libstdc++
vstring_util.h
Go to the documentation of this file.
1 // Versatile string utility -*- C++ -*-
2 
3 // Copyright (C) 2005-2024 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/vstring_util.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{ext/vstring.h}
28  */
29 
30 #ifndef _VSTRING_UTIL_H
31 #define _VSTRING_UTIL_H 1
32 
33 #pragma GCC system_header
34 
35 #include <bits/requires_hosted.h> // GNU extensions are currently omitted
36 
37 #include <ext/vstring_fwd.h>
38 #include <debug/debug.h>
39 #include <bits/stl_function.h> // For less
40 #include <bits/functexcept.h>
41 #include <bits/localefwd.h>
42 #include <bits/ostream_insert.h>
43 #include <bits/stl_iterator.h>
44 #include <ext/numeric_traits.h>
45 #include <ext/alloc_traits.h>
46 #include <bits/move.h>
47 #include <bits/range_access.h>
48 
49 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
50 {
51 _GLIBCXX_BEGIN_NAMESPACE_VERSION
52 
53  template<typename _CharT, typename _Traits, typename _Alloc>
54  struct __vstring_utility
55  {
56  typedef typename __alloc_traits<_Alloc>::template rebind<_CharT>::other
57  _CharT_alloc_type;
58  typedef __alloc_traits<_CharT_alloc_type> _CharT_alloc_traits;
59 
60  typedef _Traits traits_type;
61  typedef typename _Traits::char_type value_type;
62  typedef typename _CharT_alloc_type::size_type size_type;
63  typedef typename _CharT_alloc_type::difference_type difference_type;
64  typedef typename _CharT_alloc_traits::pointer pointer;
65  typedef typename _CharT_alloc_traits::const_pointer const_pointer;
66 
67  // For __sso_string.
68  typedef __gnu_cxx::
69  __normal_iterator<pointer, __gnu_cxx::
70  __versa_string<_CharT, _Traits, _Alloc,
71  __sso_string_base> >
72  __sso_iterator;
73  typedef __gnu_cxx::
74  __normal_iterator<const_pointer, __gnu_cxx::
75  __versa_string<_CharT, _Traits, _Alloc,
76  __sso_string_base> >
77  __const_sso_iterator;
78 
79  // For __rc_string.
80  typedef __gnu_cxx::
81  __normal_iterator<pointer, __gnu_cxx::
82  __versa_string<_CharT, _Traits, _Alloc,
83  __rc_string_base> >
84  __rc_iterator;
85  typedef __gnu_cxx::
86  __normal_iterator<const_pointer, __gnu_cxx::
87  __versa_string<_CharT, _Traits, _Alloc,
88  __rc_string_base> >
89  __const_rc_iterator;
90 
91  // NB: When the allocator is empty, deriving from it saves space
92  // (http://www.cantrip.org/emptyopt.html).
93  template<typename _Alloc1>
94  struct _Alloc_hider
95  : public _Alloc1
96  {
97  _Alloc_hider(_CharT* __ptr)
98  : _Alloc1(), _M_p(__ptr) { }
99 
100  _Alloc_hider(const _Alloc1& __a, _CharT* __ptr)
101  : _Alloc1(__a), _M_p(__ptr) { }
102 
103  _CharT* _M_p; // The actual data.
104  };
105 
106  // When __n = 1 way faster than the general multichar
107  // traits_type::copy/move/assign.
108  static void
109  _S_copy(_CharT* __d, const _CharT* __s, size_type __n)
110  {
111  if (__n == 1)
112  traits_type::assign(*__d, *__s);
113  else
114  traits_type::copy(__d, __s, __n);
115  }
116 
117  static void
118  _S_move(_CharT* __d, const _CharT* __s, size_type __n)
119  {
120  if (__n == 1)
121  traits_type::assign(*__d, *__s);
122  else
123  traits_type::move(__d, __s, __n);
124  }
125 
126  static void
127  _S_assign(_CharT* __d, size_type __n, _CharT __c)
128  {
129  if (__n == 1)
130  traits_type::assign(*__d, __c);
131  else
132  traits_type::assign(__d, __n, __c);
133  }
134 
135  // _S_copy_chars is a separate template to permit specialization
136  // to optimize for the common case of pointers as iterators.
137  template<typename _Iterator>
138  static void
139  _S_copy_chars(_CharT* __p, _Iterator __k1, _Iterator __k2)
140  {
141  for (; __k1 != __k2; ++__k1, ++__p)
142  traits_type::assign(*__p, *__k1); // These types are off.
143  }
144 
145  static void
146  _S_copy_chars(_CharT* __p, __sso_iterator __k1, __sso_iterator __k2)
147  { _S_copy_chars(__p, __k1.base(), __k2.base()); }
148 
149  static void
150  _S_copy_chars(_CharT* __p, __const_sso_iterator __k1,
151  __const_sso_iterator __k2)
152  { _S_copy_chars(__p, __k1.base(), __k2.base()); }
153 
154  static void
155  _S_copy_chars(_CharT* __p, __rc_iterator __k1, __rc_iterator __k2)
156  { _S_copy_chars(__p, __k1.base(), __k2.base()); }
157 
158  static void
159  _S_copy_chars(_CharT* __p, __const_rc_iterator __k1,
160  __const_rc_iterator __k2)
161  { _S_copy_chars(__p, __k1.base(), __k2.base()); }
162 
163  static void
164  _S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2)
165  { _S_copy(__p, __k1, __k2 - __k1); }
166 
167  static void
168  _S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2)
169  { _S_copy(__p, __k1, __k2 - __k1); }
170 
171  static int
172  _S_compare(size_type __n1, size_type __n2)
173  {
174  const difference_type __d = difference_type(__n1 - __n2);
175 
176  if (__d > __numeric_traits_integer<int>::__max)
177  return __numeric_traits_integer<int>::__max;
178  else if (__d < __numeric_traits_integer<int>::__min)
179  return __numeric_traits_integer<int>::__min;
180  else
181  return int(__d);
182  }
183  };
184 
185 _GLIBCXX_END_NAMESPACE_VERSION
186 } // namespace
187 
188 #endif /* _VSTRING_UTIL_H */
GNU extensions for public use.
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:126