fstream.tcc
Go to the documentation of this file.
// File based streams -*- C++ -*-
// Copyright (C) 1997-2021 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 3, 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.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file bits/fstream.tcc
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{fstream}
*/
//
// ISO C++ 14882: 27.8 File-based streams
//
#ifndef _FSTREAM_TCC
#define _FSTREAM_TCC 1
#pragma GCC system_header
#include <bits/cxxabi_forced.h>
#include <bits/move.h> // for swap
#include <cerrno>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _CharT, typename _Traits>
void
basic_filebuf<_CharT, _Traits>::
_M_allocate_internal_buffer()
{
// Allocate internal buffer only if one doesn't already exist
// (either allocated or provided by the user via setbuf).
if (!_M_buf_allocated && !_M_buf)
{
_M_buf = new char_type[_M_buf_size];
_M_buf_allocated = true;
}
}
template<typename _CharT, typename _Traits>
void
basic_filebuf<_CharT, _Traits>::
_M_destroy_internal_buffer() throw()
{
if (_M_buf_allocated)
{
delete [] _M_buf;
_M_buf = 0;
_M_buf_allocated = false;
}
delete [] _M_ext_buf;
_M_ext_buf = 0;
_M_ext_buf_size = 0;
_M_ext_next = 0;
_M_ext_end = 0;
}
template<typename _CharT, typename _Traits>
basic_filebuf<_CharT, _Traits>::
basic_filebuf() : __streambuf_type(), _M_lock(), _M_file(&_M_lock),
_M_mode(ios_base::openmode(0)), _M_state_beg(), _M_state_cur(),
_M_state_last(), _M_buf(0), _M_buf_size(_GLIBCXX_BUFSIZ),
_M_buf_allocated(false), _M_reading(false), _M_writing(false), _M_pback(),
_M_pback_cur_save(0), _M_pback_end_save(0), _M_pback_init(false),
_M_codecvt(0), _M_ext_buf(0), _M_ext_buf_size(0), _M_ext_next(0),
_M_ext_end(0)
{
if (has_facet<__codecvt_type>(this->_M_buf_locale))
_M_codecvt = &use_facet<__codecvt_type>(this->_M_buf_locale);
}
#if __cplusplus >= 201103L
template<typename _CharT, typename _Traits>
basic_filebuf<_CharT, _Traits>::
basic_filebuf(basic_filebuf&& __rhs)
: __streambuf_type(__rhs),
_M_lock(), _M_file(std::move(__rhs._M_file), &_M_lock),
_M_mode(std::__exchange(__rhs._M_mode, ios_base::openmode(0))),
_M_state_beg(std::move(__rhs._M_state_beg)),
_M_state_cur(std::move(__rhs._M_state_cur)),
_M_state_last(std::move(__rhs._M_state_last)),
_M_buf(std::__exchange(__rhs._M_buf, nullptr)),
_M_buf_size(std::__exchange(__rhs._M_buf_size, 1)),
_M_buf_allocated(std::__exchange(__rhs._M_buf_allocated, false)),
_M_reading(std::__exchange(__rhs._M_reading, false)),
_M_writing(std::__exchange(__rhs._M_writing, false)),
_M_pback(__rhs._M_pback),
_M_pback_cur_save(std::__exchange(__rhs._M_pback_cur_save, nullptr)),
_M_pback_end_save(std::__exchange(__rhs._M_pback_end_save, nullptr)),
_M_pback_init(std::__exchange(__rhs._M_pback_init, false)),
_M_codecvt(__rhs._M_codecvt),
_M_ext_buf(std::__exchange(__rhs._M_ext_buf, nullptr)),
_M_ext_buf_size(std::__exchange(__rhs._M_ext_buf_size, 0)),
_M_ext_next(std::__exchange(__rhs._M_ext_next, nullptr)),
_M_ext_end(std::__exchange(__rhs._M_ext_end, nullptr))
{
__rhs._M_set_buffer(-1);
__rhs._M_state_last = __rhs._M_state_cur = __rhs._M_state_beg;
}
template<typename _CharT, typename _Traits>
basic_filebuf<_CharT, _Traits>&
basic_filebuf<_CharT, _Traits>::
operator=(basic_filebuf&& __rhs)
{
this->close();
__streambuf_type::operator=(__rhs);
_M_file.swap(__rhs._M_file);
_M_mode = std::__exchange(__rhs._M_mode, ios_base::openmode(0));
_M_state_beg = std::move(__rhs._M_state_beg);
_M_state_cur = std::move(__rhs._M_state_cur);
_M_state_last = std::move(__rhs._M_state_last);
_M_buf = std::__exchange(__rhs._M_buf, nullptr);
_M_buf_size = std::__exchange(__rhs._M_buf_size, 1);
_M_buf_allocated = std::__exchange(__rhs._M_buf_allocated, false);
_M_ext_buf = std::__exchange(__rhs._M_ext_buf, nullptr);
_M_ext_buf_size = std::__exchange(__rhs._M_ext_buf_size, 0);
_M_ext_next = std::__exchange(__rhs._M_ext_next, nullptr);
_M_ext_end = std::__exchange(__rhs._M_ext_end, nullptr);
_M_reading = std::__exchange(__rhs._M_reading, false);
_M_writing = std::__exchange(__rhs._M_writing, false);
_M_pback_cur_save = std::__exchange(__rhs._M_pback_cur_save, nullptr);
_M_pback_end_save = std::__exchange(__rhs._M_pback_end_save, nullptr);
_M_pback_init = std::__exchange(__rhs._M_pback_init, false);
__rhs._M_set_buffer(-1);
__rhs._M_state_last = __rhs._M_state_cur = __rhs._M_state_beg;
return *this;
}
template<typename _CharT, typename _Traits>
void
basic_filebuf<_CharT, _Traits>::
swap(basic_filebuf& __rhs)
{
__streambuf_type::swap(__rhs);
_M_file.swap(__rhs._M_file);
std::swap(_M_mode, __rhs._M_mode);
std::swap(_M_state_beg, __rhs._M_state_beg);
std::swap(_M_state_cur, __rhs._M_state_cur);
std::swap(_M_state_last, __rhs._M_state_last);
std::swap(_M_buf, __rhs._M_buf);
std::swap(_M_buf_size, __rhs._M_buf_size);
std::swap(_M_buf_allocated, __rhs._M_buf_allocated);
std::swap(_M_ext_buf, __rhs._M_ext_buf);
std::swap(_M_ext_buf_size, __rhs._M_ext_buf_size);
std::swap(_M_ext_next, __rhs._M_ext_next);
std::swap(_M_ext_end, __rhs._M_ext_end);
std::swap(_M_reading, __rhs._M_reading);
std::swap(_M_writing, __rhs._M_writing);
std::swap(_M_pback_cur_save, __rhs._M_pback_cur_save);
std::swap(_M_pback_end_save, __rhs._M_pback_end_save);
std::swap(_M_pback_init, __rhs._M_pback_init);
}
#endif
template<typename _CharT, typename _Traits>
typename basic_filebuf<_CharT, _Traits>::__filebuf_type*
basic_filebuf<_CharT, _Traits>::
open(const char* __s, ios_base::openmode __mode)
{
__filebuf_type *__ret = 0;
if (!this->is_open())
{
_M_file.open(__s, __mode);
if (this->is_open())
{
_M_allocate_internal_buffer();
_M_mode = __mode;
// Setup initial buffer to 'uncommitted' mode.
_M_reading = false;
_M_writing = false;
_M_set_buffer(-1);
// Reset to initial state.
_M_state_last = _M_state_cur = _M_state_beg;
// 27.8.1.3,4
if ((__mode & ios_base::ate)
&& this->seekoff(0, ios_base::end, __mode)
== pos_type(off_type(-1)))
this->close();
else
__ret = this;
}
}
return __ret;
}
#if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T
template<typename _CharT, typename _Traits>
basic_filebuf<_CharT, _Traits>*
basic_filebuf<_CharT, _Traits>::
open(const wchar_t* __s, ios_base::openmode __mode)
{
__filebuf_type *__ret = 0;
if (!this->is_open())
{
_M_file.open(__s, __mode);
if (this->is_open())
{
_M_allocate_internal_buffer();
_M_mode = __mode;
// Setup initial buffer to 'uncommitted' mode.
_M_reading = false;
_M_writing = false;
_M_set_buffer(-1);
// Reset to initial state.
_M_state_last = _M_state_cur = _M_state_beg;
// 27.8.1.3,4
if ((__mode & ios_base::ate)
&& this->seekoff(0, ios_base::end, __mode)
== pos_type(off_type(-1)))
this->close();
else
__ret = this;
}
}
return __ret;
}
#endif // HAVE__WFOPEN && USE_WCHAR_T
template<typename _CharT, typename _Traits>
typename basic_filebuf<_CharT, _Traits>::__filebuf_type*
basic_filebuf<_CharT, _Traits>::
close()
{
if (!this->is_open())
return 0;
bool __testfail = false;
{
// NB: Do this here so that re-opened filebufs will be cool...
struct __close_sentry
{
basic_filebuf *__fb;
__close_sentry (basic_filebuf *__fbi): __fb(__fbi) { }
~__close_sentry ()
{
__fb->_M_mode = ios_base::openmode(0);
__fb->_M_pback_init = false;
__fb->_M_destroy_internal_buffer();
__fb->_M_reading = false;
__fb->_M_writing = false;
__fb->_M_set_buffer(-1);
__fb->_M_state_last = __fb->_M_state_cur = __fb->_M_state_beg;
}
} __cs (this);
__try
{
if (!_M_terminate_output())
__testfail = true;
}
__catch(...)
{
_M_file.close();
__throw_exception_again;
}
}
if (!_M_file.close())
__testfail = true;
if (__testfail)
return 0;
else
return this;
}
template<typename _CharT, typename _Traits>
streamsize
basic_filebuf<_CharT, _Traits>::
showmanyc()
{
streamsize __ret = -1;
const bool __testin = _M_mode & ios_base::in;
if (__testin && this->is_open())
{
// For a stateful encoding (-1) the pending sequence might be just
// shift and unshift prefixes with no actual character.
__ret = this->egptr() - this->gptr();
#if _GLIBCXX_HAVE_DOS_BASED_FILESYSTEM
// About this workaround, see libstdc++/20806.
const bool __testbinary = _M_mode & ios_base::binary;
if (__check_facet(_M_codecvt).encoding() >= 0
&& __testbinary)
#else
if (__check_facet(_M_codecvt).encoding() >= 0)
#endif
__ret += _M_file.showmanyc() / _M_codecvt->max_length();
}
return __ret;
}
template<typename _CharT, typename _Traits>
typename basic_filebuf<_CharT, _Traits>::int_type
basic_filebuf<_CharT, _Traits>::
underflow()
{
int_type __ret = traits_type::eof();
const bool __testin = _M_mode & ios_base::in;
if (__testin)
{
if (_M_writing)
{
if (overflow() == traits_type::eof())
return __ret;
_M_set_buffer(-1);
_M_writing = false;
}
// Check for pback madness, and if so switch back to the
// normal buffers and jet outta here before expensive
// fileops happen...
_M_destroy_pback();
if (this->gptr() < this->egptr())
return traits_type::to_int_type(*this->gptr());
// Get and convert input sequence.
const size_t __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1;
// Will be set to true if ::read() returns 0 indicating EOF.
bool __got_eof = false;
// Number of internal characters produced.
streamsize __ilen = 0;
codecvt_base::result __r = codecvt_base::ok;
if (__check_facet(_M_codecvt).always_noconv())
{
__ilen = _M_file.xsgetn(reinterpret_cast<char*>(this->eback()),
__buflen);
if (__ilen == 0)
__got_eof = true;
}
else
{
// Worst-case number of external bytes.
// XXX Not done encoding() == -1.
const int __enc = _M_codecvt->encoding();
streamsize __blen; // Minimum buffer size.
streamsize __rlen; // Number of chars to read.
if (__enc > 0)
__blen = __rlen = __buflen * __enc;
else
{
__blen = __buflen + _M_codecvt->max_length() - 1;
__rlen = __buflen;
}
const streamsize __remainder = _M_ext_end - _M_ext_next;
__rlen = __rlen > __remainder ? __rlen - __remainder : 0;
// An imbue in 'read' mode implies first converting the external
// chars already present.
if (_M_reading && this->egptr() == this->eback() && __remainder)
__rlen = 0;
// Allocate buffer if necessary and move unconverted
// bytes to front.
if (_M_ext_buf_size < __blen)
{
char* __buf = new char[__blen];
if (__remainder)
__builtin_memcpy(__buf, _M_ext_next, __remainder);
delete [] _M_ext_buf;
_M_ext_buf = __buf;
_M_ext_buf_size = __blen;
}
else if (__remainder)
__builtin_memmove(_M_ext_buf, _M_ext_next, __remainder);
_M_ext_next = _M_ext_buf;
_M_ext_end = _M_ext_buf + __remainder;
_M_state_last = _M_state_cur;
do
{
if (__rlen > 0)
{
// Sanity check!
// This may fail if the return value of
// codecvt::max_length() is bogus.
if (_M_ext_end - _M_ext_buf + __rlen > _M_ext_buf_size)
{
__throw_ios_failure(__N("basic_filebuf::underflow "
"codecvt::max_length() "
"is not valid"));
}
streamsize __elen = _M_file.xsgetn(_M_ext_end, __rlen);
if (__elen == 0)
__got_eof = true;
else if (__elen == -1)
break;
_M_ext_end += __elen;
}
char_type* __iend = this->eback();
if (_M_ext_next < _M_ext_end)
__r = _M_codecvt->in(_M_state_cur, _M_ext_next,
_M_ext_end, _M_ext_next,
this->eback(),
this->eback() + __buflen, __iend);
if (__r == codecvt_base::noconv)
{
size_t __avail = _M_ext_end - _M_ext_buf;
__ilen = std::min(__avail, __buflen);
traits_type::copy(this->eback(),
reinterpret_cast<char_type*>
(_M_ext_buf), __ilen);
_M_ext_next = _M_ext_buf + __ilen;
}
else
__ilen = __iend - this->eback();
// _M_codecvt->in may return error while __ilen > 0: this is
// ok, and actually occurs in case of mixed encodings (e.g.,
// XML files).
if (__r == codecvt_base::error)
break;
__rlen = 1;
}
while (__ilen == 0 && !__got_eof);
}
if (__ilen > 0)
{
_M_set_buffer(__ilen);
_M_reading = true;
__ret = traits_type::to_int_type(*this->gptr());
}
else if (__got_eof)
{
// If the actual end of file is reached, set 'uncommitted'
// mode, thus allowing an immediate write without an
// intervening seek.
_M_set_buffer(-1);
_M_reading = false;
// However, reaching it while looping on partial means that
// the file has got an incomplete character.
if (__r == codecvt_base::partial)
__throw_ios_failure(__N("basic_filebuf::underflow "
"incomplete character in file"));
}
else if (__r == codecvt_base::error)
__throw_ios_failure(__N("basic_filebuf::underflow "
"invalid byte sequence in file"));
else
__throw_ios_failure(__N("basic_filebuf::underflow "
"error reading the file"), errno);
}
return __ret;
}
template<typename _CharT, typename _Traits>
typename basic_filebuf<_CharT, _Traits>::int_type
basic_filebuf<_CharT, _Traits>::
pbackfail(int_type __i)
{
int_type __ret = traits_type::eof();
const bool __testin = _M_mode & ios_base::in;
if (__testin)
{
if (_M_writing)
{
if (overflow() == traits_type::eof())
return __ret;
_M_set_buffer(-1);
_M_writing = false;
}
// Remember whether the pback buffer is active, otherwise below
// we may try to store in it a second char (libstdc++/9761).
const bool __testpb = _M_pback_init;
const bool __testeof = traits_type::eq_int_type(__i, __ret);
int_type __tmp;
if (this->eback() < this->gptr())
{
this->gbump(-1);
__tmp = traits_type::to_int_type(*this->gptr());
}
else if (this->seekoff(-1, ios_base::cur) != pos_type(off_type(-1)))
{
__tmp = this->underflow();
if (traits_type::eq_int_type(__tmp, __ret))
return __ret;
}
else
{
// At the beginning of the buffer, need to make a
// putback position available. But the seek may fail
// (f.i., at the beginning of a file, see
// libstdc++/9439) and in that case we return
// traits_type::eof().
return __ret;
}
// Try to put back __i into input sequence in one of three ways.
// Order these tests done in is unspecified by the standard.
if (!__testeof && traits_type::eq_int_type(__i, __tmp))
__ret = __i;
else if (__testeof)
__ret = traits_type::not_eof(__i);
else if (!__testpb)
{
_M_create_pback();
_M_reading = true;
*this->gptr() = traits_type::to_char_type(__i);
__ret = __i;
}
}
return __ret;
}
template<typename _CharT, typename _Traits>
typename basic_filebuf<_CharT, _Traits>::int_type
basic_filebuf<_CharT, _Traits>::
overflow(int_type __c)
{
int_type __ret = traits_type::eof();
const bool __testeof = traits_type::eq_int_type(__c, __ret);
const bool __testout = (_M_mode & ios_base::out
|| _M_mode & ios_base::app);
if (__testout)
{
if (_M_reading)
{
_M_destroy_pback();
const int __gptr_off = _M_get_ext_pos(_M_state_last);
if (_M_seek(__gptr_off, ios_base::cur, _M_state_last)
== pos_type(off_type(-1)))
return __ret;
}
if (this->pbase() < this->pptr())
{
// If appropriate, append the overflow char.
if (!__testeof)
{
*this->pptr() = traits_type::to_char_type(__c);
this->pbump(1);
}
// Convert pending sequence to external representation,
// and output.
if (_M_convert_to_external(this->pbase(),
this->pptr() - this->pbase()))
{
_M_set_buffer(0);
__ret = traits_type::not_eof(__c);
}
}
else if (_M_buf_size > 1)
{
// Overflow in 'uncommitted' mode: set _M_writing, set
// the buffer to the initial 'write' mode, and put __c
// into the buffer.
_M_set_buffer(0);
_M_writing = true;
if (!__testeof)
{
*this->pptr() = traits_type::to_char_type(__c);
this->pbump(1);
}
__ret = traits_type::not_eof(__c);
}
else
{
// Unbuffered.
char_type __conv = traits_type::to_char_type(__c);
if (__testeof || _M_convert_to_external(&__conv, 1))
{
_M_writing = true;
__ret = traits_type::not_eof(__c);
}
}
}
return __ret;
}
template<typename _CharT, typename _Traits>
bool
basic_filebuf<_CharT, _Traits>::
_M_convert_to_external(_CharT* __ibuf, streamsize __ilen)
{
// Sizes of external and pending output.
streamsize __elen;
streamsize __plen;
if (__check_facet(_M_codecvt).always_noconv())
{
__elen = _M_file.xsputn(reinterpret_cast<char*>(__ibuf), __ilen);
__plen = __ilen;
}
else
{
// Worst-case number of external bytes needed.
// XXX Not done encoding() == -1.
streamsize __blen = __ilen * _M_codecvt->max_length();
char* __buf = static_cast<char*>(__builtin_alloca(__blen));
char* __bend;
const char_type* __iend;
codecvt_base::result __r;
__r = _M_codecvt->out(_M_state_cur, __ibuf, __ibuf + __ilen,
__iend, __buf, __buf + __blen, __bend);
if (__r == codecvt_base::ok || __r == codecvt_base::partial)
__blen = __bend - __buf;
else if (__r == codecvt_base::noconv)
{
// Same as the always_noconv case above.
__buf = reinterpret_cast<char*>(__ibuf);
__blen = __ilen;
}
else
__throw_ios_failure(__N("basic_filebuf::_M_convert_to_external "
"conversion error"));
__elen = _M_file.xsputn(__buf, __blen);
__plen = __blen;
// Try once more for partial conversions.
if (__r == codecvt_base::partial && __elen == __plen)
{
const char_type* __iresume = __iend;
streamsize __rlen = this->pptr() - __iend;
__r = _M_codecvt->out(_M_state_cur, __iresume,
__iresume + __rlen, __iend, __buf,
__buf + __blen, __bend);
if (__r != codecvt_base::error)
{
__rlen = __bend - __buf;
__elen = _M_file.xsputn(__buf, __rlen);
__plen = __rlen;
}
else
__throw_ios_failure(__N("basic_filebuf::_M_convert_to_external "
"conversion error"));
}
}
return __elen == __plen;
}
template<typename _CharT, typename _Traits>
streamsize
basic_filebuf<_CharT, _Traits>::
xsgetn(_CharT* __s, streamsize __n)
{
// Clear out pback buffer before going on to the real deal...
streamsize __ret = 0;
if (_M_pback_init)
{
if (__n > 0 && this->gptr() == this->eback())
{
*__s++ = *this->gptr(); // emulate non-underflowing sbumpc
this->gbump(1);
__ret = 1;
--__n;
}
_M_destroy_pback();
}
else if (_M_writing)
{
if (overflow() == traits_type::eof())
return __ret;
_M_set_buffer(-1);
_M_writing = false;
}
// Optimization in the always_noconv() case, to be generalized in the
// future: when __n > __buflen we read directly instead of using the
// buffer repeatedly.
const bool __testin = _M_mode & ios_base::in;
const streamsize __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1;
if (__n > __buflen && __check_facet(_M_codecvt).always_noconv()
&& __testin)
{
// First, copy the chars already present in the buffer.
const streamsize __avail = this->egptr() - this->gptr();
if (__avail != 0)
{
traits_type::copy(__s, this->gptr(), __avail);
__s += __avail;
this->setg(this->eback(), this->gptr() + __avail, this->egptr());
__ret += __avail;
__n -= __avail;
}
// Need to loop in case of short reads (relatively common
// with pipes).
streamsize __len;
for (;;)
{
__len = _M_file.xsgetn(reinterpret_cast<char*>(__s), __n);
if (__len == -1)
__throw_ios_failure(__N("basic_filebuf::xsgetn "
"error reading the file"), errno);
if (__len == 0)
break;
__n -= __len;
__ret += __len;
if (__n == 0)
break;
__s += __len;
}
if (__n == 0)
{
// Set _M_reading. Buffer is already in initial 'read' mode.
_M_reading = true;
}
else if (__len == 0)
{
// If end of file is reached, set 'uncommitted'
// mode, thus allowing an immediate write without
// an intervening seek.
_M_set_buffer(-1);
_M_reading = false;
}
}
else
__ret += __streambuf_type::xsgetn(__s, __n);
return __ret;
}
template<typename _CharT, typename _Traits>
streamsize
basic_filebuf<_CharT, _Traits>::
xsputn(const _CharT* __s, streamsize __n)
{
streamsize __ret = 0;
// Optimization in the always_noconv() case, to be generalized in the
// future: when __n is sufficiently large we write directly instead of
// using the buffer.
const bool __testout = (_M_mode & ios_base::out
|| _M_mode & ios_base::app);
if (__check_facet(_M_codecvt).always_noconv()
&& __testout && !_M_reading)
{
// Measurement would reveal the best choice.
const streamsize __chunk = 1ul << 10;
streamsize __bufavail = this->epptr() - this->pptr();
// Don't mistake 'uncommitted' mode buffered with unbuffered.
if (!_M_writing && _M_buf_size > 1)
__bufavail = _M_buf_size - 1;
const streamsize __limit = std::min(__chunk, __bufavail);
if (__n >= __limit)
{
const streamsize __buffill = this->pptr() - this->pbase();
const char* __buf = reinterpret_cast<const char*>(this->pbase());
__ret = _M_file.xsputn_2(__buf, __buffill,
reinterpret_cast<const char*>(__s),
__n);
if (__ret == __buffill + __n)
{
_M_set_buffer(0);
_M_writing = true;
}
if (__ret > __buffill)
__ret -= __buffill;
else
__ret = 0;
}
else
__ret = __streambuf_type::xsputn(__s, __n);
}
else
__ret = __streambuf_type::xsputn(__s, __n);
return __ret;
}
template<typename _CharT, typename _Traits>
typename basic_filebuf<_CharT, _Traits>::__streambuf_type*
basic_filebuf<_CharT, _Traits>::
setbuf(char_type* __s, streamsize __n)
{
if (!this->is_open())
{
if (__s == 0 && __n == 0)
_M_buf_size = 1;
else if (__s && __n > 0)
{
// This is implementation-defined behavior, and assumes that
// an external char_type array of length __n exists and has
// been pre-allocated. If this is not the case, things will
// quickly blow up. When __n > 1, __n - 1 positions will be
// used for the get area, __n - 1 for the put area and 1
// position to host the overflow char of a full put area.
// When __n == 1, 1 position will be used for the get area
// and 0 for the put area, as in the unbuffered case above.
_M_buf = __s;
_M_buf_size = __n;
}
}
return this;
}
// According to 27.8.1.4 p11 - 13, seekoff should ignore the last
// argument (of type openmode).
template<typename _CharT, typename _Traits>
typename basic_filebuf<_CharT, _Traits>::pos_type
basic_filebuf<_CharT, _Traits>::
seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode)
{
int __width = 0;
if (_M_codecvt)
__width = _M_codecvt->encoding();
if (__width < 0)
__width = 0;
pos_type __ret = pos_type(off_type(-1));
const bool __testfail = __off != 0 && __width <= 0;
if (this->is_open() && !__testfail)
{
// tellg and tellp queries do not affect any state, unless
// ! always_noconv and the put sequence is not empty.
// In that case, determining the position requires converting the
// put sequence. That doesn't use ext_buf, so requires a flush.
bool __no_movement = __way == ios_base::cur && __off == 0
&& (!_M_writing || _M_codecvt->always_noconv());
// Ditch any pback buffers to avoid confusion.
if (!__no_movement)
_M_destroy_pback();
// Correct state at destination. Note that this is the correct
// state for the current position during output, because
// codecvt::unshift() returns the state to the initial state.
// This is also the correct state at the end of the file because
// an unshift sequence should have been written at the end.
__state_type __state = _M_state_beg;
off_type __computed_off = __off * __width;
if (_M_reading && __way == ios_base::cur)
{
__state = _M_state_last;
__computed_off += _M_get_ext_pos(__state);
}
if (!__no_movement)
__ret = _M_seek(__computed_off, __way, __state);
else
{
if (_M_writing)
__computed_off = this->pptr() - this->pbase();
off_type __file_off = _M_file.seekoff(0, ios_base::cur);
if (__file_off != off_type(-1))
{
__ret = __file_off + __computed_off;
__ret.state(__state);
}
}
}
return __ret;
}
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 171. Strange seekpos() semantics due to joint position
// According to the resolution of DR 171, seekpos should ignore the last
// argument (of type openmode).
template<typename _CharT, typename _Traits>
typename basic_filebuf<_CharT, _Traits>::pos_type
basic_filebuf<_CharT, _Traits>::
seekpos(pos_type __pos, ios_base::openmode)
{
pos_type __ret = pos_type(off_type(-1));
if (this->is_open())
{
// Ditch any pback buffers to avoid confusion.
_M_destroy_pback();
__ret = _M_seek(off_type(__pos), ios_base::beg, __pos.state());
}
return __ret;
}
template<typename _CharT, typename _Traits>
typename basic_filebuf<_CharT, _Traits>::pos_type
basic_filebuf<_CharT, _Traits>::
_M_seek(off_type __off, ios_base::seekdir __way, __state_type __state)
{
pos_type __ret = pos_type(off_type(-1));
if (_M_terminate_output())
{
off_type __file_off = _M_file.seekoff(__off, __way);
if (__file_off != off_type(-1))
{
_M_reading = false;
_M_writing = false;
_M_ext_next = _M_ext_end = _M_ext_buf;
_M_set_buffer(-1);
_M_state_cur = __state;
__ret = __file_off;
__ret.state(_M_state_cur);
}
}
return __ret;
}
// Returns the distance from the end of the ext buffer to the point
// corresponding to gptr(). This is a negative value. Updates __state
// from eback() correspondence to gptr().
template<typename _CharT, typename _Traits>
int basic_filebuf<_CharT, _Traits>::
_M_get_ext_pos(__state_type& __state)
{
if (_M_codecvt->always_noconv())
return this->gptr() - this->egptr();
else
{
// Calculate offset from _M_ext_buf that corresponds to
// gptr(). Precondition: __state == _M_state_last, which
// corresponds to eback().
const int __gptr_off =
_M_codecvt->length(__state, _M_ext_buf, _M_ext_next,
this->gptr() - this->eback());
return _M_ext_buf + __gptr_off - _M_ext_end;
}
}
template<typename _CharT, typename _Traits>
bool
basic_filebuf<_CharT, _Traits>::
_M_terminate_output()
{
// Part one: update the output sequence.
bool __testvalid = true;
if (this->pbase() < this->pptr())
{
const int_type __tmp = this->overflow();
if (traits_type::eq_int_type(__tmp, traits_type::eof()))
__testvalid = false;
}
// Part two: output unshift sequence.
if (_M_writing && !__check_facet(_M_codecvt).always_noconv()
&& __testvalid)
{
// Note: this value is arbitrary, since there is no way to
// get the length of the unshift sequence from codecvt,
// without calling unshift.
const size_t __blen = 128;
char __buf[__blen];
codecvt_base::result __r;
streamsize __ilen = 0;
do
{
char* __next;
__r = _M_codecvt->unshift(_M_state_cur, __buf,
__buf + __blen, __next);
if (__r == codecvt_base::error)
__testvalid = false;
else if (__r == codecvt_base::ok ||
__r == codecvt_base::partial)
{
__ilen = __next - __buf;
if (__ilen > 0)
{
const streamsize __elen = _M_file.xsputn(__buf, __ilen);
if (__elen != __ilen)
__testvalid = false;
}
}
}
while (__r == codecvt_base::partial && __ilen > 0 && __testvalid);
if (__testvalid)
{
// This second call to overflow() is required by the standard,
// but it's not clear why it's needed, since the output buffer
// should be empty by this point (it should have been emptied
// in the first call to overflow()).
const int_type __tmp = this->overflow();
if (traits_type::eq_int_type(__tmp, traits_type::eof()))
__testvalid = false;
}
}
return __testvalid;
}
template<typename _CharT, typename _Traits>
int
basic_filebuf<_CharT, _Traits>::
sync()
{
// Make sure that the internal buffer resyncs its idea of
// the file position with the external file.
int __ret = 0;
if (this->pbase() < this->pptr())
{
const int_type __tmp = this->overflow();
if (traits_type::eq_int_type(__tmp, traits_type::eof()))
__ret = -1;
}
return __ret;
}
template<typename _CharT, typename _Traits>
void
basic_filebuf<_CharT, _Traits>::
imbue(const locale& __loc)
{
bool __testvalid = true;
const __codecvt_type* _M_codecvt_tmp = 0;
if (__builtin_expect(has_facet<__codecvt_type>(__loc), true))
_M_codecvt_tmp = &use_facet<__codecvt_type>(__loc);
if (this->is_open())
{
// encoding() == -1 is ok only at the beginning.
if ((_M_reading || _M_writing)
&& __check_facet(_M_codecvt).encoding() == -1)
__testvalid = false;
else
{
if (_M_reading)
{
if (__check_facet(_M_codecvt).always_noconv())
{
if (_M_codecvt_tmp
&& !__check_facet(_M_codecvt_tmp).always_noconv())
__testvalid = this->seekoff(0, ios_base::cur, _M_mode)
!= pos_type(off_type(-1));
}
else
{
// External position corresponding to gptr().
_M_ext_next = _M_ext_buf
+ _M_codecvt->length(_M_state_last, _M_ext_buf,
_M_ext_next,
this->gptr() - this->eback());
const streamsize __remainder = _M_ext_end - _M_ext_next;
if (__remainder)
__builtin_memmove(_M_ext_buf, _M_ext_next, __remainder);
_M_ext_next = _M_ext_buf;
_M_ext_end = _M_ext_buf + __remainder;
_M_set_buffer(-1);
_M_state_last = _M_state_cur = _M_state_beg;
}
}
else if (_M_writing && (__testvalid = _M_terminate_output()))
_M_set_buffer(-1);
}
}
if (__testvalid)
_M_codecvt = _M_codecvt_tmp;
else
_M_codecvt = 0;
}
// Inhibit implicit instantiations for required instantiations,
// which are defined via explicit instantiations elsewhere.
#if _GLIBCXX_EXTERN_TEMPLATE
extern template class basic_filebuf<char>;
extern template class basic_ifstream<char>;
extern template class basic_ofstream<char>;
extern template class basic_fstream<char>;
#ifdef _GLIBCXX_USE_WCHAR_T
extern template class basic_filebuf<wchar_t>;
extern template class basic_ifstream<wchar_t>;
extern template class basic_ofstream<wchar_t>;
extern template class basic_fstream<wchar_t>;
#endif
#endif
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif
cerrno
cxxabi_forced.h
move.h
std::move
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:104
std::swap
void swap(any &__x, any &__y) noexcept
Exchange the states of two any objects.
Definition: any:428
std::min
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:230
std
ISO C++ entities toplevel namespace is std.
std::streamsize
ptrdiff_t streamsize
Integral type for I/O operation counts and buffer sizes.
Definition: postypes.h:98
std::basic_filebuf
The actual work of input and output (for files).
Definition: fstream:86
std::basic_filebuf::seekoff
virtual pos_type seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __mode=ios_base::in|ios_base::out)
Alters the stream positions.
Definition: fstream.tcc:833
std::basic_filebuf::underflow
virtual int_type underflow()
Fetches more data from the controlled sequence.
Definition: fstream.tcc:324
std::basic_filebuf::showmanyc
virtual streamsize showmanyc()
Investigating the data available.
Definition: fstream.tcc:298
std::basic_filebuf::_M_mode
ios_base::openmode _M_mode
Place to stash in || out || in | out settings for current filebuf.
Definition: fstream:126
std::basic_filebuf::imbue
virtual void imbue(const locale &__loc)
Changes translations.
Definition: fstream.tcc:1030
std::basic_filebuf::xsgetn
virtual streamsize xsgetn(char_type *__s, streamsize __n)
Multiple character extraction.
Definition: fstream.tcc:670
std::basic_filebuf::close
__filebuf_type * close()
Closes the currently associated file.
Definition: fstream.tcc:250
std::basic_filebuf::seekpos
virtual pos_type seekpos(pos_type __pos, ios_base::openmode __mode=ios_base::in|ios_base::out)
Alters the stream positions.
Definition: fstream.tcc:893
std::basic_filebuf::pbackfail
virtual int_type pbackfail(int_type __c=_Traits::eof())
Tries to back up the input sequence.
Definition: fstream.tcc:483
std::basic_filebuf::xsputn
virtual streamsize xsputn(const char_type *__s, streamsize __n)
Multiple character insertion.
Definition: fstream.tcc:756
std::basic_filebuf::_M_pback_init
bool _M_pback_init
Definition: fstream:172
std::basic_filebuf::overflow
virtual int_type overflow(int_type __c=_Traits::eof())
Consumes data from the buffer; writes to the controlled sequence.
Definition: fstream.tcc:542
std::basic_filebuf::_M_reading
bool _M_reading
Definition: fstream:160
std::basic_filebuf::open
__filebuf_type * open(const char *__s, ios_base::openmode __mode)
Opens an external file.
Definition: fstream.tcc:180
std::basic_filebuf::basic_filebuf
basic_filebuf()
Does not open any files.
Definition: fstream.tcc:81
std::basic_filebuf::_M_set_buffer
void _M_set_buffer(streamsize __off)
Definition: fstream:464
std::basic_filebuf::sync
virtual int sync()
Synchronizes the buffer arrays with the controlled sequences.
Definition: fstream.tcc:1013
std::basic_filebuf::setbuf
virtual __streambuf_type * setbuf(char_type *__s, streamsize __n)
Manipulates the buffer.
Definition: fstream.tcc:804
std::basic_ifstream
Controlling input for files.
Definition: fstream:498
std::basic_ofstream
Controlling output for files.
Definition: fstream:759
std::basic_fstream
Controlling input and output for files.
Definition: fstream:1022
std::basic_streambuf
The actual work of input and output (interface).
Definition: streambuf:123
std::basic_streambuf::_M_buf_locale
locale _M_buf_locale
Current locale setting.
Definition: streambuf:197
std::codecvt
Primary class template codecvt.
Definition: codecvt.h:279
std::ios_base
The base of the I/O class hierarchy.
Definition: ios_base.h:229
std::ios_base::cur
static const seekdir cur
Request a seek relative to the current position within the sequence.
Definition: ios_base.h:485
std::ios_base::beg
static const seekdir beg
Request a seek relative to the beginning of the stream.
Definition: ios_base.h:482
std::ios_base::end
static const seekdir end
Request a seek relative to the current end of the sequence.
Definition: ios_base.h:488
std::ios_base::in
static const openmode in
Open for input. Default for ifstream and fstream.
Definition: ios_base.h:461
std::ios_base::out
static const openmode out
Open for output. Default for ofstream and fstream.
Definition: ios_base.h:464
std::ios_base::binary
static const openmode binary
Perform input and output in binary mode (as opposed to text mode). This is probably not what you thin...
Definition: ios_base.h:458
std::ios_base::openmode
_Ios_Openmode openmode
This is a bitmask type.
Definition: ios_base.h:447
std::ios_base::app
static const openmode app
Seek to end before each write.
Definition: ios_base.h:450
std::ios_base::ate
static const openmode ate
Open and seek to end immediately after opening.
Definition: ios_base.h:453
std::locale
Container class for localization functionality.
Definition: locale_classes.h:63