libstdc++
string_conversions.h
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1 // String Conversions -*- C++ -*-
2 
3 // Copyright (C) 2008-2025 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file ext/string_conversions.h
26  * This file is a GNU extension to the Standard C++ Library.
27  */
28 
29 #ifndef _STRING_CONVERSIONS_H
30 #define _STRING_CONVERSIONS_H 1
31 
32 #ifdef _GLIBCXX_SYSHDR
33 #pragma GCC system_header
34 #endif
35 
36 #include <bits/requires_hosted.h> // GNU extensions are currently omitted
37 
38 #if __cplusplus < 201103L
39 # include <bits/c++0x_warning.h>
40 #else
41 
42 #include <bits/c++config.h>
43 #include <ext/numeric_traits.h>
44 #include <bits/functexcept.h>
45 #include <cstdlib>
46 #include <cwchar>
47 #include <cstdio>
48 #include <cerrno>
49 
50 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
51 {
52 _GLIBCXX_BEGIN_NAMESPACE_VERSION
53 
54  // Helper for all the sto* functions.
55  template<typename _TRet, typename _Ret = _TRet, typename _CharT,
56  typename... _Base>
57  _Ret
58  __stoa(_TRet (*__convf) (const _CharT*, _CharT**, _Base...),
59  const char* __name, const _CharT* __str, std::size_t* __idx,
60  _Base... __base)
61  {
62  _Ret __ret;
63 
64  _CharT* __endptr;
65 
66  struct _Save_errno {
67  _Save_errno() : _M_errno(errno) { errno = 0; }
68  ~_Save_errno() { if (errno == 0) errno = _M_errno; }
69  int _M_errno;
70  } const __save_errno;
71 
72  struct _Range_chk {
73  static bool
74  _S_chk(_TRet, std::false_type) { return false; }
75 
76  static bool
77  _S_chk(_TRet __val, std::true_type) // only called when _Ret is int
78  {
79  return __val < _TRet(__numeric_traits<int>::__min)
80  || __val > _TRet(__numeric_traits<int>::__max);
81  }
82  };
83 
84  const _TRet __tmp = __convf(__str, &__endptr, __base...);
85 
86  if (__endptr == __str)
87  std::__throw_invalid_argument(__name);
88  else if (errno == ERANGE
89  || _Range_chk::_S_chk(__tmp, std::is_same<_Ret, int>{}))
90  std::__throw_out_of_range(__name);
91  else
92  __ret = __tmp;
93 
94  if (__idx)
95  *__idx = __endptr - __str;
96 
97  return __ret;
98  }
99 
100  // Helper for the to_string / to_wstring functions.
101  template<typename _String, typename _CharT = typename _String::value_type>
102  _String
103  __to_xstring(int (*__convf) (_CharT*, std::size_t, const _CharT*,
104  __builtin_va_list), std::size_t __n,
105  const _CharT* __fmt, ...)
106  {
107  // XXX Eventually the result should be constructed in-place in
108  // the __cxx11 string, likely with the help of internal hooks.
109  _CharT* __s = static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT)
110  * __n));
111 
112  __builtin_va_list __args;
113  __builtin_va_start(__args, __fmt);
114 
115  const int __len = __convf(__s, __n, __fmt, __args);
116 
117  __builtin_va_end(__args);
118 
119  return _String(__s, __s + __len);
120  }
121 
122 _GLIBCXX_END_NAMESPACE_VERSION
123 } // namespace
124 
125 #endif // C++11
126 
127 #endif // _STRING_CONVERSIONS_H
__bool_constant< true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:116
__bool_constant< false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:119
GNU extensions for public use.
constexpr _Iterator __base(_Iterator __it)
is_same
Definition: type_traits:1540