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       1             : // Position types -*- C++ -*-
       2             : 
       3             : // Copyright (C) 1997-2019 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 3, 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             : // Under Section 7 of GPL version 3, you are granted additional
      17             : // permissions described in the GCC Runtime Library Exception, version
      18             : // 3.1, as published by the Free Software Foundation.
      19             : 
      20             : // You should have received a copy of the GNU General Public License and
      21             : // a copy of the GCC Runtime Library Exception along with this program;
      22             : // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
      23             : // <http://www.gnu.org/licenses/>.
      24             : 
      25             : /** @file bits/postypes.h
      26             :  *  This is an internal header file, included by other library headers.
      27             :  *  Do not attempt to use it directly. @headername{iosfwd}
      28             :  */
      29             : 
      30             : //
      31             : // ISO C++ 14882: 27.4.1 - Types
      32             : // ISO C++ 14882: 27.4.3 - Template class fpos
      33             : //
      34             : 
      35             : #ifndef _GLIBCXX_POSTYPES_H
      36             : #define _GLIBCXX_POSTYPES_H 1
      37             : 
      38             : #pragma GCC system_header
      39             : 
      40             : #include <cwchar> // For mbstate_t
      41             : 
      42             : // XXX If <stdint.h> is really needed, make sure to define the macros
      43             : // before including it, in order not to break <tr1/cstdint> (and <cstdint>
      44             : // in C++11).  Reconsider all this as soon as possible...
      45             : #if (defined(_GLIBCXX_HAVE_INT64_T) && !defined(_GLIBCXX_HAVE_INT64_T_LONG) \
      46             :      && !defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG))
      47             : 
      48             : #ifndef __STDC_LIMIT_MACROS
      49             : # define _UNDEF__STDC_LIMIT_MACROS
      50             : # define __STDC_LIMIT_MACROS
      51             : #endif
      52             : #ifndef __STDC_CONSTANT_MACROS
      53             : # define _UNDEF__STDC_CONSTANT_MACROS
      54             : # define __STDC_CONSTANT_MACROS
      55             : #endif
      56             : #include <stdint.h> // For int64_t
      57             : #ifdef _UNDEF__STDC_LIMIT_MACROS
      58             : # undef __STDC_LIMIT_MACROS
      59             : # undef _UNDEF__STDC_LIMIT_MACROS
      60             : #endif
      61             : #ifdef _UNDEF__STDC_CONSTANT_MACROS
      62             : # undef __STDC_CONSTANT_MACROS
      63             : # undef _UNDEF__STDC_CONSTANT_MACROS
      64             : #endif
      65             : 
      66             : #endif
      67             : 
      68             : namespace std _GLIBCXX_VISIBILITY(default)
      69             : {
      70             : _GLIBCXX_BEGIN_NAMESPACE_VERSION
      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           0 :       fpos(streamoff __off)
     134           0 :       : _M_off(__off), _M_state() { }
     135             : 
     136             : #if __cplusplus >= 201103L
     137             :       fpos(const fpos&) = default;
     138             :       fpos& operator=(const fpos&) = default;
     139             :       ~fpos() = default;
     140             : #endif
     141             : 
     142             :       /// Convert to streamoff.
     143          35 :       operator streamoff() const { return _M_off; }
     144             : 
     145             :       /// Remember the value of @a st.
     146             :       void
     147             :       state(_StateT __st)
     148             :       { _M_state = __st; }
     149             : 
     150             :       /// Return the last set value of @a st.
     151             :       _StateT
     152             :       state() const
     153             :       { return _M_state; }
     154             : 
     155             :       // The standard requires that this operator must be defined, but
     156             :       // gives no semantics. In this implementation it just adds its
     157             :       // argument to the stored offset and returns *this.
     158             :       /// Add offset to this position.
     159             :       fpos&
     160             :       operator+=(streamoff __off)
     161             :       {
     162             :         _M_off += __off;
     163             :         return *this;
     164             :       }
     165             : 
     166             :       // The standard requires that this operator must be defined, but
     167             :       // gives no semantics. In this implementation it just subtracts
     168             :       // its argument from the stored offset and returns *this.
     169             :       /// Subtract offset from this position.
     170             :       fpos&
     171             :       operator-=(streamoff __off)
     172             :       {
     173             :         _M_off -= __off;
     174             :         return *this;
     175             :       }
     176             : 
     177             :       // The standard requires that this operator must be defined, but
     178             :       // defines its semantics only in terms of operator-. In this
     179             :       // implementation it constructs a copy of *this, adds the
     180             :       // argument to that copy using operator+= and then returns the
     181             :       // copy.
     182             :       /// Add position and offset.
     183             :       fpos
     184             :       operator+(streamoff __off) const
     185             :       {
     186             :         fpos __pos(*this);
     187             :         __pos += __off;
     188             :         return __pos;
     189             :       }
     190             : 
     191             :       // The standard requires that this operator must be defined, but
     192             :       // defines its semantics only in terms of operator+. In this
     193             :       // implementation it constructs a copy of *this, subtracts the
     194             :       // argument from that copy using operator-= and then returns the
     195             :       // copy.
     196             :       /// Subtract offset from position.
     197             :       fpos
     198             :       operator-(streamoff __off) const
     199             :       {
     200             :         fpos __pos(*this);
     201             :         __pos -= __off;
     202             :         return __pos;
     203             :       }
     204             : 
     205             :       // The standard requires that this operator must be defined, but
     206             :       // defines its semantics only in terms of operator+. In this
     207             :       // implementation it returns the difference between the offset
     208             :       // stored in *this and in the argument.
     209             :       /// Subtract position to return offset.
     210             :       streamoff
     211             :       operator-(const fpos& __other) const
     212             :       { return _M_off - __other._M_off; }
     213             :     };
     214             : 
     215             :   // The standard only requires that operator== must be an
     216             :   // equivalence relation. In this implementation two fpos<StateT>
     217             :   // objects belong to the same equivalence class if the contained
     218             :   // offsets compare equal.
     219             :   /// Test if equivalent to another position.
     220             :   template<typename _StateT>
     221             :     inline bool
     222             :     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
     223             :     { return streamoff(__lhs) == streamoff(__rhs); }
     224             : 
     225             :   template<typename _StateT>
     226             :     inline bool
     227             :     operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
     228             :     { return streamoff(__lhs) != streamoff(__rhs); }
     229             : 
     230             :   // Clauses 21.1.3.1 and 21.1.3.2 describe streampos and wstreampos
     231             :   // as implementation defined types, but clause 27.2 requires that
     232             :   // they must both be typedefs for fpos<mbstate_t>
     233             :   /// File position for char streams.
     234             :   typedef fpos<mbstate_t> streampos;
     235             :   /// File position for wchar_t streams.
     236             :   typedef fpos<mbstate_t> wstreampos;
     237             : 
     238             : #ifdef _GLIBCXX_USE_CHAR8_T
     239             :   /// File position for char8_t streams.
     240             :   typedef fpos<mbstate_t> u8streampos;
     241             : #endif
     242             : 
     243             : #if __cplusplus >= 201103L
     244             :   /// File position for char16_t streams.
     245             :   typedef fpos<mbstate_t> u16streampos;
     246             :   /// File position for char32_t streams.
     247             :   typedef fpos<mbstate_t> u32streampos;
     248             : #endif
     249             : 
     250             : _GLIBCXX_END_NAMESPACE_VERSION
     251             : } // namespace
     252             : 
     253             : #endif