1 // File descriptor layer for filebuf -*- C++ -*- 2 3 // Copyright (C) 2002, 2003, 2004, 2005, 2009, 2010 4 // Free Software Foundation, Inc. 5 // 6 // This file is part of the GNU ISO C++ Library. This library is free 7 // software; you can redistribute it and/or modify it under the 8 // terms of the GNU General Public License as published by the 9 // Free Software Foundation; either version 3, or (at your option) 10 // any later version. 11 12 // This library is distributed in the hope that it will be useful, 13 // but WITHOUT ANY WARRANTY; without even the implied warranty of 14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 // GNU General Public License for more details. 16 17 // Under Section 7 of GPL version 3, you are granted additional 18 // permissions described in the GCC Runtime Library Exception, version 19 // 3.1, as published by the Free Software Foundation. 20 21 // You should have received a copy of the GNU General Public License and 22 // a copy of the GCC Runtime Library Exception along with this program; 23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24 // <http://www.gnu.org/licenses/>. 25 26 /** @file ext/stdio_filebuf.h 27 * This file is a GNU extension to the Standard C++ Library. 28 */ 29 30 #ifndef _STDIO_FILEBUF_H 31 #define _STDIO_FILEBUF_H 1 32 33 #pragma GCC system_header 34 35 #include <fstream> 36 37 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) 38 { 39 _GLIBCXX_BEGIN_NAMESPACE_VERSION 40 41 /** 42 * @brief Provides a layer of compatibility for C/POSIX. 43 * @ingroup io 44 * 45 * This GNU extension provides extensions for working with standard C 46 * FILE*'s and POSIX file descriptors. It must be instantiated by the 47 * user with the type of character used in the file stream, e.g., 48 * stdio_filebuf<char>. 49 */ 50 template<typename _CharT, typename _Traits = std::char_traits<_CharT> > 51 class stdio_filebuf : public std::basic_filebuf<_CharT, _Traits> 52 { 53 public: 54 // Types: 55 typedef _CharT char_type; 56 typedef _Traits traits_type; 57 typedef typename traits_type::int_type int_type; 58 typedef typename traits_type::pos_type pos_type; 59 typedef typename traits_type::off_type off_type; 60 typedef std::size_t size_t; 61 62 public: 63 /** 64 * deferred initialization 65 */ 66 stdio_filebuf() : std::basic_filebuf<_CharT, _Traits>() {} 67 68 /** 69 * @param __fd An open file descriptor. 70 * @param __mode Same meaning as in a standard filebuf. 71 * @param __size Optimal or preferred size of internal buffer, 72 * in chars. 73 * 74 * This constructor associates a file stream buffer with an open 75 * POSIX file descriptor. The file descriptor will be automatically 76 * closed when the stdio_filebuf is closed/destroyed. 77 */ 78 stdio_filebuf(int __fd, std::ios_base::openmode __mode, 79 size_t __size = static_cast<size_t>(BUFSIZ)); 80 81 /** 82 * @param __f An open @c FILE*. 83 * @param __mode Same meaning as in a standard filebuf. 84 * @param __size Optimal or preferred size of internal buffer, 85 * in chars. Defaults to system's @c BUFSIZ. 86 * 87 * This constructor associates a file stream buffer with an open 88 * C @c FILE*. The @c FILE* will not be automatically closed when the 89 * stdio_filebuf is closed/destroyed. 90 */ 91 stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode, 92 size_t __size = static_cast<size_t>(BUFSIZ)); 93 94 /** 95 * Closes the external data stream if the file descriptor constructor 96 * was used. 97 */ 98 virtual 99 ~stdio_filebuf(); 100 101 /** 102 * @return The underlying file descriptor. 103 * 104 * Once associated with an external data stream, this function can be 105 * used to access the underlying POSIX file descriptor. Note that 106 * there is no way for the library to track what you do with the 107 * descriptor, so be careful. 108 */ 109 int 110 fd() { return this->_M_file.fd(); } 111 112 /** 113 * @return The underlying FILE*. 114 * 115 * This function can be used to access the underlying "C" file pointer. 116 * Note that there is no way for the library to track what you do 117 * with the file, so be careful. 118 */ 119 std::__c_file* 120 file() { return this->_M_file.file(); } 121 }; 122 123 template<typename _CharT, typename _Traits> 124 stdio_filebuf<_CharT, _Traits>::~stdio_filebuf() 125 { } 126 127 template<typename _CharT, typename _Traits> 128 stdio_filebuf<_CharT, _Traits>:: 129 stdio_filebuf(int __fd, std::ios_base::openmode __mode, size_t __size) 130 { 131 this->_M_file.sys_open(__fd, __mode); 132 if (this->is_open()) 133 { 134 this->_M_mode = __mode; 135 this->_M_buf_size = __size; 136 this->_M_allocate_internal_buffer(); 137 this->_M_reading = false; 138 this->_M_writing = false; 139 this->_M_set_buffer(-1); 140 } 141 } 142 143 template<typename _CharT, typename _Traits> 144 stdio_filebuf<_CharT, _Traits>:: 145 stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode, 146 size_t __size) 147 { 148 this->_M_file.sys_open(__f, __mode); 149 if (this->is_open()) 150 { 151 this->_M_mode = __mode; 152 this->_M_buf_size = __size; 153 this->_M_allocate_internal_buffer(); 154 this->_M_reading = false; 155 this->_M_writing = false; 156 this->_M_set_buffer(-1); 157 } 158 } 159 160 _GLIBCXX_END_NAMESPACE_VERSION 161 } // namespace 162 163 #endif 164