libstdc++-v3/include/bits/char_traits.h

   1 // Character Traits for use by standard string and iostream -*- C++ -*-
   2
   3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
   4 // 2006, 2007, 2008, 2009
   5 // Free Software Foundation, Inc.
   6 //
   7 // This file is part of the GNU ISO C++ Library.  This library is free
   8 // software; you can redistribute it and/or modify it under the
   9 // terms of the GNU General Public License as published by the
  10 // Free Software Foundation; either version 3, or (at your option)
  11 // any later version.
  12
  13 // This library is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // Under Section 7 of GPL version 3, you are granted additional
  19 // permissions described in the GCC Runtime Library Exception, version
  20 // 3.1, as published by the Free Software Foundation.
  21
  22 // You should have received a copy of the GNU General Public License and
  23 // a copy of the GCC Runtime Library Exception along with this program;
  24 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 // <http://www.gnu.org/licenses/>.
  26
  27 /** @file char_traits.h
  28  *  This is an internal header file, included by other library headers.
  29  *  You should not attempt to use it directly.
  30  */
  31
  32 //
  33 // ISO C++ 14882: 21  Strings library
  34 //
  35
  36 #ifndef _CHAR_TRAITS_H
  37 #define _CHAR_TRAITS_H 1
  38
  39 #pragma GCC system_header
  40
  41 #include <bits/stl_algobase.h>  // std::copy, std::fill_n
  42 #include <bits/postypes.h>      // For streampos
  43 #include <cwchar>               // For WEOF, wmemmove, wmemset, etc.
  44
  45 #ifndef _GLIBCXX_STDIO_MACROS
  46 # include <cstdio>              // For EOF
  47 # define _CHAR_TRAITS_EOF EOF
  48 #else
  49 # define _CHAR_TRAITS_EOF (-1)
  50 #endif
  51
  52 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
  53
  54   /**
  55    *  @brief  Mapping from character type to associated types.
  56    *
  57    *  @note This is an implementation class for the generic version
  58    *  of char_traits.  It defines int_type, off_type, pos_type, and
  59    *  state_type.  By default these are unsigned long, streamoff,
  60    *  streampos, and mbstate_t.  Users who need a different set of
  61    *  types, but who don't need to change the definitions of any function
  62    *  defined in char_traits, can specialize __gnu_cxx::_Char_types
  63    *  while leaving __gnu_cxx::char_traits alone. */
  64   template<typename _CharT>
  65     struct _Char_types
  66     {
  67       typedef unsigned long   int_type;
  68       typedef std::streampos  pos_type;
  69       typedef std::streamoff  off_type;
  70       typedef std::mbstate_t  state_type;
  71     };
  72
  73
  74   /**
  75    *  @brief  Base class used to implement std::char_traits.
  76    *
  77    *  @note For any given actual character type, this definition is
  78    *  probably wrong.  (Most of the member functions are likely to be
  79    *  right, but the int_type and state_type typedefs, and the eof()
  80    *  member function, are likely to be wrong.)  The reason this class
  81    *  exists is so users can specialize it.  Classes in namespace std
  82    *  may not be specialized for fundamental types, but classes in
  83    *  namespace __gnu_cxx may be.
  84    *
  85    *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt05ch13s03.html
  86    *  for advice on how to make use of this class for "unusual" character
  87    *  types. Also, check out include/ext/pod_char_traits.h.
  88    */
  89   template<typename _CharT>
  90     struct char_traits
  91     {
  92       typedef _CharT                                    char_type;
  93       typedef typename _Char_types<_CharT>::int_type    int_type;
  94       typedef typename _Char_types<_CharT>::pos_type    pos_type;
  95       typedef typename _Char_types<_CharT>::off_type    off_type;
  96       typedef typename _Char_types<_CharT>::state_type  state_type;
  97
  98       static void
  99       assign(char_type& __c1, const char_type& __c2)
 100       { __c1 = __c2; }
 101
 102       static bool
 103       eq(const char_type& __c1, const char_type& __c2)
 104       { return __c1 == __c2; }
 105
 106       static bool
 107       lt(const char_type& __c1, const char_type& __c2)
 108       { return __c1 < __c2; }
 109
 110       static int
 111       compare(const char_type* __s1, const char_type* __s2, std::size_t __n);
 112
 113       static std::size_t
 114       length(const char_type* __s);
 115
 116       static const char_type*
 117       find(const char_type* __s, std::size_t __n, const char_type& __a);
 118
 119       static char_type*
 120       move(char_type* __s1, const char_type* __s2, std::size_t __n);
 121
 122       static char_type*
 123       copy(char_type* __s1, const char_type* __s2, std::size_t __n);
 124
 125       static char_type*
 126       assign(char_type* __s, std::size_t __n, char_type __a);
 127
 128       static char_type
 129       to_char_type(const int_type& __c)
 130       { return static_cast<char_type>(__c); }
 131
 132       static int_type
 133       to_int_type(const char_type& __c)
 134       { return static_cast<int_type>(__c); }
 135
 136       static bool
 137       eq_int_type(const int_type& __c1, const int_type& __c2)
 138       { return __c1 == __c2; }
 139
 140       static int_type
 141       eof()
 142       { return static_cast<int_type>(_CHAR_TRAITS_EOF); }
 143
 144       static int_type
 145       not_eof(const int_type& __c)
 146       { return !eq_int_type(__c, eof()) ? __c : to_int_type(char_type()); }
 147     };
 148
 149   template<typename _CharT>
 150     int
 151     char_traits<_CharT>::
 152     compare(const char_type* __s1, const char_type* __s2, std::size_t __n)
 153     {
 154       for (std::size_t __i = 0; __i < __n; ++__i)
 155         if (lt(__s1[__i], __s2[__i]))
 156           return -1;
 157         else if (lt(__s2[__i], __s1[__i]))
 158           return 1;
 159       return 0;
 160     }
 161
 162   template<typename _CharT>
 163     std::size_t
 164     char_traits<_CharT>::
 165     length(const char_type* __p)
 166     {
 167       std::size_t __i = 0;
 168       while (!eq(__p[__i], char_type()))
 169         ++__i;
 170       return __i;
 171     }
 172
 173   template<typename _CharT>
 174     const typename char_traits<_CharT>::char_type*
 175     char_traits<_CharT>::
 176     find(const char_type* __s, std::size_t __n, const char_type& __a)
 177     {
 178       for (std::size_t __i = 0; __i < __n; ++__i)
 179         if (eq(__s[__i], __a))
 180           return __s + __i;
 181       return 0;
 182     }
 183
 184   template<typename _CharT>
 185     typename char_traits<_CharT>::char_type*
 186     char_traits<_CharT>::
 187     move(char_type* __s1, const char_type* __s2, std::size_t __n)
 188     {
 189       return static_cast<_CharT*>(__builtin_memmove(__s1, __s2,
 190                                                     __n * sizeof(char_type)));
 191     }
 192
 193   template<typename _CharT>
 194     typename char_traits<_CharT>::char_type*
 195     char_traits<_CharT>::
 196     copy(char_type* __s1, const char_type* __s2, std::size_t __n)
 197     {
 198       // NB: Inline std::copy so no recursive dependencies.
 199       std::copy(__s2, __s2 + __n, __s1);
 200       return __s1;
 201     }
 202
 203   template<typename _CharT>
 204     typename char_traits<_CharT>::char_type*
 205     char_traits<_CharT>::
 206     assign(char_type* __s, std::size_t __n, char_type __a)
 207     {
 208       // NB: Inline std::fill_n so no recursive dependencies.
 209       std::fill_n(__s, __n, __a);
 210       return __s;
 211     }
 212
 213 _GLIBCXX_END_NAMESPACE
 214
 215 _GLIBCXX_BEGIN_NAMESPACE(std)
 216
 217   // 21.1
 218   /**
 219    *  @brief  Basis for explicit traits specializations.
 220    *
 221    *  @note  For any given actual character type, this definition is
 222    *  probably wrong.  Since this is just a thin wrapper around
 223    *  __gnu_cxx::char_traits, it is possible to achieve a more
 224    *  appropriate definition by specializing __gnu_cxx::char_traits.
 225    *
 226    *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt05ch13s03.html
 227    *  for advice on how to make use of this class for "unusual" character
 228    *  types. Also, check out include/ext/pod_char_traits.h.
 229   */
 230   template<class _CharT>
 231     struct char_traits : public __gnu_cxx::char_traits<_CharT>
 232     { };
 233
 234
 235   /// 21.1.3.1  char_traits specializations
 236   template<>
 237     struct char_traits<char>
 238     {
 239       typedef char              char_type;
 240       typedef int               int_type;
 241       typedef streampos         pos_type;
 242       typedef streamoff         off_type;
 243       typedef mbstate_t         state_type;
 244
 245       static void
 246       assign(char_type& __c1, const char_type& __c2)
 247       { __c1 = __c2; }
 248
 249       static bool
 250       eq(const char_type& __c1, const char_type& __c2)
 251       { return __c1 == __c2; }
 252
 253       static bool
 254       lt(const char_type& __c1, const char_type& __c2)
 255       { return __c1 < __c2; }
 256
 257       static int
 258       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 259       { return __builtin_memcmp(__s1, __s2, __n); }
 260
 261       static size_t
 262       length(const char_type* __s)
 263       { return __builtin_strlen(__s); }
 264
 265       static const char_type*
 266       find(const char_type* __s, size_t __n, const char_type& __a)
 267       { return static_cast<const char_type*>(__builtin_memchr(__s, __a, __n)); }
 268
 269       static char_type*
 270       move(char_type* __s1, const char_type* __s2, size_t __n)
 271       { return static_cast<char_type*>(__builtin_memmove(__s1, __s2, __n)); }
 272
 273       static char_type*
 274       copy(char_type* __s1, const char_type* __s2, size_t __n)
 275       { return static_cast<char_type*>(__builtin_memcpy(__s1, __s2, __n)); }
 276
 277       static char_type*
 278       assign(char_type* __s, size_t __n, char_type __a)
 279       { return static_cast<char_type*>(__builtin_memset(__s, __a, __n)); }
 280
 281       static char_type
 282       to_char_type(const int_type& __c)
 283       { return static_cast<char_type>(__c); }
 284
 285       // To keep both the byte 0xff and the eof symbol 0xffffffff
 286       // from ending up as 0xffffffff.
 287       static int_type
 288       to_int_type(const char_type& __c)
 289       { return static_cast<int_type>(static_cast<unsigned char>(__c)); }
 290
 291       static bool
 292       eq_int_type(const int_type& __c1, const int_type& __c2)
 293       { return __c1 == __c2; }
 294
 295       static int_type
 296       eof()
 297       { return static_cast<int_type>(_CHAR_TRAITS_EOF); }
 298
 299       static int_type
 300       not_eof(const int_type& __c)
 301       { return (__c == eof()) ? 0 : __c; }
 302   };
 303
 304
 305 #ifdef _GLIBCXX_USE_WCHAR_T
 306   /// 21.1.3.2  char_traits specializations
 307   template<>
 308     struct char_traits<wchar_t>
 309     {
 310       typedef wchar_t           char_type;
 311       typedef wint_t            int_type;
 312       typedef streamoff         off_type;
 313       typedef wstreampos        pos_type;
 314       typedef mbstate_t         state_type;
 315
 316       static void
 317       assign(char_type& __c1, const char_type& __c2)
 318       { __c1 = __c2; }
 319
 320       static bool
 321       eq(const char_type& __c1, const char_type& __c2)
 322       { return __c1 == __c2; }
 323
 324       static bool
 325       lt(const char_type& __c1, const char_type& __c2)
 326       { return __c1 < __c2; }
 327
 328       static int
 329       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 330       { return wmemcmp(__s1, __s2, __n); }
 331
 332       static size_t
 333       length(const char_type* __s)
 334       { return wcslen(__s); }
 335
 336       static const char_type*
 337       find(const char_type* __s, size_t __n, const char_type& __a)
 338       { return wmemchr(__s, __a, __n); }
 339
 340       static char_type*
 341       move(char_type* __s1, const char_type* __s2, size_t __n)
 342       { return wmemmove(__s1, __s2, __n); }
 343
 344       static char_type*
 345       copy(char_type* __s1, const char_type* __s2, size_t __n)
 346       { return wmemcpy(__s1, __s2, __n); }
 347
 348       static char_type*
 349       assign(char_type* __s, size_t __n, char_type __a)
 350       { return wmemset(__s, __a, __n); }
 351
 352       static char_type
 353       to_char_type(const int_type& __c)
 354       { return char_type(__c); }
 355
 356       static int_type
 357       to_int_type(const char_type& __c)
 358       { return int_type(__c); }
 359
 360       static bool
 361       eq_int_type(const int_type& __c1, const int_type& __c2)
 362       { return __c1 == __c2; }
 363
 364       static int_type
 365       eof()
 366       { return static_cast<int_type>(WEOF); }
 367
 368       static int_type
 369       not_eof(const int_type& __c)
 370       { return eq_int_type(__c, eof()) ? 0 : __c; }
 371   };
 372 #endif //_GLIBCXX_USE_WCHAR_T
 373
 374 _GLIBCXX_END_NAMESPACE
 375
 376 #if (defined(__GXX_EXPERIMENTAL_CXX0X__) \
 377      && defined(_GLIBCXX_USE_C99_STDINT_TR1))
 378
 379 #include <cstdint>
 380
 381 _GLIBCXX_BEGIN_NAMESPACE(std)
 382
 383   template<>
 384     struct char_traits<char16_t>
 385     {
 386       typedef char16_t          char_type;
 387       typedef uint_least16_t    int_type;
 388       typedef streamoff         off_type;
 389       typedef u16streampos      pos_type;
 390       typedef mbstate_t         state_type;
 391
 392       static void
 393       assign(char_type& __c1, const char_type& __c2)
 394       { __c1 = __c2; }
 395
 396       static bool
 397       eq(const char_type& __c1, const char_type& __c2)
 398       { return __c1 == __c2; }
 399
 400       static bool
 401       lt(const char_type& __c1, const char_type& __c2)
 402       { return __c1 < __c2; }
 403
 404       static int
 405       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 406       {
 407         for (size_t __i = 0; __i < __n; ++__i)
 408           if (lt(__s1[__i], __s2[__i]))
 409             return -1;
 410           else if (lt(__s2[__i], __s1[__i]))
 411             return 1;
 412         return 0;
 413       }
 414
 415       static size_t
 416       length(const char_type* __s)
 417       {
 418         size_t __i = 0;
 419         while (!eq(__s[__i], char_type()))
 420           ++__i;
 421         return __i;
 422       }
 423
 424       static const char_type*
 425       find(const char_type* __s, size_t __n, const char_type& __a)
 426       {
 427         for (size_t __i = 0; __i < __n; ++__i)
 428           if (eq(__s[__i], __a))
 429             return __s + __i;
 430         return 0;
 431       }
 432
 433       static char_type*
 434       move(char_type* __s1, const char_type* __s2, size_t __n)
 435       {
 436         return (static_cast<char_type*>
 437                 (__builtin_memmove(__s1, __s2, __n * sizeof(char_type))));
 438       }
 439
 440       static char_type*
 441       copy(char_type* __s1, const char_type* __s2, size_t __n)
 442       {
 443         return (static_cast<char_type*>
 444                 (__builtin_memcpy(__s1, __s2, __n * sizeof(char_type))));
 445       }
 446
 447       static char_type*
 448       assign(char_type* __s, size_t __n, char_type __a)
 449       {
 450         for (size_t __i = 0; __i < __n; ++__i)
 451           assign(__s[__i], __a);
 452         return __s;
 453       }
 454
 455       static char_type
 456       to_char_type(const int_type& __c)
 457       { return char_type(__c); }
 458
 459       static int_type
 460       to_int_type(const char_type& __c)
 461       { return int_type(__c); }
 462
 463       static bool
 464       eq_int_type(const int_type& __c1, const int_type& __c2)
 465       { return __c1 == __c2; }
 466
 467       static int_type
 468       eof()
 469       { return static_cast<int_type>(-1); }
 470
 471       static int_type
 472       not_eof(const int_type& __c)
 473       { return eq_int_type(__c, eof()) ? 0 : __c; }
 474     };
 475
 476   template<>
 477     struct char_traits<char32_t>
 478     {
 479       typedef char32_t          char_type;
 480       typedef uint_least32_t    int_type;
 481       typedef streamoff         off_type;
 482       typedef u32streampos      pos_type;
 483       typedef mbstate_t         state_type;
 484
 485       static void
 486       assign(char_type& __c1, const char_type& __c2)
 487       { __c1 = __c2; }
 488
 489       static bool
 490       eq(const char_type& __c1, const char_type& __c2)
 491       { return __c1 == __c2; }
 492
 493       static bool
 494       lt(const char_type& __c1, const char_type& __c2)
 495       { return __c1 < __c2; }
 496
 497       static int
 498       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 499       {
 500         for (size_t __i = 0; __i < __n; ++__i)
 501           if (lt(__s1[__i], __s2[__i]))
 502             return -1;
 503           else if (lt(__s2[__i], __s1[__i]))
 504             return 1;
 505         return 0;
 506       }
 507
 508       static size_t
 509       length(const char_type* __s)
 510       {
 511         size_t __i = 0;
 512         while (!eq(__s[__i], char_type()))
 513           ++__i;
 514         return __i;
 515       }
 516
 517       static const char_type*
 518       find(const char_type* __s, size_t __n, const char_type& __a)
 519       {
 520         for (size_t __i = 0; __i < __n; ++__i)
 521           if (eq(__s[__i], __a))
 522             return __s + __i;
 523         return 0;
 524       }
 525
 526       static char_type*
 527       move(char_type* __s1, const char_type* __s2, size_t __n)
 528       {
 529         return (static_cast<char_type*>
 530                 (__builtin_memmove(__s1, __s2, __n * sizeof(char_type))));
 531       }
 532
 533       static char_type*
 534       copy(char_type* __s1, const char_type* __s2, size_t __n)
 535       {
 536         return (static_cast<char_type*>
 537                 (__builtin_memcpy(__s1, __s2, __n * sizeof(char_type))));
 538       }
 539
 540       static char_type*
 541       assign(char_type* __s, size_t __n, char_type __a)
 542       {
 543         for (size_t __i = 0; __i < __n; ++__i)
 544           assign(__s[__i], __a);
 545         return __s;
 546       }
 547
 548       static char_type
 549       to_char_type(const int_type& __c)
 550       { return char_type(__c); }
 551
 552       static int_type
 553       to_int_type(const char_type& __c)
 554       { return int_type(__c); }
 555
 556       static bool
 557       eq_int_type(const int_type& __c1, const int_type& __c2)
 558       { return __c1 == __c2; }
 559
 560       static int_type
 561       eof()
 562       { return static_cast<int_type>(-1); }
 563
 564       static int_type
 565       not_eof(const int_type& __c)
 566       { return eq_int_type(__c, eof()) ? 0 : __c; }
 567     };
 568
 569 _GLIBCXX_END_NAMESPACE
 570
 571 #endif
 572
 573 #undef _CHAR_TRAITS_EOF
 574
 575 #endif // _CHAR_TRAITS_H