epoc32/include/stdapis/stlport/stl/_fstream.c
branchSymbian3
changeset 4 837f303aceeb
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/epoc32/include/stdapis/stlport/stl/_fstream.c	Wed Mar 31 12:33:34 2010 +0100
@@ -0,0 +1,891 @@
+/*
+ * © Portions copyright (c) 2006-2007 Nokia Corporation.  All rights reserved.
+ *
+ * Copyright (c) 1996,1997
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Copyright (c) 1999 
+ * Boris Fomitchev
+ *
+ * This material is provided "as is", with absolutely no warranty expressed
+ * or implied. Any use is at your own risk.
+ *
+ * Permission to use or copy this software for any purpose is hereby granted 
+ * without fee, provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ *
+ */
+#ifndef _STLP_FSTREAM_C
+#define _STLP_FSTREAM_C
+
+# ifndef _STLP_INTERNAL_FSTREAM_H
+#  include <stl/_fstream.h>
+# endif
+
+# if defined (_STLP_EXPOSE_STREAM_IMPLEMENTATION)
+
+_STLP_BEGIN_NAMESPACE
+
+# if defined ( _STLP_NESTED_TYPE_PARAM_BUG )
+// no wchar_t is supported for this mode
+# define __BF_int_type__ int
+# define __BF_pos_type__ streampos
+# define __BF_off_type__ streamoff
+# else
+# define __BF_int_type__ _STLP_TYPENAME_ON_RETURN_TYPE basic_filebuf<_CharT, _Traits>::int_type
+# define __BF_pos_type__ _STLP_TYPENAME_ON_RETURN_TYPE basic_filebuf<_CharT, _Traits>::pos_type
+# define __BF_off_type__ _STLP_TYPENAME_ON_RETURN_TYPE basic_filebuf<_CharT, _Traits>::off_type
+# endif
+
+
+//----------------------------------------------------------------------
+// Public basic_filebuf<> member functions
+
+template <class _CharT, class _Traits>
+basic_filebuf<_CharT, _Traits>::basic_filebuf()
+     :  basic_streambuf<_CharT, _Traits>(), _M_base(),
+    _M_constant_width(false), _M_always_noconv(false),
+    _M_int_buf_dynamic(false),
+    _M_in_input_mode(false), _M_in_output_mode(false),
+    _M_in_error_mode(false), _M_in_putback_mode(false),
+    _M_int_buf(0), _M_int_buf_EOS(0),
+    _M_ext_buf(0), _M_ext_buf_EOS(0),
+    _M_ext_buf_converted(0), _M_ext_buf_end(0),
+    _M_state(_STLP_DEFAULT_CONSTRUCTED(_State_type)),
+    _M_end_state(_STLP_DEFAULT_CONSTRUCTED(_State_type)),
+    _M_mmap_base(0), _M_mmap_len(0),
+    _M_saved_eback(0), _M_saved_gptr(0), _M_saved_egptr(0),
+    _M_codecvt(0),
+    _M_width(1), _M_max_width(1)
+{
+  this->_M_setup_codecvt(locale());
+}
+
+template <class _CharT, class _Traits>
+basic_filebuf<_CharT, _Traits>::~basic_filebuf() {
+  this->close();
+  _M_deallocate_buffers();
+}
+
+
+template <class _CharT, class _Traits>
+_STLP_TYPENAME_ON_RETURN_TYPE basic_filebuf<_CharT, _Traits>::int_type 
+basic_filebuf<_CharT, _Traits>::underflow() 
+{
+  return _Underflow<_CharT, _Traits>::_M_doit(this);
+}
+
+template <class _CharT, class _Traits>
+basic_filebuf<_CharT, _Traits>* 
+basic_filebuf<_CharT, _Traits>::close()
+{
+  bool __ok = this->is_open();
+
+  if (_M_in_output_mode) {
+    __ok = __ok && !_Traits::eq_int_type(this->overflow(traits_type::eof()),
+                                         traits_type::eof());
+    __ok == __ok && this->_M_unshift();
+  }
+  else if (_M_in_input_mode)
+      this->_M_exit_input_mode();
+
+  // Note order of arguments.  We close the file even if __ok is false.
+  __ok = _M_base._M_close() && __ok;
+
+  // Restore the initial state, except that we don't deallocate the buffer
+  // or mess with the cached codecvt information.
+  _M_state = _M_end_state = _State_type();
+  _M_ext_buf_converted = _M_ext_buf_end = 0;
+
+  _M_mmap_base = 0;
+  _M_mmap_len = 0;
+
+#ifdef __SYMBIAN32__
+  if (__ok) {
+#endif // __SYMBIAN32__
+  this->setg(0, 0, 0);
+  this->setp(0, 0);
+#ifdef __SYMBIAN32__  
+  }
+#endif // __SYMBIAN32__
+
+  _M_saved_eback = _M_saved_gptr = _M_saved_egptr = 0;
+
+  _M_in_input_mode = _M_in_output_mode = _M_in_error_mode = _M_in_putback_mode
+    = false;
+
+  return __ok ? this : 0;
+}
+
+// This member function is called whenever we exit input mode.
+// It unmaps the memory-mapped file, if any, and sets
+// _M_in_input_mode to false.  
+template <class _CharT, class _Traits>
+void basic_filebuf<_CharT, _Traits>::_M_exit_input_mode()
+{
+   if (_M_mmap_base != 0)
+     _M_base._M_unmap(_M_mmap_base, _M_mmap_len); 
+   _M_in_input_mode = false;
+   _M_mmap_base = 0;
+}
+
+
+//----------------------------------------------------------------------
+// basic_filebuf<> overridden protected virtual member functions
+
+template <class _CharT, class _Traits>
+streamsize basic_filebuf<_CharT, _Traits>::showmanyc()
+{
+  // Is there any possibility that reads can succeed?
+#ifdef __SYMBIAN32__
+  if (!this->is_open() || !(_M_base.__o_mode() & (int)ios_base::in) || _M_in_error_mode)
+#else
+  if (!this->is_open() || _M_in_output_mode || _M_in_error_mode)
+#endif
+    return -1;
+
+  else if (_M_in_putback_mode)
+    return this->egptr() - this->gptr();
+
+  else if (_M_constant_width) {
+    streamoff __pos  = _M_base._M_seek(0, ios_base::cur);
+    streamoff __size = _M_base._M_file_size();
+#ifdef __SYMBIAN32__
+    if(__size == 0)
+        return 0;
+#endif
+    return __pos >= 0 && __size > __pos ? __size - __pos : -1;
+  }
+
+  else 
+    return 0;
+}
+
+
+// Make a putback position available, if necessary, by switching to a 
+// special internal buffer used only for putback.  The buffer is
+// [_M_pback_buf, _M_pback_buf + _S_pback_buf_size), but the base
+// class only sees a piece of it at a time.  (We want to make sure
+// that we don't try to read a character that hasn't been initialized.)
+// The end of the putback buffer is always _M_pback_buf + _S_pback_buf_size,
+// but the beginning is usually not _M_pback_buf.
+template <class _CharT, class _Traits>
+__BF_int_type__ 
+basic_filebuf<_CharT, _Traits>::pbackfail(int_type __c)
+{
+  const int_type __eof = traits_type::eof();
+
+  // If we aren't already in input mode, pushback is impossible.
+  if (!_M_in_input_mode)
+    return __eof;
+
+  // We can use the ordinary get buffer if there's enough space, and
+  // if it's a buffer that we're allowed to write to.
+  if (this->gptr() != this->eback() &&
+      (traits_type::eq_int_type(__c, __eof) ||
+       traits_type::eq(traits_type::to_char_type(__c), this->gptr()[-1]) ||
+       !_M_mmap_base)) {
+    this->gbump(-1);
+    if (traits_type::eq_int_type(__c, __eof) ||
+        traits_type::eq(traits_type::to_char_type(__c), *this->gptr()))
+      return traits_type::to_int_type(*this->gptr());
+  }
+  else if (!traits_type::eq_int_type(__c, __eof)) {
+    // Are we in the putback buffer already?
+    _CharT* __pback_end = _M_pback_buf + __STATIC_CAST(int,_S_pback_buf_size);
+    if (_M_in_putback_mode) {
+      // Do we have more room in the putback buffer?
+      if (this->eback() != _M_pback_buf) 
+        this->setg(this->egptr() - 1, this->egptr() - 1, __pback_end);
+      else
+        return __eof;           // No more room in the buffer, so fail.
+    }
+    else {                      // We're not yet in the putback buffer.
+      _M_saved_eback = this->eback();
+      _M_saved_gptr  = this->gptr();
+      _M_saved_egptr = this->egptr();
+      this->setg(__pback_end - 1, __pback_end - 1, __pback_end);
+      _M_in_putback_mode = true;
+    }
+  }
+  else
+  {
+#ifdef __SYMBIAN32__
+    if (traits_type::eq_int_type(__c, __eof) )
+    {
+        if(_M_in_putback_mode)
+        {
+            _M_in_putback_mode = false;
+            // we are at putback mode
+            if(_M_saved_eback != _M_saved_gptr)
+            {
+                this->setg(_M_saved_eback, _M_saved_gptr - 1, _M_saved_egptr);
+                return *this->gptr();
+            }
+            else
+                this->setg(_M_saved_eback, _M_saved_gptr, _M_saved_egptr);
+         
+         }
+         else
+         {
+            if(!this->eback())
+            {
+                streamoff __pos  = _M_base._M_seek(0, ios_base::cur);
+                streamoff __size = _M_base._M_file_size();
+                if( __size > 0 && __pos > 0 && __pos == __size)
+                    __pos  = _M_base._M_seek(__pos - 1, ios_base::beg);
+                this->underflow();
+                this->setg(this->eback(), this->gptr(), this->egptr());
+                return *this->gptr();
+            }
+            else
+            {
+                this->setg(this->eback(), this->gptr() - 1, this->egptr());
+                return *this->gptr();
+            }
+         }
+    }
+#endif
+    return __eof;
+  }
+  // We have made a putback position available.  Assign to it, and return.
+  *this->gptr() = traits_type::to_char_type(__c);
+  return __c;
+}
+
+// This member function flushes the put area, and also outputs the
+// character __c (unless __c is eof).  Invariant: we always leave room
+// in the internal buffer for one character more than the base class knows
+// about.  We see the internal buffer as [_M_int_buf, _M_int_buf_EOS), but
+// the base class only sees [_M_int_buf, _M_int_buf_EOS - 1).
+template <class _CharT, class _Traits>
+__BF_int_type__
+basic_filebuf<_CharT, _Traits>::overflow(int_type __c)
+{
+  // Switch to output mode, if necessary.
+  bool putflag = false;
+  if (!_M_in_output_mode)
+  {
+#ifdef __SYMBIAN32__
+    if(this->_M_int_buf)
+        putflag = true;
+#endif
+    if (!_M_switch_to_output_mode())
+      return traits_type::eof();
+  }
+  _CharT* __ibegin = this->_M_int_buf;
+  _CharT* __iend   = this->pptr();
+  this->setp(_M_int_buf, _M_int_buf_EOS - 1);
+
+  // Put __c at the end of the internal buffer.
+  if (!traits_type::eq_int_type(__c, traits_type::eof()))
+    *__iend++ = __c;
+#ifdef __SYMBIAN32__
+  int current_pos = this->gptr() - this->eback();
+  streamoff __size = _M_base._M_file_size();
+  if(current_pos > 0 && current_pos < __size && _M_base.__is_open())
+    _M_base._M_seek(current_pos, ios_base::beg);
+#endif
+
+  // For variable-width encodings, output may take more than one pass.
+  while (__ibegin != __iend) {
+    const _CharT* __inext = __ibegin;
+    char* __enext         = _M_ext_buf;
+    typename _Codecvt::result __status
+      = _M_codecvt->out(_M_state, __ibegin, __iend, __inext,
+                                  _M_ext_buf, _M_ext_buf_EOS, __enext);
+    if (__status == _Codecvt::noconv)
+#ifdef __SYMBIAN32__    
+    {
+      if(_Noconv_output<_Traits>::_M_doit(this, __ibegin, __iend))
+      {
+        if (this->eback())
+            {
+            *(this->gptr()) = __c;
+            this->setg(this->eback(), this->gptr() + 1, this->egptr());
+            }
+        if(putflag && this->pptr()  < this->epptr())
+            this->setp(this->pptr() + 1, this->epptr());
+        return traits_type::not_eof(__c);
+      }
+      else
+        return _M_output_error();
+    }
+#else
+      return _Noconv_output<_Traits>::_M_doit(this, __ibegin, __iend)
+        ? traits_type::not_eof(__c)
+        : _M_output_error();
+#endif
+    // For a constant-width encoding we know that the external buffer
+    // is large enough, so failure to consume the entire internal buffer
+    // or to produce the correct number of external characters, is an error.
+    // For a variable-width encoding, however, we require only that we 
+    // consume at least one internal character
+    else if (__status != _Codecvt::error && 
+             ((__inext == __iend && (__enext - _M_ext_buf == 
+                                     _M_width * (__iend - __ibegin))) ||
+              (!_M_constant_width && __inext != __ibegin))) {
+        // We successfully converted part or all of the internal buffer.
+      ptrdiff_t __n = __enext - _M_ext_buf;
+      if (_M_write(_M_ext_buf, __n))
+        __ibegin += __inext - __ibegin;
+      else
+        return _M_output_error();
+    }
+    else
+      return _M_output_error();
+  }
+
+  return traits_type::not_eof(__c);
+}
+
+// This member function must be called before any I/O has been
+// performed on the stream, otherwise it has no effect.
+//
+// __buf == 0 && __n == 0 means to make ths stream unbuffered.
+// __buf != 0 && __n > 0 means to use __buf as the stream's internal
+// buffer, rather than the buffer that would otherwise be allocated
+// automatically.  __buf must be a pointer to an array of _CharT whose
+// size is at least __n.
+template <class _CharT, class _Traits>
+basic_streambuf<_CharT, _Traits>*
+basic_filebuf<_CharT, _Traits>::setbuf(_CharT* __buf, streamsize __n)
+{
+  if (!_M_in_input_mode &&! _M_in_output_mode && !_M_in_error_mode &&
+      _M_int_buf == 0) {
+    if (__buf == 0 && __n == 0)
+      _M_allocate_buffers(0, 1);
+    else if (__buf != 0 && __n > 0)
+      _M_allocate_buffers(__buf, __n);
+  }
+  return this;
+}
+
+template <class _CharT, class _Traits>
+__BF_pos_type__
+basic_filebuf<_CharT, _Traits>::seekoff(off_type __off,
+                                        ios_base::seekdir __whence,
+                                        ios_base::openmode /* dummy */)
+{
+  if (this->is_open() &&
+      (__off == 0 || (_M_constant_width && this->_M_base._M_in_binary_mode()))) {
+
+    if (!_M_seek_init(__off != 0 || __whence != ios_base::cur))
+      return pos_type(-1);
+
+    // Seek to beginning or end, regardless of whether we're in input mode.
+    if (__whence == ios_base::beg || __whence == ios_base::end)
+      return _M_seek_return(_M_base._M_seek(_M_width * __off, __whence),
+                            _State_type());
+
+    // Seek relative to current position.  Complicated if we're in input mode.
+    else if (__whence == ios_base::cur) {
+
+      if (!_M_in_input_mode)
+        return _M_seek_return(_M_base._M_seek(_M_width * __off, __whence),
+                              _State_type());
+      else if (_M_mmap_base != 0) {
+        // __off is relative to gptr().  We need to do a bit of arithmetic
+        // to get an offset relative to the external file pointer.
+        streamoff __adjust = _M_mmap_len - (this->gptr() - (_CharT*) _M_mmap_base);
+
+        // if __off == 0, we do not need to exit input mode and to shift file pointer
+        if (__off == 0) {
+          return pos_type(_M_base._M_seek(0, ios_base::cur) - __adjust);
+        }
+        else
+#ifdef __SYMBIAN32__       
+        return _M_seek_return(_M_base._M_seek(__off, ios_base::cur), _State_type());
+#else      
+          return _M_seek_return(_M_base._M_seek(__off - __adjust, ios_base::cur), _State_type());
+#endif
+      }
+      else if (_M_constant_width) { // Get or set the position.  
+
+        streamoff __iadj = _M_width * (this->gptr() - this->eback());
+        
+        // Compensate for offset relative to gptr versus offset relative
+        // to external pointer.  For a text-oriented stream, where the 
+        // compensation is more than just pointer arithmetic, we may get
+        // but not set the current position.
+        
+        if (__iadj <= _M_ext_buf_end - _M_ext_buf) {
+          
+          streamoff __eadj =  _M_base._M_get_offset(_M_ext_buf + __iadj, _M_ext_buf_end);
+
+          if (__off == 0) {
+            return pos_type(_M_base._M_seek(0, ios_base::cur) - __eadj);
+          }  else {
+            return _M_seek_return(_M_base._M_seek(__off - __eadj, ios_base::cur), _State_type());
+          }
+        }
+        else
+          return pos_type(-1);
+      }
+      else {                    // Get the position.  Encoding is var width.
+        // Get position in internal buffer.
+        ptrdiff_t __ipos = this->gptr() - this->eback();
+        
+        // Get corresponding position in external buffer.
+        _State_type __state = _M_state;
+        int __epos = _M_codecvt->length(__state, _M_ext_buf, _M_ext_buf_end,
+                                        __ipos);
+
+        // Sanity check (expensive): make sure __epos is the right answer.
+        _State_type __tmp_state = _M_state;
+        _Filebuf_Tmp_Buf<_CharT> __buf(__ipos);
+        _CharT* __ibegin = __buf._M_ptr;
+        _CharT* __inext  = __ibegin;
+
+        const char* __dummy;
+        typename _Codecvt::result __status
+          = _M_codecvt->in(__tmp_state,
+                           _M_ext_buf, _M_ext_buf + __epos, __dummy,
+                           __ibegin, __ibegin + __ipos, __inext);
+        if (__status != _Codecvt::error &&
+            (__status == _Codecvt::noconv ||
+             (__inext == __ibegin + __ipos &&
+              equal(this->gptr(), this->eback(), __ibegin,
+                    _Eq_traits<traits_type>())))) {
+          // Get the current position (at the end of the external buffer),
+          // then adjust it.  Again, it might be a text-oriented stream.
+          streamoff __cur = _M_base._M_seek(0, ios_base::cur);
+          streamoff __adj =
+            _M_base._M_get_offset(_M_ext_buf, _M_ext_buf + __epos) -
+            _M_base._M_get_offset(_M_ext_buf, _M_ext_buf_end);
+          if (__cur != -1 && __cur + __adj >= 0)
+            return _M_seek_return(__cur + __adj, __state);
+          else
+            return pos_type(-1);
+        }
+        else                    // We failed the sanity check.
+          return pos_type(-1);
+      }
+    }
+    else                        // Unrecognized value for __whence.
+      return pos_type(-1);
+  }
+  else
+    return pos_type(-1);
+}
+
+
+template <class _CharT, class _Traits>
+__BF_pos_type__
+basic_filebuf<_CharT, _Traits>::seekpos(pos_type __pos,
+                                        ios_base::openmode /* dummy */)
+{
+  if (this->is_open()) {
+    if (!_M_seek_init(true))
+      return pos_type(-1);
+
+    streamoff __off = off_type(__pos);
+    if (__off != -1 && _M_base._M_seek(__off, ios_base::beg) != -1) {
+      _M_state = __pos.state();
+      return _M_seek_return(__off, __pos.state());
+    }
+    else
+      return pos_type(-1);
+  }
+  else
+    return pos_type(-1);
+}
+
+
+template <class _CharT, class _Traits>
+int basic_filebuf<_CharT, _Traits>::sync()
+{
+  if (_M_in_output_mode)
+    return traits_type::eq_int_type(this->overflow(traits_type::eof()),
+                                    traits_type::eof())
+      ? -1
+      : 0;
+  else
+    return 0;
+}
+
+
+// Change the filebuf's locale.  This member function has no effect
+// unless it is called before any I/O is performed on the stream.
+template <class _CharT, class _Traits>
+void basic_filebuf<_CharT, _Traits>::imbue(const locale& __loc)
+{
+  if (!_M_in_input_mode &&! _M_in_output_mode && !_M_in_error_mode) {
+    this->_M_setup_codecvt(__loc);
+  }
+}
+
+//----------------------------------------------------------------------
+// basic_filebuf<> helper functions.
+
+//----------------------------------------
+// Helper functions for switching between modes.
+
+// This member function is called if we're performing the first I/O
+// operation on a filebuf, or if we're performing an input operation 
+// immediately after a seek.
+template <class _CharT, class _Traits>
+bool basic_filebuf<_CharT, _Traits>::_M_switch_to_input_mode()
+{
+
+  if (this->is_open() && (((int)_M_base.__o_mode() & (int)ios_base::in) !=0)
+#ifndef __SYMBIAN32__
+      && (_M_in_output_mode == 0) 
+#endif
+      && (_M_in_error_mode == 0)) {
+#ifdef __STLP_NO_WRITE_SIDE_BUFFERING__
+    // If file has been opened in input|output mode
+    if ((((int)_M_base.__o_mode() & (int)ios_base::out) !=0) 
+#ifndef __SYMBIAN32__
+        && sync()
+#endif
+        && !_M_int_buf && !_M_allocate_buffers(0, 1))
+#else
+    if (!_M_int_buf && !_M_allocate_buffers())
+#endif
+      return false;
+
+    _M_ext_buf_converted = _M_ext_buf;
+    _M_ext_buf_end       = _M_ext_buf;
+
+    _M_end_state    = _M_state;
+
+    _M_in_input_mode = true;
+    return true;
+  }
+  else
+
+    return false;
+}
+
+
+// This member function is called if we're performing the first I/O
+// operation on a filebuf, or if we're performing an output operation 
+// immediately after a seek.
+template <class _CharT, class _Traits>
+bool basic_filebuf<_CharT, _Traits>::_M_switch_to_output_mode()
+{
+  if (this->is_open() && (_M_base.__o_mode() & (int)ios_base::out) &&
+#ifdef __SYMBIAN32__  
+      _M_in_error_mode == 0) {
+#else      
+      _M_in_input_mode == 0 && _M_in_error_mode == 0) {
+#endif //__SYMBIAN32__      
+
+#ifdef __STLP_NO_WRITE_SIDE_BUFFERING__
+    if (!_M_int_buf && !_M_allocate_buffers(0, 1))
+#else
+    if (!_M_int_buf && !_M_allocate_buffers())
+#endif
+      return false;
+
+    // In append mode, every write does an implicit seek to the end
+    // of the file.  Whenever leaving output mode, the end of file
+    // get put in the initial shift state.
+    if (_M_base.__o_mode() & ios_base::app)
+      _M_state = _State_type();
+
+    this->setp(_M_int_buf, _M_int_buf_EOS - 1);
+    _M_in_output_mode = true;
+
+    return true;
+  }
+  else
+    return false;
+}
+
+
+//----------------------------------------
+// Helper functions for input
+
+// This member function is called if there is an error during input.
+// It puts the filebuf in error mode, clear the get area buffer, and
+// returns eof.
+// returns eof.  Error mode is sticky; it is cleared only by close or
+// seek.
+
+template <class _CharT, class _Traits>
+__BF_int_type__
+basic_filebuf<_CharT, _Traits>::_M_input_error()
+{
+   this->_M_exit_input_mode();   
+  _M_in_output_mode = false;
+  _M_in_error_mode = true;
+  this->setg(0, 0, 0);
+  return traits_type::eof();
+}
+
+template <class _CharT, class _Traits>
+__BF_int_type__ 
+basic_filebuf<_CharT, _Traits>::_M_underflow_aux() 
+{
+  // We have the state and file position from the end of the internal
+  // buffer.  This round, they become the beginning of the internal buffer.
+  _M_state    = _M_end_state;
+
+  // Fill the external buffer.  Start with any leftover characters that
+  // didn't get converted last time.
+  if (_M_ext_buf_end > _M_ext_buf_converted)
+
+    _M_ext_buf_end = copy(_M_ext_buf_converted, _M_ext_buf_end, _M_ext_buf);
+    // boris : copy_backward did not work
+    //_M_ext_buf_end = copy_backward(_M_ext_buf_converted, _M_ext_buf_end, 
+    //_M_ext_buf+ (_M_ext_buf_end - _M_ext_buf_converted));
+  else
+    {
+#ifdef __SYMBIAN32__
+     if(_M_ext_buf == NULL)
+    _M_allocate_buffers(0, MMAP_CHUNK);
+#endif
+    _M_ext_buf_end = _M_ext_buf;
+    }
+  // Now fill the external buffer with characters from the file.  This is
+  // a loop because occasonally we don't get enough external characters
+  // to make progress.
+  while (true) {
+    ptrdiff_t __n = _M_base._M_read(_M_ext_buf_end, _M_ext_buf_EOS - _M_ext_buf_end);
+ 
+    // Don't enter error mode for a failed read.  Error mode is sticky,
+    // and we might succeed if we try again.
+#ifdef __SYMBIAN32__    //plum hall bug 577
+    int nn = (char*)_M_ext_buf_end-(char*)_M_ext_buf; //number of chars unconverted last time
+    if ( (__n <= 0) && ( nn<=0 ) )
+#else
+	if (__n <= 0)
+#endif    
+      return traits_type::eof();
+
+    // Convert the external buffer to internal characters.  
+    _M_ext_buf_end += __n;
+    const char*   __enext;
+    _CharT* __inext;
+
+    typename _Codecvt::result __status
+      = _M_codecvt->in(_M_end_state,
+                       _M_ext_buf, _M_ext_buf_end, __enext,
+                       _M_int_buf, _M_int_buf_EOS, __inext);
+
+    // Error conditions: (1) Return value of error.  (2) Producing internal
+    // characters without consuming external characters.  (3) In fixed-width
+    // encodings, producing an internal sequence whose length is inconsistent
+    // with that of the internal sequence.  (4) Failure to produce any 
+    // characters if we have enough characters in the external buffer, where
+    // "enough" means the largest possible width of a single character.
+    if (__status == _Codecvt::noconv)
+      return _Noconv_input<_Traits>::_M_doit(this);
+
+    else if (__status == _Codecvt::error ||
+             (__inext != _M_int_buf && __enext == _M_ext_buf) ||
+             (_M_constant_width &&
+              //         __inext - _M_int_buf != _M_width * (__enext - _M_ext_buf)) ||
+              (__inext - _M_int_buf) *  _M_width != (__enext - _M_ext_buf)) ||
+             (__inext == _M_int_buf && __enext - _M_ext_buf >= _M_max_width))
+      return _M_input_error();
+    
+    else if (__inext != _M_int_buf) {
+      _M_ext_buf_converted = _M_ext_buf + (__enext - _M_ext_buf);
+      this->setg(_M_int_buf, _M_int_buf, __inext);
+      return traits_type::to_int_type(*_M_int_buf);
+    }
+    // We need to go around the loop again to get more external characters.
+  } 
+}
+
+//----------------------------------------
+// Helper functions for output
+
+// This member function is called if there is an error during output.
+// It puts the filebuf in error mode, clear the put area buffer, and
+// returns eof.  Error mode is sticky; it is cleared only by close or
+// seek.
+template <class _CharT, class _Traits>
+__BF_int_type__
+basic_filebuf<_CharT, _Traits>::_M_output_error()
+{
+  _M_in_output_mode = false;
+  _M_in_input_mode = false;
+  _M_in_error_mode = true;
+  this->setp(0, 0);
+  return traits_type::eof();
+}
+
+
+// Write whatever sequence of characters is necessary to get back to
+// the initial shift state.  This function overwrites the external
+// buffer, changes the external file position, and changes the state.
+// Precondition: the internal buffer is empty.
+template <class _CharT, class _Traits>
+bool basic_filebuf<_CharT, _Traits>::_M_unshift()
+{
+  if (_M_in_output_mode && !_M_constant_width) {
+    typename _Codecvt::result __status;
+    do {
+      char* __enext = _M_ext_buf;
+      __status = _M_codecvt->unshift(_M_state,
+                                     _M_ext_buf, _M_ext_buf_EOS, __enext);
+      if (__status == _Codecvt::noconv ||
+          (__enext == _M_ext_buf && __status == _Codecvt::ok))
+        return true;
+      else if (__status == _Codecvt::error)
+        return false;
+      else if (!_M_write(_M_ext_buf, __enext - _M_ext_buf))
+        return false;
+    } while(__status == _Codecvt::partial);
+  }
+
+  return true;
+}
+
+
+//----------------------------------------
+// Helper functions for buffer allocation and deallocation
+
+// This member function is called when we're initializing a filebuf's
+// internal and external buffers.  The argument is the size of the
+// internal buffer; the external buffer is sized using the character
+// width in the current encoding.  Preconditions: the buffers are currently
+// null.  __n >= 1.  __buf is either a null pointer or a pointer to an 
+// array show size is at least __n.
+
+// We need __n >= 1 for two different reasons.  For input, the base
+// class always needs a buffer because of the sementics of underflow().
+// For output, we want to have an internal buffer that's larger by one
+// element than the buffer that the base class knows about.  (See 
+// basic_filebuf<>::overflow() for the reason.)
+template <class _CharT, class _Traits>
+bool 
+basic_filebuf<_CharT, _Traits>::_M_allocate_buffers(_CharT* __buf, streamsize __n)
+{
+
+  if (__buf == 0) {
+    _M_int_buf = __STATIC_CAST(_CharT*,malloc(__n * sizeof(_CharT)));
+    if (! _M_int_buf)
+      return false;
+    _M_int_buf_dynamic = true;
+  }
+  else {
+    _M_int_buf = __buf;
+    _M_int_buf_dynamic = false;
+  }
+  
+  size_t __ebufsiz = (max)(__n * (max)(_M_codecvt->encoding(), 1),
+                      streamsize(_M_codecvt->max_length()));
+
+  _M_ext_buf = __STATIC_CAST(char*,malloc(__ebufsiz));
+  if (!_M_ext_buf) {
+    _M_deallocate_buffers();
+    return false;
+  }
+
+  _M_int_buf_EOS = _M_int_buf + __n;
+  _M_ext_buf_EOS = _M_ext_buf + __ebufsiz;
+  return true;
+}
+
+// Abbreviation for the most common case.
+template <class _CharT, class _Traits>
+bool basic_filebuf<_CharT, _Traits>::_M_allocate_buffers()
+{
+  // Choose a buffer that's at least 4096 characters long and that's a
+  // multiple of the page size.
+  streamsize __default_bufsiz =
+    ((_M_base.__page_size() + 4095UL) / _M_base.__page_size()) * _M_base.__page_size();
+  return _M_allocate_buffers(0, __default_bufsiz);
+}
+
+template <class _CharT, class _Traits>
+void basic_filebuf<_CharT, _Traits>::_M_deallocate_buffers()
+{
+  if (_M_int_buf_dynamic)
+    free(_M_int_buf);
+  free(_M_ext_buf);
+  _M_int_buf     = 0;
+  _M_int_buf_EOS = 0;
+  _M_ext_buf     = 0;
+  _M_ext_buf_EOS = 0;
+}
+
+
+//----------------------------------------
+// Helper functiosn for seek and imbue
+
+template <class _CharT, class _Traits>
+bool basic_filebuf<_CharT, _Traits>::_M_seek_init(bool __do_unshift) {
+  // If we're in error mode, leave it.
+   _M_in_error_mode = false;
+   
+  // Flush the output buffer if we're in output mode, and (conditionally)
+  // emit an unshift sequence.
+  if (_M_in_output_mode) {
+    bool __ok = !traits_type::eq_int_type(this->overflow(traits_type::eof()),
+                                          traits_type::eof());
+    if (__do_unshift)
+      __ok = __ok && this->_M_unshift();
+    if (!__ok) {
+      _M_in_output_mode = false;
+      _M_in_error_mode = true;
+      this->setp(0, 0);
+      return false;
+    }
+  }
+
+  // Discard putback characters, if any.
+  if (_M_in_input_mode && _M_in_putback_mode)
+    _M_exit_putback_mode();
+
+  return true;
+}
+
+
+// Change the filebuf's locale.  This member function has no effect
+// unless it is called before any I/O is performed on the stream.
+template <class _CharT, class _Traits>
+void basic_filebuf<_CharT, _Traits>::_M_setup_codecvt(const locale& __loc)
+{
+  _M_codecvt = &use_facet<_Codecvt>(__loc) ;
+  int __encoding    = _M_codecvt->encoding();
+
+  _M_width          = (max)(__encoding, 1);
+  _M_max_width      = _M_codecvt->max_length();
+  _M_constant_width = __encoding > 0;
+  _M_always_noconv  = _M_codecvt->always_noconv();
+}
+
+
+
+template <class _CharT, class _Traits>
+  _STLP_EXP_DECLSPEC basic_fstream<_CharT, _Traits>::basic_fstream()
+    : basic_ios<_CharT, _Traits>(), basic_iostream<_CharT, _Traits>(0), _M_buf() {
+      this->init(&_M_buf);
+  }
+
+
+template <class _CharT, class _Traits>
+  _STLP_EXP_DECLSPEC basic_fstream<_CharT, _Traits>::~basic_fstream(){}
+  
+#ifdef __SYMBIAN32__
+template <class _CharT, class _Traits>
+int basic_filebuf<_CharT, _Traits>::save_read_buffer ()
+    {
+    return _M_in_putback_mode ? _M_saved_egptr - _M_saved_gptr : 0;
+    }
+template <class _CharT, class _Traits>
+void basic_filebuf<_CharT, _Traits>::_change_input_mode ()
+    {
+    _M_in_input_mode = 1;
+    }
+
+#endif
+
+_STLP_END_NAMESPACE
+
+# undef __BF_int_type__
+# undef __BF_pos_type__
+# undef __BF_off_type__
+
+# endif /* defined (_STLP_EXPOSE_STREAM_IMPLEMENTATION) */
+
+#endif /* _STLP_FSTREAM_C */
+