libstdc++-v3/include/ext/string_conversions.h

   1 // String Conversions -*- C++ -*-
   2
   3 // Copyright (C) 2008-2023 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 #pragma GCC system_header
  33
  34 #include <bits/requires_hosted.h> // GNU extensions are currently omitted
  35
  36 #if __cplusplus < 201103L
  37 # include <bits/c++0x_warning.h>
  38 #else
  39
  40 #include <bits/c++config.h>
  41 #include <ext/numeric_traits.h>
  42 #include <bits/functexcept.h>
  43 #include <cstdlib>
  44 #include <cwchar>
  45 #include <cstdio>
  46 #include <cerrno>
  47
  48 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
  49 {
  50 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  51
  52   // Helper for all the sto* functions.
  53   template<typename _TRet, typename _Ret = _TRet, typename _CharT,
  54            typename... _Base>
  55     _Ret
  56     __stoa(_TRet (*__convf) (const _CharT*, _CharT**, _Base...),
  57            const char* __name, const _CharT* __str, std::size_t* __idx,
  58            _Base... __base)
  59     {
  60       _Ret __ret;
  61
  62       _CharT* __endptr;
  63
  64       struct _Save_errno {
  65         _Save_errno() : _M_errno(errno) { errno = 0; }
  66         ~_Save_errno() { if (errno == 0) errno = _M_errno; }
  67         int _M_errno;
  68       } const __save_errno;
  69
  70       struct _Range_chk {
  71           static bool
  72           _S_chk(_TRet, std::false_type) { return false; }
  73
  74           static bool
  75           _S_chk(_TRet __val, std::true_type) // only called when _Ret is int
  76           {
  77             return __val < _TRet(__numeric_traits<int>::__min)
  78               || __val > _TRet(__numeric_traits<int>::__max);
  79           }
  80       };
  81
  82       const _TRet __tmp = __convf(__str, &__endptr, __base...);
  83
  84       if (__endptr == __str)
  85         std::__throw_invalid_argument(__name);
  86       else if (errno == ERANGE
  87           || _Range_chk::_S_chk(__tmp, std::is_same<_Ret, int>{}))
  88         std::__throw_out_of_range(__name);
  89       else
  90         __ret = __tmp;
  91
  92       if (__idx)
  93         *__idx = __endptr - __str;
  94
  95       return __ret;
  96     }
  97
  98   // Helper for the to_string / to_wstring functions.
  99   template<typename _String, typename _CharT = typename _String::value_type>
 100     _String
 101     __to_xstring(int (*__convf) (_CharT*, std::size_t, const _CharT*,
 102                                  __builtin_va_list), std::size_t __n,
 103                  const _CharT* __fmt, ...)
 104     {
 105       // XXX Eventually the result should be constructed in-place in
 106       // the __cxx11 string, likely with the help of internal hooks.
 107       _CharT* __s = static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT)
 108                                                           * __n));
 109
 110       __builtin_va_list __args;
 111       __builtin_va_start(__args, __fmt);
 112
 113       const int __len = __convf(__s, __n, __fmt, __args);
 114
 115       __builtin_va_end(__args);
 116
 117       return _String(__s, __s + __len);
 118     }
 119
 120 _GLIBCXX_END_NAMESPACE_VERSION
 121 } // namespace
 122
 123 #endif // C++11
 124
 125 #endif // _STRING_CONVERSIONS_H