libstdc++
pod_char_traits.h
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1 // POD character, std::char_traits specialization -*- C++ -*-
2 
3 // Copyright (C) 2002-2025 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/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 #ifdef _GLIBCXX_SYSHDR
36 #pragma GCC system_header
37 #endif
38 
39 #include <bits/requires_hosted.h> // GNU extensions are currently omitted
40 
41 #include <string>
42 
43 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
44 {
45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
46 
47  // POD character abstraction.
48  // NB: The char_type parameter is a subset of int_type, as to allow
49  // int_type to properly hold the full range of char_type values as
50  // well as EOF.
51  /// @brief A POD class that serves as a character abstraction class.
52  template<typename _Value, typename _Int, typename _St = std::mbstate_t>
53  struct character
54  {
55  typedef _Value value_type;
56  typedef _Int int_type;
57  typedef _St state_type;
59 
60  value_type value;
61 
62  template<typename V2>
63  static char_type
64  from(const V2& v)
65  {
66  char_type ret = { static_cast<value_type>(v) };
67  return ret;
68  }
69 
70  template<typename V2>
71  static V2
72  to(const char_type& c)
73  {
74  V2 ret = { static_cast<V2>(c.value) };
75  return ret;
76  }
77 
78  };
79 
80  template<typename _Value, typename _Int, typename _St>
81  inline bool
82  operator==(const character<_Value, _Int, _St>& lhs,
84  { return lhs.value == rhs.value; }
85 
86  template<typename _Value, typename _Int, typename _St>
87  inline bool
88  operator<(const character<_Value, _Int, _St>& lhs,
89  const character<_Value, _Int, _St>& rhs)
90  { return lhs.value < rhs.value; }
91 
92 _GLIBCXX_END_NAMESPACE_VERSION
93 } // namespace
94 
95 namespace std _GLIBCXX_VISIBILITY(default)
96 {
97 _GLIBCXX_BEGIN_NAMESPACE_VERSION
98 
99  /// char_traits<__gnu_cxx::character> specialization.
100  template<typename _Value, typename _Int, typename _St>
101  struct char_traits<__gnu_cxx::character<_Value, _Int, _St> >
102  {
104  typedef typename char_type::int_type int_type;
105  typedef typename char_type::state_type state_type;
106  typedef fpos<state_type> pos_type;
107  typedef streamoff off_type;
108 
109  static void
110  assign(char_type& __c1, const char_type& __c2)
111  { __c1 = __c2; }
112 
113  static bool
114  eq(const char_type& __c1, const char_type& __c2)
115  { return __c1 == __c2; }
116 
117  static bool
118  lt(const char_type& __c1, const char_type& __c2)
119  { return __c1 < __c2; }
120 
121  static int
122  compare(const char_type* __s1, const char_type* __s2, size_t __n)
123  {
124  for (size_t __i = 0; __i < __n; ++__i)
125  if (!eq(__s1[__i], __s2[__i]))
126  return lt(__s1[__i], __s2[__i]) ? -1 : 1;
127  return 0;
128  }
129 
130  static size_t
131  length(const char_type* __s)
132  {
133  const char_type* __p = __s;
134  while (__p->value)
135  ++__p;
136  return (__p - __s);
137  }
138 
139  static const char_type*
140  find(const char_type* __s, size_t __n, const char_type& __a)
141  {
142  for (const char_type* __p = __s; size_t(__p - __s) < __n; ++__p)
143  if (*__p == __a)
144  return __p;
145  return 0;
146  }
147 
148  static char_type*
149  move(char_type* __s1, const char_type* __s2, size_t __n)
150  {
151  if (__n == 0)
152  return __s1;
153  return static_cast<char_type*>
154  (__builtin_memmove(__s1, __s2, __n * sizeof(char_type)));
155  }
156 
157  static char_type*
158  copy(char_type* __s1, const char_type* __s2, size_t __n)
159  {
160  if (__n == 0)
161  return __s1;
162  std::copy(__s2, __s2 + __n, __s1);
163  return __s1;
164  }
165 
166  static char_type*
167  assign(char_type* __s, size_t __n, char_type __a)
168  {
169  std::fill_n(__s, __n, __a);
170  return __s;
171  }
172 
173  static char_type
174  to_char_type(const int_type& __i)
175  { return char_type::template from(__i); }
176 
177  static int_type
178  to_int_type(const char_type& __c)
179  { return char_type::template to<int_type>(__c); }
180 
181  static bool
182  eq_int_type(const int_type& __c1, const int_type& __c2)
183  { return __c1 == __c2; }
184 
185  static int_type
186  eof()
187  {
188  int_type __r = { static_cast<typename __gnu_cxx::__conditional_type
189  <std::__is_integer<int_type>::__value,
190  int_type, int>::__type>(-1) };
191  return __r;
192  }
193 
194  static int_type
195  not_eof(const int_type& __c)
196  { return eq_int_type(__c, eof()) ? int_type() : __c; }
197  };
198 
199 _GLIBCXX_END_NAMESPACE_VERSION
200 } // namespace
201 
202 #endif
ISO C++ entities toplevel namespace is std.
long long streamoff
Type used by fpos, char_traits<char>, and char_traits<wchar_t>.
Definition: postypes.h:68
GNU extensions for public use.
Basis for explicit traits specializations.
Definition: char_traits.h:326
Class representing stream positions.
Definition: postypes.h:88
A POD class that serves as a character abstraction class.