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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 // Copyright (c) Microsoft Corporation. 10 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 11 12 // Copyright 2018 Ulf Adams 13 // Copyright (c) Microsoft Corporation. All rights reserved. 14 15 // Boost Software License - Version 1.0 - August 17th, 2003 16 17 // Permission is hereby granted, free of charge, to any person or organization 18 // obtaining a copy of the software and accompanying documentation covered by 19 // this license (the "Software") to use, reproduce, display, distribute, 20 // execute, and transmit the Software, and to prepare derivative works of the 21 // Software, and to permit third-parties to whom the Software is furnished to 22 // do so, all subject to the following: 23 24 // The copyright notices in the Software and this entire statement, including 25 // 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, and 27 // all derivative works of the Software, unless such copies or derivative 28 // works are solely in the form of machine-executable object code generated by 29 // a source language processor. 30 31 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 32 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 33 // FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT 34 // SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE 35 // 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 OTHER 37 // DEALINGS IN THE SOFTWARE. 38 39 #ifndef _LIBCPP_SRC_INCLUDE_RYU_COMMON_H 40 #define _LIBCPP_SRC_INCLUDE_RYU_COMMON_H 41 42 // Avoid formatting to keep the changes with the original code minimal. 43 // clang-format off 44 45 #include <__assert> 46 #include <__config> 47 #include <cstring> 48 49 _LIBCPP_BEGIN_NAMESPACE_STD 50 51 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __decimalLength9(const uint32_t __v) { 52 // Function precondition: __v is not a 10-digit number. 53 // (f2s: 9 digits are sufficient for round-tripping.) 54 // (d2fixed: We print 9-digit blocks.) 55 _LIBCPP_ASSERT_UNCATEGORIZED(__v < 1000000000, ""); 56 if (__v >= 100000000) { return 9; } 57 if (__v >= 10000000) { return 8; } 58 if (__v >= 1000000) { return 7; } 59 if (__v >= 100000) { return 6; } 60 if (__v >= 10000) { return 5; } 61 if (__v >= 1000) { return 4; } 62 if (__v >= 100) { return 3; } 63 if (__v >= 10) { return 2; } 64 return 1; 65 } 66 67 // Returns __e == 0 ? 1 : ceil(log_2(5^__e)). 68 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline int32_t __pow5bits(const int32_t __e) { 69 // This approximation works up to the point that the multiplication overflows at __e = 3529. 70 // If the multiplication were done in 64 bits, it would fail at 5^4004 which is just greater 71 // than 2^9297. 72 _LIBCPP_ASSERT_UNCATEGORIZED(__e >= 0, ""); 73 _LIBCPP_ASSERT_UNCATEGORIZED(__e <= 3528, ""); 74 return static_cast<int32_t>(((static_cast<uint32_t>(__e) * 1217359) >> 19) + 1); 75 } 76 77 // Returns floor(log_10(2^__e)). 78 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __log10Pow2(const int32_t __e) { 79 // The first value this approximation fails for is 2^1651 which is just greater than 10^297. 80 _LIBCPP_ASSERT_UNCATEGORIZED(__e >= 0, ""); 81 _LIBCPP_ASSERT_UNCATEGORIZED(__e <= 1650, ""); 82 return (static_cast<uint32_t>(__e) * 78913) >> 18; 83 } 84 85 // Returns floor(log_10(5^__e)). 86 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __log10Pow5(const int32_t __e) { 87 // The first value this approximation fails for is 5^2621 which is just greater than 10^1832. 88 _LIBCPP_ASSERT_UNCATEGORIZED(__e >= 0, ""); 89 _LIBCPP_ASSERT_UNCATEGORIZED(__e <= 2620, ""); 90 return (static_cast<uint32_t>(__e) * 732923) >> 20; 91 } 92 93 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __float_to_bits(const float __f) { 94 uint32_t __bits = 0; 95 std::memcpy(&__bits, &__f, sizeof(float)); 96 return __bits; 97 } 98 99 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint64_t __double_to_bits(const double __d) { 100 uint64_t __bits = 0; 101 std::memcpy(&__bits, &__d, sizeof(double)); 102 return __bits; 103 } 104 105 _LIBCPP_END_NAMESPACE_STD 106 107 // clang-format on 108 109 #endif // _LIBCPP_SRC_INCLUDE_RYU_COMMON_H 110