gcc/libstdc++-v3/include/std/std_fstream.h

434 lines
12 KiB
C++

// File based streams -*- C++ -*-
// Copyright (C) 1997, 1998, 1999, 2000, 2001 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 std_fstream.h
* This is an internal header file, included by other library headers.
* You should not attempt to use it directly.
*/
#ifndef _CPP_FSTREAM
#define _CPP_FSTREAM 1
#pragma GCC system_header
#include <istream>
#include <ostream>
#include <bits/basic_file.h>
#include <locale> // For codecvt
#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_type> __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.
private:
// Data Members:
// External buffer.
__file_type* _M_file;
// Current and beginning state type for codecvt.
__state_type _M_state_cur;
__state_type _M_state_beg;
// MT lock inherited from libio or other low-level io library.
__c_lock _M_lock;
// Set iff _M_buf is allocated memory from _M_allocate_internal_buffer..
bool _M_buf_allocated;
// XXX Needed?
bool _M_last_overflowed;
public:
// Constructors/destructor:
basic_filebuf();
// Non-standard ctor:
basic_filebuf(__c_file_type* __f, ios_base::openmode __mode,
int_type __s = static_cast<int_type>(BUFSIZ));
// Non-standard member:
int
fd();
virtual
~basic_filebuf()
{
this->close();
_M_last_overflowed = false;
}
// Members:
bool
is_open(void) const { return _M_file ? _M_file->is_open() : false; }
__filebuf_type*
open(const char* __s, ios_base::openmode __mode);
__filebuf_type*
close(void);
protected:
void
_M_allocate_internal_buffer();
void
_M_destroy_internal_buffer();
void
_M_allocate_pback_buffer();
// Create __file_type object and initialize it properly.
void
_M_allocate_file();
// Overridden virtual functions:
virtual streamsize
showmanyc(void);
// 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()
virtual int_type
underflow(void);
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());
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(void)
{
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 && !_M_file->sync())
{
// Need to restore current position. This interpreted as
// the position of the external byte sequence (_M_file)
// plus the offset in the current internal buffer
// (_M_out_beg - _M_out_cur)
streamoff __cur = _M_file->seekoff(0, ios_base::cur);
off_type __off = _M_out_cur - _M_out_beg;
_M_really_overflow();
_M_file->seekpos(__cur + __off);
}
_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();
};
// 27.8.1.5 Template class basic_ifstream
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:
basic_ifstream()
: __istream_type(NULL), _M_filebuf()
{ this->init(&_M_filebuf); }
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:
__filebuf_type*
rdbuf() const
{ return const_cast<__filebuf_type*>(&_M_filebuf); }
bool
is_open(void) { 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) == NULL)
this->setstate(ios_base::failbit);
}
void
close(void)
{
if (!_M_filebuf.close())
this->setstate(ios_base::failbit);
}
};
// 27.8.1.8 Template class basic_ofstream
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:
basic_ofstream()
: __ostream_type(NULL), _M_filebuf()
{ this->init(&_M_filebuf); }
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:
__filebuf_type*
rdbuf(void) const
{ return const_cast<__filebuf_type*>(&_M_filebuf); }
bool
is_open(void) { return _M_filebuf.is_open(); }
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);
}
void
close(void)
{
if (!_M_filebuf.close())
this->setstate(ios_base::failbit);
}
};
// 27.8.1.11 Template class basic_fstream
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:
basic_fstream()
: __iostream_type(NULL), _M_filebuf()
{ this->init(&_M_filebuf); }
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:
__filebuf_type*
rdbuf(void) const
{ return const_cast<__filebuf_type*>(&_M_filebuf); }
bool
is_open(void) { return _M_filebuf.is_open(); }
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);
}
void
close(void)
{
if (!_M_filebuf.close())
setstate(ios_base::failbit);
}
};
} // namespace std
#ifdef _GLIBCPP_NO_TEMPLATE_EXPORT
# define export
#ifdef _GLIBCPP_FULLY_COMPLIANT_HEADERS
# include <bits/fstream.tcc>
#endif
#endif
#endif