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Whole document tree                   basic_file.h Go to the documentation of this file. // Wrapper of C-language FILE struct -*- C++ -*- // Copyright (C) 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_BASIC_FILE #define _CPP_BASIC_FILE 1 #pragma GCC system_header #include <bits/c++config.h> #include <bits/std_ios.h> namespace std { // Ulrich is going to make some detailed comment here, explaining // all this unpleasantness, providing detailed performance analysis // as to why we have to do all this lame vtable hacking instead of a // sane, function-based approach. This verbiage will provide a clear // and detailed description of the whole object-layout, // vtable-swapping, sordid history of this hack. template<typename _CharT> struct __basic_file_base: public __c_file_type { virtual ~__basic_file_base() { }; virtual int overflow(int __c = EOF) = 0; virtual int underflow() = 0; virtual int uflow() = 0; virtual int pbackfail(int __c) = 0; virtual streamsize xsputn(const _CharT* __s, streamsize __n) = 0; virtual streamsize xsgetn(_CharT* __s, streamsize __n) = 0; virtual streamoff seekoff(streamoff __off, ios_base::seekdir __way, ios_base::openmode __mode = ios_base::in | ios_base::out) = 0; virtual streamoff seekpos(streamoff __pos, ios_base::openmode __mode = ios_base::in | ios_base::out) = 0; virtual streambuf* setbuf(_CharT* __b, int __len) = 0; virtual int sync() = 0; virtual int doallocate() = 0; virtual streamsize sys_read(_CharT* __s, streamsize __n) = 0; virtual streamsize sys_write(const _CharT* __s, streamsize __n) = 0; virtual streamoff sys_seek(streamoff __off, ios_base::seekdir __way) = 0; virtual int sys_close() = 0; virtual int sys_stat(void* __v) = 0; virtual int showmanyc() = 0; virtual void imbue(void* __v) = 0; }; // Some of these member functions are based on libio/filebuf.cc. // Also note that the order and number of virtual functions has to precisely // match the order and number in the _IO_jump_t struct defined in libioP.h. template<typename _CharT> #ifdef _GLIBCPP_BASIC_FILE_INHERITANCE class __basic_file: public __basic_file_base<_CharT> #else class __basic_file #endif { #if _GLIBCPP_BASIC_FILE_ENCAPSULATION __c_file_type* _M_cfile; bool _M_cfile_created; #else # ifdef _GLIBCPP_USE_WCHAR_T __c_wfile_type _M_wfile; # endif #endif public: __basic_file(__c_lock* __lock = 0); void _M_open_mode(ios_base::openmode __mode, int& __p_mode, int& __rw_mode, char* __c_mode); // Equivalent to the normal fopen function. __basic_file* open(const char* __name, ios_base::openmode __mode, int __prot = 0664); // Used for opening the standard streams, cin, cout, cerr, clog, // and their wide-stream equivalents. Instead of calling open, it // just sets __c_file_type->_fileno and the respective _flags bits, and // returns. __basic_file* sys_open(__c_file_type* __file, ios_base::openmode __mode); _CharT sys_getc(); _CharT sys_ungetc(_CharT); __basic_file* close(); bool is_open(); // NB: Must match FILE specific jump table starting here--this // means all virtual functions starting with the dtor must match, // slot by slot. For glibc-based dystems, this means the _IO_FILE // as the FILE struct and _IO_jump_t as the jump table. virtual ~__basic_file(); // Takes the place of __finish. virtual int overflow(int __c = EOF); virtual int underflow(); virtual int uflow(); virtual int pbackfail(int __c); // A complex "write" function that sets all of __c_file_type's // pointers and associated data members correctly and manages its // relation to the external byte sequence. virtual streamsize xsputn(const _CharT* __s, streamsize __n); // A complex "read" function that sets all of __c_file_type's // pointers and associated data members correctly and manages its // relation to the external byte sequence. virtual streamsize xsgetn(_CharT* __s, streamsize __n); // A complex "seekoff" function that sets all of __c_file_type's // pointers and associated data members correctly and manages its // relation to the external byte sequence. virtual streamoff seekoff(streamoff __off, ios_base::seekdir __way, ios_base::openmode __mode = ios_base::in | ios_base::out); // A complex "seekpos" function that sets all of __c_file_type's // pointers and associated data members correctly and manages its // relation to the external byte sequence. virtual streamoff seekpos(streamoff __pos, ios_base::openmode __mode = ios_base::in | ios_base::out); virtual streambuf* setbuf(_CharT* __b, int __len); virtual int sync(); virtual int doallocate(); // A simple read function for the external byte sequence, that // does no mucking around with or setting of the pointers or flags // in __c_file_type. virtual streamsize sys_read(_CharT* __s, streamsize __n); // A simple write function for the external byte sequence, that // does no mucking around with or setting of the pointers or flags // in __c_file_type. virtual streamsize sys_write(const _CharT* __s, streamsize __n); // A simple seek function for the external byte sequence, that // does no mucking around with or setting of the pointers or flags // in __c_file_type. virtual streamoff sys_seek(streamoff __off, ios_base::seekdir __way); virtual int sys_close(); virtual int sys_stat(void* __v); virtual int showmanyc(); virtual void imbue(void* __v); }; } // namespace std // Now include the bits that are dependant on the underlying I/O // model chosen at configure time. #include <bits/basic_file_model.h> #endif // _CPP_BASIC_FILE