contrib/gcc-5.0/libstdc++-v3/include/bits/char_traits.h

   1 // Character Traits for use by standard string and iostream -*- C++ -*-
   2
   3 // Copyright (C) 1997-2015 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 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
  44 {
  45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  46
  47   /**
  48    *  @brief  Mapping from character type to associated types.
  49    *
  50    *  @note This is an implementation class for the generic version
  51    *  of char_traits.  It defines int_type, off_type, pos_type, and
  52    *  state_type.  By default these are unsigned long, streamoff,
  53    *  streampos, and mbstate_t.  Users who need a different set of
  54    *  types, but who don't need to change the definitions of any function
  55    *  defined in char_traits, can specialize __gnu_cxx::_Char_types
  56    *  while leaving __gnu_cxx::char_traits alone. */
  57   template<typename _CharT>
  58     struct _Char_types
  59     {
  60       typedef unsigned long   int_type;
  61       typedef std::streampos  pos_type;
  62       typedef std::streamoff  off_type;
  63       typedef std::mbstate_t  state_type;
  64     };
  65
  66
  67   /**
  68    *  @brief  Base class used to implement std::char_traits.
  69    *
  70    *  @note For any given actual character type, this definition is
  71    *  probably wrong.  (Most of the member functions are likely to be
  72    *  right, but the int_type and state_type typedefs, and the eof()
  73    *  member function, are likely to be wrong.)  The reason this class
  74    *  exists is so users can specialize it.  Classes in namespace std
  75    *  may not be specialized for fundamental types, but classes in
  76    *  namespace __gnu_cxx may be.
  77    *
  78    *  See https://gcc.gnu.org/onlinedocs/libstdc++/manual/strings.html#strings.string.character_types
  79    *  for advice on how to make use of this class for @a unusual character
  80    *  types. Also, check out include/ext/pod_char_traits.h.
  81    */
  82   template<typename _CharT>
  83     struct char_traits
  84     {
  85       typedef _CharT                                    char_type;
  86       typedef typename _Char_types<_CharT>::int_type    int_type;
  87       typedef typename _Char_types<_CharT>::pos_type    pos_type;
  88       typedef typename _Char_types<_CharT>::off_type    off_type;
  89       typedef typename _Char_types<_CharT>::state_type  state_type;
  90
  91       static void
  92       assign(char_type& __c1, const char_type& __c2)
  93       { __c1 = __c2; }
  94
  95       static _GLIBCXX_CONSTEXPR bool
  96       eq(const char_type& __c1, const char_type& __c2)
  97       { return __c1 == __c2; }
  98
  99       static _GLIBCXX_CONSTEXPR bool
 100       lt(const char_type& __c1, const char_type& __c2)
 101       { return __c1 < __c2; }
 102
 103       static int
 104       compare(const char_type* __s1, const char_type* __s2, std::size_t __n);
 105
 106       static std::size_t
 107       length(const char_type* __s);
 108
 109       static const char_type*
 110       find(const char_type* __s, std::size_t __n, const char_type& __a);
 111
 112       static char_type*
 113       move(char_type* __s1, const char_type* __s2, std::size_t __n);
 114
 115       static char_type*
 116       copy(char_type* __s1, const char_type* __s2, std::size_t __n);
 117
 118       static char_type*
 119       assign(char_type* __s, std::size_t __n, char_type __a);
 120
 121       static _GLIBCXX_CONSTEXPR char_type
 122       to_char_type(const int_type& __c)
 123       { return static_cast<char_type>(__c); }
 124
 125       static _GLIBCXX_CONSTEXPR int_type
 126       to_int_type(const char_type& __c)
 127       { return static_cast<int_type>(__c); }
 128
 129       static _GLIBCXX_CONSTEXPR bool
 130       eq_int_type(const int_type& __c1, const int_type& __c2)
 131       { return __c1 == __c2; }
 132
 133       static _GLIBCXX_CONSTEXPR int_type
 134       eof()
 135       { return static_cast<int_type>(_GLIBCXX_STDIO_EOF); }
 136
 137       static _GLIBCXX_CONSTEXPR int_type
 138       not_eof(const int_type& __c)
 139       { return !eq_int_type(__c, eof()) ? __c : to_int_type(char_type()); }
 140     };
 141
 142   template<typename _CharT>
 143     int
 144     char_traits<_CharT>::
 145     compare(const char_type* __s1, const char_type* __s2, std::size_t __n)
 146     {
 147       for (std::size_t __i = 0; __i < __n; ++__i)
 148         if (lt(__s1[__i], __s2[__i]))
 149           return -1;
 150         else if (lt(__s2[__i], __s1[__i]))
 151           return 1;
 152       return 0;
 153     }
 154
 155   template<typename _CharT>
 156     std::size_t
 157     char_traits<_CharT>::
 158     length(const char_type* __p)
 159     {
 160       std::size_t __i = 0;
 161       while (!eq(__p[__i], char_type()))
 162         ++__i;
 163       return __i;
 164     }
 165
 166   template<typename _CharT>
 167     const typename char_traits<_CharT>::char_type*
 168     char_traits<_CharT>::
 169     find(const char_type* __s, std::size_t __n, const char_type& __a)
 170     {
 171       for (std::size_t __i = 0; __i < __n; ++__i)
 172         if (eq(__s[__i], __a))
 173           return __s + __i;
 174       return 0;
 175     }
 176
 177   template<typename _CharT>
 178     typename char_traits<_CharT>::char_type*
 179     char_traits<_CharT>::
 180     move(char_type* __s1, const char_type* __s2, std::size_t __n)
 181     {
 182       return static_cast<_CharT*>(__builtin_memmove(__s1, __s2,
 183                                                     __n * sizeof(char_type)));
 184     }
 185
 186   template<typename _CharT>
 187     typename char_traits<_CharT>::char_type*
 188     char_traits<_CharT>::
 189     copy(char_type* __s1, const char_type* __s2, std::size_t __n)
 190     {
 191       // NB: Inline std::copy so no recursive dependencies.
 192       std::copy(__s2, __s2 + __n, __s1);
 193       return __s1;
 194     }
 195
 196   template<typename _CharT>
 197     typename char_traits<_CharT>::char_type*
 198     char_traits<_CharT>::
 199     assign(char_type* __s, std::size_t __n, char_type __a)
 200     {
 201       // NB: Inline std::fill_n so no recursive dependencies.
 202       std::fill_n(__s, __n, __a);
 203       return __s;
 204     }
 205
 206 _GLIBCXX_END_NAMESPACE_VERSION
 207 } // namespace
 208
 209 namespace std _GLIBCXX_VISIBILITY(default)
 210 {
 211 _GLIBCXX_BEGIN_NAMESPACE_VERSION
 212
 213   // 21.1
 214   /**
 215    *  @brief  Basis for explicit traits specializations.
 216    *
 217    *  @note  For any given actual character type, this definition is
 218    *  probably wrong.  Since this is just a thin wrapper around
 219    *  __gnu_cxx::char_traits, it is possible to achieve a more
 220    *  appropriate definition by specializing __gnu_cxx::char_traits.
 221    *
 222    *  See https://gcc.gnu.org/onlinedocs/libstdc++/manual/strings.html#strings.string.character_types
 223    *  for advice on how to make use of this class for @a unusual character
 224    *  types. Also, check out include/ext/pod_char_traits.h.
 225   */
 226   template<class _CharT>
 227     struct char_traits : public __gnu_cxx::char_traits<_CharT>
 228     { };
 229
 230
 231   /// 21.1.3.1  char_traits specializations
 232   template<>
 233     struct char_traits<char>
 234     {
 235       typedef char              char_type;
 236       typedef int               int_type;
 237       typedef streampos         pos_type;
 238       typedef streamoff         off_type;
 239       typedef mbstate_t         state_type;
 240
 241       static void
 242       assign(char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
 243       { __c1 = __c2; }
 244
 245       static _GLIBCXX_CONSTEXPR bool
 246       eq(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
 247       { return __c1 == __c2; }
 248
 249       static _GLIBCXX_CONSTEXPR bool
 250       lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
 251       {
 252         // LWG 467.
 253         return (static_cast<unsigned char>(__c1)
 254                 < static_cast<unsigned char>(__c2));
 255       }
 256
 257       static int
 258       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 259       {
 260         if (__n == 0)
 261           return 0;
 262         return __builtin_memcmp(__s1, __s2, __n);
 263       }
 264
 265       static size_t
 266       length(const char_type* __s)
 267       { return __builtin_strlen(__s); }
 268
 269       static const char_type*
 270       find(const char_type* __s, size_t __n, const char_type& __a)
 271       {
 272         if (__n == 0)
 273           return 0;
 274         return static_cast<const char_type*>(__builtin_memchr(__s, __a, __n));
 275       }
 276
 277       static char_type*
 278       move(char_type* __s1, const char_type* __s2, size_t __n)
 279       {
 280         if (__n == 0)
 281           return __s1;
 282         return static_cast<char_type*>(__builtin_memmove(__s1, __s2, __n));
 283       }
 284
 285       static char_type*
 286       copy(char_type* __s1, const char_type* __s2, size_t __n)
 287       {
 288         if (__n == 0)
 289           return __s1;
 290         return static_cast<char_type*>(__builtin_memcpy(__s1, __s2, __n));
 291       }
 292
 293       static char_type*
 294       assign(char_type* __s, size_t __n, char_type __a)
 295       {
 296         if (__n == 0)
 297           return __s;
 298         return static_cast<char_type*>(__builtin_memset(__s, __a, __n));
 299       }
 300
 301       static _GLIBCXX_CONSTEXPR char_type
 302       to_char_type(const int_type& __c) _GLIBCXX_NOEXCEPT
 303       { return static_cast<char_type>(__c); }
 304
 305       // To keep both the byte 0xff and the eof symbol 0xffffffff
 306       // from ending up as 0xffffffff.
 307       static _GLIBCXX_CONSTEXPR int_type
 308       to_int_type(const char_type& __c) _GLIBCXX_NOEXCEPT
 309       { return static_cast<int_type>(static_cast<unsigned char>(__c)); }
 310
 311       static _GLIBCXX_CONSTEXPR bool
 312       eq_int_type(const int_type& __c1, const int_type& __c2) _GLIBCXX_NOEXCEPT
 313       { return __c1 == __c2; }
 314
 315       static _GLIBCXX_CONSTEXPR int_type
 316       eof() _GLIBCXX_NOEXCEPT
 317       { return static_cast<int_type>(_GLIBCXX_STDIO_EOF); }
 318
 319       static _GLIBCXX_CONSTEXPR int_type
 320       not_eof(const int_type& __c) _GLIBCXX_NOEXCEPT
 321       { return (__c == eof()) ? 0 : __c; }
 322   };
 323
 324
 325 #ifdef _GLIBCXX_USE_WCHAR_T
 326   /// 21.1.3.2  char_traits specializations
 327   template<>
 328     struct char_traits<wchar_t>
 329     {
 330       typedef wchar_t           char_type;
 331       typedef wint_t            int_type;
 332       typedef streamoff         off_type;
 333       typedef wstreampos        pos_type;
 334       typedef mbstate_t         state_type;
 335
 336       static void
 337       assign(char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
 338       { __c1 = __c2; }
 339
 340       static _GLIBCXX_CONSTEXPR bool
 341       eq(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
 342       { return __c1 == __c2; }
 343
 344       static _GLIBCXX_CONSTEXPR bool
 345       lt(const char_type& __c1, const char_type& __c2) _GLIBCXX_NOEXCEPT
 346       { return __c1 < __c2; }
 347
 348       static int
 349       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 350       {
 351         if (__n == 0)
 352           return 0;
 353         return wmemcmp(__s1, __s2, __n);
 354       }
 355
 356       static size_t
 357       length(const char_type* __s)
 358       { return wcslen(__s); }
 359
 360       static const char_type*
 361       find(const char_type* __s, size_t __n, const char_type& __a)
 362       {
 363         if (__n == 0)
 364           return 0;
 365         return wmemchr(__s, __a, __n);
 366       }
 367
 368       static char_type*
 369       move(char_type* __s1, const char_type* __s2, size_t __n)
 370       {
 371         if (__n == 0)
 372           return __s1;
 373         return wmemmove(__s1, __s2, __n);
 374       }
 375
 376       static char_type*
 377       copy(char_type* __s1, const char_type* __s2, size_t __n)
 378       {
 379         if (__n == 0)
 380           return __s1;
 381         return wmemcpy(__s1, __s2, __n);
 382       }
 383
 384       static char_type*
 385       assign(char_type* __s, size_t __n, char_type __a)
 386       {
 387         if (__n == 0)
 388           return __s;
 389         return wmemset(__s, __a, __n);
 390       }
 391
 392       static _GLIBCXX_CONSTEXPR char_type
 393       to_char_type(const int_type& __c) _GLIBCXX_NOEXCEPT
 394       { return char_type(__c); }
 395
 396       static _GLIBCXX_CONSTEXPR int_type
 397       to_int_type(const char_type& __c) _GLIBCXX_NOEXCEPT
 398       { return int_type(__c); }
 399
 400       static _GLIBCXX_CONSTEXPR bool
 401       eq_int_type(const int_type& __c1, const int_type& __c2) _GLIBCXX_NOEXCEPT
 402       { return __c1 == __c2; }
 403
 404       static _GLIBCXX_CONSTEXPR int_type
 405       eof() _GLIBCXX_NOEXCEPT
 406       { return static_cast<int_type>(WEOF); }
 407
 408       static _GLIBCXX_CONSTEXPR int_type
 409       not_eof(const int_type& __c) _GLIBCXX_NOEXCEPT
 410       { return eq_int_type(__c, eof()) ? 0 : __c; }
 411   };
 412 #endif //_GLIBCXX_USE_WCHAR_T
 413
 414 _GLIBCXX_END_NAMESPACE_VERSION
 415 } // namespace
 416
 417 #if ((__cplusplus >= 201103L) \
 418      && defined(_GLIBCXX_USE_C99_STDINT_TR1))
 419
 420 #include <cstdint>
 421
 422 namespace std _GLIBCXX_VISIBILITY(default)
 423 {
 424 _GLIBCXX_BEGIN_NAMESPACE_VERSION
 425
 426   template<>
 427     struct char_traits<char16_t>
 428     {
 429       typedef char16_t          char_type;
 430       typedef uint_least16_t    int_type;
 431       typedef streamoff         off_type;
 432       typedef u16streampos      pos_type;
 433       typedef mbstate_t         state_type;
 434
 435       static void
 436       assign(char_type& __c1, const char_type& __c2) noexcept
 437       { __c1 = __c2; }
 438
 439       static constexpr bool
 440       eq(const char_type& __c1, const char_type& __c2) noexcept
 441       { return __c1 == __c2; }
 442
 443       static constexpr bool
 444       lt(const char_type& __c1, const char_type& __c2) noexcept
 445       { return __c1 < __c2; }
 446
 447       static int
 448       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 449       {
 450         for (size_t __i = 0; __i < __n; ++__i)
 451           if (lt(__s1[__i], __s2[__i]))
 452             return -1;
 453           else if (lt(__s2[__i], __s1[__i]))
 454             return 1;
 455         return 0;
 456       }
 457
 458       static size_t
 459       length(const char_type* __s)
 460       {
 461         size_t __i = 0;
 462         while (!eq(__s[__i], char_type()))
 463           ++__i;
 464         return __i;
 465       }
 466
 467       static const char_type*
 468       find(const char_type* __s, size_t __n, const char_type& __a)
 469       {
 470         for (size_t __i = 0; __i < __n; ++__i)
 471           if (eq(__s[__i], __a))
 472             return __s + __i;
 473         return 0;
 474       }
 475
 476       static char_type*
 477       move(char_type* __s1, const char_type* __s2, size_t __n)
 478       {
 479         if (__n == 0)
 480           return __s1;
 481         return (static_cast<char_type*>
 482                 (__builtin_memmove(__s1, __s2, __n * sizeof(char_type))));
 483       }
 484
 485       static char_type*
 486       copy(char_type* __s1, const char_type* __s2, size_t __n)
 487       {
 488         if (__n == 0)
 489           return __s1;
 490         return (static_cast<char_type*>
 491                 (__builtin_memcpy(__s1, __s2, __n * sizeof(char_type))));
 492       }
 493
 494       static char_type*
 495       assign(char_type* __s, size_t __n, char_type __a)
 496       {
 497         for (size_t __i = 0; __i < __n; ++__i)
 498           assign(__s[__i], __a);
 499         return __s;
 500       }
 501
 502       static constexpr char_type
 503       to_char_type(const int_type& __c) noexcept
 504       { return char_type(__c); }
 505
 506       static constexpr int_type
 507       to_int_type(const char_type& __c) noexcept
 508       { return int_type(__c); }
 509
 510       static constexpr bool
 511       eq_int_type(const int_type& __c1, const int_type& __c2) noexcept
 512       { return __c1 == __c2; }
 513
 514       static constexpr int_type
 515       eof() noexcept
 516       { return static_cast<int_type>(-1); }
 517
 518       static constexpr int_type
 519       not_eof(const int_type& __c) noexcept
 520       { return eq_int_type(__c, eof()) ? 0 : __c; }
 521     };
 522
 523   template<>
 524     struct char_traits<char32_t>
 525     {
 526       typedef char32_t          char_type;
 527       typedef uint_least32_t    int_type;
 528       typedef streamoff         off_type;
 529       typedef u32streampos      pos_type;
 530       typedef mbstate_t         state_type;
 531
 532       static void
 533       assign(char_type& __c1, const char_type& __c2) noexcept
 534       { __c1 = __c2; }
 535
 536       static constexpr bool
 537       eq(const char_type& __c1, const char_type& __c2) noexcept
 538       { return __c1 == __c2; }
 539
 540       static constexpr bool
 541       lt(const char_type& __c1, const char_type& __c2) noexcept
 542       { return __c1 < __c2; }
 543
 544       static int
 545       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 546       {
 547         for (size_t __i = 0; __i < __n; ++__i)
 548           if (lt(__s1[__i], __s2[__i]))
 549             return -1;
 550           else if (lt(__s2[__i], __s1[__i]))
 551             return 1;
 552         return 0;
 553       }
 554
 555       static size_t
 556       length(const char_type* __s)
 557       {
 558         size_t __i = 0;
 559         while (!eq(__s[__i], char_type()))
 560           ++__i;
 561         return __i;
 562       }
 563
 564       static const char_type*
 565       find(const char_type* __s, size_t __n, const char_type& __a)
 566       {
 567         for (size_t __i = 0; __i < __n; ++__i)
 568           if (eq(__s[__i], __a))
 569             return __s + __i;
 570         return 0;
 571       }
 572
 573       static char_type*
 574       move(char_type* __s1, const char_type* __s2, size_t __n)
 575       {
 576         if (__n == 0)
 577           return __s1;
 578         return (static_cast<char_type*>
 579                 (__builtin_memmove(__s1, __s2, __n * sizeof(char_type))));
 580       }
 581
 582       static char_type*
 583       copy(char_type* __s1, const char_type* __s2, size_t __n)
 584       {
 585         if (__n == 0)
 586           return __s1;
 587         return (static_cast<char_type*>
 588                 (__builtin_memcpy(__s1, __s2, __n * sizeof(char_type))));
 589       }
 590
 591       static char_type*
 592       assign(char_type* __s, size_t __n, char_type __a)
 593       {
 594         for (size_t __i = 0; __i < __n; ++__i)
 595           assign(__s[__i], __a);
 596         return __s;
 597       }
 598
 599       static constexpr char_type
 600       to_char_type(const int_type& __c) noexcept
 601       { return char_type(__c); }
 602
 603       static constexpr int_type
 604       to_int_type(const char_type& __c) noexcept
 605       { return int_type(__c); }
 606
 607       static constexpr bool
 608       eq_int_type(const int_type& __c1, const int_type& __c2) noexcept
 609       { return __c1 == __c2; }
 610
 611       static constexpr int_type
 612       eof() noexcept
 613       { return static_cast<int_type>(-1); }
 614
 615       static constexpr int_type
 616       not_eof(const int_type& __c) noexcept
 617       { return eq_int_type(__c, eof()) ? 0 : __c; }
 618     };
 619
 620 _GLIBCXX_END_NAMESPACE_VERSION
 621 } // namespace
 622
 623 #endif
 624
 625 #endif // _CHAR_TRAITS_H