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.
  60   */
  61   template<class _CharT>
  62     struct char_traits
  63     {
  64       typedef _CharT            char_type;
  65       // Unsigned as wint_t is unsigned.
  66       typedef unsigned long     int_type;
  67       typedef streampos         pos_type;
  68       typedef streamoff         off_type;
  69       typedef mbstate_t         state_type;
  70
  71       static void
  72       assign(char_type& __c1, const char_type& __c2);
  73
  74       static bool
  75       eq(const char_type& __c1, const char_type& __c2);
  76
  77       static bool
  78       lt(const char_type& __c1, const char_type& __c2);
  79
  80       static int
  81       compare(const char_type* __s1, const char_type* __s2, size_t __n);
  82
  83       static size_t
  84       length(const char_type* __s);
  85
  86       static const char_type*
  87       find(const char_type* __s, size_t __n, const char_type& __a);
  88
  89       static char_type*
  90       move(char_type* __s1, const char_type* __s2, size_t __n);
  91
  92       static char_type*
  93       copy(char_type* __s1, const char_type* __s2, size_t __n);
  94
  95       static char_type*
  96       assign(char_type* __s, size_t __n, char_type __a);
  97
  98       static char_type
  99       to_char_type(const int_type& __c);
 100
 101       static int_type
 102       to_int_type(const char_type& __c);
 103
 104       static bool
 105       eq_int_type(const int_type& __c1, const int_type& __c2);
 106
 107       static int_type
 108       eof();
 109
 110       static int_type
 111       not_eof(const int_type& __c);
 112     };
 113
 114
 115   /// 21.1.3.1  char_traits specializations
 116   template<>
 117     struct char_traits<char>
 118     {
 119       typedef char              char_type;
 120       typedef int               int_type;
 121       typedef streampos         pos_type;
 122       typedef streamoff         off_type;
 123       typedef mbstate_t         state_type;
 124
 125       static void
 126       assign(char_type& __c1, const char_type& __c2)
 127       { __c1 = __c2; }
 128
 129       static bool
 130       eq(const char_type& __c1, const char_type& __c2)
 131       { return __c1 == __c2; }
 132
 133       static bool
 134       lt(const char_type& __c1, const char_type& __c2)
 135       { return __c1 < __c2; }
 136
 137       static int
 138       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 139       { return memcmp(__s1, __s2, __n); }
 140
 141       static size_t
 142       length(const char_type* __s)
 143       { return strlen(__s); }
 144
 145       static const char_type*
 146       find(const char_type* __s, size_t __n, const char_type& __a)
 147       { return static_cast<const char_type*>(memchr(__s, __a, __n)); }
 148
 149       static char_type*
 150       move(char_type* __s1, const char_type* __s2, size_t __n)
 151       { return static_cast<char_type*>(memmove(__s1, __s2, __n)); }
 152
 153       static char_type*
 154       copy(char_type* __s1, const char_type* __s2, size_t __n)
 155       {  return static_cast<char_type*>(memcpy(__s1, __s2, __n)); }
 156
 157       static char_type*
 158       assign(char_type* __s, size_t __n, char_type __a)
 159       { return static_cast<char_type*>(memset(__s, __a, __n)); }
 160
 161       static char_type
 162       to_char_type(const int_type& __c)
 163       { return static_cast<char_type>(__c); }
 164
 165       // To keep both the byte 0xff and the eof symbol 0xffffffff
 166       // from ending up as 0xffffffff.
 167       static int_type
 168       to_int_type(const char_type& __c)
 169       { return static_cast<int_type>(static_cast<unsigned char>(__c)); }
 170
 171       static bool
 172       eq_int_type(const int_type& __c1, const int_type& __c2)
 173       { return __c1 == __c2; }
 174
 175       static int_type
 176       eof() { return static_cast<int_type>(EOF); }
 177
 178       static int_type
 179       not_eof(const int_type& __c)
 180       { return (__c == eof()) ? 0 : __c; }
 181   };
 182
 183
 184 #ifdef _GLIBCXX_USE_WCHAR_T
 185   /// 21.1.3.2  char_traits specializations
 186   template<>
 187     struct char_traits<wchar_t>
 188     {
 189       typedef wchar_t           char_type;
 190       typedef wint_t            int_type;
 191       typedef streamoff         off_type;
 192       typedef wstreampos        pos_type;
 193       typedef mbstate_t         state_type;
 194
 195       static void
 196       assign(char_type& __c1, const char_type& __c2)
 197       { __c1 = __c2; }
 198
 199       static bool
 200       eq(const char_type& __c1, const char_type& __c2)
 201       { return __c1 == __c2; }
 202
 203       static bool
 204       lt(const char_type& __c1, const char_type& __c2)
 205       { return __c1 < __c2; }
 206
 207       static int
 208       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 209       { return wmemcmp(__s1, __s2, __n); }
 210
 211       static size_t
 212       length(const char_type* __s)
 213       { return wcslen(__s); }
 214
 215       static const char_type*
 216       find(const char_type* __s, size_t __n, const char_type& __a)
 217       { return wmemchr(__s, __a, __n); }
 218
 219       static char_type*
 220       move(char_type* __s1, const char_type* __s2, int_type __n)
 221       { return wmemmove(__s1, __s2, __n); }
 222
 223       static char_type*
 224       copy(char_type* __s1, const char_type* __s2, size_t __n)
 225       { return wmemcpy(__s1, __s2, __n); }
 226
 227       static char_type*
 228       assign(char_type* __s, size_t __n, char_type __a)
 229       { return wmemset(__s, __a, __n); }
 230
 231       static char_type
 232       to_char_type(const int_type& __c) { return char_type(__c); }
 233
 234       static int_type
 235       to_int_type(const char_type& __c) { return int_type(__c); }
 236
 237       static bool
 238       eq_int_type(const int_type& __c1, const int_type& __c2)
 239       { return __c1 == __c2; }
 240
 241       static int_type
 242       eof() { return static_cast<int_type>(WEOF); }
 243
 244       static int_type
 245       not_eof(const int_type& __c)
 246       { return eq_int_type(__c, eof()) ? 0 : __c; }
 247   };
 248 #endif //_GLIBCXX_USE_WCHAR_T
 249
 250   template<typename _CharT, typename _Traits>
 251     struct _Char_traits_match
 252     {
 253       _CharT _M_c;
 254       _Char_traits_match(_CharT const& __c) : _M_c(__c) { }
 255
 256       bool
 257       operator()(_CharT const& __a) { return _Traits::eq(_M_c, __a); }
 258     };
 259 } // namespace std
 260
 261 #endif