00001 // File descriptor layer for filebuf -*- C++ -*- 00002 00003 // Copyright (C) 2002, 2003, 2004, 2005, 2009, 2010 00004 // Free Software Foundation, Inc. 00005 // 00006 // This file is part of the GNU ISO C++ Library. This library is free 00007 // software; you can redistribute it and/or modify it under the 00008 // terms of the GNU General Public License as published by the 00009 // Free Software Foundation; either version 3, or (at your option) 00010 // any later version. 00011 00012 // This library is distributed in the hope that it will be useful, 00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00015 // GNU General Public License for more details. 00016 00017 // Under Section 7 of GPL version 3, you are granted additional 00018 // permissions described in the GCC Runtime Library Exception, version 00019 // 3.1, as published by the Free Software Foundation. 00020 00021 // You should have received a copy of the GNU General Public License and 00022 // a copy of the GCC Runtime Library Exception along with this program; 00023 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00024 // <http://www.gnu.org/licenses/>. 00025 00026 /** @file ext/stdio_filebuf.h 00027 * This file is a GNU extension to the Standard C++ Library. 00028 */ 00029 00030 #ifndef _STDIO_FILEBUF_H 00031 #define _STDIO_FILEBUF_H 1 00032 00033 #pragma GCC system_header 00034 00035 #include <fstream> 00036 00037 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) 00038 00039 /** 00040 * @brief Provides a layer of compatibility for C/POSIX. 00041 * @ingroup io 00042 * 00043 * This GNU extension provides extensions for working with standard C 00044 * FILE*'s and POSIX file descriptors. It must be instantiated by the 00045 * user with the type of character used in the file stream, e.g., 00046 * stdio_filebuf<char>. 00047 */ 00048 template<typename _CharT, typename _Traits = std::char_traits<_CharT> > 00049 class stdio_filebuf : public std::basic_filebuf<_CharT, _Traits> 00050 { 00051 public: 00052 // Types: 00053 typedef _CharT char_type; 00054 typedef _Traits traits_type; 00055 typedef typename traits_type::int_type int_type; 00056 typedef typename traits_type::pos_type pos_type; 00057 typedef typename traits_type::off_type off_type; 00058 typedef std::size_t size_t; 00059 00060 public: 00061 /** 00062 * deferred initialization 00063 */ 00064 stdio_filebuf() : std::basic_filebuf<_CharT, _Traits>() {} 00065 00066 /** 00067 * @param fd An open file descriptor. 00068 * @param mode Same meaning as in a standard filebuf. 00069 * @param size Optimal or preferred size of internal buffer, in chars. 00070 * 00071 * This constructor associates a file stream buffer with an open 00072 * POSIX file descriptor. The file descriptor will be automatically 00073 * closed when the stdio_filebuf is closed/destroyed. 00074 */ 00075 stdio_filebuf(int __fd, std::ios_base::openmode __mode, 00076 size_t __size = static_cast<size_t>(BUFSIZ)); 00077 00078 /** 00079 * @param f An open @c FILE*. 00080 * @param mode Same meaning as in a standard filebuf. 00081 * @param size Optimal or preferred size of internal buffer, in chars. 00082 * Defaults to system's @c BUFSIZ. 00083 * 00084 * This constructor associates a file stream buffer with an open 00085 * C @c FILE*. The @c FILE* will not be automatically closed when the 00086 * stdio_filebuf is closed/destroyed. 00087 */ 00088 stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode, 00089 size_t __size = static_cast<size_t>(BUFSIZ)); 00090 00091 /** 00092 * Closes the external data stream if the file descriptor constructor 00093 * was used. 00094 */ 00095 virtual 00096 ~stdio_filebuf(); 00097 00098 /** 00099 * @return The underlying file descriptor. 00100 * 00101 * Once associated with an external data stream, this function can be 00102 * used to access the underlying POSIX file descriptor. Note that 00103 * there is no way for the library to track what you do with the 00104 * descriptor, so be careful. 00105 */ 00106 int 00107 fd() { return this->_M_file.fd(); } 00108 00109 /** 00110 * @return The underlying FILE*. 00111 * 00112 * This function can be used to access the underlying "C" file pointer. 00113 * Note that there is no way for the library to track what you do 00114 * with the file, so be careful. 00115 */ 00116 std::__c_file* 00117 file() { return this->_M_file.file(); } 00118 }; 00119 00120 template<typename _CharT, typename _Traits> 00121 stdio_filebuf<_CharT, _Traits>::~stdio_filebuf() 00122 { } 00123 00124 template<typename _CharT, typename _Traits> 00125 stdio_filebuf<_CharT, _Traits>:: 00126 stdio_filebuf(int __fd, std::ios_base::openmode __mode, size_t __size) 00127 { 00128 this->_M_file.sys_open(__fd, __mode); 00129 if (this->is_open()) 00130 { 00131 this->_M_mode = __mode; 00132 this->_M_buf_size = __size; 00133 this->_M_allocate_internal_buffer(); 00134 this->_M_reading = false; 00135 this->_M_writing = false; 00136 this->_M_set_buffer(-1); 00137 } 00138 } 00139 00140 template<typename _CharT, typename _Traits> 00141 stdio_filebuf<_CharT, _Traits>:: 00142 stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode, 00143 size_t __size) 00144 { 00145 this->_M_file.sys_open(__f, __mode); 00146 if (this->is_open()) 00147 { 00148 this->_M_mode = __mode; 00149 this->_M_buf_size = __size; 00150 this->_M_allocate_internal_buffer(); 00151 this->_M_reading = false; 00152 this->_M_writing = false; 00153 this->_M_set_buffer(-1); 00154 } 00155 } 00156 00157 _GLIBCXX_END_NAMESPACE 00158 00159 #endif