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, 2009, 2010
   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 bits/postypes.h
  28  *  This is an internal header file, included by other library headers.
  29  *  Do not attempt to use it directly. @headername{iosfwd}
  30  */
  31
  32 //
  33 // ISO C++ 14882: 27.4.1 - Types
  34 // ISO C++ 14882: 27.4.3 - Template class fpos
  35 //
  36
  37 #ifndef _GLIBCXX_POSTYPES_H
  38 #define _GLIBCXX_POSTYPES_H 1
  39
  40 #pragma GCC system_header
  41
  42 #include <cwchar> // For mbstate_t
  43
  44 // XXX If <stdint.h> is really needed, make sure to define the macros
  45 // before including it, in order not to break <tr1/cstdint> (and <cstdint>
  46 // in C++0x).  Reconsider all this as soon as possible...
  47 #if (defined(_GLIBCXX_HAVE_INT64_T) && !defined(_GLIBCXX_HAVE_INT64_T_LONG) \
  48      && !defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG))
  49
  50 #ifndef __STDC_LIMIT_MACROS
  51 # define _UNDEF__STDC_LIMIT_MACROS
  52 # define __STDC_LIMIT_MACROS
  53 #endif
  54 #ifndef __STDC_CONSTANT_MACROS
  55 # define _UNDEF__STDC_CONSTANT_MACROS
  56 # define __STDC_CONSTANT_MACROS
  57 #endif
  58 #include <stdint.h> // For int64_t
  59 #ifdef _UNDEF__STDC_LIMIT_MACROS
  60 # undef __STDC_LIMIT_MACROS
  61 # undef _UNDEF__STDC_LIMIT_MACROS
  62 #endif
  63 #ifdef _UNDEF__STDC_CONSTANT_MACROS
  64 # undef __STDC_CONSTANT_MACROS
  65 # undef _UNDEF__STDC_CONSTANT_MACROS
  66 #endif
  67
  68 #endif
  69
  70 _GLIBCXX_BEGIN_NAMESPACE(std)
  71
  72   // The types streamoff, streampos and wstreampos and the class
  73   // template fpos<> are described in clauses 21.1.2, 21.1.3, 27.1.2,
  74   // 27.2, 27.4.1, 27.4.3 and D.6. Despite all this verbiage, the
  75   // behaviour of these types is mostly implementation defined or
  76   // unspecified. The behaviour in this implementation is as noted
  77   // below.
  78
  79   /**
  80    *  @brief  Type used by fpos, char_traits<char>, and char_traits<wchar_t>.
  81    *
  82    *  In clauses 21.1.3.1 and 27.4.1 streamoff is described as an
  83    *  implementation defined type.
  84    *  Note: In versions of GCC up to and including GCC 3.3, streamoff
  85    *  was typedef long.
  86   */
  87 #ifdef _GLIBCXX_HAVE_INT64_T_LONG
  88   typedef long          streamoff;
  89 #elif defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG)
  90   typedef long long     streamoff;
  91 #elif defined(_GLIBCXX_HAVE_INT64_T)
  92   typedef int64_t       streamoff;
  93 #else
  94   typedef long long     streamoff;
  95 #endif
  96
  97   /// Integral type for I/O operation counts and buffer sizes.
  98   typedef ptrdiff_t     streamsize; // Signed integral type
  99
 100   /**
 101    *  @brief  Class representing stream positions.
 102    *
 103    *  The standard places no requirements upon the template parameter StateT.
 104    *  In this implementation StateT must be DefaultConstructible,
 105    *  CopyConstructible and Assignable.  The standard only requires that fpos
 106    *  should contain a member of type StateT. In this implementation it also
 107    *  contains an offset stored as a signed integer.
 108    *
 109    *  @param  StateT  Type passed to and returned from state().
 110    */
 111   template<typename _StateT>
 112     class fpos
 113     {
 114     private:
 115       streamoff                 _M_off;
 116       _StateT                   _M_state;
 117
 118     public:
 119       // The standard doesn't require that fpos objects can be default
 120       // constructed. This implementation provides a default
 121       // constructor that initializes the offset to 0 and default
 122       // constructs the state.
 123       fpos()
 124       : _M_off(0), _M_state() { }
 125
 126       // The standard requires that fpos objects can be constructed
 127       // from streamoff objects using the constructor syntax, and
 128       // fails to give any meaningful semantics. In this
 129       // implementation implicit conversion is also allowed, and this
 130       // constructor stores the streamoff as the offset and default
 131       // constructs the state.
 132       /// Construct position from offset.
 133       fpos(streamoff __off)
 134       : _M_off(__off), _M_state() { }
 135
 136       /// Convert to streamoff.
 137       operator streamoff() const { return _M_off; }
 138
 139       /// Remember the value of @a st.
 140       void
 141       state(_StateT __st)
 142       { _M_state = __st; }
 143
 144       /// Return the last set value of @a st.
 145       _StateT
 146       state() const
 147       { return _M_state; }
 148
 149       // The standard requires that this operator must be defined, but
 150       // gives no semantics. In this implementation it just adds its
 151       // argument to the stored offset and returns *this.
 152       /// Add offset to this position.
 153       fpos&
 154       operator+=(streamoff __off)
 155       {
 156         _M_off += __off;
 157         return *this;
 158       }
 159
 160       // The standard requires that this operator must be defined, but
 161       // gives no semantics. In this implementation it just subtracts
 162       // its argument from the stored offset and returns *this.
 163       /// Subtract offset from this position.
 164       fpos&
 165       operator-=(streamoff __off)
 166       {
 167         _M_off -= __off;
 168         return *this;
 169       }
 170
 171       // The standard requires that this operator must be defined, but
 172       // defines its semantics only in terms of operator-. In this
 173       // implementation it constructs a copy of *this, adds the
 174       // argument to that copy using operator+= and then returns the
 175       // copy.
 176       /// Add position and offset.
 177       fpos
 178       operator+(streamoff __off) const
 179       {
 180         fpos __pos(*this);
 181         __pos += __off;
 182         return __pos;
 183       }
 184
 185       // The standard requires that this operator must be defined, but
 186       // defines its semantics only in terms of operator+. In this
 187       // implementation it constructs a copy of *this, subtracts the
 188       // argument from that copy using operator-= and then returns the
 189       // copy.
 190       /// Subtract offset from position.
 191       fpos
 192       operator-(streamoff __off) const
 193       {
 194         fpos __pos(*this);
 195         __pos -= __off;
 196         return __pos;
 197       }
 198
 199       // The standard requires that this operator must be defined, but
 200       // defines its semantics only in terms of operator+. In this
 201       // implementation it returns the difference between the offset
 202       // stored in *this and in the argument.
 203       /// Subtract position to return offset.
 204       streamoff
 205       operator-(const fpos& __other) const
 206       { return _M_off - __other._M_off; }
 207     };
 208
 209   // The standard only requires that operator== must be an
 210   // equivalence relation. In this implementation two fpos<StateT>
 211   // objects belong to the same equivalence class if the contained
 212   // offsets compare equal.
 213   /// Test if equivalent to another position.
 214   template<typename _StateT>
 215     inline bool
 216     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
 217     { return streamoff(__lhs) == streamoff(__rhs); }
 218
 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   // Clauses 21.1.3.1 and 21.1.3.2 describe streampos and wstreampos
 225   // as implementation defined types, but clause 27.2 requires that
 226   // they must both be typedefs for fpos<mbstate_t>
 227   /// File position for char streams.
 228   typedef fpos<mbstate_t> streampos;
 229   /// File position for wchar_t streams.
 230   typedef fpos<mbstate_t> wstreampos;
 231
 232 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 233   /// File position for char16_t streams.
 234   typedef fpos<mbstate_t> u16streampos;
 235   /// File position for char32_t streams.
 236   typedef fpos<mbstate_t> u32streampos;
 237 #endif
 238
 239 _GLIBCXX_END_NAMESPACE
 240
 241 #endif