1 // File descriptor layer for filebuf -*- C++ -*- 2 3 // Copyright (C) 2002, 2003, 2004, 2005, 2009 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 3, 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 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file ext/stdio_filebuf.h 26 * This file is a GNU extension to the Standard C++ Library. 27 */ 28 29 #ifndef _STDIO_FILEBUF_H 30 #define _STDIO_FILEBUF_H 1 31 32 #pragma GCC system_header 33 34 #include <fstream> 35 36 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) 37 38 /** 39 * @brief Provides a layer of compatibility for C/POSIX. 40 * 41 * This GNU extension provides extensions for working with standard C 42 * FILE*'s and POSIX file descriptors. It must be instantiated by the 43 * user with the type of character used in the file stream, e.g., 44 * stdio_filebuf<char>. 45 */ 46 template<typename _CharT, typename _Traits = std::char_traits<_CharT> > 47 class stdio_filebuf : public std::basic_filebuf<_CharT, _Traits> 48 { 49 public: 50 // Types: 51 typedef _CharT char_type; 52 typedef _Traits traits_type; 53 typedef typename traits_type::int_type int_type; 54 typedef typename traits_type::pos_type pos_type; 55 typedef typename traits_type::off_type off_type; 56 typedef std::size_t size_t; 57 58 public: 59 /** 60 * deferred initialization 61 */ 62 stdio_filebuf() : std::basic_filebuf<_CharT, _Traits>() {} 63 64 /** 65 * @param fd An open file descriptor. 66 * @param mode Same meaning as in a standard filebuf. 67 * @param size Optimal or preferred size of internal buffer, in chars. 68 * 69 * This constructor associates a file stream buffer with an open 70 * POSIX file descriptor. The file descriptor will be automatically 71 * closed when the stdio_filebuf is closed/destroyed. 72 */ 73 stdio_filebuf(int __fd, std::ios_base::openmode __mode, 74 size_t __size = static_cast<size_t>(BUFSIZ)); 75 76 /** 77 * @param f An open @c FILE*. 78 * @param mode Same meaning as in a standard filebuf. 79 * @param size Optimal or preferred size of internal buffer, in chars. 80 * Defaults to system's @c BUFSIZ. 81 * 82 * This constructor associates a file stream buffer with an open 83 * C @c FILE*. The @c FILE* will not be automatically closed when the 84 * stdio_filebuf is closed/destroyed. 85 */ 86 stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode, 87 size_t __size = static_cast<size_t>(BUFSIZ)); 88 89 /** 90 * Closes the external data stream if the file descriptor constructor 91 * was used. 92 */ 93 virtual 94 ~stdio_filebuf(); 95 96 /** 97 * @return The underlying file descriptor. 98 * 99 * Once associated with an external data stream, this function can be 100 * used to access the underlying POSIX file descriptor. Note that 101 * there is no way for the library to track what you do with the 102 * descriptor, so be careful. 103 */ 104 int 105 fd() { return this->_M_file.fd(); } 106 107 /** 108 * @return The underlying FILE*. 109 * 110 * This function can be used to access the underlying "C" file pointer. 111 * Note that there is no way for the library to track what you do 112 * with the file, so be careful. 113 */ 114 std::__c_file* 115 file() { return this->_M_file.file(); } 116 }; 117 118 template<typename _CharT, typename _Traits> 119 stdio_filebuf<_CharT, _Traits>::~stdio_filebuf() 120 { } 121 122 template<typename _CharT, typename _Traits> 123 stdio_filebuf<_CharT, _Traits>:: 124 stdio_filebuf(int __fd, std::ios_base::openmode __mode, size_t __size) 125 { 126 this->_M_file.sys_open(__fd, __mode); 127 if (this->is_open()) 128 { 129 this->_M_mode = __mode; 130 this->_M_buf_size = __size; 131 this->_M_allocate_internal_buffer(); 132 this->_M_reading = false; 133 this->_M_writing = false; 134 this->_M_set_buffer(-1); 135 } 136 } 137 138 template<typename _CharT, typename _Traits> 139 stdio_filebuf<_CharT, _Traits>:: 140 stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode, 141 size_t __size) 142 { 143 this->_M_file.sys_open(__f, __mode); 144 if (this->is_open()) 145 { 146 this->_M_mode = __mode; 147 this->_M_buf_size = __size; 148 this->_M_allocate_internal_buffer(); 149 this->_M_reading = false; 150 this->_M_writing = false; 151 this->_M_set_buffer(-1); 152 } 153 } 154 155 _GLIBCXX_END_NAMESPACE 156 157 #endif 158
