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 <__debug>
51#include <__errc>
52#include <cstdint>
53#include <cstring>
54#include <type_traits>
55
56#include "include/ryu/f2s.h"
57#include "include/ryu/d2s.h"
58#include "include/ryu/d2fixed.h"
59
60#if defined(_MSC_VER)
61#include <intrin.h> // for _umul128(), __shiftright128(), _BitScanForward{,64}
62#endif // defined(_MSC_VER)
63
64#if defined(_WIN64) || defined(_M_AMD64) || defined(__x86_64__) ||  defined(__aarch64__)
65#define _LIBCPP_64_BIT
66#endif
67
68_LIBCPP_BEGIN_NAMESPACE_STD
69
70// https://github.com/ulfjack/ryu/tree/59661c3/ryu
71
72#if !defined(_MSC_VER)
73_LIBCPP_HIDE_FROM_ABI inline unsigned char _BitScanForward64(unsigned long* __index, unsigned long long __mask) {
74  if (__mask == 0) {
75    return false;
76  }
77  *__index = __builtin_ctzll(__mask);
78  return true;
79}
80
81_LIBCPP_HIDE_FROM_ABI inline unsigned char _BitScanForward(unsigned long* __index, unsigned int __mask) {
82  if (__mask == 0) {
83    return false;
84  }
85  *__index = __builtin_ctz(__mask);
86  return true;
87}
88#endif  // !_MSC_VER
89
90template <class _Floating>
91[[nodiscard]] to_chars_result _Floating_to_chars_ryu(
92    char* const _First, char* const _Last, const _Floating _Value, const chars_format _Fmt) noexcept {
93    if constexpr (_IsSame<_Floating, float>::value) {
94        return __f2s_buffered_n(_First, _Last, _Value, _Fmt);
95    } else {
96        return __d2s_buffered_n(_First, _Last, _Value, _Fmt);
97    }
98}
99
100template <class _Floating>
101[[nodiscard]] _LIBCPP_HIDE_FROM_ABI to_chars_result _Floating_to_chars_scientific_precision(
102    char* const _First, char* const _Last, const _Floating _Value, int _Precision) noexcept {
103
104    // C11 7.21.6.1 "The fprintf function"/5:
105    // "A negative precision argument is taken as if the precision were omitted."
106    // /8: "e,E [...] if the precision is missing, it is taken as 6"
107
108    if (_Precision < 0) {
109        _Precision = 6;
110    } else if (_Precision < 1'000'000'000) { // Match ' to fix compilation with GCC in C++11 mode
111        // _Precision is ok.
112    } else {
113        // Avoid integer overflow.
114        // (This defensive check is slightly nonconformant; it can be carefully improved in the future.)
115        return {_Last, errc::value_too_large};
116    }
117
118    return __d2exp_buffered_n(_First, _Last, _Value, static_cast<uint32_t>(_Precision));
119}
120
121template <class _Floating>
122[[nodiscard]] _LIBCPP_HIDE_FROM_ABI to_chars_result _Floating_to_chars_fixed_precision(
123    char* const _First, char* const _Last, const _Floating _Value, int _Precision) noexcept {
124
125    // C11 7.21.6.1 "The fprintf function"/5:
126    // "A negative precision argument is taken as if the precision were omitted."
127    // /8: "f,F [...] If the precision is missing, it is taken as 6"
128
129    if (_Precision < 0) {
130        _Precision = 6;
131    } else if (_Precision < 1'000'000'000) { // Match ' to fix compilation with GCC in C++11 mode
132        // _Precision is ok.
133    } else {
134        // Avoid integer overflow.
135        // (This defensive check is slightly nonconformant; it can be carefully improved in the future.)
136        return {_Last, errc::value_too_large};
137    }
138
139    return __d2fixed_buffered_n(_First, _Last, _Value, static_cast<uint32_t>(_Precision));
140}
141
142#undef _LIBCPP_64_BIT
143#undef _LIBCPP_INTRINSIC128
144
145_LIBCPP_END_NAMESPACE_STD
146
147// clang-format on
148
149#endif // _LIBCPP_SRC_INCLUDE_RYU_RYU_H
150