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+// File based streams -*- C++ -*-
+
+// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003
+// Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 2, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING.  If not, write to the Free
+// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+// USA.
+
+// As a special exception, you may use this file as part of a free software
+// library without restriction.  Specifically, if other files instantiate
+// templates or use macros or inline functions from this file, or you compile
+// this file and link it with other files to produce an executable, this
+// file does not by itself cause the resulting executable to be covered by
+// the GNU General Public License.  This exception does not however
+// invalidate any other reasons why the executable file might be covered by
+// the GNU General Public License.
+
+//
+// ISO C++ 14882: 27.8  File-based streams
+//
+
+/** @file fstream
+ *  This is a Standard C++ Library header.  You should @c #include this header
+ *  in your programs, rather than any of the "st[dl]_*.h" implementation files.
+ */
+
+#ifndef _CPP_FSTREAM
+#define _CPP_FSTREAM	1
+
+#pragma GCC system_header
+
+#include <istream>
+#include <ostream>
+#include <locale>	// For codecvt
+#include <bits/basic_file.h>
+#include <bits/gthr.h>
+
+namespace std
+{
+  template<typename _CharT, typename _Traits>
+    class basic_filebuf : public basic_streambuf<_CharT, _Traits>
+    {
+    public:
+      // Types:
+      typedef _CharT                     	        char_type;
+      typedef _Traits                    	        traits_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+
+      // Non-standard Types:
+      typedef basic_streambuf<char_type, traits_type>  	__streambuf_type;
+      typedef basic_filebuf<char_type, traits_type>     __filebuf_type;
+      typedef __basic_file<char>		        __file_type;
+      typedef typename traits_type::state_type          __state_type;
+      typedef codecvt<char_type, char, __state_type>    __codecvt_type;
+      typedef typename __codecvt_type::result 	        __res_type;
+      typedef ctype<char_type>                          __ctype_type;
+
+      friend class ios_base; // For sync_with_stdio.
+
+    protected:
+      // Data Members:
+      // MT lock inherited from libio or other low-level io library.
+      __c_lock          	_M_lock;
+
+      // External buffer.
+      __file_type 		_M_file;
+
+      // Current and beginning state type for codecvt.
+      __state_type		_M_state_cur;
+      __state_type 		_M_state_beg;
+
+      // Set iff _M_buf is allocated memory from _M_allocate_internal_buffer.
+      bool			_M_buf_allocated;
+      
+      // XXX Needed?
+      bool			_M_last_overflowed;
+
+      // The position in the buffer corresponding to the external file
+      // pointer.
+      char_type*		_M_filepos;
+
+    public:
+      // Constructors/destructor:
+      basic_filebuf();
+
+      virtual
+      ~basic_filebuf()
+      {
+	this->close();
+	_M_last_overflowed = false;
+      }
+
+      // Members:
+      bool
+      is_open() const { return _M_file.is_open(); }
+
+      __filebuf_type*
+      open(const char* __s, ios_base::openmode __mode);
+
+      __filebuf_type*
+      close();
+
+    protected:
+      void
+      _M_allocate_internal_buffer();
+
+      void
+      _M_destroy_internal_buffer();
+
+      // Overridden virtual functions:
+      virtual streamsize
+      showmanyc();
+
+      // Stroustrup, 1998, p. 628
+      // underflow() and uflow() functions are called to get the next
+      // charater from the real input source when the buffer is empty.
+      // Buffered input uses underflow()
+
+      // The only difference between underflow() and uflow() is that the
+      // latter bumps _M_in_cur after the read.  In the sync_with_stdio
+      // case, this is important, as we need to unget the read character in
+      // the underflow() case in order to maintain synchronization.  So
+      // instead of calling underflow() from uflow(), we create a common
+      // subroutine to do the real work.
+      int_type
+      _M_underflow_common(bool __bump);
+
+      virtual int_type
+      underflow();
+
+      virtual int_type
+      uflow();
+
+      virtual int_type
+      pbackfail(int_type __c = _Traits::eof());
+
+      // NB: For what the standard expects of the overflow function,
+      // see _M_really_overflow(), below. Because basic_streambuf's
+      // sputc/sputn call overflow directly, and the complications of
+      // this implementation's setting of the initial pointers all
+      // equal to _M_buf when initializing, it seems essential to have
+      // this in actuality be a helper function that checks for the
+      // eccentricities of this implementation, and then call
+      // overflow() if indeed the buffer is full.
+      virtual int_type
+      overflow(int_type __c = _Traits::eof());
+
+      // Stroustrup, 1998, p 648
+      // The overflow() function is called to transfer characters to the
+      // real output destination when the buffer is full. A call to
+      // overflow(c) outputs the contents of the buffer plus the
+      // character c.
+      // 27.5.2.4.5
+      // Consume some sequence of the characters in the pending sequence.
+      int_type
+      _M_really_overflow(int_type __c = _Traits::eof());
+
+      // Convert internal byte sequence to external, char-based
+      // sequence via codecvt.
+      void
+      _M_convert_to_external(char_type*, streamsize, streamsize&, streamsize&);
+
+      virtual __streambuf_type*
+      setbuf(char_type* __s, streamsize __n);
+
+      virtual pos_type
+      seekoff(off_type __off, ios_base::seekdir __way,
+	      ios_base::openmode __mode = ios_base::in | ios_base::out);
+
+      virtual pos_type
+      seekpos(pos_type __pos,
+	      ios_base::openmode __mode = ios_base::in | ios_base::out);
+
+      virtual int
+      sync()
+      {
+	bool __testput = _M_out_cur && _M_out_beg < _M_out_end;
+
+	// Make sure that the internal buffer resyncs its idea of
+	// the file position with the external file.
+	if (__testput)
+	  {
+	    // Need to restore current position after the write.
+	    off_type __off = _M_out_cur - _M_out_end;
+	    _M_really_overflow(); // _M_file.sync() will be called within
+	    if (__off)
+	      _M_file.seekoff(__off, ios_base::cur);
+	  }
+	else
+	  _M_file.sync();
+	_M_last_overflowed = false;
+	return 0;
+      }
+
+      virtual void
+      imbue(const locale& __loc);
+
+      virtual streamsize
+      xsgetn(char_type* __s, streamsize __n)
+      {
+	streamsize __ret = 0;
+	// Clear out pback buffer before going on to the real deal...
+	if (_M_pback_init)
+	  {
+	    while (__ret < __n && _M_in_cur < _M_in_end)
+	      {
+		*__s = *_M_in_cur;
+		++__ret;
+		++__s;
+		++_M_in_cur;
+	      }
+	    _M_pback_destroy();
+	  }
+	if (__ret < __n)
+	  __ret += __streambuf_type::xsgetn(__s, __n - __ret);
+	return __ret;
+      }
+
+      virtual streamsize
+      xsputn(const char_type* __s, streamsize __n)
+      {
+	_M_pback_destroy();
+	return __streambuf_type::xsputn(__s, __n);
+      }
+
+      void
+      _M_output_unshift();
+
+      // These three functions are used to clarify internal buffer
+      // maintenance. After an overflow, or after a seekoff call that
+      // started at beg or end, or possibly when the stream becomes
+      // unbuffered, and a myrid other obscure corner cases, the
+      // internal buffer does not truly reflect the contents of the
+      // external buffer. At this point, for whatever reason, it is in
+      // an indeterminate state.
+      void
+      _M_set_indeterminate(void)
+      {
+	if (_M_mode & ios_base::in)
+	  this->setg(_M_buf, _M_buf, _M_buf);
+	if (_M_mode & ios_base::out)
+	  this->setp(_M_buf, _M_buf);
+	_M_filepos = _M_buf;
+      }
+
+      void
+      _M_set_determinate(off_type __off)
+      {
+	bool __testin = _M_mode & ios_base::in;
+	bool __testout = _M_mode & ios_base::out;
+	if (__testin)
+	  this->setg(_M_buf, _M_buf, _M_buf + __off);
+	if (__testout)
+	  this->setp(_M_buf, _M_buf + __off);
+	_M_filepos = _M_buf + __off;
+      }
+
+      bool
+      _M_is_indeterminate(void)
+      { 
+	bool __ret = false;
+	// Don't return true if unbuffered.
+	if (_M_buf)
+	  {
+	    if (_M_mode & ios_base::in)
+	      __ret = _M_in_beg == _M_in_cur && _M_in_cur == _M_in_end;
+	    if (_M_mode & ios_base::out)
+	      __ret = _M_out_beg == _M_out_cur && _M_out_cur == _M_out_end;
+	  }
+	return __ret;
+      }
+    };
+
+  // Explicit specializations.
+  template<> 
+    basic_filebuf<char>::int_type 
+    basic_filebuf<char>::_M_underflow_common(bool __bump);
+
+ #ifdef _GLIBCPP_USE_WCHAR_T
+  template<> 
+    basic_filebuf<wchar_t>::int_type 
+    basic_filebuf<wchar_t>::_M_underflow_common(bool __bump);
+ #endif
+
+  // Generic definitions.
+  template <typename _CharT, typename _Traits>
+    basic_filebuf<_CharT, _Traits>::int_type
+    basic_filebuf<_CharT, _Traits>::underflow() 
+    { return _M_underflow_common(false); }
+
+  template <typename _CharT, typename _Traits>
+    basic_filebuf<_CharT, _Traits>::int_type
+    basic_filebuf<_CharT, _Traits>::uflow() 
+    { return _M_underflow_common(true); }
+
+
+  // 27.8.1.5  Template class basic_ifstream
+  /**
+   *  Derivation of general input streams, specific to files.
+  */
+  template<typename _CharT, typename _Traits>
+    class basic_ifstream : public basic_istream<_CharT, _Traits>
+    {
+    public:
+      // Types:
+      typedef _CharT 					char_type;
+      typedef _Traits 					traits_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+
+      // Non-standard types:
+      typedef basic_filebuf<char_type, traits_type> 	__filebuf_type;
+      typedef basic_istream<char_type, traits_type>	__istream_type;
+
+    private:
+      __filebuf_type	_M_filebuf;
+
+    public:
+     // Constructors/Destructors:
+     /** Default constructor.  Create an input file stream.  */
+      basic_ifstream()
+      : __istream_type(NULL), _M_filebuf()
+      { this->init(&_M_filebuf); }
+
+      /**
+       *  @brief Create an input file stream.
+       *  @param  s  Null terminated string specifying filename.
+       *  @param  mode  Open file in specified mode (see std::ios_base).
+       *
+       *  Tip:  When using std::string to hold the filename, you must use
+       *  .c_str() before passing it to this constructor.
+      */
+      explicit
+      basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in)
+      : __istream_type(NULL), _M_filebuf()
+      {
+	this->init(&_M_filebuf);
+	this->open(__s, __mode);
+      }
+
+      ~basic_ifstream()
+      { }
+
+      // Members:
+      /**
+       *  @brief  Get a pointer to the file stream's buffer.
+       *  @return Pointer to basic_filebuf.
+      */
+      __filebuf_type*
+      rdbuf() const
+      { return const_cast<__filebuf_type*>(&_M_filebuf); }
+
+      bool
+      is_open() { return _M_filebuf.is_open(); }
+
+      void
+      open(const char* __s, ios_base::openmode __mode = ios_base::in)
+      {
+	if (!_M_filebuf.open(__s, __mode | ios_base::in))
+	  this->setstate(ios_base::failbit);
+      }
+
+      /** Close the file.  */
+      void
+      close()
+      {
+	if (!_M_filebuf.close())
+	  this->setstate(ios_base::failbit);
+      }
+    };
+
+
+  // 27.8.1.8  Template class basic_ofstream
+  /**
+   *  Derivation of general output streams, specific to files.
+  */
+  template<typename _CharT, typename _Traits>
+    class basic_ofstream : public basic_ostream<_CharT,_Traits>
+    {
+    public:
+      // Types:
+      typedef _CharT 					char_type;
+      typedef _Traits 					traits_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+
+      // Non-standard types:
+      typedef basic_filebuf<char_type, traits_type> 	__filebuf_type;
+      typedef basic_ostream<char_type, traits_type>	__ostream_type;
+
+    private:
+      __filebuf_type	_M_filebuf;
+
+    public:
+      // Constructors:
+      /** Default constructor for output file_stream.  */
+      basic_ofstream()
+      : __ostream_type(NULL), _M_filebuf()
+      { this->init(&_M_filebuf); }
+
+      /**
+       *  @brief  Create an output stream.
+       *  @param  s  Null terminated string specifying filename.
+       *  @param  mode  Open file in specified mode (see std::ios_base).
+       *
+       *  Tip:  When using std::string to hold the filename, you must use
+       *  .c_str() before passing it to this constructor.
+      */
+      explicit
+      basic_ofstream(const char* __s,
+		     ios_base::openmode __mode = ios_base::out|ios_base::trunc)
+      : __ostream_type(NULL), _M_filebuf()
+      {
+	this->init(&_M_filebuf);
+	this->open(__s, __mode);
+      }
+
+      ~basic_ofstream()
+      { }
+
+      // Members:
+      /**
+       *  @brief  Get a pointer to the file stream's buffer.
+       *  @return Pointer to basic_filebuf.
+      */
+      __filebuf_type*
+      rdbuf() const
+      { return const_cast<__filebuf_type*>(&_M_filebuf); }
+
+      /**
+       *  @brief Query to see if file stream is open.
+       *  @return True if stream is open.
+      */
+      bool
+      is_open() { return _M_filebuf.is_open(); }
+
+      /**
+       *  @brief Specify a file to open for output.
+       *  @param  s  Null terminated string specifying filename.
+       *  @param  mode  Mode in which to open file (see std::ios_base).
+       *
+       *  Tip:  When using std::string to hold the filename, you must use
+       *  .c_str() before passing it to this constructor.
+      */
+      void
+      open(const char* __s,
+	   ios_base::openmode __mode = ios_base::out | ios_base::trunc)
+      {
+	if (!_M_filebuf.open(__s, __mode | ios_base::out))
+	  this->setstate(ios_base::failbit);
+      }
+
+      /** Close the file stream.  */
+      void
+      close()
+      {
+	if (!_M_filebuf.close())
+	  this->setstate(ios_base::failbit);
+      }
+    };
+
+
+  // 27.8.1.11  Template class basic_fstream
+  /**
+   *  Derivation of general input/output streams, specific to files.
+  */
+  template<typename _CharT, typename _Traits>
+    class basic_fstream : public basic_iostream<_CharT, _Traits>
+    {
+    public:
+      // Types:
+      typedef _CharT 					char_type;
+      typedef _Traits 					traits_type;
+      typedef typename traits_type::int_type 		int_type;
+      typedef typename traits_type::pos_type 		pos_type;
+      typedef typename traits_type::off_type 		off_type;
+
+      // Non-standard types:
+      typedef basic_filebuf<char_type, traits_type> 	__filebuf_type;
+      typedef basic_ios<char_type, traits_type>		__ios_type;
+      typedef basic_iostream<char_type, traits_type>	__iostream_type;
+
+    private:
+      __filebuf_type	_M_filebuf;
+
+    public:
+      // Constructors/destructor:
+      /** Default constructor.  Create a file stream.  */
+      basic_fstream()
+      : __iostream_type(NULL), _M_filebuf()
+      { this->init(&_M_filebuf); }
+
+      /**
+       *  @brief Create an input/output stream.
+       *  @param  s  Null terminated string specifying filename.
+       *  @param  mode  Open file in specified mode (see std::ios_base).
+       *
+       *  Tip:  When using std::string to hold the filename, you must use
+       *  .c_str() before passing it to this constructor.
+      */
+      explicit
+      basic_fstream(const char* __s,
+		    ios_base::openmode __mode = ios_base::in | ios_base::out)
+      : __iostream_type(NULL), _M_filebuf()
+      {
+	this->init(&_M_filebuf);
+	this->open(__s, __mode);
+      }
+
+      ~basic_fstream()
+      { }
+
+      // Members:
+      /**
+       *  @brief  Get a pointer to the file stream's buffer.
+       *  @return Pointer to basic_filebuf.
+      */
+      __filebuf_type*
+      rdbuf() const
+      { return const_cast<__filebuf_type*>(&_M_filebuf); }
+
+      /**
+       *  @brief Query to see if file stream is open.
+       *  @return True if stream is open.
+      */
+      bool
+      is_open() { return _M_filebuf.is_open(); }
+
+      /**
+       *  @brief Specify a file to open for input and/or output.
+       *  @param  s  Null terminated string specifying filename.
+       *  @param  mode  Mode in which to open file (see std::ios_base).
+       *
+       *  Tip:  When using std::string to hold the filename, you must use
+       *  .c_str() before passing it to this constructor.
+      */
+      void
+      open(const char* __s,
+	   ios_base::openmode __mode = ios_base::in | ios_base::out)
+      {
+	if (!_M_filebuf.open(__s, __mode))
+	  setstate(ios_base::failbit);
+      }
+
+      /** Close the file stream.  */
+      void
+      close()
+      {
+	if (!_M_filebuf.close())
+	  setstate(ios_base::failbit);
+      }
+    };
+} // namespace std
+
+#ifdef _GLIBCPP_NO_TEMPLATE_EXPORT
+# define export
+#endif
+#ifdef  _GLIBCPP_FULLY_COMPLIANT_HEADERS
+# include <bits/fstream.tcc>
+#endif
+
+#endif