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

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// Stream buffer classes -*- 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: 27.5 Stream buffers
//
/** @file streambuf
* 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_STREAMBUF
#define _CPP_STREAMBUF 1
#pragma GCC system_header
#include <bits/c++config.h>
#include <iosfwd>
#include <cstdio> // For SEEK_SET, SEEK_CUR, SEEK_END
#include <bits/localefwd.h>
#include <bits/ios_base.h>
namespace std
{
template<typename _CharT, typename _Traits>
streamsize
__copy_streambufs(basic_ios<_CharT, _Traits>& _ios,
basic_streambuf<_CharT, _Traits>* __sbin,
basic_streambuf<_CharT, _Traits>* __sbout);
// 27.5.2 Template class basic_streambuf<_CharT, _Traits>
template<typename _CharT, typename _Traits>
class basic_streambuf
{
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 ctype<char_type> __ctype_type;
typedef basic_streambuf<char_type, traits_type> __streambuf_type;
friend class basic_ios<char_type, traits_type>;
friend class basic_istream<char_type, traits_type>;
friend class basic_ostream<char_type, traits_type>;
friend class istreambuf_iterator<char_type, traits_type>;
friend class ostreambuf_iterator<char_type, traits_type>;
friend streamsize
__copy_streambufs<>(basic_ios<char_type, traits_type>& __ios,
__streambuf_type* __sbin,__streambuf_type* __sbout);
protected:
// Pointer to the beginning of internally-allocated
// space. Filebuf manually allocates/deallocates this, whereas
// stringstreams attempt to use the built-in intelligence of the
// string class. If you are managing memory, set this. If not,
// leave it NULL.
char_type* _M_buf;
// Actual size of allocated internal buffer, in bytes.
int_type _M_buf_size;
// Optimal or preferred size of internal buffer, in bytes.
int_type _M_buf_size_opt;
// True iff _M_in_* and _M_out_* buffers should always point to
// the same place. True for fstreams, false for sstreams.
bool _M_buf_unified;
// This is based on _IO_FILE, just reordered to be more
// consistent, and is intended to be the most minimal abstraction
// for an internal buffer.
// get == input == read
// put == output == write
char_type* _M_in_beg; // Start of get area.
char_type* _M_in_cur; // Current read area.
char_type* _M_in_end; // End of get area.
char_type* _M_out_beg; // Start of put area.
char_type* _M_out_cur; // Current put area.
char_type* _M_out_end; // End of put area.
// Place to stash in || out || in | out settings for current streambuf.
ios_base::openmode _M_mode;
// Current locale setting.
locale _M_buf_locale;
// True iff locale is initialized.
bool _M_buf_locale_init;
// Necessary bits for putback buffer management. Only used in
// the basic_filebuf class, as necessary for the standard
// requirements. The only basic_streambuf member function that
// needs access to these data members is in_avail...
// NB: pbacks of over one character are not currently supported.
int_type _M_pback_size;
char_type* _M_pback;
char_type* _M_pback_cur_save;
char_type* _M_pback_end_save;
bool _M_pback_init;
// Initializes pback buffers, and moves normal buffers to safety.
// Assumptions:
// _M_in_cur has already been moved back
void
_M_pback_create()
{
if (!_M_pback_init)
{
int_type __dist = _M_in_end - _M_in_cur;
int_type __len = min(_M_pback_size, __dist);
traits_type::copy(_M_pback, _M_in_cur, __len);
_M_pback_cur_save = _M_in_cur;
_M_pback_end_save = _M_in_end;
this->setg(_M_pback, _M_pback, _M_pback + __len);
_M_pback_init = true;
}
}
// Deactivates pback buffer contents, and restores normal buffer.
// Assumptions:
// The pback buffer has only moved forward.
void
_M_pback_destroy()
{
if (_M_pback_init)
{
// Length _M_in_cur moved in the pback buffer.
int_type __off_cur = _M_in_cur - _M_pback;
// For in | out buffers, the end can be pushed back...
int_type __off_end = 0;
int_type __pback_len = _M_in_end - _M_pback;
int_type __save_len = _M_pback_end_save - _M_buf;
if (__pback_len > __save_len)
__off_end = __pback_len - __save_len;
this->setg(_M_buf, _M_pback_cur_save + __off_cur,
_M_pback_end_save + __off_end);
_M_pback_cur_save = NULL;
_M_pback_end_save = NULL;
_M_pback_init = false;
}
}
// Correctly sets the _M_in_cur pointer, and bumps the
// _M_out_cur pointer as well if necessary.
void
_M_in_cur_move(off_type __n) // argument needs to be +-
{
bool __testout = _M_out_cur;
_M_in_cur += __n;
if (__testout && _M_buf_unified)
_M_out_cur += __n;
}
// Correctly sets the _M_out_cur pointer, and bumps the
// appropriate _M_*_end pointers as well. Necessary for the
// un-tied stringbufs, in in|out mode.
// Invariant:
// __n + _M_out_[cur, end] <= _M_buf + _M_buf_size
// Assuming all _M_*_[beg, cur, end] pointers are operating on
// the same range:
// _M_buf <= _M_*_ <= _M_buf + _M_buf_size
void
_M_out_cur_move(off_type __n) // argument needs to be +-
{
bool __testin = _M_in_cur;
_M_out_cur += __n;
if (__testin && _M_buf_unified)
_M_in_cur += __n;
if (_M_out_cur > _M_out_end)
{
_M_out_end = _M_out_cur;
// NB: in | out buffers drag the _M_in_end pointer along...
if (__testin)
_M_in_end += __n;
}
}
// Return the size of the output buffer. This depends on the
// buffer in use: allocated buffers have a stored size in
// _M_buf_size and setbuf() buffers don't.
off_type
_M_out_buf_size()
{
off_type __ret = 0;
if (_M_out_cur)
{
// Using allocated buffer.
if (_M_out_beg == _M_buf)
__ret = _M_out_beg + _M_buf_size - _M_out_cur;
// Using non-allocated buffer.
else
__ret = _M_out_end - _M_out_cur;
}
return __ret;
}
// 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);
}
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);
}
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;
}
public:
virtual
~basic_streambuf()
{
_M_buf_unified = false;
_M_buf_size = 0;
_M_buf_size_opt = 0;
_M_mode = ios_base::openmode(0);
_M_buf_locale_init = false;
}
// Locales:
locale
pubimbue(const locale &__loc)
{
locale __tmp(this->getloc());
this->imbue(__loc);
return __tmp;
}
locale
getloc() const
{
if (_M_buf_locale_init)
return _M_buf_locale;
else
return locale();
}
// Buffer and positioning:
__streambuf_type*
pubsetbuf(char_type* __s, streamsize __n)
{ return this->setbuf(__s, __n); }
pos_type
pubseekoff(off_type __off, ios_base::seekdir __way,
ios_base::openmode __mode = ios_base::in | ios_base::out)
{ return this->seekoff(__off, __way, __mode); }
pos_type
pubseekpos(pos_type __sp,
ios_base::openmode __mode = ios_base::in | ios_base::out)
{ return this->seekpos(__sp, __mode); }
int
pubsync() { return this->sync(); }
// Get and put areas:
// Get area:
streamsize
in_avail()
{
streamsize __ret;
if (_M_in_cur && _M_in_cur < _M_in_end)
{
if (_M_pback_init)
{
int_type __save_len = _M_pback_end_save - _M_pback_cur_save;
int_type __pback_len = _M_in_cur - _M_pback;
__ret = __save_len - __pback_len;
}
else
__ret = this->egptr() - this->gptr();
}
else
__ret = this->showmanyc();
return __ret;
}
int_type
snextc()
{
int_type __eof = traits_type::eof();
return (this->sbumpc() == __eof ? __eof : this->sgetc());
}
int_type
sbumpc();
int_type
sgetc()
{
int_type __ret;
if (_M_in_cur && _M_in_cur < _M_in_end)
__ret = traits_type::to_int_type(*(this->gptr()));
else
__ret = this->underflow();
return __ret;
}
streamsize
sgetn(char_type* __s, streamsize __n)
{ return this->xsgetn(__s, __n); }
// Putback:
int_type
sputbackc(char_type __c);
int_type
sungetc();
// Put area:
int_type
sputc(char_type __c);
streamsize
sputn(const char_type* __s, streamsize __n)
{ return this->xsputn(__s, __n); }
protected:
basic_streambuf()
: _M_buf(NULL), _M_buf_size(0),
_M_buf_size_opt(static_cast<int_type>(BUFSIZ)), _M_buf_unified(false),
_M_in_beg(0), _M_in_cur(0), _M_in_end(0), _M_out_beg(0), _M_out_cur(0),
_M_out_end(0), _M_mode(ios_base::openmode(0)), _M_buf_locale(locale()),
_M_buf_locale_init(false), _M_pback_size(1), _M_pback(NULL),
_M_pback_cur_save(NULL), _M_pback_end_save(NULL), _M_pback_init(false)
{ }
// Get area:
char_type*
eback() const { return _M_in_beg; }
char_type*
gptr() const { return _M_in_cur; }
char_type*
egptr() const { return _M_in_end; }
void
gbump(int __n) { _M_in_cur += __n; }
void
setg(char_type* __gbeg, char_type* __gnext, char_type* __gend)
{
_M_in_beg = __gbeg;
_M_in_cur = __gnext;
_M_in_end = __gend;
if (!(_M_mode & ios_base::in) && __gbeg && __gnext && __gend)
_M_mode = _M_mode | ios_base::in;
}
// Put area:
char_type*
pbase() const { return _M_out_beg; }
char_type*
pptr() const { return _M_out_cur; }
char_type*
epptr() const { return _M_out_end; }
void
pbump(int __n) { _M_out_cur += __n; }
void
setp(char_type* __pbeg, char_type* __pend)
{
_M_out_beg = _M_out_cur = __pbeg;
_M_out_end = __pend;
if (!(_M_mode & ios_base::out) && __pbeg && __pend)
_M_mode = _M_mode | ios_base::out;
}
// Virtual functions:
// Locales:
virtual void
imbue(const locale& __loc)
{
_M_buf_locale_init = true;
if (_M_buf_locale != __loc)
_M_buf_locale = __loc;
}
// Buffer management and positioning:
virtual basic_streambuf<char_type,_Traits>*
setbuf(char_type*, streamsize)
{ return this; }
virtual pos_type
seekoff(off_type, ios_base::seekdir,
ios_base::openmode /*__mode*/ = ios_base::in | ios_base::out)
{ return pos_type(off_type(-1)); }
virtual pos_type
seekpos(pos_type,
ios_base::openmode /*__mode*/ = ios_base::in | ios_base::out)
{ return pos_type(off_type(-1)); }
virtual int
sync() { return 0; }
// Get area:
virtual streamsize
showmanyc() { return 0; }
virtual streamsize
xsgetn(char_type* __s, streamsize __n);
virtual int_type
underflow()
{ return traits_type::eof(); }
virtual int_type
uflow()
{
int_type __ret = traits_type::eof();
bool __testeof = this->underflow() == __ret;
bool __testpending = _M_in_cur && _M_in_cur < _M_in_end;
if (!__testeof && __testpending)
{
__ret = traits_type::to_int_type(*_M_in_cur);
++_M_in_cur;
if (_M_buf_unified && _M_mode & ios_base::out)
++_M_out_cur;
}
return __ret;
}
// Putback:
virtual int_type
pbackfail(int_type /* __c */ = traits_type::eof())
{ return traits_type::eof(); }
// Put area:
virtual streamsize
xsputn(const char_type* __s, streamsize __n);
virtual int_type
overflow(int_type /* __c */ = traits_type::eof())
{ return traits_type::eof(); }
#ifdef _GLIBCPP_DEPRECATED
public:
void
stossc()
{
if (_M_in_cur < _M_in_end)
++_M_in_cur;
else
this->uflow();
}
#endif
#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
// Side effect of DR 50.
private:
basic_streambuf(const __streambuf_type&);
__streambuf_type&
operator=(const __streambuf_type&);
#endif
};
} // namespace std
#ifdef _GLIBCPP_NO_TEMPLATE_EXPORT
# define export
#ifdef _GLIBCPP_FULLY_COMPLIANT_HEADERS
#include <bits/streambuf.tcc>
#endif
#endif
#endif
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