1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // Copyright (c) Microsoft Corporation.
11 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
12 
13 
14 // Copyright 2018 Ulf Adams
15 // Copyright (c) Microsoft Corporation. All rights reserved.
16 
17 // Boost Software License - Version 1.0 - August 17th, 2003
18 
19 // Permission is hereby granted, free of charge, to any person or organization
20 // obtaining a copy of the software and accompanying documentation covered by
21 // this license (the "Software") to use, reproduce, display, distribute,
22 // execute, and transmit the Software, and to prepare derivative works of the
23 // Software, and to permit third-parties to whom the Software is furnished to
24 // do so, all subject to the following:
25 
26 // The copyright notices in the Software and this entire statement, including
27 // the above license grant, this restriction and the following disclaimer,
28 // must be included in all copies of the Software, in whole or in part, and
29 // all derivative works of the Software, unless such copies or derivative
30 // works are solely in the form of machine-executable object code generated by
31 // a source language processor.
32 
33 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
34 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
35 // FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
36 // SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
37 // FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
38 // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
39 // DEALINGS IN THE SOFTWARE.
40 
41 #ifndef _LIBCPP_SRC_INCLUDE_RYU_RYU_H
42 #define _LIBCPP_SRC_INCLUDE_RYU_RYU_H
43 
44 // Avoid formatting to keep the changes with the original code minimal.
45 // clang-format off
46 
47 #include <__charconv/chars_format.h>
48 #include <__charconv/to_chars_result.h>
49 #include <__config>
50 #include <__system_error/errc.h>
51 #include <cstdint>
52 #include <cstring>
53 #include <type_traits>
54 
55 #include "include/ryu/f2s.h"
56 #include "include/ryu/d2s.h"
57 #include "include/ryu/d2fixed.h"
58 
59 #if defined(_MSC_VER)
60 #include <intrin.h> // for _umul128(), __shiftright128(), _BitScanForward{,64}
61 #endif // defined(_MSC_VER)
62 
63 #if defined(_WIN64) || defined(_M_AMD64) || defined(__x86_64__) ||  defined(__aarch64__)
64 #define _LIBCPP_64_BIT
65 #endif
66 
67 _LIBCPP_BEGIN_NAMESPACE_STD
68 
69 // https://github.com/ulfjack/ryu/tree/59661c3/ryu
70 
71 #if !defined(_MSC_VER)
72 _LIBCPP_HIDE_FROM_ABI inline unsigned char _BitScanForward64(unsigned long* __index, unsigned long long __mask) {
73   if (__mask == 0) {
74     return false;
75   }
76   *__index = __builtin_ctzll(__mask);
77   return true;
78 }
79 
80 _LIBCPP_HIDE_FROM_ABI inline unsigned char _BitScanForward(unsigned long* __index, unsigned int __mask) {
81   if (__mask == 0) {
82     return false;
83   }
84   *__index = __builtin_ctz(__mask);
85   return true;
86 }
87 #endif  // !_MSC_VER
88 
89 template <class _Floating>
90 [[nodiscard]] to_chars_result _Floating_to_chars_ryu(
91     char* const _First, char* const _Last, const _Floating _Value, const chars_format _Fmt) noexcept {
92     if constexpr (_IsSame<_Floating, float>::value) {
93         return __f2s_buffered_n(_First, _Last, _Value, _Fmt);
94     } else {
95         return __d2s_buffered_n(_First, _Last, _Value, _Fmt);
96     }
97 }
98 
99 template <class _Floating>
100 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI to_chars_result _Floating_to_chars_scientific_precision(
101     char* const _First, char* const _Last, const _Floating _Value, int _Precision) noexcept {
102 
103     // C11 7.21.6.1 "The fprintf function"/5:
104     // "A negative precision argument is taken as if the precision were omitted."
105     // /8: "e,E [...] if the precision is missing, it is taken as 6"
106 
107     if (_Precision < 0) {
108         _Precision = 6;
109     } else if (_Precision < 1'000'000'000) { // Match ' to fix compilation with GCC in C++11 mode
110         // _Precision is ok.
111     } else {
112         // Avoid integer overflow.
113         // (This defensive check is slightly nonconformant; it can be carefully improved in the future.)
114         return {_Last, errc::value_too_large};
115     }
116 
117     return __d2exp_buffered_n(_First, _Last, _Value, static_cast<uint32_t>(_Precision));
118 }
119 
120 template <class _Floating>
121 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI to_chars_result _Floating_to_chars_fixed_precision(
122     char* const _First, char* const _Last, const _Floating _Value, int _Precision) noexcept {
123 
124     // C11 7.21.6.1 "The fprintf function"/5:
125     // "A negative precision argument is taken as if the precision were omitted."
126     // /8: "f,F [...] If the precision is missing, it is taken as 6"
127 
128     if (_Precision < 0) {
129         _Precision = 6;
130     } else if (_Precision < 1'000'000'000) { // Match ' to fix compilation with GCC in C++11 mode
131         // _Precision is ok.
132     } else {
133         // Avoid integer overflow.
134         // (This defensive check is slightly nonconformant; it can be carefully improved in the future.)
135         return {_Last, errc::value_too_large};
136     }
137 
138     return __d2fixed_buffered_n(_First, _Last, _Value, static_cast<uint32_t>(_Precision));
139 }
140 
141 #undef _LIBCPP_64_BIT
142 #undef _LIBCPP_INTRINSIC128
143 
144 _LIBCPP_END_NAMESPACE_STD
145 
146 // clang-format on
147 
148 #endif // _LIBCPP_SRC_INCLUDE_RYU_RYU_H
149