00001 // File descriptor layer for filebuf -*- C++ -*- 00002 00003 // Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 2, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // You should have received a copy of the GNU General Public License along 00017 // with this library; see the file COPYING. If not, write to the Free 00018 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, 00019 // USA. 00020 00021 // As a special exception, you may use this file as part of a free software 00022 // library without restriction. Specifically, if other files instantiate 00023 // templates or use macros or inline functions from this file, or you compile 00024 // this file and link it with other files to produce an executable, this 00025 // file does not by itself cause the resulting executable to be covered by 00026 // the GNU General Public License. This exception does not however 00027 // invalidate any other reasons why the executable file might be covered by 00028 // the GNU General Public License. 00029 00030 /** @file ext/stdio_filebuf.h 00031 * This file is a GNU extension to the Standard C++ Library. 00032 */ 00033 00034 #ifndef _STDIO_FILEBUF_H 00035 #define _STDIO_FILEBUF_H 1 00036 00037 #pragma GCC system_header 00038 00039 #include <fstream> 00040 00041 namespace __gnu_cxx 00042 { 00043 /** 00044 * @brief Provides a layer of compatibility for C/POSIX. 00045 * 00046 * This GNU extension provides extensions for working with standard C 00047 * FILE*'s and POSIX file descriptors. It must be instantiated by the 00048 * user with the type of character used in the file stream, e.g., 00049 * stdio_filebuf<char>. 00050 */ 00051 template<typename _CharT, typename _Traits = std::char_traits<_CharT> > 00052 class stdio_filebuf : public std::basic_filebuf<_CharT, _Traits> 00053 { 00054 public: 00055 // Types: 00056 typedef _CharT char_type; 00057 typedef _Traits traits_type; 00058 typedef typename traits_type::int_type int_type; 00059 typedef typename traits_type::pos_type pos_type; 00060 typedef typename traits_type::off_type off_type; 00061 typedef std::size_t size_t; 00062 00063 public: 00064 /** 00065 * deferred initialization 00066 */ 00067 stdio_filebuf() : std::basic_filebuf<_CharT, _Traits>() {} 00068 00069 /** 00070 * @param fd An open file descriptor. 00071 * @param mode Same meaning as in a standard filebuf. 00072 * @param size Optimal or preferred size of internal buffer, in chars. 00073 * 00074 * This constructor associates a file stream buffer with an open 00075 * POSIX file descriptor. The file descriptor will be automatically 00076 * closed when the stdio_filebuf is closed/destroyed. 00077 */ 00078 stdio_filebuf(int __fd, std::ios_base::openmode __mode, 00079 size_t __size = static_cast<size_t>(BUFSIZ)); 00080 00081 /** 00082 * @param f An open @c FILE*. 00083 * @param mode Same meaning as in a standard filebuf. 00084 * @param size Optimal or preferred size of internal buffer, in chars. 00085 * Defaults to system's @c BUFSIZ. 00086 * 00087 * This constructor associates a file stream buffer with an open 00088 * C @c FILE*. The @c FILE* will not be automatically closed when the 00089 * stdio_filebuf is closed/destroyed. 00090 */ 00091 stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode, 00092 size_t __size = static_cast<size_t>(BUFSIZ)); 00093 00094 /** 00095 * Closes the external data stream if the file descriptor constructor 00096 * was used. 00097 */ 00098 virtual 00099 ~stdio_filebuf(); 00100 00101 /** 00102 * @return The underlying file descriptor. 00103 * 00104 * Once associated with an external data stream, this function can be 00105 * used to access the underlying POSIX file descriptor. Note that 00106 * there is no way for the library to track what you do with the 00107 * descriptor, so be careful. 00108 */ 00109 int 00110 fd() { return this->_M_file.fd(); } 00111 00112 /** 00113 * @return The underlying FILE*. 00114 * 00115 * This function can be used to access the underlying "C" file pointer. 00116 * Note that there is no way for the library to track what you do 00117 * with the file, so be careful. 00118 */ 00119 std::__c_file* 00120 file() { return this->_M_file.file(); } 00121 }; 00122 00123 template<typename _CharT, typename _Traits> 00124 stdio_filebuf<_CharT, _Traits>::~stdio_filebuf() 00125 { } 00126 00127 template<typename _CharT, typename _Traits> 00128 stdio_filebuf<_CharT, _Traits>:: 00129 stdio_filebuf(int __fd, std::ios_base::openmode __mode, size_t __size) 00130 { 00131 this->_M_file.sys_open(__fd, __mode); 00132 if (this->is_open()) 00133 { 00134 this->_M_mode = __mode; 00135 this->_M_buf_size = __size; 00136 this->_M_allocate_internal_buffer(); 00137 this->_M_reading = false; 00138 this->_M_writing = false; 00139 this->_M_set_buffer(-1); 00140 } 00141 } 00142 00143 template<typename _CharT, typename _Traits> 00144 stdio_filebuf<_CharT, _Traits>:: 00145 stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode, 00146 size_t __size) 00147 { 00148 this->_M_file.sys_open(__f, __mode); 00149 if (this->is_open()) 00150 { 00151 this->_M_mode = __mode; 00152 this->_M_buf_size = __size; 00153 this->_M_allocate_internal_buffer(); 00154 this->_M_reading = false; 00155 this->_M_writing = false; 00156 this->_M_set_buffer(-1); 00157 } 00158 } 00159 } // namespace __gnu_cxx 00160 00161 #endif