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

   1 // Position types -*- C++ -*-
   2
   3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
   4 // 2006, 2007, 2008
   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 2, 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 // You should have received a copy of the GNU General Public License along
  19 // with this library; see the file COPYING.  If not, write to the Free
  20 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  21 // USA.
  22
  23 // As a special exception, you may use this file as part of a free software
  24 // library without restriction.  Specifically, if other files instantiate
  25 // templates or use macros or inline functions from this file, or you compile
  26 // this file and link it with other files to produce an executable, this
  27 // file does not by itself cause the resulting executable to be covered by
  28 // the GNU General Public License.  This exception does not however
  29 // invalidate any other reasons why the executable file might be covered by
  30 // the GNU General Public License.
  31
  32 /** @file postypes.h
  33  *  This is an internal header file, included by other library headers.
  34  *  You should not attempt to use it directly.
  35  */
  36
  37 //
  38 // ISO C++ 14882: 27.4.1 - Types
  39 // ISO C++ 14882: 27.4.3 - Template class fpos
  40 //
  41
  42 #ifndef _GLIBCXX_POSTYPES_H
  43 #define _GLIBCXX_POSTYPES_H 1
  44
  45 #pragma GCC system_header
  46
  47 #include <cwchar> // For mbstate_t
  48
  49 // XXX If <stdint.h> is really needed, make sure to define the macros
  50 // before including it, in order not to break <tr1/cstdint> (and <cstdint>
  51 // in C++0x).  Reconsider all this as soon as possible...
  52 #if (defined(_GLIBCXX_HAVE_INT64_T) && !defined(_GLIBCXX_HAVE_INT64_T_LONG) \
  53      && !defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG))
  54
  55 #ifndef __STDC_LIMIT_MACROS
  56 # define _UNDEF__STDC_LIMIT_MACROS
  57 # define __STDC_LIMIT_MACROS
  58 #endif
  59 #ifndef __STDC_CONSTANT_MACROS
  60 # define _UNDEF__STDC_CONSTANT_MACROS
  61 # define __STDC_CONSTANT_MACROS
  62 #endif
  63 #include <stdint.h> // For int64_t
  64 #ifdef _UNDEF__STDC_LIMIT_MACROS
  65 # undef __STDC_LIMIT_MACROS
  66 # undef _UNDEF__STDC_LIMIT_MACROS
  67 #endif
  68 #ifdef _UNDEF__STDC_CONSTANT_MACROS
  69 # undef __STDC_CONSTANT_MACROS
  70 # undef _UNDEF__STDC_CONSTANT_MACROS
  71 #endif
  72
  73 #endif
  74
  75 _GLIBCXX_BEGIN_NAMESPACE(std)
  76
  77   // The types streamoff, streampos and wstreampos and the class
  78   // template fpos<> are described in clauses 21.1.2, 21.1.3, 27.1.2,
  79   // 27.2, 27.4.1, 27.4.3 and D.6. Despite all this verbiage, the
  80   // behaviour of these types is mostly implementation defined or
  81   // unspecified. The behaviour in this implementation is as noted
  82   // below.
  83
  84   /**
  85    *  @brief  Type used by fpos, char_traits<char>, and char_traits<wchar_t>.
  86    *
  87    *  In clauses 21.1.3.1 and 27.4.1 streamoff is described as an
  88    *  implementation defined type.
  89    *  Note: In versions of GCC up to and including GCC 3.3, streamoff
  90    *  was typedef long.
  91   */
  92 #ifdef _GLIBCXX_HAVE_INT64_T_LONG
  93   typedef long          streamoff;
  94 #elif defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG)
  95   typedef long long     streamoff;
  96 #elif defined(_GLIBCXX_HAVE_INT64_T)
  97   typedef int64_t       streamoff;
  98 #else
  99   typedef long long     streamoff;
 100 #endif
 101
 102   /// Integral type for I/O operation counts and buffer sizes.
 103   typedef ptrdiff_t     streamsize; // Signed integral type
 104
 105   /**
 106    *  @brief  Class representing stream positions.
 107    *
 108    *  The standard places no requirements upon the template parameter StateT.
 109    *  In this implementation StateT must be DefaultConstructible,
 110    *  CopyConstructible and Assignable.  The standard only requires that fpos
 111    *  should contain a member of type StateT. In this implementation it also
 112    *  contains an offset stored as a signed integer.
 113    *
 114    *  @param  StateT  Type passed to and returned from state().
 115    */
 116   template<typename _StateT>
 117     class fpos
 118     {
 119     private:
 120       streamoff                 _M_off;
 121       _StateT                   _M_state;
 122
 123     public:
 124       // The standard doesn't require that fpos objects can be default
 125       // constructed. This implementation provides a default
 126       // constructor that initializes the offset to 0 and default
 127       // constructs the state.
 128       fpos()
 129       : _M_off(0), _M_state() { }
 130
 131       // The standard requires that fpos objects can be constructed
 132       // from streamoff objects using the constructor syntax, and
 133       // fails to give any meaningful semantics. In this
 134       // implementation implicit conversion is also allowed, and this
 135       // constructor stores the streamoff as the offset and default
 136       // constructs the state.
 137       /// Construct position from offset.
 138       fpos(streamoff __off)
 139       : _M_off(__off), _M_state() { }
 140
 141       /// Convert to streamoff.
 142       operator streamoff() const { return _M_off; }
 143
 144       /// Remember the value of @a st.
 145       void
 146       state(_StateT __st)
 147       { _M_state = __st; }
 148
 149       /// Return the last set value of @a st.
 150       _StateT
 151       state() const
 152       { return _M_state; }
 153
 154       // The standard requires that this operator must be defined, but
 155       // gives no semantics. In this implementation it just adds its
 156       // argument to the stored offset and returns *this.
 157       /// Add offset to this position.
 158       fpos&
 159       operator+=(streamoff __off)
 160       {
 161         _M_off += __off;
 162         return *this;
 163       }
 164
 165       // The standard requires that this operator must be defined, but
 166       // gives no semantics. In this implementation it just subtracts
 167       // its argument from the stored offset and returns *this.
 168       /// Subtract offset from this position.
 169       fpos&
 170       operator-=(streamoff __off)
 171       {
 172         _M_off -= __off;
 173         return *this;
 174       }
 175
 176       // The standard requires that this operator must be defined, but
 177       // defines its semantics only in terms of operator-. In this
 178       // implementation it constructs a copy of *this, adds the
 179       // argument to that copy using operator+= and then returns the
 180       // copy.
 181       /// Add position and offset.
 182       fpos
 183       operator+(streamoff __off) const
 184       {
 185         fpos __pos(*this);
 186         __pos += __off;
 187         return __pos;
 188       }
 189
 190       // The standard requires that this operator must be defined, but
 191       // defines its semantics only in terms of operator+. In this
 192       // implementation it constructs a copy of *this, subtracts the
 193       // argument from that copy using operator-= and then returns the
 194       // copy.
 195       /// Subtract offset from position.
 196       fpos
 197       operator-(streamoff __off) const
 198       {
 199         fpos __pos(*this);
 200         __pos -= __off;
 201         return __pos;
 202       }
 203
 204       // The standard requires that this operator must be defined, but
 205       // defines its semantics only in terms of operator+. In this
 206       // implementation it returns the difference between the offset
 207       // stored in *this and in the argument.
 208       /// Subtract position to return offset.
 209       streamoff
 210       operator-(const fpos& __other) const
 211       { return _M_off - __other._M_off; }
 212     };
 213
 214   // The standard only requires that operator== must be an
 215   // equivalence relation. In this implementation two fpos<StateT>
 216   // objects belong to the same equivalence class if the contained
 217   // offsets compare equal.
 218   /// Test if equivalent to another position.
 219   template<typename _StateT>
 220     inline bool
 221     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
 222     { return streamoff(__lhs) == streamoff(__rhs); }
 223
 224   template<typename _StateT>
 225     inline bool
 226     operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
 227     { return streamoff(__lhs) != streamoff(__rhs); }
 228
 229   // Clauses 21.1.3.1 and 21.1.3.2 describe streampos and wstreampos
 230   // as implementation defined types, but clause 27.2 requires that
 231   // they must both be typedefs for fpos<mbstate_t>
 232   /// File position for char streams.
 233   typedef fpos<mbstate_t> streampos;
 234   /// File position for wchar_t streams.
 235   typedef fpos<mbstate_t> wstreampos;
 236
 237 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 238   /// File position for char16_t streams.
 239   typedef fpos<mbstate_t> u16streampos;
 240   /// File position for char32_t streams.
 241   typedef fpos<mbstate_t> u32streampos;
 242 #endif
 243
 244 _GLIBCXX_END_NAMESPACE
 245
 246 #endif