libstdc++
vstring_util.h
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1 // Versatile string utility -*- C++ -*-
2 
3 // Copyright (C) 2005-2025 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/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 #ifdef _GLIBCXX_SYSHDR
34 #pragma GCC system_header
35 #endif
36 
37 #include <bits/requires_hosted.h> // GNU extensions are currently omitted
38 
39 #include <ext/vstring_fwd.h>
40 #include <debug/debug.h>
41 #include <bits/stl_function.h> // For less
42 #include <bits/functexcept.h>
43 #include <bits/localefwd.h>
44 #include <bits/ostream_insert.h>
45 #include <bits/stl_iterator.h>
46 #include <ext/numeric_traits.h>
47 #include <ext/alloc_traits.h>
48 #include <bits/move.h>
49 #include <bits/range_access.h>
50 
51 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
52 {
53 _GLIBCXX_BEGIN_NAMESPACE_VERSION
54 
55  template<typename _CharT, typename _Traits, typename _Alloc>
56  struct __vstring_utility
57  {
58  typedef typename __alloc_traits<_Alloc>::template rebind<_CharT>::other
59  _CharT_alloc_type;
60  typedef __alloc_traits<_CharT_alloc_type> _CharT_alloc_traits;
61 
62  typedef _Traits traits_type;
63  typedef typename _Traits::char_type value_type;
64  typedef typename _CharT_alloc_type::size_type size_type;
65  typedef typename _CharT_alloc_type::difference_type difference_type;
66  typedef typename _CharT_alloc_traits::pointer pointer;
67  typedef typename _CharT_alloc_traits::const_pointer const_pointer;
68 
69  // For __sso_string.
70  typedef __gnu_cxx::
71  __normal_iterator<pointer, __gnu_cxx::
72  __versa_string<_CharT, _Traits, _Alloc,
73  __sso_string_base> >
74  __sso_iterator;
75  typedef __gnu_cxx::
76  __normal_iterator<const_pointer, __gnu_cxx::
77  __versa_string<_CharT, _Traits, _Alloc,
78  __sso_string_base> >
79  __const_sso_iterator;
80 
81  // For __rc_string.
82  typedef __gnu_cxx::
83  __normal_iterator<pointer, __gnu_cxx::
84  __versa_string<_CharT, _Traits, _Alloc,
85  __rc_string_base> >
86  __rc_iterator;
87  typedef __gnu_cxx::
88  __normal_iterator<const_pointer, __gnu_cxx::
89  __versa_string<_CharT, _Traits, _Alloc,
90  __rc_string_base> >
91  __const_rc_iterator;
92 
93  // NB: When the allocator is empty, deriving from it saves space
94  // (http://www.cantrip.org/emptyopt.html).
95  template<typename _Alloc1>
96  struct _Alloc_hider
97  : public _Alloc1
98  {
99  _Alloc_hider(_CharT* __ptr)
100  : _Alloc1(), _M_p(__ptr) { }
101 
102  _Alloc_hider(const _Alloc1& __a, _CharT* __ptr)
103  : _Alloc1(__a), _M_p(__ptr) { }
104 
105  _CharT* _M_p; // The actual data.
106  };
107 
108  // When __n = 1 way faster than the general multichar
109  // traits_type::copy/move/assign.
110  static void
111  _S_copy(_CharT* __d, const _CharT* __s, size_type __n)
112  {
113  if (__n == 1)
114  traits_type::assign(*__d, *__s);
115  else
116  traits_type::copy(__d, __s, __n);
117  }
118 
119  static void
120  _S_move(_CharT* __d, const _CharT* __s, size_type __n)
121  {
122  if (__n == 1)
123  traits_type::assign(*__d, *__s);
124  else
125  traits_type::move(__d, __s, __n);
126  }
127 
128  static void
129  _S_assign(_CharT* __d, size_type __n, _CharT __c)
130  {
131  if (__n == 1)
132  traits_type::assign(*__d, __c);
133  else
134  traits_type::assign(__d, __n, __c);
135  }
136 
137  // _S_copy_chars is a separate template to permit specialization
138  // to optimize for the common case of pointers as iterators.
139  template<typename _Iterator>
140  static void
141  _S_copy_chars(_CharT* __p, _Iterator __k1, _Iterator __k2)
142  {
143  for (; __k1 != __k2; ++__k1, ++__p)
144  traits_type::assign(*__p, *__k1); // These types are off.
145  }
146 
147  static void
148  _S_copy_chars(_CharT* __p, __sso_iterator __k1, __sso_iterator __k2)
149  { _S_copy_chars(__p, __k1.base(), __k2.base()); }
150 
151  static void
152  _S_copy_chars(_CharT* __p, __const_sso_iterator __k1,
153  __const_sso_iterator __k2)
154  { _S_copy_chars(__p, __k1.base(), __k2.base()); }
155 
156  static void
157  _S_copy_chars(_CharT* __p, __rc_iterator __k1, __rc_iterator __k2)
158  { _S_copy_chars(__p, __k1.base(), __k2.base()); }
159 
160  static void
161  _S_copy_chars(_CharT* __p, __const_rc_iterator __k1,
162  __const_rc_iterator __k2)
163  { _S_copy_chars(__p, __k1.base(), __k2.base()); }
164 
165  static void
166  _S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2)
167  { _S_copy(__p, __k1, __k2 - __k1); }
168 
169  static void
170  _S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2)
171  { _S_copy(__p, __k1, __k2 - __k1); }
172 
173  static int
174  _S_compare(size_type __n1, size_type __n2)
175  {
176  const difference_type __d = difference_type(__n1 - __n2);
177 
178  if (__d > __numeric_traits_integer<int>::__max)
179  return __numeric_traits_integer<int>::__max;
180  else if (__d < __numeric_traits_integer<int>::__min)
181  return __numeric_traits_integer<int>::__min;
182  else
183  return int(__d);
184  }
185  };
186 
187 _GLIBCXX_END_NAMESPACE_VERSION
188 } // namespace
189 
190 #endif /* _VSTRING_UTIL_H */
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:138
GNU extensions for public use.