5Factor(__mv) - __e2 >= __q - 1
			// <=> ntz(__mv) >= __q - 1 (__e2 is negative and -__e2 >= __q)
			// <=> (__mv & ((1 << (__q - 1)) - 1)) == 0
			// We also need to make sure that the left shift does not overflow.
			__vrIsTrailingZeros = __multipleOfPowerOf2(__mv, __q - 1);
		}
	}

	// Step 4: Find the shortest decimal representation in the interval of valid representations.
	int32_t __removed = 0;
	uint8_t __lastRemovedDigit = 0;
	uint64_t __output;
	// On average, we remove ~2 digits.
	if (__vmIsTrailingZeros || __vrIsTrailingZeros) {
		// General case, which happens rarely (~0.7%).
		for (;;) {
			const uint64_t __vpDiv10 = __div10(__vp);
			const uint64_t __vmDiv10 = __div10(__vm);
			if (__vpDiv10 <= __vmDiv10) {
				break;
			}
			const uint32_t __vmMod10 = static_cast<uint32_t>(__vm - 10 * __vmDiv10);
			const uint64_t __vrDiv10 = __div10(__vr);
			const uint32_t __vrMod10 = static_cast<uint32_t>(__vr - 10 * __vrDiv10);
			__vmIsTrailingZeros &= __vmMod10 == 0;
			__vrIsTrailingZeros &= __lastRemovedDigit == 0;
			__lastRemovedDigit = static_cast<uint8_t>(__vrMod10);
			__vr = __vrDiv10;
			__vp = __vpDiv10;
			__vm = __vmDiv10;
			++__removed;
		}
		if (__vmIsTrailingZeros) {
			for (;;) {
				const uint64_t __vmDiv10 = __div10(__vm);
				const uint32_t __vmMod10 = static_cast<uint32_t>(__vm - 10 * __vmDiv10);
				if (__vmMod10 != 0) {
					break;
				}
				const uint64_t __vpDiv10 = __div10(__vp);
				const uint64_t __vrDiv10 = __div10(__vr);
				const uint32_t __vrMod10 = static_cast<uint32_t>(__vr - 10 * __vrDiv10);
				__vrIsTrailingZeros &= __lastRemovedDigit == 0;
				__lastRemovedDigit = static_cast<uint8_t>(__vrMod10);
				__vr = __vrDiv10;
				__vp = __vpDiv10;
				__vm = __vmDiv10;
				++__removed;
			}
		}
		if (__vrIsTrailingZeros && __lastRemovedDigit == 5 && __vr % 2 == 0) {
			// Round even if the exact number is .....50..0.
			__lastRemovedDigit = 4;
		}
		// We need to take __vr + 1 if __vr is outside bounds or we need to round up.
		__output = __vr + ((__vr == __vm && (!__acceptBounds || !__vmIsTrailingZeros)) || __lastRemovedDigit >= 5);
	} else {
		// Specialized for the common case (~99.3%). Percentages below are relative to this.
		bool __roundUp = false;
		const uint64_t __vpDiv100 = __div100(__vp);
		const uint64_t __vmDiv100 = __div100(__vm);
		if (__vpDiv100 > __vmDiv100) { // Optimization: remove two digits at a time (~86.2%).
			const uint64_t __vrDiv100 = __div100(__vr);
			const uint32_t __vrMod100 = static_cast<uint32_t>(__vr - 100 * __vrDiv100);
			__roundUp = __vrMod100 >= 50;
			__vr = __vrDiv100;
			__vp = __vpDiv100;
			__vm = __vmDiv100;
			__removed += 2;
		}
		// Loop iterations below (approximately), without optimization above:
		// 0: 0.03%, 1: 13.8%, 2: 70.6%, 3: 14.0%, 4: 1.40%, 5: 0.14%, 6+: 0.02%
		// Loop iterations below (approximately), with optimization above:
		// 0: 70.6%, 1: 27.8%, 2: 1.40%, 3: 0.14%, 4+: 0.02%
		for (;;) {
			const uint64_t __vpDiv10 = __div10(__vp);
			const uint64_t __vmDiv10 = __div10(__vm);
			if (__vpDiv10 <= __vmDiv10) {
				break;
			}
			const uint64_t __vrDiv10 = __div10(__vr);
			const uint32_t __vrMod10 = static_cast<uint32_t>(__vr - 10 * __vrDiv10);
			__roundUp = __vrMod10 >= 5;
			__vr = __vrDiv10;
			__vp = __vpDiv10;
			__vm = __vmDiv10;
			++__removed;
		}
		// We need to take __vr + 1 if __vr is outside bounds or we need to round up.
		__output = __vr + (__vr == __vm || __roundUp);
	}
	const int32_t __exp = __e10 + __removed;

	__floating_decimal_64 __fd;
	__fd.__exponent = __exp;
	__fd.__mantissa = __output;
	return __fd;
}

_NODISCARD inline to_chars_result __to_chars(char * const _First, char * const _Last, const __floating_decimal_64 __v,
	chars_format _Fmt, const uint64_t __ieeeMantissa, const uint32_t __ieeeExponent) {
	// Step 5: Print the decimal representation.
	uint64_t __output = __v.__mantissa;
	const uint32_t __olength = __decimalLength(__output);
	int32_t _Scientific_exponent = __v.__exponent + static_cast<int32_t>(__olength) - 1;

	if (_Fmt == chars_format{}) {
		int32_t _Lower;
		int32_t _Upper;

		if (__olength == 1) {
			// Value | Fixed   | Scientific
			// 1e-3  | "0.001" | "1e-03"
			// 1e4   | "10000" | "1e+04"
			_Lower = -3;
			_Upper = 4;
		} else {
			// Value   | Fixed       | Scientific
			// 1234e-7 | "0.0001234" | "1.234e-04"
			// 1234e5  | "123400000" | "1.234e+08"
			_Lower = -static_cast<int32_t>(__olength + 3);
			_Upper = 5;
		}

		if (_Lower <= __v.__exponent && __v.__exponent <= _Upper) {
			_Fmt = chars_format::fixed;
		} else {
			_Fmt = chars_format::scientific;
		}
	} else if (_Fmt == chars_format::general) {
		// C11 7.21.6.1 "The fprintf function"/8:
		// "Let P equal [...] 6 if the precision is omitted [...].
		// Then, if a conversion with style E would have an exponent of X:
		// - if P > X >= -4, the conversion is with style f [...].
		// - otherwise, the conversion is with style e [...]."
		if (-4 <= _Scientific_exponent && _Scientific_exponent < 6) {
			_Fmt = chars_format::fixed;
		} else {
			_Fmt = chars_format::scientific;
		}
	}

	if (_Fmt == chars_format::fixed) {
		// Example: __output == 1729, __olength == 4

		// __v.__exponent | Printed  | _Whole_digits | _Total_fixed_length  | Notes
		// ---------------|----------|---------------|----------------------|---------------------------------------
		//              2 | 172900   |  6            | _Whole_digits        | Ryu can't be used for printing
		//              1 | 17290    |  5            | (sometimes adjusted) | when the trimmed digits are nonzero.
		// ---------------|----------|---------------|----------------------|---------------------------------------
		//              0 | 1729     |  4            | _Whole_digits        | Unified length cases.
		// ---------------|----------|---------------|----------------------|---------------------------------------
		//             -1 | 172.9    |  3            | __olength + 1        | This case can't happen for
		//             -2 | 17.29    |  2            |                      | __olength == 1, but no additional
		//             -3 | 1.729    |  1            |                      | code is needed to avoid it.
		// ---------------|----------|---------------|----------------------|---------------------------------------
		//             -4 | 0.1729   |  0            | 2 - __v.__exponent   | C11 7.21.6.1 "The fprintf function"/8:
		//             -5 | 0.01729  | -1            |                      | "If a decimal-point character appears,
		//             -6 | 0.001729 | -2            |                      | at least one digit appears before it."

		const int32_t _Whole_digits = static_cast<int32_t>(__olength) + __v.__exponent;

		uint32_t _Total_fixed_length;
		if (__v.__exponent >= 0) { // cases "172900" and "1729"
			_Total_fixed_length = static_cast<uint32_t>(_Whole_digits);
			if (__output == 1) {
				// Rounding can affect the number of digits.
				// For example, 1e23 is exactly "99999999999999991611392" which is 23 digits instead of 24.
				// We can use a lookup table to detect this and adjust the total length.
				static constexpr uint8_t _Adjustment[309] = {
					0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,0,0,0,1,1,0,1,0,1,1,1,0,1,1,1,0,0,0,0,0,
					1,1,0,0,1,0,1,1,1,0,0,0,0,1,1,1,1,0,0,0,1,1,1,1,0,0,0,1,1,1,1,0,1,0,1,0,1,1,0,0,0,0,1,1,1,
					1,0,0,0,0,0,0,0,1,1,0,1,1,0,0,1,0,1,0,1,0,1,1,0,0,0,0,0,1,1,1,0,0,1,1,1,1,1,0,1,0,1,1,0,1,
					1,0,0,0,0,0,0,0,0,0,1,1,1,0,0,1,0,0,1,0,0,1,1,1,1,0,0,1,1,0,1,1,0,1,1,0,1,0,0,0,1,0,0,0,1,
					0,1,0,1,0,1,1,1,0,0,0,0,0,0,1,1,1,1,0,0,1,0,1,1,1,0,0,0,1,0,1,1,1,1,1,1,0,1,0,1,1,0,0,0,1,
					1,1,0,1,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,1,0,1,1,0,0,1,1,1,0,0,0,1,0,1,0,0,0,0,0,1,1,0,
					0,1,0,1,1,1,0,0,1,0,0,0,0,1,0,1,0,0,0,0,0,1,0,1,0,1,1,0,1,0,0,0,0,0,1,1,0,1,0 };
				_Total_fixed_length -= _Adjustment[__v.__exponent];
				// _Whole_digits doesn't need to be adjusted because these cases won't refer to it later.
			}
		} else if (_Whole_digits > 0) { // case "17.29"
			_Total_fixed_length = __olength + 1;
		} else { // case "0.001729"
			_Total_fixed_length = static_cast<uint32_t>(2 - __v.__exponent);
		}

		if (_Last - _First < static_cast<ptrdiff_t>(_Total_fixed_length)) {
			return { _Last, errc::value_too_large };
		}

		char * _Mid;
		if (__v.__exponent > 0) { // case "172900"
			bool _Can_use_ryu;

			if (__v.__exponent > 22) { // 10^22 is the largest power of 10
				_Can_use_ryu = false; // that's exactly representable as a double
			} else {
				// Ryu generated X: __v.__mantissa * 10^__v.__exponent
				// __v.__mantissa == 2^_Trailing_zero_bits * (__v.__mantissa >> _Trailing_zero_bits)
				// 10^__v.__exponent == 2^__v.__exponent * 5^__v.__exponent

				// _Trailing_zero_bits is [0, 56] (aside: because 2^56 is the largest power of 2
				// with 17 decimal digits, which is double's round-trip limit.)
				// __v.__exponent is [1, 22].
				// Normalization adds [2, 52] (aside: at least 2 because the pre-normalized mantissa is at least 5).
				// This adds up to [3, 130], which is well below double's maximum binary exponent 1023.

				// Therefore, we just need to consider (__v.__mantissa >> _Trailing_zero_bits) * 5^__v.__exponent.

				// If that product would exceed 53 bits, then X can't be exactly represented as a double.
				// (That's not a problem for round-tripping, because X is close enough to the original double,
				// but X isn't mathematically equal to the original double.) This requires a high-precision fallback.

				// If the product is 53 bits or smaller, then X can be exactly represented as a double (and we don't
				// need to re-synthesize it; the original double must have been X, because Ryu wouldn't produce the
				// same output for two different doubles X and Y). This allows Ryu's output to be used (zero-filled).

				// (2^53 - 1) / 5^0 (for indexing), (2^53 - 1) / 5^1, ..., (2^53 - 1) / 5^22
				static constexpr uint64_t _Max_shifted_mantissa[23] = {
					9007199254740991u, 1801439850948198u, 360287970189639u, 72057594037927u, 14411518807585u,
					2882303761517u, 576460752303u, 115292150460u, 23058430092u, 4611686018u, 922337203u, 184467440u,
					36893488u, 7378697u, 1475739u, 295147u, 59029u, 11805u, 2361u, 472u, 94u, 18u, 3u };

				unsigned long _Trailing_zero_bits;
#ifdef _WIN64
				(void) _BitScanForward64(&_Trailing_zero_bits, __v.__mantissa); // __v.__mantissa is guaranteed nonzero
#else // ^^^ 64-bit ^^^ / vvv 32-bit vvv
				const uint32_t _Low_mantissa = static_cast<uint32_t>(__v.__mantissa);
				if (_Low_mantissa != 0) {
					(void) _BitScanForward(&_Trailing_zero_bits, _Low_mantissa);
				} else {
					const uint32_t _High_mantissa = static_cast<uint32_t>(__v.__mantissa >> 32); // nonzero here
					(void) _BitScanForward(&_Trailing_zero_bits, _High_mantissa);
					_Trailing_zero_bits += 32;
				}
#endif // ^^^ 32-bit ^^^
				const uint64_t _Shifted_mantissa = __v.__mantissa >> _Trailing_zero_bits;
				_Can_use_ryu = _Shifted_mantissa <= _Max_shifted_mantissa[__v.__exponent];
			}

			if (!_Can_use_ryu) {
				_Print_exact_integer_from_double(_First, __ieeeMantissa, __ieeeExponent, _Total_fixed_length);
				return { _First + _Total_fixed_length, errc{} };
			}

			// Print the decimal digits, left-aligned within [_First, _First + _Total_fixed_length).
			_Mid = _First + __olength;
		} else { // cases "1729", "17.29", and "0.001729"
			// Print the decimal digits, right-aligned within [_First, _First + _Total_fixed_length).
			_Mid = _First + _Total_fixed_length;
		}

		// We prefer 32-bit operations, even on 64-bit platforms.
		// We have at most 17 digits, and uint32_t can store 9 digits.
		// If __output doesn't fit into uint32_t, we cut off 8 digits,
		// so the rest will fit into uint32_t.
		if ((__output >> 32) != 0) {
			// Expensive 64-bit division.
			const uint64_t __q = __div100000000(__output);
			uint32_t __output2 = static_cast<uint32_t>(__output - 100000000 * __q);
			__output = __q;

			const uint32_t __c = __output2 % 10000;
			__output2 /= 10000;
			const uint32_t __d = __output2 % 10000;
			const uint32_t __c0 = (__c % 100) << 1;
			const uint32_t __c1 = (__c / 100) << 1;
			const uint32_t __d0 = (__d % 100) << 1;
			const uint32_t __d1 = (__d / 100) << 1;

			_CSTD memcpy(_Mid -= 2, __DIGIT_TABLE + __c0, 2);
			_CSTD memcpy(_Mid -= 2, __DIGIT_TABLE + __c1, 2);
			_CSTD memcpy(_Mid -= 2, __DIGIT_TABLE + __d0, 2);
			_CSTD memcpy(_Mid -= 2, __DIGIT_TABLE + __d1, 2);
		}
		uint32_t __output2 = static_cast<uint32_t>(__output);
		while (__output2 >= 10000) {
#ifdef __clang__ // TRANSITION, LLVM#38217
			const uint32_t __c = __output2 - 10000 * (__output2 / 10000);
#else
			const uint32_t __c = __output2 % 10000;
#endif
			__output2 /= 10000;
			const uint32_t __c0 = (__c % 100) << 1;
			const uint32_t __c1 = (__c / 100) << 1;
			_CSTD memcpy(_Mid -= 2, __DIGIT_TABLE + __c0, 2);
			_CSTD memcpy(_Mid -= 2, __DIGIT_TABLE + __c1, 2);
		}
		if (__output2 >= 100) {
			const uint32_t __c = (__output2 % 100) << 1;
			__output2 /= 100;
			_CSTD memcpy(_Mid -= 2, __DIGIT_TABLE + __c, 2);
		}
		if (__output2 >= 10) {
			const uint32_t __c = __output2 << 1;
			_CSTD memcpy(_Mid -= 2, __DIGIT_TABLE + __c, 2);
		} else {
			*--_Mid = static_cast<char>('0' + __output2);
		}

		if (__v.__exponent > 0) { // case "172900"
			// Performance note: it might be more efficient to do this immediately after setting _Mid.
			_CSTD memset(_First + __olength, '0', static_cast<size_t>(__v.__exponent));
		} else if (__v.__exponent == 0) { // case "1729"
			// Done!
		} else if (_Whole_digits > 0) { // case "17.29"
			// Performance note: moving digits might not be optimal.
			_CSTD memmove(_First, _First + 1, static_cast<size_t>(_Whole_digits));
			_First[_Whole_digits] = '.';
		} else { // case "0.001729"
			// Performance note: a larger memset() followed by overwriting '.' might be more efficient.
			_First[0] = '0';
			_First[1] = '.';
			_CSTD memset(_First + 2, '0', static_cast<size_t>(-_Whole_digits));
		}

		return { _First + _Total_fixed_length, errc{} };
	}

	const uint32_t _Total_scientific_length = __olength + (__olength > 1) // digits + possible decimal point
		+ (-100 < _Scientific_exponent && _Scientific_exponent < 100 ? 4 : 5); // + scientific exponent
	if (_Last - _First < static_cast<ptrdiff_t>(_Total_scientific_length)) {
		return { _Last, errc::value_too_large };
	}
	char * const __result = _First;

	// Print the decimal digits.
	uint32_t __i = 0;
	// We prefer 32-bit operations, even on 64-bit platforms.
	// We have at most 17 digits, and uint32_t can store 9 digits.
	// If __output doesn't fit into uint32_t, we cut off 8 digits,
	// so the rest will fit into uint32_t.
	if ((__output >> 32) != 0) {
		// Expensive 64-bit division.
		const uint64_t __q = __div100000000(__output);
		uint32_t __output2 = static_cast<uint32_t>(__output - 100000000 * __q);
		__output = __q;

		const uint32_t __c = __output2 % 10000;
		__output2 /= 10000;
		const uint32_t __d = __output2 % 10000;
		const uint32_t __c0 = (__c % 100) << 1;
		const uint32_t __c1 = (__c / 100) << 1;
		const uint32_t __d0 = (__d % 100) << 1;
		const uint32_t __d1 = (__d / 100) << 1;
		_CSTD memcpy(__result + __olength - __i - 1, __DIGIT_TABLE + __c0, 2);
		_CSTD memcpy(__result + __olength - __i - 3, __DIGIT_TABLE + __c1, 2);
		_CSTD memcpy(__result + __olength - __i - 5, __DIGIT_TABLE + __d0, 2);
		_CSTD memcpy(__result + __olength - __i - 7, __DIGIT_TABLE + __d1, 2);
		__i += 8;
	}
	uint32_t __output2 = static_cast<uint32_t>(__output);
	while (__output2 >= 10000) {
#ifdef __clang__ // TRANSITION, LLVM#38217
		const uint32_t __c = __output2 - 10000 * (__output2 / 10000);
#else
		const uint32_t __c = __output2 % 10000;
#endif
		__output2 /= 10000;
		const uint32_t __c0 = (__c % 100) << 1;
		const uint32_t __c1 = (__c / 100) << 1;
		_CSTD memcpy(__result + __olength - __i - 1, __DIGIT_TABLE + __c0, 2);
		_CSTD memcpy(__result + __olength - __i - 3, __DIGIT_TABLE + __c1, 2);
		__i += 4;
	}
	if (__output2 >= 100) {
		const uint32_t __c = (__output2 % 100) << 1;
		__output2 /= 100;
		_CSTD memcpy(__result + __olength - __i - 1, __DIGIT_TABLE + __c, 2);
		__i += 2;
	}
	if (__output2 >= 10) {
		const uint32_t __c = __output2 << 1;
		// We can't use memcpy here: the decimal dot goes between these two digits.
		__result[__olength - __i] = __DIGIT_TABLE[__c + 1];
		__result[0] = __DIGIT_TABLE[__c];
	} else {
		__result[0] = static_cast<char>('0' + __output2);
	}

	// Print decimal point if needed.
	uint32_t __index;
	if (__olength > 1) {
		__result[1] = '.';
		__index = __olength + 1;
	} else {
		__index = 1;
	}

	// Print the exponent.
	__result[__index++] = 'e';
	if (_Scientific_exponent < 0) {
		__result[__index++] = '-';
		_Scientific_exponent = -_Scientific_exponent;
	} else {
		__result[__index++] = '+';
	}

	if (_Scientific_exponent >= 100) {
		const int32_t __c = _Scientific_exponent % 10;
		_CSTD memcpy(__result + __index, __DIGIT_TABLE + 2 * (_Scientific_exponent / 10), 2);
		__result[__index + 2] = static_cast<char>('0' + __c);
		__index += 3;
	} else {
		_CSTD memcpy(__result + __index, __DIGIT_TABLE + 2 * _Scientific_exponent, 2);
		__index += 2;
	}

	return { _First + _Total_scientific_length, errc{} };
}

_NODISCARD inline to_chars_result __d2s_buffered_n(char * const _First, char * const _Last, const double __f,
	const chars_format _Fmt) {

	// Step 1: Decode the floating-point number, and unify normalized and subnormal cases.
	const uint64_t __bits = __double_to_bits(__f);

	// Case distinction; exit early for the easy cases.
	if (__bits == 0) {
		if (_Fmt == chars_format::scientific) {
			if (_Last - _First < 5) {
				return { _Last, errc::value_too_large };
			}

			_CSTD memcpy(_First, "0e+00", 5);

			return { _First + 5, errc{} };
		}

		// Print "0" for chars_format::fixed, chars_format::general, and chars_format{}.
		if (_First == _Last) {
			return { _Last, errc::value_too_large };
		}

		*_First = '0';

		return { _First + 1, errc{} };
	}

	// Decode __bits into mantissa and exponent.
	const uint64_t __ieeeMantissa = __bits & ((1ull << __DOUBLE_MANTISSA_BITS) - 1);
	const uint32_t __ieeeExponent = static_cast<uint32_t>(__bits >> __DOUBLE_MANTISSA_BITS);

	const __floating_decimal_64 __v = __d2d(__ieeeMantissa, __ieeeExponent);
	return __to_chars(_First, _Last, __v, _Fmt, __ieeeMantissa, __ieeeExponent);
}

// ^^^^^^^^^^ DERIVED FROM d2s.c ^^^^^^^^^^

template<class _Floating>
	_NODISCARD inline to_chars_result _Floating_to_chars_ryu(char * const _First, char * const _Last,
	const _Floating _Value, const chars_format _Fmt) noexcept // strengthened
	{
	if constexpr (is_same_v<_Floating, float>)
		{
		return __f2s_buffered_n(_First, _Last, _Value, _Fmt);
		}
	else
		{
		return __d2s_buffered_n(_First, _Last, _Value, _Fmt);
		}
	}

_STD_END

#pragma pop_macro("new")
_STL_RESTORE_CLANG_WARNINGS
#pragma warning(pop)
#pragma pack(pop)

#endif /* RC_INVOKED */
#endif /* _XCHARCONV_RYU_H */