/home/ntakagi/work/STLport-5.1.5/stlport/stl/_fstream.c Go to the documentation of this file. /* * Copyright (c) 1996,1997 * Silicon Graphics Computer Systems, Inc. * * Copyright (c) 1999 * Boris Fomitchev * * This material is provided "as is", with absolutely no warranty expressed * or implied. Any use is at your own risk. * * Permission to use or copy this software for any purpose is hereby granted * without fee, provided the above notices are retained on all copies. * Permission to modify the code and to distribute modified code is granted, * provided the above notices are retained, and a notice that the code was * modified is included with the above copyright notice. * */ #ifndef _STLP_FSTREAM_C #define _STLP_FSTREAM_C #ifndef _STLP_INTERNAL_FSTREAM_H # include <stl/_fstream.h> #endif #ifndef _STLP_INTERNAL_LIMITS # include <stl/_limits.h> #endif _STLP_BEGIN_NAMESPACE # if defined ( _STLP_NESTED_TYPE_PARAM_BUG ) // no wchar_t is supported for this mode # define __BF_int_type__ int # define __BF_pos_type__ streampos # define __BF_off_type__ streamoff # else # define __BF_int_type__ _STLP_TYPENAME_ON_RETURN_TYPE basic_filebuf<_CharT, _Traits>::int_type # define __BF_pos_type__ _STLP_TYPENAME_ON_RETURN_TYPE basic_filebuf<_CharT, _Traits>::pos_type # define __BF_off_type__ _STLP_TYPENAME_ON_RETURN_TYPE basic_filebuf<_CharT, _Traits>::off_type # endif //---------------------------------------------------------------------- // Public basic_filebuf<> member functions template <class _CharT, class _Traits> basic_filebuf<_CharT, _Traits>::basic_filebuf() : basic_streambuf<_CharT, _Traits>(), _M_base(), _M_constant_width(false), _M_always_noconv(false), _M_int_buf_dynamic(false), _M_in_input_mode(false), _M_in_output_mode(false), _M_in_error_mode(false), _M_in_putback_mode(false), _M_int_buf(0), _M_int_buf_EOS(0), _M_ext_buf(0), _M_ext_buf_EOS(0), _M_ext_buf_converted(0), _M_ext_buf_end(0), _M_state(_STLP_DEFAULT_CONSTRUCTED(_State_type)), _M_end_state(_STLP_DEFAULT_CONSTRUCTED(_State_type)), _M_mmap_base(0), _M_mmap_len(0), _M_saved_eback(0), _M_saved_gptr(0), _M_saved_egptr(0), _M_codecvt(0), _M_width(1), _M_max_width(1) { this->_M_setup_codecvt(locale(), false); } template <class _CharT, class _Traits> basic_filebuf<_CharT, _Traits>::~basic_filebuf() { this->close(); _M_deallocate_buffers(); } template <class _CharT, class _Traits> _STLP_TYPENAME_ON_RETURN_TYPE basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>::underflow() { return _Underflow<_CharT, _Traits>::_M_doit(this); } template <class _CharT, class _Traits> basic_filebuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::close() { bool __ok = this->is_open(); if (_M_in_output_mode) { __ok = __ok && !_Traits::eq_int_type(this->overflow(traits_type::eof()), traits_type::eof()); __ok == __ok && this->_M_unshift(); } else if (_M_in_input_mode) this->_M_exit_input_mode(); // Note order of arguments. We close the file even if __ok is false. __ok = _M_base._M_close() && __ok; // Restore the initial state, except that we don't deallocate the buffer // or mess with the cached codecvt information. _M_state = _M_end_state = _State_type(); _M_ext_buf_converted = _M_ext_buf_end = 0; _M_mmap_base = 0; _M_mmap_len = 0; this->setg(0, 0, 0); this->setp(0, 0); _M_saved_eback = _M_saved_gptr = _M_saved_egptr = 0; _M_in_input_mode = _M_in_output_mode = _M_in_error_mode = _M_in_putback_mode = false; return __ok ? this : 0; } // This member function is called whenever we exit input mode. // It unmaps the memory-mapped file, if any, and sets // _M_in_input_mode to false. template <class _CharT, class _Traits> void basic_filebuf<_CharT, _Traits>::_M_exit_input_mode() { if (_M_mmap_base != 0) _M_base._M_unmap(_M_mmap_base, _M_mmap_len); _M_in_input_mode = false; _M_mmap_base = 0; } //---------------------------------------------------------------------- // basic_filebuf<> overridden protected virtual member functions template <class _CharT, class _Traits> streamsize basic_filebuf<_CharT, _Traits>::showmanyc() { // Is there any possibility that reads can succeed? if (!this->is_open() || _M_in_output_mode || _M_in_error_mode) return -1; else if (_M_in_putback_mode) return this->egptr() - this->gptr(); else if (_M_constant_width) { streamoff __pos = _M_base._M_seek(0, ios_base::cur); streamoff __size = _M_base._M_file_size(); return __pos >= 0 && __size > __pos ? __size - __pos : 0; } else return 0; } // Make a putback position available, if necessary, by switching to a // special internal buffer used only for putback. The buffer is // [_M_pback_buf, _M_pback_buf + _S_pback_buf_size), but the base // class only sees a piece of it at a time. (We want to make sure // that we don't try to read a character that hasn't been initialized.) // The end of the putback buffer is always _M_pback_buf + _S_pback_buf_size, // but the beginning is usually not _M_pback_buf. template <class _CharT, class _Traits> __BF_int_type__ basic_filebuf<_CharT, _Traits>::pbackfail(int_type __c) { const int_type __eof = traits_type::eof(); // If we aren't already in input mode, pushback is impossible. if (!_M_in_input_mode) return __eof; // We can use the ordinary get buffer if there's enough space, and // if it's a buffer that we're allowed to write to. if (this->gptr() != this->eback() && (traits_type::eq_int_type(__c, __eof) || traits_type::eq(traits_type::to_char_type(__c), this->gptr()[-1]) || !_M_mmap_base)) { this->gbump(-1); if (traits_type::eq_int_type(__c, __eof) || traits_type::eq(traits_type::to_char_type(__c), *this->gptr())) return traits_type::to_int_type(*this->gptr()); } else if (!traits_type::eq_int_type(__c, __eof)) { // Are we in the putback buffer already? _CharT* __pback_end = _M_pback_buf + __STATIC_CAST(int,_S_pback_buf_size); if (_M_in_putback_mode) { // Do we have more room in the putback buffer? if (this->eback() != _M_pback_buf) this->setg(this->egptr() - 1, this->egptr() - 1, __pback_end); else return __eof; // No more room in the buffer, so fail. } else { // We're not yet in the putback buffer. _M_saved_eback = this->eback(); _M_saved_gptr = this->gptr(); _M_saved_egptr = this->egptr(); this->setg(__pback_end - 1, __pback_end - 1, __pback_end); _M_in_putback_mode = true; } } else return __eof; // We have made a putback position available. Assign to it, and return. *this->gptr() = traits_type::to_char_type(__c); return __c; } // This member function flushes the put area, and also outputs the // character __c (unless __c is eof). Invariant: we always leave room // in the internal buffer for one character more than the base class knows // about. We see the internal buffer as [_M_int_buf, _M_int_buf_EOS), but // the base class only sees [_M_int_buf, _M_int_buf_EOS - 1). template <class _CharT, class _Traits> __BF_int_type__ basic_filebuf<_CharT, _Traits>::overflow(int_type __c) { // Switch to output mode, if necessary. if (!_M_in_output_mode) if (!_M_switch_to_output_mode()) return traits_type::eof(); _CharT* __ibegin = this->_M_int_buf; _CharT* __iend = this->pptr(); this->setp(_M_int_buf, _M_int_buf_EOS - 1); // Put __c at the end of the internal buffer. if (!traits_type::eq_int_type(__c, traits_type::eof())) *__iend++ = _Traits::to_char_type(__c); // For variable-width encodings, output may take more than one pass. while (__ibegin != __iend) { const _CharT* __inext = __ibegin; char* __enext = _M_ext_buf; typename _Codecvt::result __status = _M_codecvt->out(_M_state, __ibegin, __iend, __inext, _M_ext_buf, _M_ext_buf_EOS, __enext); if (__status == _Codecvt::noconv) { return _Noconv_output<_Traits>::_M_doit(this, __ibegin, __iend) ? traits_type::not_eof(__c) : _M_output_error(); } // For a constant-width encoding we know that the external buffer // is large enough, so failure to consume the entire internal buffer // or to produce the correct number of external characters, is an error. // For a variable-width encoding, however, we require only that we // consume at least one internal character else if (__status != _Codecvt::error && (((__inext == __iend) && (__enext - _M_ext_buf == _M_width * (__iend - __ibegin))) || (!_M_constant_width && __inext != __ibegin))) { // We successfully converted part or all of the internal buffer. ptrdiff_t __n = __enext - _M_ext_buf; if (_M_write(_M_ext_buf, __n)) __ibegin += __inext - __ibegin; else return _M_output_error(); } else return _M_output_error(); } return traits_type::not_eof(__c); } // This member function must be called before any I/O has been // performed on the stream, otherwise it has no effect. // // __buf == 0 && __n == 0 means to make this stream unbuffered. // __buf != 0 && __n > 0 means to use __buf as the stream's internal // buffer, rather than the buffer that would otherwise be allocated // automatically. __buf must be a pointer to an array of _CharT whose // size is at least __n. template <class _CharT, class _Traits> basic_streambuf<_CharT, _Traits>* basic_filebuf<_CharT, _Traits>::setbuf(_CharT* __buf, streamsize __n) { if (!_M_in_input_mode &&! _M_in_output_mode && !_M_in_error_mode && _M_int_buf == 0) { if (__buf == 0 && __n == 0) _M_allocate_buffers(0, 1); else if (__buf != 0 && __n > 0) _M_allocate_buffers(__buf, __n); } return this; } template <class _CharT, class _Traits> __BF_pos_type__ basic_filebuf<_CharT, _Traits>::seekoff(off_type __off, ios_base::seekdir __whence, ios_base::openmode /* dummy */) { if (this->is_open() && (__off == 0 || (_M_constant_width && this->_M_base._M_in_binary_mode()))) { if (!_M_seek_init(__off != 0 || __whence != ios_base::cur)) return pos_type(-1); // Seek to beginning or end, regardless of whether we're in input mode. if (__whence == ios_base::beg || __whence == ios_base::end) return _M_seek_return(_M_base._M_seek(_M_width * __off, __whence), _State_type()); // Seek relative to current position. Complicated if we're in input mode. else if (__whence == ios_base::cur) { if (!_M_in_input_mode) return _M_seek_return(_M_base._M_seek(_M_width * __off, __whence), _State_type()); else if (_M_mmap_base != 0) { // __off is relative to gptr(). We need to do a bit of arithmetic // to get an offset relative to the external file pointer. streamoff __adjust = _M_mmap_len - (this->gptr() - (_CharT*) _M_mmap_base); // if __off == 0, we do not need to exit input mode and to shift file pointer return __off == 0 ? pos_type(_M_base._M_seek(0, ios_base::cur) - __adjust) : _M_seek_return(_M_base._M_seek(__off - __adjust, ios_base::cur), _State_type()); } else if (_M_constant_width) { // Get or set the position. streamoff __iadj = _M_width * (this->gptr() - this->eback()); // Compensate for offset relative to gptr versus offset relative // to external pointer. For a text-oriented stream, where the // compensation is more than just pointer arithmetic, we may get // but not set the current position. if (__iadj <= _M_ext_buf_end - _M_ext_buf) { streamoff __eadj = _M_base._M_get_offset(_M_ext_buf + __STATIC_CAST(ptrdiff_t, __iadj), _M_ext_buf_end); return __off == 0 ? pos_type(_M_base._M_seek(0, ios_base::cur) - __eadj) : _M_seek_return(_M_base._M_seek(__off - __eadj, ios_base::cur), _State_type()); } } else { // Get the position. Encoding is var width. // Get position in internal buffer. ptrdiff_t __ipos = this->gptr() - this->eback(); // Get corresponding position in external buffer. _State_type __state = _M_state; int __epos = _M_codecvt->length(__state, _M_ext_buf, _M_ext_buf_end, __ipos); if (__epos >= 0) { // Sanity check (expensive): make sure __epos is the right answer. _State_type __tmp_state = _M_state; _Filebuf_Tmp_Buf<_CharT> __buf(__ipos); _CharT* __ibegin = __buf._M_ptr; _CharT* __inext = __ibegin; const char* __dummy; typename _Codecvt::result __status = _M_codecvt->in(__tmp_state, _M_ext_buf, _M_ext_buf + __epos, __dummy, __ibegin, __ibegin + __ipos, __inext); if (__status != _Codecvt::error && (__status == _Codecvt::noconv || (__inext == __ibegin + __ipos && equal(this->eback(), this->gptr(), __ibegin, _STLP_PRIV _Eq_traits<traits_type>())))) { // Get the current position (at the end of the external buffer), // then adjust it. Again, it might be a text-oriented stream. streamoff __cur = _M_base._M_seek(0, ios_base::cur); streamoff __adj = _M_base._M_get_offset(_M_ext_buf, _M_ext_buf + __epos) - _M_base._M_get_offset(_M_ext_buf, _M_ext_buf_end); if (__cur != -1 && __cur + __adj >= 0) return __off == 0 ? pos_type(__cur + __adj) : _M_seek_return(__cur + __adj, __state); //return _M_seek_return(__cur + __adj, __state); } // We failed the sanity check here. } } } // Unrecognized value for __whence here. } return pos_type(-1); } template <class _CharT, class _Traits> __BF_pos_type__ basic_filebuf<_CharT, _Traits>::seekpos(pos_type __pos, ios_base::openmode /* dummy */) { if (this->is_open()) { if (!_M_seek_init(true)) return pos_type(-1); streamoff __off = off_type(__pos); if (__off != -1 && _M_base._M_seek(__off, ios_base::beg) != -1) { _M_state = __pos.state(); return _M_seek_return(__off, __pos.state()); } } return pos_type(-1); } template <class _CharT, class _Traits> int basic_filebuf<_CharT, _Traits>::sync() { if (_M_in_output_mode) return traits_type::eq_int_type(this->overflow(traits_type::eof()), traits_type::eof()) ? -1 : 0; return 0; } // Change the filebuf's locale. This member function has no effect // unless it is called before any I/O is performed on the stream. template <class _CharT, class _Traits> void basic_filebuf<_CharT, _Traits>::imbue(const locale& __loc) { if (!_M_in_input_mode && !_M_in_output_mode && !_M_in_error_mode) { this->_M_setup_codecvt(__loc); } } //---------------------------------------------------------------------- // basic_filebuf<> helper functions. //---------------------------------------- // Helper functions for switching between modes. // This member function is called if we're performing the first I/O // operation on a filebuf, or if we're performing an input operation // immediately after a seek. template <class _CharT, class _Traits> bool basic_filebuf<_CharT, _Traits>::_M_switch_to_input_mode() { if (this->is_open() && (((int)_M_base.__o_mode() & (int)ios_base::in) != 0) && (_M_in_output_mode == 0) && (_M_in_error_mode == 0)) { if (!_M_int_buf && !_M_allocate_buffers()) return false; _M_ext_buf_converted = _M_ext_buf; _M_ext_buf_end = _M_ext_buf; _M_end_state = _M_state; _M_in_input_mode = true; return true; } return false; } // This member function is called if we're performing the first I/O // operation on a filebuf, or if we're performing an output operation // immediately after a seek. template <class _CharT, class _Traits> bool basic_filebuf<_CharT, _Traits>::_M_switch_to_output_mode() { if (this->is_open() && (_M_base.__o_mode() & (int)ios_base::out) && _M_in_input_mode == 0 && _M_in_error_mode == 0) { if (!_M_int_buf && !_M_allocate_buffers()) return false; // In append mode, every write does an implicit seek to the end // of the file. Whenever leaving output mode, the end of file // get put in the initial shift state. if (_M_base.__o_mode() & ios_base::app) _M_state = _State_type(); this->setp(_M_int_buf, _M_int_buf_EOS - 1); _M_in_output_mode = true; return true; } return false; } //---------------------------------------- // Helper functions for input // This member function is called if there is an error during input. // It puts the filebuf in error mode, clear the get area buffer, and // returns eof. // returns eof. Error mode is sticky; it is cleared only by close or // seek. template <class _CharT, class _Traits> __BF_int_type__ basic_filebuf<_CharT, _Traits>::_M_input_error() { this->_M_exit_input_mode(); _M_in_output_mode = false; _M_in_error_mode = true; this->setg(0, 0, 0); return traits_type::eof(); } template <class _CharT, class _Traits> __BF_int_type__ basic_filebuf<_CharT, _Traits>::_M_underflow_aux() { // We have the state and file position from the end of the internal // buffer. This round, they become the beginning of the internal buffer. _M_state = _M_end_state; // Fill the external buffer. Start with any leftover characters that // didn't get converted last time. if (_M_ext_buf_end > _M_ext_buf_converted) _M_ext_buf_end = copy(_M_ext_buf_converted, _M_ext_buf_end, _M_ext_buf); // boris : copy_backward did not work //_M_ext_buf_end = copy_backward(_M_ext_buf_converted, _M_ext_buf_end, //_M_ext_buf+ (_M_ext_buf_end - _M_ext_buf_converted)); else _M_ext_buf_end = _M_ext_buf; // Now fill the external buffer with characters from the file. This is // a loop because occasionally we don't get enough external characters // to make progress. for (;;) { ptrdiff_t __n = _M_base._M_read(_M_ext_buf_end, _M_ext_buf_EOS - _M_ext_buf_end); _M_ext_buf_end += __n; // If external buffer is empty there is nothing to do. if (_M_ext_buf == _M_ext_buf_end) { this->setg(0, 0, 0); return traits_type::eof(); } // Convert the external buffer to internal characters. const char* __enext; _CharT* __inext; typename _Codecvt::result __status = _M_codecvt->in(_M_end_state, _M_ext_buf, _M_ext_buf_end, __enext, _M_int_buf, _M_int_buf_EOS, __inext); /* Error conditions: * (1) Return value of error. * (2) Producing internal characters without consuming external characters. * (3) In fixed-width encodings, producing an internal sequence whose length * is inconsistent with that of the internal sequence. * (4) Failure to produce any characters if we have enough characters in * the external buffer, where "enough" means the largest possible width * of a single character. */ if (__status == _Codecvt::noconv) return _Noconv_input<_Traits>::_M_doit(this); else if (__status == _Codecvt::error || (__inext != _M_int_buf && __enext == _M_ext_buf) || (_M_constant_width && (__inext - _M_int_buf) * _M_width != (__enext - _M_ext_buf)) || (__inext == _M_int_buf && __enext - _M_ext_buf >= _M_max_width)) return _M_input_error(); else if (__inext != _M_int_buf) { _M_ext_buf_converted = _M_ext_buf + (__enext - _M_ext_buf); this->setg(_M_int_buf, _M_int_buf, __inext); return traits_type::to_int_type(*_M_int_buf); } /* We need to go around the loop again to get more external characters. * But if the previous read failed then don't try again for now. * Don't enter error mode for a failed read. Error mode is sticky, * and we might succeed if we try again. */ if (__n <= 0) { this->setg(0, 0, 0); return traits_type::eof(); } } } //---------------------------------------- // Helper functions for output // This member function is called if there is an error during output. // It puts the filebuf in error mode, clear the put area buffer, and // returns eof. Error mode is sticky; it is cleared only by close or // seek. template <class _CharT, class _Traits> __BF_int_type__ basic_filebuf<_CharT, _Traits>::_M_output_error() { _M_in_output_mode = false; _M_in_input_mode = false; _M_in_error_mode = true; this->setp(0, 0); return traits_type::eof(); } // Write whatever sequence of characters is necessary to get back to // the initial shift state. This function overwrites the external // buffer, changes the external file position, and changes the state. // Precondition: the internal buffer is empty. template <class _CharT, class _Traits> bool basic_filebuf<_CharT, _Traits>::_M_unshift() { if (_M_in_output_mode && !_M_constant_width) { typename _Codecvt::result __status; do { char* __enext = _M_ext_buf; __status = _M_codecvt->unshift(_M_state, _M_ext_buf, _M_ext_buf_EOS, __enext); if (__status == _Codecvt::noconv || (__enext == _M_ext_buf && __status == _Codecvt::ok)) return true; else if (__status == _Codecvt::error) return false; else if (!_M_write(_M_ext_buf, __enext - _M_ext_buf)) return false; } while (__status == _Codecvt::partial); } return true; } //---------------------------------------- // Helper functions for buffer allocation and deallocation // This member function is called when we're initializing a filebuf's // internal and external buffers. The argument is the size of the // internal buffer; the external buffer is sized using the character // width in the current encoding. Preconditions: the buffers are currently // null. __n >= 1. __buf is either a null pointer or a pointer to an // array show size is at least __n. // We need __n >= 1 for two different reasons. For input, the base // class always needs a buffer because of the semantics of underflow(). // For output, we want to have an internal buffer that's larger by one // element than the buffer that the base class knows about. (See // basic_filebuf<>::overflow() for the reason.) template <class _CharT, class _Traits> bool basic_filebuf<_CharT, _Traits>::_M_allocate_buffers(_CharT* __buf, streamsize __n) { //The major hypothesis in the following implementation is that size_t is unsigned. //We also need streamsize byte representation to be larger or equal to the int //representation to correctly store the encoding information. _STLP_STATIC_ASSERT(!numeric_limits<size_t>::is_signed && sizeof(streamsize) >= sizeof(int)) if (__buf == 0) { streamsize __bufsize = __n * sizeof(_CharT); //We first check that the streamsize representation can't overflow a size_t one. //If it can, we check that __bufsize is not higher than the size_t max value. if ((sizeof(streamsize) > sizeof(size_t)) && (__bufsize > __STATIC_CAST(streamsize, (numeric_limits<size_t>::max)()))) return false; _M_int_buf = __STATIC_CAST(_CharT*, malloc(__STATIC_CAST(size_t, __bufsize))); if (!_M_int_buf) return false; _M_int_buf_dynamic = true; } else { _M_int_buf = __buf; _M_int_buf_dynamic = false; } streamsize __ebufsiz = (max)(__n * __STATIC_CAST(streamsize, _M_width), __STATIC_CAST(streamsize, _M_codecvt->max_length())); _M_ext_buf = 0; if ((sizeof(streamsize) < sizeof(size_t)) || ((sizeof(streamsize) == sizeof(size_t)) && numeric_limits<streamsize>::is_signed) || (__ebufsiz <= __STATIC_CAST(streamsize, (numeric_limits<size_t>::max)()))) { _M_ext_buf = __STATIC_CAST(char*, malloc(__STATIC_CAST(size_t, __ebufsiz))); } if (!_M_ext_buf) { _M_deallocate_buffers(); return false; } _M_int_buf_EOS = _M_int_buf + __STATIC_CAST(ptrdiff_t, __n); _M_ext_buf_EOS = _M_ext_buf + __STATIC_CAST(ptrdiff_t, __ebufsiz); return true; } // Abbreviation for the most common case. template <class _CharT, class _Traits> bool basic_filebuf<_CharT, _Traits>::_M_allocate_buffers() { // Choose a buffer that's at least 4096 characters long and that's a // multiple of the page size. streamsize __default_bufsiz = ((_M_base.__page_size() + 4095UL) / _M_base.__page_size()) * _M_base.__page_size(); return _M_allocate_buffers(0, __default_bufsiz); } template <class _CharT, class _Traits> void basic_filebuf<_CharT, _Traits>::_M_deallocate_buffers() { if (_M_int_buf_dynamic) free(_M_int_buf); free(_M_ext_buf); _M_int_buf = 0; _M_int_buf_EOS = 0; _M_ext_buf = 0; _M_ext_buf_EOS = 0; } //---------------------------------------- // Helper functiosn for seek and imbue template <class _CharT, class _Traits> bool basic_filebuf<_CharT, _Traits>::_M_seek_init(bool __do_unshift) { // If we're in error mode, leave it. _M_in_error_mode = false; // Flush the output buffer if we're in output mode, and (conditionally) // emit an unshift sequence. if (_M_in_output_mode) { bool __ok = !traits_type::eq_int_type(this->overflow(traits_type::eof()), traits_type::eof()); if (__do_unshift) __ok = __ok && this->_M_unshift(); if (!__ok) { _M_in_output_mode = false; _M_in_error_mode = true; this->setp(0, 0); return false; } } // Discard putback characters, if any. if (_M_in_input_mode && _M_in_putback_mode) _M_exit_putback_mode(); return true; } /* Change the filebuf's locale. This member function has no effect * unless it is called before any I/O is performed on the stream. * This function is called on construction and on an imbue call. In the * case of the construction the codecvt facet might be a custom one if * the basic_filebuf user has instanciate it with a custom char_traits. * The user will have to call imbue before any I/O operation. */ template <class _CharT, class _Traits> void basic_filebuf<_CharT, _Traits>::_M_setup_codecvt(const locale& __loc, bool __on_imbue) { if (has_facet<_Codecvt>(__loc)) { _M_codecvt = &use_facet<_Codecvt>(__loc) ; int __encoding = _M_codecvt->encoding(); _M_width = (max)(__encoding, 1); _M_max_width = _M_codecvt->max_length(); _M_constant_width = __encoding > 0; _M_always_noconv = _M_codecvt->always_noconv(); } else { _M_codecvt = 0; _M_width = _M_max_width = 1; _M_constant_width = _M_always_noconv = false; if (__on_imbue) { //This call will generate an exception reporting the problem. use_facet<_Codecvt>(__loc); } } } _STLP_END_NAMESPACE # undef __BF_int_type__ # undef __BF_pos_type__ # undef __BF_off_type__ #endif /* _STLP_FSTREAM_C */ // Local Variables: // mode:C++ // End:

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