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9385d9cb0d
gcc/libstdc++-v3/include/std/std_fstream.h
Loren J. Rittle 9385d9cb0d std_fstream.h (basic_filebuf::sync): Hoist unconditional flush on lower-layer handle to here... 
* include/std/std_fstream.h (basic_filebuf::sync): Hoist
	unconditional flush on lower-layer handle to here...
	* include/bits/fstream.tcc (basic_filebuf::_M_really_overflow):
	...from here.  Optimize remaining _M_file.sync() call pattern.
	* testsuite/27_io/narrow_stream_objects.cc (test04): New test.
	(test05): Likewise.

From-SVN: r52699
2002-04-24 00:33:28 +00:00

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// File based streams -*- C++ -*-
// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002
// 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;
// Stack-based buffer for unbuffered input.
char_type _M_unbuf[4];
// 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();
// Non-standard ctor:
basic_filebuf(__c_file* __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() 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() { return _M_underflow_common(false); }
virtual int_type
uflow() { return _M_underflow_common(true); }
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;
}
};
// 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
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