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 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 2, 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 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 //
  31 // ISO C++ 14882: 21  Strings library
  32 //
  33
  34 /** @file char_traits.h
  35  *  This is an internal header file, included by other library headers.
  36  *  You should not attempt to use it directly.
  37  */
  38
  39 #ifndef _CPP_BITS_CHAR_TRAITS_H
  40 #define _CPP_BITS_CHAR_TRAITS_H 1
  41
  42 #pragma GCC system_header
  43
  44 #include <cstring>      // For memmove, memset, memchr
  45 #include <bits/fpos.h>          // For streampos
  46
  47 namespace std
  48 {
  49   // 21.1.2
  50   /**
  51    *  @brief  Basis for explicit traits specializations.
  52    *
  53    *  @note  For any given actual character type, this definition is
  54    *  probably wrong.
  55   */
  56   template<class _CharT>
  57     struct char_traits
  58     {
  59       typedef _CharT            char_type;
  60       // Unsigned as wint_t in unsigned.
  61       typedef unsigned long     int_type;
  62       typedef streampos         pos_type;
  63       typedef streamoff         off_type;
  64       typedef mbstate_t         state_type;
  65
  66       static void
  67       assign(char_type& __c1, const char_type& __c2)
  68       { __c1 = __c2; }
  69
  70       static bool
  71       eq(const char_type& __c1, const char_type& __c2)
  72       { return __c1 == __c2; }
  73
  74       static bool
  75       lt(const char_type& __c1, const char_type& __c2)
  76       { return __c1 < __c2; }
  77
  78       static int
  79       compare(const char_type* __s1, const char_type* __s2, size_t __n)
  80       {
  81         for (size_t __i = 0; __i < __n; ++__i)
  82           if (!eq(__s1[__i], __s2[__i]))
  83             return lt(__s1[__i], __s2[__i]) ? -1 : 1;
  84         return 0;
  85       }
  86
  87       static size_t
  88       length(const char_type* __s)
  89       {
  90         const char_type* __p = __s;
  91         while (*__p) ++__p;
  92         return (__p - __s);
  93       }
  94
  95       static const char_type*
  96       find(const char_type* __s, size_t __n, const char_type& __a)
  97       {
  98         for (const char_type* __p = __s; size_t(__p - __s) < __n; ++__p)
  99           if (*__p == __a) return __p;
 100         return 0;
 101       }
 102
 103       static char_type*
 104       move(char_type* __s1, const char_type* __s2, size_t __n)
 105       { return (char_type*) memmove(__s1, __s2, __n * sizeof(char_type)); }
 106
 107       static char_type*
 108       copy(char_type* __s1, const char_type* __s2, size_t __n)
 109       { return (char_type*) memcpy(__s1, __s2, __n * sizeof(char_type)); }
 110
 111       static char_type*
 112       assign(char_type* __s, size_t __n, char_type __a)
 113       {
 114         for (char_type* __p = __s; __p < __s + __n; ++__p)
 115           assign(*__p, __a);
 116         return __s;
 117       }
 118
 119       static char_type
 120       to_char_type(const int_type& __c)
 121       { return char_type(__c); }
 122
 123       static int_type
 124       to_int_type(const char_type& __c) { return int_type(__c); }
 125
 126       static bool
 127       eq_int_type(const int_type& __c1, const int_type& __c2)
 128       { return __c1 == __c2; }
 129
 130       static int_type
 131       eof() { return static_cast<int_type>(-1); }
 132
 133       static int_type
 134       not_eof(const int_type& __c)
 135       { return eq_int_type(__c, eof()) ? int_type(0) : __c; }
 136     };
 137
 138
 139   /// 21.1.4  char_traits specializations
 140   template<>
 141     struct char_traits<char>
 142     {
 143       typedef char              char_type;
 144       typedef int               int_type;
 145       typedef streampos         pos_type;
 146       typedef streamoff         off_type;
 147       typedef mbstate_t         state_type;
 148
 149       static void
 150       assign(char_type& __c1, const char_type& __c2)
 151       { __c1 = __c2; }
 152
 153       static bool
 154       eq(const char_type& __c1, const char_type& __c2)
 155       { return __c1 == __c2; }
 156
 157       static bool
 158       lt(const char_type& __c1, const char_type& __c2)
 159       { return __c1 < __c2; }
 160
 161       static int
 162       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 163       { return memcmp(__s1, __s2, __n); }
 164
 165       static size_t
 166       length(const char_type* __s)
 167       { return strlen(__s); }
 168
 169       static const char_type*
 170       find(const char_type* __s, size_t __n, const char_type& __a)
 171       { return static_cast<const char_type*>(memchr(__s, __a, __n)); }
 172
 173       static char_type*
 174       move(char_type* __s1, const char_type* __s2, size_t __n)
 175       { return static_cast<char_type*>(memmove(__s1, __s2, __n)); }
 176
 177       static char_type*
 178       copy(char_type* __s1, const char_type* __s2, size_t __n)
 179       {  return static_cast<char_type*>(memcpy(__s1, __s2, __n)); }
 180
 181       static char_type*
 182       assign(char_type* __s, size_t __n, char_type __a)
 183       { return static_cast<char_type*>(memset(__s, __a, __n)); }
 184
 185       static char_type
 186       to_char_type(const int_type& __c)
 187       { return static_cast<char_type>(__c); }
 188
 189       // To keep both the byte 0xff and the eof symbol 0xffffffff
 190       // from ending up as 0xffffffff.
 191       static int_type
 192       to_int_type(const char_type& __c)
 193       { return static_cast<int_type>(static_cast<unsigned char>(__c)); }
 194
 195       static bool
 196       eq_int_type(const int_type& __c1, const int_type& __c2)
 197       { return __c1 == __c2; }
 198
 199       static int_type
 200       eof() { return static_cast<int_type>(EOF); }
 201
 202       static int_type
 203       not_eof(const int_type& __c)
 204       { return (__c == eof()) ? 0 : __c; }
 205   };
 206
 207
 208 #ifdef _GLIBCPP_USE_WCHAR_T
 209   template<>
 210     struct char_traits<wchar_t>
 211     {
 212       typedef wchar_t           char_type;
 213       typedef wint_t            int_type;
 214       typedef streamoff         off_type;
 215       typedef wstreampos        pos_type;
 216       typedef mbstate_t         state_type;
 217
 218       static void
 219       assign(char_type& __c1, const char_type& __c2)
 220       { __c1 = __c2; }
 221
 222       static bool
 223       eq(const char_type& __c1, const char_type& __c2)
 224       { return __c1 == __c2; }
 225
 226       static bool
 227       lt(const char_type& __c1, const char_type& __c2)
 228       { return __c1 < __c2; }
 229
 230       static int
 231       compare(const char_type* __s1, const char_type* __s2, size_t __n)
 232       { return wmemcmp(__s1, __s2, __n); }
 233
 234       static size_t
 235       length(const char_type* __s)
 236       { return wcslen(__s); }
 237
 238       static const char_type*
 239       find(const char_type* __s, size_t __n, const char_type& __a)
 240       { return wmemchr(__s, __a, __n); }
 241
 242       static char_type*
 243       move(char_type* __s1, const char_type* __s2, int_type __n)
 244       { return wmemmove(__s1, __s2, __n); }
 245
 246       static char_type*
 247       copy(char_type* __s1, const char_type* __s2, size_t __n)
 248       { return wmemcpy(__s1, __s2, __n); }
 249
 250       static char_type*
 251       assign(char_type* __s, size_t __n, char_type __a)
 252       { return wmemset(__s, __a, __n); }
 253
 254       static char_type
 255       to_char_type(const int_type& __c) { return char_type(__c); }
 256
 257       static int_type
 258       to_int_type(const char_type& __c) { return int_type(__c); }
 259
 260       static bool
 261       eq_int_type(const int_type& __c1, const int_type& __c2)
 262       { return __c1 == __c2; }
 263
 264       static int_type
 265       eof() { return static_cast<int_type>(WEOF); }
 266
 267       static int_type
 268       not_eof(const int_type& __c)
 269       { return eq_int_type(__c, eof()) ? 0 : __c; }
 270   };
 271 #endif //_GLIBCPP_USE_WCHAR_T
 272
 273   template<typename _CharT, typename _Traits>
 274     struct _Char_traits_match
 275     {
 276       _CharT _M_c;
 277       _Char_traits_match(_CharT const& __c) : _M_c(__c) { }
 278
 279       bool
 280       operator()(_CharT const& __a) { return _Traits::eq(_M_c, __a); }
 281     };
 282 } // namespace std
 283
 284 #endif