streambuf.tcc (__copy_streambufs): Don't use _M_buf_size (synced input is now correct...

[gcc.git] / libstdc++-v3 / include / bits / streambuf.tcc

// Stream buffer classes -*- 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: 27.5  Stream buffers
//

#ifndef _CPP_BITS_STREAMBUF_TCC
#define _CPP_BITS_STREAMBUF_TCC 1

#pragma GCC system_header

namespace std 
{
  template<typename _CharT, typename _Traits>
    typename basic_streambuf<_CharT, _Traits>::int_type
    basic_streambuf<_CharT, _Traits>::
    sbumpc()
    {
      int_type __ret;
      if (_M_in_cur < _M_in_end)
	{
	  char_type __c = *this->_M_in_cur;
	  _M_move_in_cur(1);
	  __ret = traits_type::to_int_type(__c);
	}
      else 
	__ret = this->uflow();
      return __ret;
    }

  template<typename _CharT, typename _Traits>
    typename basic_streambuf<_CharT, _Traits>::int_type
    basic_streambuf<_CharT, _Traits>::
    sputbackc(char_type __c) 
    {
      int_type __ret;
      const bool __testpos = _M_in_beg < _M_in_cur;
      if (!__testpos || !traits_type::eq(__c, this->_M_in_cur[-1]))
	__ret = this->pbackfail(traits_type::to_int_type(__c));
      else 
	{
	  _M_move_in_cur(-1);
	  __ret = traits_type::to_int_type(*this->_M_in_cur);
	}
      return __ret;
    }
  
  template<typename _CharT, typename _Traits>
    typename basic_streambuf<_CharT, _Traits>::int_type
    basic_streambuf<_CharT, _Traits>::
    sungetc()
    {
      int_type __ret;
      if (_M_in_beg < _M_in_cur)
	{
	  _M_move_in_cur(-1);
	  __ret = traits_type::to_int_type(*_M_in_cur);
	}
      else 
	__ret = this->pbackfail();
      return __ret;
    }

  template<typename _CharT, typename _Traits>
    typename basic_streambuf<_CharT, _Traits>::int_type
    basic_streambuf<_CharT, _Traits>::
    sputc(char_type __c)
    {
      int_type __ret;
      if (_M_out_cur < _M_out_end)
	{
	  *_M_out_cur = __c;
	  _M_move_out_cur(1);
	  __ret = traits_type::to_int_type(__c);
	}
      else
	__ret = this->overflow(traits_type::to_int_type(__c));
      return __ret;
    }

  template<typename _CharT, typename _Traits>
    streamsize
    basic_streambuf<_CharT, _Traits>::
    xsgetn(char_type* __s, streamsize __n)
    {
      streamsize __ret = 0;
      while (__ret < __n)
	{
	  size_t __buf_len = _M_in_end - _M_in_cur;
	  if (__buf_len > 0)
	    {
	      size_t __remaining = __n - __ret;
	      size_t __len = std::min(__buf_len, __remaining);
	      traits_type::copy(__s, _M_in_cur, __len);
	      __ret += __len;
	      __s += __len;
	      _M_move_in_cur(__len);
	    }
	  
	  if (__ret < __n)
	    {
	      int_type __c = this->uflow();  
	      if (!traits_type::eq_int_type(__c, traits_type::eof()))
		{
		  traits_type::assign(*__s++, traits_type::to_char_type(__c));
		  ++__ret;
		}
	      else
		break;
	    }
	}
      return __ret;
    }

  template<typename _CharT, typename _Traits>
    streamsize
    basic_streambuf<_CharT, _Traits>::
    xsputn(const char_type* __s, streamsize __n)
    {
      streamsize __ret = 0;
      while (__ret < __n)
	{
	  off_type __buf_len = _M_out_end - _M_out_cur;
	  if (__buf_len > 0)
	    {
	      off_type __remaining = __n - __ret;
	      off_type __len = std::min(__buf_len, __remaining);
	      traits_type::copy(_M_out_cur, __s, __len);
	      __ret += __len;
	      __s += __len;
	      _M_move_out_cur(__len);
	    }

	  if (__ret < __n)
	    {
	      int_type __c = this->overflow(traits_type::to_int_type(*__s));
	      if (!traits_type::eq_int_type(__c, traits_type::eof()))
		{
		  ++__ret;
		  ++__s;
		}
	      else
		break;
	    }
	}
      return __ret;
    }

  // Conceivably, this could be used to implement buffer-to-buffer
  // copies, if this was ever desired in an un-ambiguous way by the
  // standard. If so, then checks for __ios being zero would be
  // necessary.
  template<typename _CharT, typename _Traits>
    streamsize
    __copy_streambufs(basic_ios<_CharT, _Traits>& __ios,
		      basic_streambuf<_CharT, _Traits>* __sbin,
		      basic_streambuf<_CharT, _Traits>* __sbout) 
  {
      typedef typename _Traits::int_type	int_type;
      typedef typename _Traits::off_type	off_type;

      streamsize __ret = 0;
      try 
	{
	  for (;;)
  	    {
	      streamsize __xtrct;
	      const off_type __avail = __sbin->_M_in_end
		                       - __sbin->_M_in_cur;
 	      if (__avail)
		{
		  __xtrct = __sbout->sputn(__sbin->_M_in_cur, __avail);
		  __ret += __xtrct;
		  __sbin->_M_move_in_cur(__xtrct);
		  if (__xtrct != __avail)
		    break;
		}
 	      else 
		{
		  streamsize __charsread;
		  const off_type __size = __sbout->_M_out_end
		                          - __sbout->_M_out_cur;
		  if (__size)
		    {
		      _CharT* __buf =
			static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT)
							      * __size));
		      // Since the next sputn cannot fail sgetn can be
		      // safely used.
		      __charsread = __sbin->sgetn(__buf, __size);
		      __xtrct = __sbout->sputn(__buf, __charsread);
		    }
		  else
		    {
		      __xtrct = __charsread = 0;
		      const int_type __c = __sbin->sgetc();
		      if (!_Traits::eq_int_type(__c, _Traits::eof()))
			{
			  ++__charsread;
			  if (_Traits::eq_int_type(__sbout->overflow(__c),
						   _Traits::eof()))
			    break;
			  ++__xtrct;
			  __sbin->sbumpc();
			}
		    }		      
		  __ret += __xtrct;
		  if (__xtrct != __charsread)
		    break;
		}
 	      if (_Traits::eq_int_type(__sbin->sgetc(), _Traits::eof()))
  		break;
  	    }
	}
      catch(exception& __fail) 
	{
	  __ios.setstate(ios_base::failbit);
	  if ((__ios.exceptions() & ios_base::failbit) != 0)
	    __throw_exception_again;
	}
      return __ret;
    }

  // Inhibit implicit instantiations for required instantiations,
  // which are defined via explicit instantiations elsewhere.  
  // NB:  This syntax is a GNU extension.
#if _GLIBCPP_EXTERN_TEMPLATE
  extern template class basic_streambuf<char>;
  extern template
    streamsize
    __copy_streambufs(basic_ios<char>&, basic_streambuf<char>*,
		      basic_streambuf<char>*); 

#ifdef _GLIBCPP_USE_WCHAR_T
  extern template class basic_streambuf<wchar_t>;
  extern template
    streamsize
    __copy_streambufs(basic_ios<wchar_t>&, basic_streambuf<wchar_t>*,
		      basic_streambuf<wchar_t>*); 
#endif
#endif
} // namespace std

#endif