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1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9// Copyright (c) Microsoft Corporation.10// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception11 12// Copyright 2018 Ulf Adams13// Copyright (c) Microsoft Corporation. All rights reserved.14 15// Boost Software License - Version 1.0 - August 17th, 200316 17// Permission is hereby granted, free of charge, to any person or organization18// obtaining a copy of the software and accompanying documentation covered by19// this license (the "Software") to use, reproduce, display, distribute,20// execute, and transmit the Software, and to prepare derivative works of the21// Software, and to permit third-parties to whom the Software is furnished to22// do so, all subject to the following:23 24// The copyright notices in the Software and this entire statement, including25// the above license grant, this restriction and the following disclaimer,26// must be included in all copies of the Software, in whole or in part, and27// all derivative works of the Software, unless such copies or derivative28// works are solely in the form of machine-executable object code generated by29// a source language processor.30 31// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR32// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,33// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT34// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE35// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,36// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER37// DEALINGS IN THE SOFTWARE.38 39#ifndef _LIBCPP_SRC_INCLUDE_RYU_COMMON_H40#define _LIBCPP_SRC_INCLUDE_RYU_COMMON_H41 42// Avoid formatting to keep the changes with the original code minimal.43// clang-format off44 45#include <__assert>46#include <__config>47#include <cstdint>48#include <cstring>49 50_LIBCPP_BEGIN_NAMESPACE_STD51 52[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __decimalLength9(const uint32_t __v) {53 // Function precondition: __v is not a 10-digit number.54 // (f2s: 9 digits are sufficient for round-tripping.)55 // (d2fixed: We print 9-digit blocks.)56 _LIBCPP_ASSERT_INTERNAL(__v < 1000000000, "");57 if (__v >= 100000000) { return 9; }58 if (__v >= 10000000) { return 8; }59 if (__v >= 1000000) { return 7; }60 if (__v >= 100000) { return 6; }61 if (__v >= 10000) { return 5; }62 if (__v >= 1000) { return 4; }63 if (__v >= 100) { return 3; }64 if (__v >= 10) { return 2; }65 return 1;66}67 68// Returns __e == 0 ? 1 : ceil(log_2(5^__e)).69[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline int32_t __pow5bits(const int32_t __e) {70 // This approximation works up to the point that the multiplication overflows at __e = 3529.71 // If the multiplication were done in 64 bits, it would fail at 5^4004 which is just greater72 // than 2^9297.73 _LIBCPP_ASSERT_INTERNAL(__e >= 0, "");74 _LIBCPP_ASSERT_INTERNAL(__e <= 3528, "");75 return static_cast<int32_t>(((static_cast<uint32_t>(__e) * 1217359) >> 19) + 1);76}77 78// Returns floor(log_10(2^__e)).79[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __log10Pow2(const int32_t __e) {80 // The first value this approximation fails for is 2^1651 which is just greater than 10^297.81 _LIBCPP_ASSERT_INTERNAL(__e >= 0, "");82 _LIBCPP_ASSERT_INTERNAL(__e <= 1650, "");83 return (static_cast<uint32_t>(__e) * 78913) >> 18;84}85 86// Returns floor(log_10(5^__e)).87[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __log10Pow5(const int32_t __e) {88 // The first value this approximation fails for is 5^2621 which is just greater than 10^1832.89 _LIBCPP_ASSERT_INTERNAL(__e >= 0, "");90 _LIBCPP_ASSERT_INTERNAL(__e <= 2620, "");91 return (static_cast<uint32_t>(__e) * 732923) >> 20;92}93 94[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __float_to_bits(const float __f) {95 uint32_t __bits = 0;96 std::memcpy(&__bits, &__f, sizeof(float));97 return __bits;98}99 100[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint64_t __double_to_bits(const double __d) {101 uint64_t __bits = 0;102 std::memcpy(&__bits, &__d, sizeof(double));103 return __bits;104}105 106_LIBCPP_END_NAMESPACE_STD107 108// clang-format on109 110#endif // _LIBCPP_SRC_INCLUDE_RYU_COMMON_H111