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Whole document tree                   std_fstream.h Go to the documentation of this file. // 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 // #ifndef _CPP_FSTREAM #define _CPP_FSTREAM 1 #pragma GCC system_header #include <bits/std_istream.h> #include <bits/std_ostream.h> #include <bits/basic_file.h> #include <bits/std_locale.h> // 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)); 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; if (__testput) { // Make sure that libio resyncs its idea of the file position // with the external file. _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()) 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