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The C and C++ Include Header Files
/usr/include/c++/11/ext/stdio_sync_filebuf.h
$ cat -n /usr/include/c++/11/ext/stdio_sync_filebuf.h 1 // Iostreams wrapper for stdio FILE* -*- C++ -*- 2 3 // Copyright (C) 2003-2021 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_sync_filebuf.h 26 * This file is a GNU extension to the Standard C++ Library. 27 */ 28 29 #ifndef _STDIO_SYNC_FILEBUF_H 30 #define _STDIO_SYNC_FILEBUF_H 1 31 32 #pragma GCC system_header 33 34 #include <streambuf> 35 #include <cstdio> 36 #include <bits/c++io.h> // For __c_file 37 #include <bits/move.h> // For __exchange 38 39 #ifdef _GLIBCXX_USE_WCHAR_T 40 #include <cwchar> 41 #endif 42 43 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) 44 { 45 _GLIBCXX_BEGIN_NAMESPACE_VERSION 46 47 /** 48 * @brief Provides a layer of compatibility for C. 49 * @ingroup io 50 * 51 * This GNU extension provides extensions for working with standard 52 * C FILE*'s. It must be instantiated by the user with the type of 53 * character used in the file stream, e.g., stdio_filebuf<char>. 54 */ 55 template<typename _CharT, typename _Traits = std::char_traits<_CharT> > 56 class stdio_sync_filebuf : public std::basic_streambuf<_CharT, _Traits> 57 { 58 public: 59 // Types: 60 typedef _CharT char_type; 61 typedef _Traits traits_type; 62 typedef typename traits_type::int_type int_type; 63 typedef typename traits_type::pos_type pos_type; 64 typedef typename traits_type::off_type off_type; 65 66 private: 67 typedef std::basic_streambuf<_CharT, _Traits> __streambuf_type; 68 69 // Underlying stdio FILE 70 std::__c_file* _M_file; 71 72 // Last character gotten. This is used when pbackfail is 73 // called from basic_streambuf::sungetc() 74 int_type _M_unget_buf; 75 76 public: 77 explicit 78 stdio_sync_filebuf(std::__c_file* __f) 79 : _M_file(__f), _M_unget_buf(traits_type::eof()) 80 { } 81 82 #if __cplusplus >= 201103L 83 stdio_sync_filebuf(stdio_sync_filebuf&& __fb) noexcept 84 : __streambuf_type(std::move(__fb)), 85 _M_file(__fb._M_file), _M_unget_buf(__fb._M_unget_buf) 86 { 87 __fb._M_file = nullptr; 88 __fb._M_unget_buf = traits_type::eof(); 89 } 90 91 stdio_sync_filebuf& 92 operator=(stdio_sync_filebuf&& __fb) noexcept 93 { 94 __streambuf_type::operator=(__fb); 95 _M_file = std::__exchange(__fb._M_file, nullptr); 96 _M_unget_buf = std::__exchange(__fb._M_unget_buf, traits_type::eof()); 97 return *this; 98 } 99 100 void 101 swap(stdio_sync_filebuf& __fb) 102 { 103 __streambuf_type::swap(__fb); 104 std::swap(_M_file, __fb._M_file); 105 std::swap(_M_unget_buf, __fb._M_unget_buf); 106 } 107 #endif 108 109 /** 110 * @return The underlying FILE*. 111 * 112 * This function can be used to access the underlying C file pointer. 113 * Note that there is no way for the library to track what you do 114 * with the file, so be careful. 115 */ 116 std::__c_file* 117 file() { return this->_M_file; } 118 119 protected: 120 int_type 121 syncgetc(); 122 123 int_type 124 syncungetc(int_type __c); 125 126 int_type 127 syncputc(int_type __c); 128 129 virtual int_type 130 underflow() 131 { 132 int_type __c = this->syncgetc(); 133 return this->syncungetc(__c); 134 } 135 136 virtual int_type 137 uflow() 138 { 139 // Store the gotten character in case we need to unget it. 140 _M_unget_buf = this->syncgetc(); 141 return _M_unget_buf; 142 } 143 144 virtual int_type 145 pbackfail(int_type __c = traits_type::eof()) 146 { 147 int_type __ret; 148 const int_type __eof = traits_type::eof(); 149 150 // Check if the unget or putback was requested 151 if (traits_type::eq_int_type(__c, __eof)) // unget 152 { 153 if (!traits_type::eq_int_type(_M_unget_buf, __eof)) 154 __ret = this->syncungetc(_M_unget_buf); 155 else // buffer invalid, fail. 156 __ret = __eof; 157 } 158 else // putback 159 __ret = this->syncungetc(__c); 160 161 // The buffered character is no longer valid, discard it. 162 _M_unget_buf = __eof; 163 return __ret; 164 } 165 166 virtual std::streamsize 167 xsgetn(char_type* __s, std::streamsize __n); 168 169 virtual int_type 170 overflow(int_type __c = traits_type::eof()) 171 { 172 int_type __ret; 173 if (traits_type::eq_int_type(__c, traits_type::eof())) 174 { 175 if (std::fflush(_M_file)) 176 __ret = traits_type::eof(); 177 else 178 __ret = traits_type::not_eof(__c); 179 } 180 else 181 __ret = this->syncputc(__c); 182 return __ret; 183 } 184 185 virtual std::streamsize 186 xsputn(const char_type* __s, std::streamsize __n); 187 188 virtual int 189 sync() 190 { return std::fflush(_M_file); } 191 192 virtual std::streampos 193 seekoff(std::streamoff __off, std::ios_base::seekdir __dir, 194 std::ios_base::openmode = std::ios_base::in | std::ios_base::out) 195 { 196 std::streampos __ret(std::streamoff(-1)); 197 int __whence; 198 if (__dir == std::ios_base::beg) 199 __whence = SEEK_SET; 200 else if (__dir == std::ios_base::cur) 201 __whence = SEEK_CUR; 202 else 203 __whence = SEEK_END; 204 #ifdef _GLIBCXX_USE_LFS 205 if (!fseeko64(_M_file, __off, __whence)) 206 __ret = std::streampos(ftello64(_M_file)); 207 #else 208 if (!fseek(_M_file, __off, __whence)) 209 __ret = std::streampos(std::ftell(_M_file)); 210 #endif 211 return __ret; 212 } 213 214 virtual std::streampos 215 seekpos(std::streampos __pos, 216 std::ios_base::openmode __mode = 217 std::ios_base::in | std::ios_base::out) 218 { return seekoff(std::streamoff(__pos), std::ios_base::beg, __mode); } 219 }; 220 221 template<> 222 inline stdio_sync_filebuf<char>::int_type 223 stdio_sync_filebuf<char>::syncgetc() 224 { return std::getc(_M_file); } 225 226 template<> 227 inline stdio_sync_filebuf<char>::int_type 228 stdio_sync_filebuf<char>::syncungetc(int_type __c) 229 { return std::ungetc(__c, _M_file); } 230 231 template<> 232 inline stdio_sync_filebuf<char>::int_type 233 stdio_sync_filebuf<char>::syncputc(int_type __c) 234 { return std::putc(__c, _M_file); } 235 236 template<> 237 inline std::streamsize 238 stdio_sync_filebuf<char>::xsgetn(char* __s, std::streamsize __n) 239 { 240 std::streamsize __ret = std::fread(__s, 1, __n, _M_file); 241 if (__ret > 0) 242 _M_unget_buf = traits_type::to_int_type(__s[__ret - 1]); 243 else 244 _M_unget_buf = traits_type::eof(); 245 return __ret; 246 } 247 248 template<> 249 inline std::streamsize 250 stdio_sync_filebuf<char>::xsputn(const char* __s, std::streamsize __n) 251 { return std::fwrite(__s, 1, __n, _M_file); } 252 253 #ifdef _GLIBCXX_USE_WCHAR_T 254 template<> 255 inline stdio_sync_filebuf<wchar_t>::int_type 256 stdio_sync_filebuf<wchar_t>::syncgetc() 257 { return std::getwc(_M_file); } 258 259 template<> 260 inline stdio_sync_filebuf<wchar_t>::int_type 261 stdio_sync_filebuf<wchar_t>::syncungetc(int_type __c) 262 { return std::ungetwc(__c, _M_file); } 263 264 template<> 265 inline stdio_sync_filebuf<wchar_t>::int_type 266 stdio_sync_filebuf<wchar_t>::syncputc(int_type __c) 267 { return std::putwc(__c, _M_file); } 268 269 template<> 270 inline std::streamsize 271 stdio_sync_filebuf<wchar_t>::xsgetn(wchar_t* __s, std::streamsize __n) 272 { 273 std::streamsize __ret = 0; 274 const int_type __eof = traits_type::eof(); 275 while (__n--) 276 { 277 int_type __c = this->syncgetc(); 278 if (traits_type::eq_int_type(__c, __eof)) 279 break; 280 __s[__ret] = traits_type::to_char_type(__c); 281 ++__ret; 282 } 283 284 if (__ret > 0) 285 _M_unget_buf = traits_type::to_int_type(__s[__ret - 1]); 286 else 287 _M_unget_buf = traits_type::eof(); 288 return __ret; 289 } 290 291 template<> 292 inline std::streamsize 293 stdio_sync_filebuf<wchar_t>::xsputn(const wchar_t* __s, 294 std::streamsize __n) 295 { 296 std::streamsize __ret = 0; 297 const int_type __eof = traits_type::eof(); 298 while (__n--) 299 { 300 if (traits_type::eq_int_type(this->syncputc(*__s++), __eof)) 301 break; 302 ++__ret; 303 } 304 return __ret; 305 } 306 #endif 307 308 #if _GLIBCXX_EXTERN_TEMPLATE 309 extern template class stdio_sync_filebuf<char>; 310 #ifdef _GLIBCXX_USE_WCHAR_T 311 extern template class stdio_sync_filebuf<wchar_t>; 312 #endif 313 #endif 314 315 _GLIBCXX_END_NAMESPACE_VERSION 316 } // namespace 317 318 #endif
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