// 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 { // [27.8.1.1] template class basic_filebuf /** * @brief The actual work of input and output (for files). * * This class associates both its input and output sequence with an * external disk file, and maintains a joint file position for both * sequences. Many of its sematics are described in terms of similar * behavior in the Standard C Library's @c FILE streams. */ 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; //@{ /** * @if maint * @doctodo * @endif */ 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. /** * @if maint * @doctodo * @endif */ __c_lock _M_lock; // External buffer. /** * @if maint * @doctodo * @endif */ __file_type _M_file; // Current and beginning state type for codecvt. /** * @if maint * @doctodo * @endif */ __state_type _M_state_cur; __state_type _M_state_beg; // Set iff _M_buf is allocated memory from _M_allocate_internal_buffer. /** * @if maint * @doctodo * @endif */ bool _M_buf_allocated; // XXX Needed? bool _M_last_overflowed; // The position in the buffer corresponding to the external file // pointer. /** * @if maint * @doctodo * @endif */ char_type* _M_filepos; public: // Constructors/destructor: /** * @brief Does not open any files. * * The default constructor initializes the parent class using its * own default ctor. */ basic_filebuf(); /** * @brief The destructor closes the file first. */ virtual ~basic_filebuf() { this->close(); _M_last_overflowed = false; } // Members: /** * @brief Returns true if the external file is open. */ bool is_open() const { return _M_file.is_open(); } /** * @brief Opens an external file. * @param s The name of the file. * @param mode The open mode flags. * @return @c this on success, NULL on failure * * If a file is already open, this function immediately fails. * Otherwise it tries to open the file named @a s using the flags * given in @a mode. * * [Table 92 gives the relation between openmode combinations and the * equivalent fopen() flags, but the table has not been copied yet.] */ __filebuf_type* open(const char* __s, ios_base::openmode __mode); /** * @brief Closes the currently associated file. * @return @c this on success, NULL on failure * * If no file is currently open, this function immediately fails. * * If a "put buffer area" exists, @c overflow(eof) is called to flush * all the characters. The file is then closed. * * If any operations fail, this function also fails. */ __filebuf_type* close(); protected: /** * @if maint * @doctodo * @endif */ void _M_allocate_internal_buffer(); /** * @if maint * @doctodo * @endif */ void _M_destroy_internal_buffer(); // [27.8.1.4] overridden virtual functions // [documentation is inherited] 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. /** * @if maint * @doctodo * @endif */ int_type _M_underflow_common(bool __bump); // [documentation is inherited] virtual int_type underflow(); // [documentation is inherited] virtual int_type uflow(); // [documentation is inherited] 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. // [documentation is inherited] 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. /** * @if maint * @doctodo * @endif */ int_type _M_really_overflow(int_type __c = _Traits::eof()); // Convert internal byte sequence to external, char-based // sequence via codecvt. /** * @if maint * @doctodo * @endif */ void _M_convert_to_external(char_type*, streamsize, streamsize&, streamsize&); /** * @brief Manipulates the buffer. * @param s Pointer to a buffer area. * @param n Size of @a s. * @return @c this * * If no file has been opened, and both @a s and @a n are zero, then * the stream becomes unbuffered. Otherwise, @c s is used as a * buffer; see * http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 * for more. */ virtual __streambuf_type* setbuf(char_type* __s, streamsize __n); // [documentation is inherited] virtual pos_type seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __mode = ios_base::in | ios_base::out); // [documentation is inherited] virtual pos_type seekpos(pos_type __pos, ios_base::openmode __mode = ios_base::in | ios_base::out); // [documentation is inherited] 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; } // [documentation is inherited] virtual void imbue(const locale& __loc); // [documentation is inherited] 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; } // [documentation is inherited] virtual streamsize xsputn(const char_type* __s, streamsize __n) { _M_pback_destroy(); return __streambuf_type::xsputn(__s, __n); } /** * @if maint * @doctodo * @endif */ 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. /** * @if maint * @doctodo * @endif */ 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; } /** * @if maint * @doctodo * @endif */ 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; } /** * @if maint * @doctodo * @endif */ 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; } }; // Explicit specialization declarations, defined in src/fstream.cc. template<> basic_filebuf<char>::int_type basic_filebuf<char>::_M_underflow_common(bool __bump); #ifdef _GLIBCPP_USE_WCHAR_T template<> basic_filebuf<wchar_t>::int_type basic_filebuf<wchar_t>::_M_underflow_common(bool __bump); #endif // Generic definitions. template <typename _CharT, typename _Traits> basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>::underflow() { return _M_underflow_common(false); } template <typename _CharT, typename _Traits> basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>::uflow() { return _M_underflow_common(true); } // [27.8.1.5] Template class basic_ifstream /** * @brief Controlling input for files. * * This class supports reading from named files, using the inherited * functions from std::basic_istream. To control the associated * sequence, an instance of std::basic_filebuf is used, which this page * refers to as @c sb. */ 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: /** * @if maint * @doctodo * @endif */ __filebuf_type _M_filebuf; public: // Constructors/Destructors: /** * @brief Default constructor. * * Initializes @c sb using its default constructor, and passes * @c &sb to the base class initializer. Does not open any files * (you haven't given it a filename to open). */ basic_ifstream() : __istream_type(NULL), _M_filebuf() { this->init(&_M_filebuf); } /** * @brief Create an input file stream. * @param s Null terminated string specifying the filename. * @param mode Open file in specified mode (see std::ios_base). * * @c ios_base::in is automatically included in @a mode. * * 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); } /** * @brief The destructor does nothing. * * The file is closed by the filebuf object, not the formatting * stream. */ ~basic_ifstream() { } // Members: /** * @brief Accessing the underlying buffer. * @return The current basic_filebuf buffer. * * This hides both signatures of std::basic_ios::rdbuf(). */ __filebuf_type* rdbuf() const { return const_cast<__filebuf_type*>(&_M_filebuf); } /** * @brief Wrapper to test for an open file. * @return @c rdbuf()->is_open() */ bool is_open() { return _M_filebuf.is_open(); } /** * @brief Opens an external file. * @param s The name of the file. * @param mode The open mode flags. * * Calls @c std::basic_filebuf::open(s,mode|in). If that function * fails, @c failbit is set in the stream's error state. * * 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) { if (!_M_filebuf.open(__s, __mode | ios_base::in)) this->setstate(ios_base::failbit); } /** * @brief Close the file. * * Calls @c std::basic_filebuf::close(). If that function * fails, @c failbit is set in the stream's error state. */ void close() { if (!_M_filebuf.close()) this->setstate(ios_base::failbit); } }; // [27.8.1.8] Template class basic_ofstream /** * @brief Controlling output for files. * * This class supports reading from named files, using the inherited * functions from std::basic_ostream. To control the associated * sequence, an instance of std::basic_filebuf is used, which this page * refers to as @c sb. */ 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: /** * @if maint * @doctodo * @endif */ __filebuf_type _M_filebuf; public: // Constructors: /** * @brief Default constructor. * * Initializes @c sb using its default constructor, and passes * @c &sb to the base class initializer. Does not open any files * (you haven't given it a filename to open). */ basic_ofstream() : __ostream_type(NULL), _M_filebuf() { this->init(&_M_filebuf); } /** * @brief Create an output file stream. * @param s Null terminated string specifying the filename. * @param mode Open file in specified mode (see std::ios_base). * * @c ios_base::out|ios_base::trunc is automatically included in * @a mode. * * 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); } /** * @brief The destructor does nothing. * * The file is closed by the filebuf object, not the formatting * stream. */ ~basic_ofstream() { } // Members: /** * @brief Accessing the underlying buffer. * @return The current basic_filebuf buffer. * * This hides both signatures of std::basic_ios::rdbuf(). */ __filebuf_type* rdbuf() const { return const_cast<__filebuf_type*>(&_M_filebuf); } /** * @brief Wrapper to test for an open file. * @return @c rdbuf()->is_open() */ bool is_open() { return _M_filebuf.is_open(); } /** * @brief Opens an external file. * @param s The name of the file. * @param mode The open mode flags. * * Calls @c std::basic_filebuf::open(s,mode|out|trunc). If that * function fails, @c failbit is set in the stream's error state. * * 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); } /** * @brief Close the file. * * Calls @c std::basic_filebuf::close(). If that function * fails, @c failbit is set in the stream's error state. */ void close() { if (!_M_filebuf.close()) this->setstate(ios_base::failbit); } }; // [27.8.1.11] Template class basic_fstream /** * @brief Controlling intput and output for files. * * This class supports reading from and writing to named files, using * the inherited functions from std::basic_iostream. To control the * associated sequence, an instance of std::basic_filebuf is used, which * this page refers to as @c sb. */ 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: /** * @if maint * @doctodo * @endif */ __filebuf_type _M_filebuf; public: // Constructors/destructor: /** * @brief Default constructor. * * Initializes @c sb using its default constructor, and passes * @c &sb to the base class initializer. Does not open any files * (you haven't given it a filename to open). */ basic_fstream() : __iostream_type(NULL), _M_filebuf() { this->init(&_M_filebuf); } /** * @brief Create an input/output file stream. * @param s Null terminated string specifying the 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); } /** * @brief The destructor does nothing. * * The file is closed by the filebuf object, not the formatting * stream. */ ~basic_fstream() { } // Members: /** * @brief Accessing the underlying buffer. * @return The current basic_filebuf buffer. * * This hides both signatures of std::basic_ios::rdbuf(). */ __filebuf_type* rdbuf() const { return const_cast<__filebuf_type*>(&_M_filebuf); } /** * @brief Wrapper to test for an open file. * @return @c rdbuf()->is_open() */ bool is_open() { return _M_filebuf.is_open(); } /** * @brief Opens an external file. * @param s The name of the file. * @param mode The open mode flags. * * Calls @c std::basic_filebuf::open(s,mode). If that * function fails, @c failbit is set in the stream's error state. * * 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); } /** * @brief Close the file. * * Calls @c std::basic_filebuf::close(). If that function * fails, @c failbit is set in the stream's error state. */ 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