libstdc++
char_traits.h
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1 // Character Traits for use by standard string and iostream -*- C++ -*-
2 
3 // Copyright (C) 1997-2019 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 bits/char_traits.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{string}
28  */
29 
30 //
31 // ISO C++ 14882: 21 Strings library
32 //
33 
34 #ifndef _CHAR_TRAITS_H
35 #define _CHAR_TRAITS_H 1
36 
37 #pragma GCC system_header
38 
39 #include <bits/stl_algobase.h> // std::copy, std::fill_n
40 #include <bits/postypes.h> // For streampos
41 #include <cwchar> // For WEOF, wmemmove, wmemset, etc.
42 
43 #ifndef _GLIBCXX_ALWAYS_INLINE
44 # define _GLIBCXX_ALWAYS_INLINE inline __attribute__((__always_inline__))
45 #endif
46 
47 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
48 {
49 _GLIBCXX_BEGIN_NAMESPACE_VERSION
50 
51  /**
52  * @brief Mapping from character type to associated types.
53  *
54  * @note This is an implementation class for the generic version
55  * of char_traits. It defines int_type, off_type, pos_type, and
56  * state_type. By default these are unsigned long, streamoff,
57  * streampos, and mbstate_t. Users who need a different set of
58  * types, but who don't need to change the definitions of any function
59  * defined in char_traits, can specialize __gnu_cxx::_Char_types
60  * while leaving __gnu_cxx::char_traits alone. */
61  template<typename _CharT>
62  struct _Char_types
63  {
64  typedef unsigned long int_type;
65  typedef std::streampos pos_type;
66  typedef std::streamoff off_type;
67  typedef std::mbstate_t state_type;
68  };
69 
70 
71  /**
72  * @brief Base class used to implement std::char_traits.
73  *
74  * @note For any given actual character type, this definition is
75  * probably wrong. (Most of the member functions are likely to be
76  * right, but the int_type and state_type typedefs, and the eof()
77  * member function, are likely to be wrong.) The reason this class
78  * exists is so users can specialize it. Classes in namespace std
79  * may not be specialized for fundamental types, but classes in
80  * namespace __gnu_cxx may be.
81  *
82  * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/strings.html#strings.string.character_types
83  * for advice on how to make use of this class for @a unusual character
84  * types. Also, check out include/ext/pod_char_traits.h.
85  */
86  template<typename _CharT>
87  struct char_traits
88  {
89  typedef _CharT char_type;
90  typedef typename _Char_types<_CharT>::int_type int_type;
91  typedef typename _Char_types<_CharT>::pos_type pos_type;
92  typedef typename _Char_types<_CharT>::off_type off_type;
93  typedef typename _Char_types<_CharT>::state_type state_type;
94 
95  static _GLIBCXX14_CONSTEXPR void
96  assign(char_type& __c1, const char_type& __c2)
97  { __c1 = __c2; }
98 
99  static _GLIBCXX_CONSTEXPR bool
100  eq(const char_type& __c1, const char_type& __c2)
101  { return __c1 == __c2; }
102 
103  static _GLIBCXX_CONSTEXPR bool
104  lt(const char_type& __c1, const char_type& __c2)
105  { return __c1 < __c2; }
106 
107  static _GLIBCXX14_CONSTEXPR int
108  compare(const char_type* __s1, const char_type* __s2, std::size_t __n);
109 
110  static _GLIBCXX14_CONSTEXPR std::size_t
111  length(const char_type* __s);
112 
113  static _GLIBCXX14_CONSTEXPR const char_type*
114  find(const char_type* __s, std::size_t __n, const char_type& __a);
115 
116  static char_type*
117  move(char_type* __s1, const char_type* __s2, std::size_t __n);
118 
119  static char_type*
120  copy(char_type* __s1, const char_type* __s2, std::size_t __n);
121 
122  static char_type*
123  assign(char_type* __s, std::size_t __n, char_type __a);
124 
125  static _GLIBCXX_CONSTEXPR char_type
126  to_char_type(const int_type& __c)
127  { return static_cast<char_type>(__c); }
128 
129  static _GLIBCXX_CONSTEXPR int_type
130  to_int_type(const char_type& __c)
131  { return static_cast<int_type>(__c); }
132 
133  static _GLIBCXX_CONSTEXPR bool
134  eq_int_type(const int_type& __c1, const int_type& __c2)
135  { return __c1 == __c2; }
136 
137  static _GLIBCXX_CONSTEXPR int_type
138  eof()
139  { return static_cast<int_type>(_GLIBCXX_STDIO_EOF); }
140 
141  static _GLIBCXX_CONSTEXPR int_type
142  not_eof(const int_type& __c)
143  { return !eq_int_type(__c, eof()) ? __c : to_int_type(char_type()); }
144  };
145 
146  template<typename _CharT>
147  _GLIBCXX14_CONSTEXPR int
149  compare(const char_type* __s1, const char_type* __s2, std::size_t __n)
150  {
151  for (std::size_t __i = 0; __i < __n; ++__i)
152  if (lt(__s1[__i], __s2[__i]))
153  return -1;
154  else if (lt(__s2[__i], __s1[__i]))
155  return 1;
156  return 0;
157  }
158 
159  template<typename _CharT>
160  _GLIBCXX14_CONSTEXPR std::size_t
161  char_traits<_CharT>::
162  length(const char_type* __p)
163  {
164  std::size_t __i = 0;
165  while (!eq(__p[__i], char_type()))
166  ++__i;
167  return __i;
168  }
169 
170  template<typename _CharT>
171  _GLIBCXX14_CONSTEXPR const typename char_traits<_CharT>::char_type*
172  char_traits<_CharT>::
173  find(const char_type* __s, std::size_t __n, const char_type& __a)
174  {
175  for (std::size_t __i = 0; __i < __n; ++__i)
176  if (eq(__s[__i], __a))
177  return __s + __i;
178  return 0;
179  }
180 
181  template<typename _CharT>
182  typename char_traits<_CharT>::char_type*
183  char_traits<_CharT>::
184  move(char_type* __s1, const char_type* __s2, std::size_t __n)
185  {
186  if (__n == 0)
187  return __s1;
188  return static_cast<_CharT*>(__builtin_memmove(__s1, __s2,
189  __n * sizeof(char_type)));
190  }
191 
192  template<typename _CharT>
193  typename char_traits<_CharT>::char_type*
194  char_traits<_CharT>::
195  copy(char_type* __s1, const char_type* __s2, std::size_t __n)
196  {
197  // NB: Inline std::copy so no recursive dependencies.
198  std::copy(__s2, __s2 + __n, __s1);
199  return __s1;
200  }
201 
202  template<typename _CharT>
203  typename char_traits<_CharT>::char_type*
204  char_traits<_CharT>::
205  assign(char_type* __s, std::size_t __n, char_type __a)
206  {
207  // NB: Inline std::fill_n so no recursive dependencies.
208  std::fill_n(__s, __n, __a);
209  return __s;
210  }
211 
212 _GLIBCXX_END_NAMESPACE_VERSION
213 } // namespace
214 
215 namespace std _GLIBCXX_VISIBILITY(default)
216 {
217 _GLIBCXX_BEGIN_NAMESPACE_VERSION
218 
219 #if __cplusplus >= 201703L
220 #define __cpp_lib_constexpr_char_traits 201611
221 
222  /**
223  * @brief Determine whether the characters of a NULL-terminated
224  * string are known at compile time.
225  * @param __s The string.
226  *
227  * Assumes that _CharT is a built-in character type.
228  */
229  template<typename _CharT>
230  _GLIBCXX_ALWAYS_INLINE constexpr bool
231  __constant_string_p(const _CharT* __s)
232  {
233 #ifdef _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED
234  (void) __s;
235  // In constexpr contexts all strings should be constant.
236  return __builtin_is_constant_evaluated();
237 #else
238  while (__builtin_constant_p(*__s) && *__s)
239  __s++;
240  return __builtin_constant_p(*__s);
241 #endif
242  }
243 
244  /**
245  * @brief Determine whether the characters of a character array are
246  * known at compile time.
247  * @param __a The character array.
248  * @param __n Number of characters.
249  *
250  * Assumes that _CharT is a built-in character type.
251  */
252  template<typename _CharT>
253  _GLIBCXX_ALWAYS_INLINE constexpr bool
254  __constant_char_array_p(const _CharT* __a, size_t __n)
255  {
256 #ifdef _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED
257  (void) __a;
258  (void) __n;
259  // In constexpr contexts all character arrays should be constant.
260  return __builtin_is_constant_evaluated();
261 #else
262  size_t __i = 0;
263  while (__i < __n && __builtin_constant_p(__a[__i]))
264  __i++;
265  return __i == __n;
266 #endif
267  }
268 #endif
269 
270  // 21.1
271  /**
272  * @brief Basis for explicit traits specializations.
273  *
274  * @note For any given actual character type, this definition is
275  * probably wrong. Since this is just a thin wrapper around
276  * __gnu_cxx::char_traits, it is possible to achieve a more
277  * appropriate definition by specializing __gnu_cxx::char_traits.
278  *
279  * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/strings.html#strings.string.character_types
280  * for advice on how to make use of this class for @a unusual character
281  * types. Also, check out include/ext/pod_char_traits.h.
282  */
283  template<class _CharT>
284  struct char_traits : public __gnu_cxx::char_traits<_CharT>
285  { };
286 
287 
288  /// 21.1.3.1 char_traits specializations
289  template<>
290  struct char_traits<char>
291  {
292  typedef char char_type;
293  typedef int int_type;
294  typedef streampos pos_type;
295  typedef streamoff off_type;
296  typedef mbstate_t state_type;
297 
298  static _GLIBCXX17_CONSTEXPR void
299  assign(char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
300  { __c1 = __c2; }
301 
302  static _GLIBCXX_CONSTEXPR bool
303  eq(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
304  { return __c1 == __c2; }
305 
306  static _GLIBCXX_CONSTEXPR bool
307  lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
308  {
309  // LWG 467.
310  return (static_cast<unsigned char>(__c1)
311  < static_cast<unsigned char>(__c2));
312  }
313 
314  static _GLIBCXX17_CONSTEXPR int
315  compare(const char_type* __s1, const char_type* __s2, size_t __n)
316  {
317  if (__n == 0)
318  return 0;
319 #if __cplusplus >= 201703L
320  if (__builtin_constant_p(__n)
321  && __constant_char_array_p(__s1, __n)
322  && __constant_char_array_p(__s2, __n))
323  {
324  for (size_t __i = 0; __i < __n; ++__i)
325  if (lt(__s1[__i], __s2[__i]))
326  return -1;
327  else if (lt(__s2[__i], __s1[__i]))
328  return 1;
329  return 0;
330  }
331 #endif
332  return __builtin_memcmp(__s1, __s2, __n);
333  }
334 
335  static _GLIBCXX17_CONSTEXPR size_t
336  length(const char_type* __s)
337  {
338 #if __cplusplus >= 201703L
339  if (__constant_string_p(__s))
341 #endif
342  return __builtin_strlen(__s);
343  }
344 
345  static _GLIBCXX17_CONSTEXPR const char_type*
346  find(const char_type* __s, size_t __n, const char_type& __a)
347  {
348  if (__n == 0)
349  return 0;
350 #if __cplusplus >= 201703L
351  if (__builtin_constant_p(__n)
352  && __builtin_constant_p(__a)
353  && __constant_char_array_p(__s, __n))
354  return __gnu_cxx::char_traits<char_type>::find(__s, __n, __a);
355 #endif
356  return static_cast<const char_type*>(__builtin_memchr(__s, __a, __n));
357  }
358 
359  static char_type*
360  move(char_type* __s1, const char_type* __s2, size_t __n)
361  {
362  if (__n == 0)
363  return __s1;
364  return static_cast<char_type*>(__builtin_memmove(__s1, __s2, __n));
365  }
366 
367  static char_type*
368  copy(char_type* __s1, const char_type* __s2, size_t __n)
369  {
370  if (__n == 0)
371  return __s1;
372  return static_cast<char_type*>(__builtin_memcpy(__s1, __s2, __n));
373  }
374 
375  static char_type*
376  assign(char_type* __s, size_t __n, char_type __a)
377  {
378  if (__n == 0)
379  return __s;
380  return static_cast<char_type*>(__builtin_memset(__s, __a, __n));
381  }
382 
383  static _GLIBCXX_CONSTEXPR char_type
384  to_char_type(const int_type& __c) _GLIBCXX_NOEXCEPT
385  { return static_cast<char_type>(__c); }
386 
387  // To keep both the byte 0xff and the eof symbol 0xffffffff
388  // from ending up as 0xffffffff.
389  static _GLIBCXX_CONSTEXPR int_type
390  to_int_type(const char_type& __c) _GLIBCXX_NOEXCEPT
391  { return static_cast<int_type>(static_cast<unsigned char>(__c)); }
392 
393  static _GLIBCXX_CONSTEXPR bool
394  eq_int_type(const int_type& __c1, const int_type& __c2) _GLIBCXX_NOEXCEPT
395  { return __c1 == __c2; }
396 
397  static _GLIBCXX_CONSTEXPR int_type
398  eof() _GLIBCXX_NOEXCEPT
399  { return static_cast<int_type>(_GLIBCXX_STDIO_EOF); }
400 
401  static _GLIBCXX_CONSTEXPR int_type
402  not_eof(const int_type& __c) _GLIBCXX_NOEXCEPT
403  { return (__c == eof()) ? 0 : __c; }
404  };
405 
406 
407 #ifdef _GLIBCXX_USE_WCHAR_T
408  /// 21.1.3.2 char_traits specializations
409  template<>
410  struct char_traits<wchar_t>
411  {
412  typedef wchar_t char_type;
413  typedef wint_t int_type;
414  typedef streamoff off_type;
415  typedef wstreampos pos_type;
416  typedef mbstate_t state_type;
417 
418  static _GLIBCXX17_CONSTEXPR void
419  assign(char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
420  { __c1 = __c2; }
421 
422  static _GLIBCXX_CONSTEXPR bool
423  eq(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
424  { return __c1 == __c2; }
425 
426  static _GLIBCXX_CONSTEXPR bool
427  lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
428  { return __c1 < __c2; }
429 
430  static _GLIBCXX17_CONSTEXPR int
431  compare(const char_type* __s1, const char_type* __s2, size_t __n)
432  {
433  if (__n == 0)
434  return 0;
435 #if __cplusplus >= 201703L
436  if (__builtin_constant_p(__n)
437  && __constant_char_array_p(__s1, __n)
438  && __constant_char_array_p(__s2, __n))
439  return __gnu_cxx::char_traits<char_type>::compare(__s1, __s2, __n);
440 #endif
441  return wmemcmp(__s1, __s2, __n);
442  }
443 
444  static _GLIBCXX17_CONSTEXPR size_t
445  length(const char_type* __s)
446  {
447 #if __cplusplus >= 201703L
448  if (__constant_string_p(__s))
450 #endif
451  return wcslen(__s);
452  }
453 
454  static _GLIBCXX17_CONSTEXPR const char_type*
455  find(const char_type* __s, size_t __n, const char_type& __a)
456  {
457  if (__n == 0)
458  return 0;
459 #if __cplusplus >= 201703L
460  if (__builtin_constant_p(__n)
461  && __builtin_constant_p(__a)
462  && __constant_char_array_p(__s, __n))
463  return __gnu_cxx::char_traits<char_type>::find(__s, __n, __a);
464 #endif
465  return wmemchr(__s, __a, __n);
466  }
467 
468  static char_type*
469  move(char_type* __s1, const char_type* __s2, size_t __n)
470  {
471  if (__n == 0)
472  return __s1;
473  return wmemmove(__s1, __s2, __n);
474  }
475 
476  static char_type*
477  copy(char_type* __s1, const char_type* __s2, size_t __n)
478  {
479  if (__n == 0)
480  return __s1;
481  return wmemcpy(__s1, __s2, __n);
482  }
483 
484  static char_type*
485  assign(char_type* __s, size_t __n, char_type __a)
486  {
487  if (__n == 0)
488  return __s;
489  return wmemset(__s, __a, __n);
490  }
491 
492  static _GLIBCXX_CONSTEXPR char_type
493  to_char_type(const int_type& __c) _GLIBCXX_NOEXCEPT
494  { return char_type(__c); }
495 
496  static _GLIBCXX_CONSTEXPR int_type
497  to_int_type(const char_type& __c) _GLIBCXX_NOEXCEPT
498  { return int_type(__c); }
499 
500  static _GLIBCXX_CONSTEXPR bool
501  eq_int_type(const int_type& __c1, const int_type& __c2) _GLIBCXX_NOEXCEPT
502  { return __c1 == __c2; }
503 
504  static _GLIBCXX_CONSTEXPR int_type
505  eof() _GLIBCXX_NOEXCEPT
506  { return static_cast<int_type>(WEOF); }
507 
508  static _GLIBCXX_CONSTEXPR int_type
509  not_eof(const int_type& __c) _GLIBCXX_NOEXCEPT
510  { return eq_int_type(__c, eof()) ? 0 : __c; }
511  };
512 #endif //_GLIBCXX_USE_WCHAR_T
513 
514 #ifdef _GLIBCXX_USE_CHAR8_T
515  template<>
516  struct char_traits<char8_t>
517  {
518  typedef char8_t char_type;
519  typedef unsigned int int_type;
520  typedef u8streampos pos_type;
521  typedef streamoff off_type;
522  typedef mbstate_t state_type;
523 
524  static _GLIBCXX17_CONSTEXPR void
525  assign(char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
526  { __c1 = __c2; }
527 
528  static _GLIBCXX_CONSTEXPR bool
529  eq(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
530  { return __c1 == __c2; }
531 
532  static _GLIBCXX_CONSTEXPR bool
533  lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
534  { return __c1 < __c2; }
535 
536  static _GLIBCXX17_CONSTEXPR int
537  compare(const char_type* __s1, const char_type* __s2, size_t __n)
538  {
539  if (__n == 0)
540  return 0;
541 #if __cplusplus > 201402
542  if (__builtin_constant_p(__n)
543  && __constant_char_array_p(__s1, __n)
544  && __constant_char_array_p(__s2, __n))
545  return __gnu_cxx::char_traits<char_type>::compare(__s1, __s2, __n);
546 #endif
547  return __builtin_memcmp(__s1, __s2, __n);
548  }
549 
550  static _GLIBCXX17_CONSTEXPR size_t
551  length(const char_type* __s)
552  {
553 #if __cplusplus > 201402
554  if (__constant_string_p(__s))
556 #endif
557  size_t __i = 0;
558  while (!eq(__s[__i], char_type()))
559  ++__i;
560  return __i;
561  }
562 
563  static _GLIBCXX17_CONSTEXPR const char_type*
564  find(const char_type* __s, size_t __n, const char_type& __a)
565  {
566  if (__n == 0)
567  return 0;
568 #if __cplusplus > 201402
569  if (__builtin_constant_p(__n)
570  && __builtin_constant_p(__a)
571  && __constant_char_array_p(__s, __n))
572  return __gnu_cxx::char_traits<char_type>::find(__s, __n, __a);
573 #endif
574  return static_cast<const char_type*>(__builtin_memchr(__s, __a, __n));
575  }
576 
577  static char_type*
578  move(char_type* __s1, const char_type* __s2, size_t __n)
579  {
580  if (__n == 0)
581  return __s1;
582  return static_cast<char_type*>(__builtin_memmove(__s1, __s2, __n));
583  }
584 
585  static char_type*
586  copy(char_type* __s1, const char_type* __s2, size_t __n)
587  {
588  if (__n == 0)
589  return __s1;
590  return static_cast<char_type*>(__builtin_memcpy(__s1, __s2, __n));
591  }
592 
593  static char_type*
594  assign(char_type* __s, size_t __n, char_type __a)
595  {
596  if (__n == 0)
597  return __s;
598  return static_cast<char_type*>(__builtin_memset(__s, __a, __n));
599  }
600 
601  static _GLIBCXX_CONSTEXPR char_type
602  to_char_type(const int_type& __c) _GLIBCXX_NOEXCEPT
603  { return char_type(__c); }
604 
605  static _GLIBCXX_CONSTEXPR int_type
606  to_int_type(const char_type& __c) _GLIBCXX_NOEXCEPT
607  { return int_type(__c); }
608 
609  static _GLIBCXX_CONSTEXPR bool
610  eq_int_type(const int_type& __c1, const int_type& __c2) _GLIBCXX_NOEXCEPT
611  { return __c1 == __c2; }
612 
613  static _GLIBCXX_CONSTEXPR int_type
614  eof() _GLIBCXX_NOEXCEPT
615  { return static_cast<int_type>(-1); }
616 
617  static _GLIBCXX_CONSTEXPR int_type
618  not_eof(const int_type& __c) _GLIBCXX_NOEXCEPT
619  { return eq_int_type(__c, eof()) ? 0 : __c; }
620  };
621 #endif //_GLIBCXX_USE_CHAR8_T
622 
623 _GLIBCXX_END_NAMESPACE_VERSION
624 } // namespace
625 
626 #if __cplusplus >= 201103L
627 
628 #include <cstdint>
629 
630 namespace std _GLIBCXX_VISIBILITY(default)
631 {
632 _GLIBCXX_BEGIN_NAMESPACE_VERSION
633 
634  template<>
635  struct char_traits<char16_t>
636  {
637  typedef char16_t char_type;
638 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
639  typedef uint_least16_t int_type;
640 #elif defined __UINT_LEAST16_TYPE__
641  typedef __UINT_LEAST16_TYPE__ int_type;
642 #else
643  typedef make_unsigned<char16_t>::type int_type;
644 #endif
645  typedef streamoff off_type;
646  typedef u16streampos pos_type;
647  typedef mbstate_t state_type;
648 
649  static _GLIBCXX17_CONSTEXPR void
650  assign(char_type& __c1, const char_type& __c2) noexcept
651  { __c1 = __c2; }
652 
653  static constexpr bool
654  eq(const char_type& __c1, const char_type& __c2) noexcept
655  { return __c1 == __c2; }
656 
657  static constexpr bool
658  lt(const char_type& __c1, const char_type& __c2) noexcept
659  { return __c1 < __c2; }
660 
661  static _GLIBCXX17_CONSTEXPR int
662  compare(const char_type* __s1, const char_type* __s2, size_t __n)
663  {
664  for (size_t __i = 0; __i < __n; ++__i)
665  if (lt(__s1[__i], __s2[__i]))
666  return -1;
667  else if (lt(__s2[__i], __s1[__i]))
668  return 1;
669  return 0;
670  }
671 
672  static _GLIBCXX17_CONSTEXPR size_t
673  length(const char_type* __s)
674  {
675  size_t __i = 0;
676  while (!eq(__s[__i], char_type()))
677  ++__i;
678  return __i;
679  }
680 
681  static _GLIBCXX17_CONSTEXPR const char_type*
682  find(const char_type* __s, size_t __n, const char_type& __a)
683  {
684  for (size_t __i = 0; __i < __n; ++__i)
685  if (eq(__s[__i], __a))
686  return __s + __i;
687  return 0;
688  }
689 
690  static char_type*
691  move(char_type* __s1, const char_type* __s2, size_t __n)
692  {
693  if (__n == 0)
694  return __s1;
695  return (static_cast<char_type*>
696  (__builtin_memmove(__s1, __s2, __n * sizeof(char_type))));
697  }
698 
699  static char_type*
700  copy(char_type* __s1, const char_type* __s2, size_t __n)
701  {
702  if (__n == 0)
703  return __s1;
704  return (static_cast<char_type*>
705  (__builtin_memcpy(__s1, __s2, __n * sizeof(char_type))));
706  }
707 
708  static char_type*
709  assign(char_type* __s, size_t __n, char_type __a)
710  {
711  for (size_t __i = 0; __i < __n; ++__i)
712  assign(__s[__i], __a);
713  return __s;
714  }
715 
716  static constexpr char_type
717  to_char_type(const int_type& __c) noexcept
718  { return char_type(__c); }
719 
720  static constexpr int_type
721  to_int_type(const char_type& __c) noexcept
722  { return __c == eof() ? int_type(0xfffd) : int_type(__c); }
723 
724  static constexpr bool
725  eq_int_type(const int_type& __c1, const int_type& __c2) noexcept
726  { return __c1 == __c2; }
727 
728  static constexpr int_type
729  eof() noexcept
730  { return static_cast<int_type>(-1); }
731 
732  static constexpr int_type
733  not_eof(const int_type& __c) noexcept
734  { return eq_int_type(__c, eof()) ? 0 : __c; }
735  };
736 
737  template<>
738  struct char_traits<char32_t>
739  {
740  typedef char32_t char_type;
741 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
742  typedef uint_least32_t int_type;
743 #elif defined __UINT_LEAST32_TYPE__
744  typedef __UINT_LEAST32_TYPE__ int_type;
745 #else
746  typedef make_unsigned<char32_t>::type int_type;
747 #endif
748  typedef streamoff off_type;
749  typedef u32streampos pos_type;
750  typedef mbstate_t state_type;
751 
752  static _GLIBCXX17_CONSTEXPR void
753  assign(char_type& __c1, const char_type& __c2) noexcept
754  { __c1 = __c2; }
755 
756  static constexpr bool
757  eq(const char_type& __c1, const char_type& __c2) noexcept
758  { return __c1 == __c2; }
759 
760  static constexpr bool
761  lt(const char_type& __c1, const char_type& __c2) noexcept
762  { return __c1 < __c2; }
763 
764  static _GLIBCXX17_CONSTEXPR int
765  compare(const char_type* __s1, const char_type* __s2, size_t __n)
766  {
767  for (size_t __i = 0; __i < __n; ++__i)
768  if (lt(__s1[__i], __s2[__i]))
769  return -1;
770  else if (lt(__s2[__i], __s1[__i]))
771  return 1;
772  return 0;
773  }
774 
775  static _GLIBCXX17_CONSTEXPR size_t
776  length(const char_type* __s)
777  {
778  size_t __i = 0;
779  while (!eq(__s[__i], char_type()))
780  ++__i;
781  return __i;
782  }
783 
784  static _GLIBCXX17_CONSTEXPR const char_type*
785  find(const char_type* __s, size_t __n, const char_type& __a)
786  {
787  for (size_t __i = 0; __i < __n; ++__i)
788  if (eq(__s[__i], __a))
789  return __s + __i;
790  return 0;
791  }
792 
793  static char_type*
794  move(char_type* __s1, const char_type* __s2, size_t __n)
795  {
796  if (__n == 0)
797  return __s1;
798  return (static_cast<char_type*>
799  (__builtin_memmove(__s1, __s2, __n * sizeof(char_type))));
800  }
801 
802  static char_type*
803  copy(char_type* __s1, const char_type* __s2, size_t __n)
804  {
805  if (__n == 0)
806  return __s1;
807  return (static_cast<char_type*>
808  (__builtin_memcpy(__s1, __s2, __n * sizeof(char_type))));
809  }
810 
811  static char_type*
812  assign(char_type* __s, size_t __n, char_type __a)
813  {
814  for (size_t __i = 0; __i < __n; ++__i)
815  assign(__s[__i], __a);
816  return __s;
817  }
818 
819  static constexpr char_type
820  to_char_type(const int_type& __c) noexcept
821  { return char_type(__c); }
822 
823  static constexpr int_type
824  to_int_type(const char_type& __c) noexcept
825  { return int_type(__c); }
826 
827  static constexpr bool
828  eq_int_type(const int_type& __c1, const int_type& __c2) noexcept
829  { return __c1 == __c2; }
830 
831  static constexpr int_type
832  eof() noexcept
833  { return static_cast<int_type>(-1); }
834 
835  static constexpr int_type
836  not_eof(const int_type& __c) noexcept
837  { return eq_int_type(__c, eof()) ? 0 : __c; }
838  };
839 
840 _GLIBCXX_END_NAMESPACE_VERSION
841 } // namespace
842 
843 #endif // C++11
844 
845 #endif // _CHAR_TRAITS_H
ISO C++ entities toplevel namespace is std.
fpos< mbstate_t > u32streampos
File position for char32_t streams.
Definition: postypes.h:247
long long streamoff
Type used by fpos, char_traits<char>, and char_traits<wchar_t>.
Definition: postypes.h:94
fpos< mbstate_t > u16streampos
File position for char16_t streams.
Definition: postypes.h:245
GNU extensions for public use.
Mapping from character type to associated types.
Definition: char_traits.h:63
Base class used to implement std::char_traits.
Definition: char_traits.h:88
Basis for explicit traits specializations.
Definition: char_traits.h:285
Class representing stream positions.
Definition: postypes.h:113