1 // File descriptor layer for filebuf -*- C++ -*- 2 3 // Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 2, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // You should have received a copy of the GNU General Public License along 17 // with this library; see the file COPYING. If not, write to the Free 18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, 19 // USA. 20 21 // As a special exception, you may use this file as part of a free software 22 // library without restriction. Specifically, if other files instantiate 23 // templates or use macros or inline functions from this file, or you compile 24 // this file and link it with other files to produce an executable, this 25 // file does not by itself cause the resulting executable to be covered by 26 // the GNU General Public License. This exception does not however 27 // invalidate any other reasons why the executable file might be covered by 28 // the GNU General Public License. 29 30 /** @file ext/stdio_filebuf.h 31 * This file is a GNU extension to the Standard C++ Library. 32 */ 33 34 #ifndef _STDIO_FILEBUF_H 35 #define _STDIO_FILEBUF_H 1 36 37 #pragma GCC system_header 38 39 #include <fstream> 40 41 namespace __gnu_cxx 42 { 43 /** 44 * @class stdio_filebuf ext/stdio_filebuf.h <ext/stdio_filebuf.h> 45 * @brief Provides a layer of compatibility for C/POSIX. 46 * 47 * This GNU extension provides extensions for working with standard C 48 * FILE*'s and POSIX file descriptors. It must be instantiated by the 49 * user with the type of character used in the file stream, e.g., 50 * stdio_filebuf<char>. 51 */ 52 template<typename _CharT, typename _Traits = std::char_traits<_CharT> > 53 class stdio_filebuf : public std::basic_filebuf<_CharT, _Traits> 54 { 55 public: 56 // Types: 57 typedef _CharT char_type; 58 typedef _Traits traits_type; 59 typedef typename traits_type::int_type int_type; 60 typedef typename traits_type::pos_type pos_type; 61 typedef typename traits_type::off_type off_type; 62 typedef std::size_t size_t; 63 64 public: 65 /** 66 * deferred initialization 67 */ 68 stdio_filebuf() : std::basic_filebuf<_CharT, _Traits>() {} 69 70 /** 71 * @param fd An open file descriptor. 72 * @param mode Same meaning as in a standard filebuf. 73 * @param size Optimal or preferred size of internal buffer, in chars. 74 * 75 * This constructor associates a file stream buffer with an open 76 * POSIX file descriptor. The file descriptor will be automatically 77 * closed when the stdio_filebuf is closed/destroyed. 78 */ 79 stdio_filebuf(int __fd, std::ios_base::openmode __mode, 80 size_t __size = static_cast<size_t>(BUFSIZ)); 81 82 /** 83 * @param f An open @c FILE*. 84 * @param mode Same meaning as in a standard filebuf. 85 * @param size Optimal or preferred size of internal buffer, in chars. 86 * Defaults to system's @c BUFSIZ. 87 * 88 * This constructor associates a file stream buffer with an open 89 * C @c FILE*. The @c FILE* will not be automatically closed when the 90 * stdio_filebuf is closed/destroyed. 91 */ 92 stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode, 93 size_t __size = static_cast<size_t>(BUFSIZ)); 94 95 /** 96 * Closes the external data stream if the file descriptor constructor 97 * was used. 98 */ 99 virtual 100 ~stdio_filebuf(); 101 102 /** 103 * @return The underlying file descriptor. 104 * 105 * Once associated with an external data stream, this function can be 106 * used to access the underlying POSIX file descriptor. Note that 107 * there is no way for the library to track what you do with the 108 * descriptor, so be careful. 109 */ 110 int 111 fd() { return this->_M_file.fd(); } 112 113 /** 114 * @return The underlying FILE*. 115 * 116 * This function can be used to access the underlying "C" file pointer. 117 * Note that there is no way for the library to track what you do 118 * with the file, so be careful. 119 */ 120 std::__c_file* 121 file() { return this->_M_file.file(); } 122 }; 123 124 template<typename _CharT, typename _Traits> 125 stdio_filebuf<_CharT, _Traits>::~stdio_filebuf() 126 { } 127 128 template<typename _CharT, typename _Traits> 129 stdio_filebuf<_CharT, _Traits>:: 130 stdio_filebuf(int __fd, std::ios_base::openmode __mode, size_t __size) 131 { 132 this->_M_file.sys_open(__fd, __mode); 133 if (this->is_open()) 134 { 135 this->_M_mode = __mode; 136 this->_M_buf_size = __size; 137 this->_M_allocate_internal_buffer(); 138 this->_M_reading = false; 139 this->_M_writing = false; 140 this->_M_set_buffer(-1); 141 } 142 } 143 144 template<typename _CharT, typename _Traits> 145 stdio_filebuf<_CharT, _Traits>:: 146 stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode, 147 size_t __size) 148 { 149 this->_M_file.sys_open(__f, __mode); 150 if (this->is_open()) 151 { 152 this->_M_mode = __mode; 153 this->_M_buf_size = __size; 154 this->_M_allocate_internal_buffer(); 155 this->_M_reading = false; 156 this->_M_writing = false; 157 this->_M_set_buffer(-1); 158 } 159 } 160 } // namespace __gnu_cxx 161 162 #endif 163