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

   1 // POD character, std::char_traits specialization -*- C++ -*-
   2
   3 // Copyright (C) 2002-2023 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/pod_char_traits.h
  26  *  This file is a GNU extension to the Standard C++ Library.
  27  */
  28
  29 // Gabriel Dos Reis <gdr@integrable-solutions.net>
  30 // Benjamin Kosnik <bkoz@redhat.com>
  31
  32 #ifndef _POD_CHAR_TRAITS_H
  33 #define _POD_CHAR_TRAITS_H 1
  34
  35 #pragma GCC system_header
  36
  37 #include <bits/requires_hosted.h> // GNU extensions are currently omitted
  38
  39 #include <string>
  40
  41 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
  42 {
  43 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  44
  45   // POD character abstraction.
  46   // NB: The char_type parameter is a subset of int_type, as to allow
  47   // int_type to properly hold the full range of char_type values as
  48   // well as EOF.
  49   /// @brief A POD class that serves as a character abstraction class.
  50   template<typename _Value, typename _Int, typename _St = std::mbstate_t>
  51     struct character
  52     {
  53       typedef _Value                            value_type;
  54       typedef _Int                              int_type;
  55       typedef _St                               state_type;
  56       typedef character<_Value, _Int, _St>      char_type;
  57
  58       value_type        value;
  59
  60       template<typename V2>
  61         static char_type
  62         from(const V2& v)
  63         {
  64           char_type ret = { static_cast<value_type>(v) };
  65           return ret;
  66         }
  67
  68       template<typename V2>
  69         static V2
  70         to(const char_type& c)
  71         {
  72           V2 ret = { static_cast<V2>(c.value) };
  73           return ret;
  74         }
  75
  76     };
  77
  78   template<typename _Value, typename _Int, typename _St>
  79     inline bool
  80     operator==(const character<_Value, _Int, _St>& lhs,
  81                const character<_Value, _Int, _St>& rhs)
  82     { return lhs.value == rhs.value; }
  83
  84   template<typename _Value, typename _Int, typename _St>
  85     inline bool
  86     operator<(const character<_Value, _Int, _St>& lhs,
  87               const character<_Value, _Int, _St>& rhs)
  88     { return lhs.value < rhs.value; }
  89
  90 _GLIBCXX_END_NAMESPACE_VERSION
  91 } // namespace
  92
  93 namespace std _GLIBCXX_VISIBILITY(default)
  94 {
  95 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  96
  97   /// char_traits<__gnu_cxx::character> specialization.
  98   template<typename _Value, typename _Int, typename _St>
  99     struct char_traits<__gnu_cxx::character<_Value, _Int, _St> >
 100     {
 101       typedef __gnu_cxx::character<_Value, _Int, _St>   char_type;
 102       typedef typename char_type::int_type              int_type;
 103       typedef typename char_type::state_type            state_type;
 104       typedef fpos<state_type>                          pos_type;
 105       typedef streamoff                                 off_type;
 106
 107       static void
 108       assign(char_type& __c1, const char_type& __c2)
 109       { __c1 = __c2; }
 110
 111       static bool
 112       eq(const char_type& __c1, const char_type& __c2)
 113       { return __c1 == __c2; }
 114
 115       static bool
 116       lt(const char_type& __c1, const char_type& __c2)
 117       { return __c1 < __c2; }
 118
 119       static int
 120       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 121       {
 122         for (size_t __i = 0; __i < __n; ++__i)
 123           if (!eq(__s1[__i], __s2[__i]))
 124             return lt(__s1[__i], __s2[__i]) ? -1 : 1;
 125         return 0;
 126       }
 127
 128       static size_t
 129       length(const char_type* __s)
 130       {
 131         const char_type* __p = __s;
 132         while (__p->value)
 133           ++__p;
 134         return (__p - __s);
 135       }
 136
 137       static const char_type*
 138       find(const char_type* __s, size_t __n, const char_type& __a)
 139       {
 140         for (const char_type* __p = __s; size_t(__p - __s) < __n; ++__p)
 141           if (*__p == __a)
 142             return __p;
 143         return 0;
 144       }
 145
 146       static char_type*
 147       move(char_type* __s1, const char_type* __s2, size_t __n)
 148       {
 149         if (__n == 0)
 150           return __s1;
 151         return static_cast<char_type*>
 152           (__builtin_memmove(__s1, __s2, __n * sizeof(char_type)));
 153       }
 154
 155       static char_type*
 156       copy(char_type* __s1, const char_type* __s2, size_t __n)
 157       {
 158         if (__n == 0)
 159           return __s1;
 160         std::copy(__s2, __s2 + __n, __s1);
 161         return __s1;
 162       }
 163
 164       static char_type*
 165       assign(char_type* __s, size_t __n, char_type __a)
 166       {
 167         std::fill_n(__s, __n, __a);
 168         return __s;
 169       }
 170
 171       static char_type
 172       to_char_type(const int_type& __i)
 173       { return char_type::template from(__i); }
 174
 175       static int_type
 176       to_int_type(const char_type& __c)
 177       { return char_type::template to<int_type>(__c); }
 178
 179       static bool
 180       eq_int_type(const int_type& __c1, const int_type& __c2)
 181       { return __c1 == __c2; }
 182
 183       static int_type
 184       eof()
 185       {
 186         int_type __r = { static_cast<typename __gnu_cxx::__conditional_type
 187                          <std::__is_integer<int_type>::__value,
 188                          int_type, int>::__type>(-1) };
 189         return __r;
 190       }
 191
 192       static int_type
 193       not_eof(const int_type& __c)
 194       { return eq_int_type(__c, eof()) ? int_type() : __c; }
 195     };
 196
 197 _GLIBCXX_END_NAMESPACE_VERSION
 198 } // namespace
 199
 200 #endif