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
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 2, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING.  If not, write to the Free
  19 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  20 // USA.
  21
  22 // As a special exception, you may use this file as part of a free software
  23 // library without restriction.  Specifically, if other files instantiate
  24 // templates or use macros or inline functions from this file, or you compile
  25 // this file and link it with other files to produce an executable, this
  26 // file does not by itself cause the resulting executable to be covered by
  27 // the GNU General Public License.  This exception does not however
  28 // invalidate any other reasons why the executable file might be covered by
  29 // the GNU General Public License.
  30
  31 //
  32 // ISO C++ 14882: 21  Strings library
  33 //
  34
  35 /** @file char_traits.h
  36  *  This is an internal header file, included by other library headers.
  37  *  You should not attempt to use it directly.
  38  */
  39
  40 #ifndef _CHAR_TRAITS_H
  41 #define _CHAR_TRAITS_H 1
  42
  43 #pragma GCC system_header
  44
  45 #include <cstring>            // For memmove, memset, memchr
  46 #include <bits/fpos.h>        // For streampos
  47
  48 namespace std
  49 {
  50   // 21.1
  51   /**
  52    *  @brief  Basis for explicit traits specializations.
  53    *
  54    *  @note  For any given actual character type, this definition is
  55    *  probably wrong.
  56    *
  57    *  See http://gcc.gnu.org/onlinedocs/libstdc++/21_strings/howto.html#5
  58    *  for advice on how to make use of this class for "unusual" character
  59    *  types. Also, check out include/ext/pod_char_traits.h.
  60   */
  61   template<class _CharT>
  62     struct char_traits
  63     {
  64       typedef _CharT            char_type;
  65       typedef unsigned long     int_type;
  66       typedef streampos         pos_type;
  67       typedef streamoff         off_type;
  68       typedef mbstate_t         state_type;
  69
  70       static void
  71       assign(char_type& __c1, const char_type& __c2);
  72
  73       static bool
  74       eq(const char_type& __c1, const char_type& __c2);
  75
  76       static bool
  77       lt(const char_type& __c1, const char_type& __c2);
  78
  79       static int
  80       compare(const char_type* __s1, const char_type* __s2, size_t __n);
  81
  82       static size_t
  83       length(const char_type* __s);
  84
  85       static const char_type*
  86       find(const char_type* __s, size_t __n, const char_type& __a);
  87
  88       static char_type*
  89       move(char_type* __s1, const char_type* __s2, size_t __n);
  90
  91       static char_type*
  92       copy(char_type* __s1, const char_type* __s2, size_t __n);
  93
  94       static char_type*
  95       assign(char_type* __s, size_t __n, char_type __a);
  96
  97       static char_type
  98       to_char_type(const int_type& __c);
  99
 100       static int_type
 101       to_int_type(const char_type& __c);
 102
 103       static bool
 104       eq_int_type(const int_type& __c1, const int_type& __c2);
 105
 106       static int_type
 107       eof();
 108
 109       static int_type
 110       not_eof(const int_type& __c);
 111     };
 112
 113
 114   /// 21.1.3.1  char_traits specializations
 115   template<>
 116     struct char_traits<char>
 117     {
 118       typedef char              char_type;
 119       typedef int               int_type;
 120       typedef streampos         pos_type;
 121       typedef streamoff         off_type;
 122       typedef mbstate_t         state_type;
 123
 124       static void
 125       assign(char_type& __c1, const char_type& __c2)
 126       { __c1 = __c2; }
 127
 128       static bool
 129       eq(const char_type& __c1, const char_type& __c2)
 130       { return __c1 == __c2; }
 131
 132       static bool
 133       lt(const char_type& __c1, const char_type& __c2)
 134       { return __c1 < __c2; }
 135
 136       static int
 137       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 138       { return memcmp(__s1, __s2, __n); }
 139
 140       static size_t
 141       length(const char_type* __s)
 142       { return strlen(__s); }
 143
 144       static const char_type*
 145       find(const char_type* __s, size_t __n, const char_type& __a)
 146       { return static_cast<const char_type*>(memchr(__s, __a, __n)); }
 147
 148       static char_type*
 149       move(char_type* __s1, const char_type* __s2, size_t __n)
 150       { return static_cast<char_type*>(memmove(__s1, __s2, __n)); }
 151
 152       static char_type*
 153       copy(char_type* __s1, const char_type* __s2, size_t __n)
 154       { return static_cast<char_type*>(memcpy(__s1, __s2, __n)); }
 155
 156       static char_type*
 157       assign(char_type* __s, size_t __n, char_type __a)
 158       { return static_cast<char_type*>(memset(__s, __a, __n)); }
 159
 160       static char_type
 161       to_char_type(const int_type& __c)
 162       { return static_cast<char_type>(__c); }
 163
 164       // To keep both the byte 0xff and the eof symbol 0xffffffff
 165       // from ending up as 0xffffffff.
 166       static int_type
 167       to_int_type(const char_type& __c)
 168       { return static_cast<int_type>(static_cast<unsigned char>(__c)); }
 169
 170       static bool
 171       eq_int_type(const int_type& __c1, const int_type& __c2)
 172       { return __c1 == __c2; }
 173
 174       static int_type
 175       eof() { return static_cast<int_type>(EOF); }
 176
 177       static int_type
 178       not_eof(const int_type& __c)
 179       { return (__c == eof()) ? 0 : __c; }
 180   };
 181
 182
 183 #ifdef _GLIBCXX_USE_WCHAR_T
 184   /// 21.1.3.2  char_traits specializations
 185   template<>
 186     struct char_traits<wchar_t>
 187     {
 188       typedef wchar_t           char_type;
 189       typedef wint_t            int_type;
 190       typedef streamoff         off_type;
 191       typedef wstreampos        pos_type;
 192       typedef mbstate_t         state_type;
 193
 194       static void
 195       assign(char_type& __c1, const char_type& __c2)
 196       { __c1 = __c2; }
 197
 198       static bool
 199       eq(const char_type& __c1, const char_type& __c2)
 200       { return __c1 == __c2; }
 201
 202       static bool
 203       lt(const char_type& __c1, const char_type& __c2)
 204       { return __c1 < __c2; }
 205
 206       static int
 207       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 208       { return wmemcmp(__s1, __s2, __n); }
 209
 210       static size_t
 211       length(const char_type* __s)
 212       { return wcslen(__s); }
 213
 214       static const char_type*
 215       find(const char_type* __s, size_t __n, const char_type& __a)
 216       { return wmemchr(__s, __a, __n); }
 217
 218       static char_type*
 219       move(char_type* __s1, const char_type* __s2, int_type __n)
 220       { return wmemmove(__s1, __s2, __n); }
 221
 222       static char_type*
 223       copy(char_type* __s1, const char_type* __s2, size_t __n)
 224       { return wmemcpy(__s1, __s2, __n); }
 225
 226       static char_type*
 227       assign(char_type* __s, size_t __n, char_type __a)
 228       { return wmemset(__s, __a, __n); }
 229
 230       static char_type
 231       to_char_type(const int_type& __c) { return char_type(__c); }
 232
 233       static int_type
 234       to_int_type(const char_type& __c) { return int_type(__c); }
 235
 236       static bool
 237       eq_int_type(const int_type& __c1, const int_type& __c2)
 238       { return __c1 == __c2; }
 239
 240       static int_type
 241       eof() { return static_cast<int_type>(WEOF); }
 242
 243       static int_type
 244       not_eof(const int_type& __c)
 245       { return eq_int_type(__c, eof()) ? 0 : __c; }
 246   };
 247 #endif //_GLIBCXX_USE_WCHAR_T
 248
 249   template<typename _CharT, typename _Traits>
 250     struct _Char_traits_match
 251     {
 252       _CharT _M_c;
 253       _Char_traits_match(_CharT const& __c) : _M_c(__c) { }
 254
 255       bool
 256       operator()(_CharT const& __a) { return _Traits::eq(_M_c, __a); }
 257     };
 258 } // namespace std
 259
 260 #endif