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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-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 <cstdint>
48#include <cstring>
49
50_LIBCPP_BEGIN_NAMESPACE_STD
51
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 greater
72 // 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_STD
107
108// clang-format on
109
110#endif // _LIBCPP_SRC_INCLUDE_RYU_COMMON_H