libstdc++-v3/include/ext/stdio_sync_filebuf.h

   1 // Iostreams wrapper for stdio FILE* -*- C++ -*-
   2
   3 // Copyright (C) 2003, 2004 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 2, 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 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /** @file ext/stdiostream.h
  31  *  This file is a GNU extension to the Standard C++ Library.
  32  */
  33
  34 #ifndef _STDIO_SYNC_FILEBUF_H
  35 #define _STDIO_SYNC_FILEBUF_H 1
  36
  37 #pragma GCC system_header
  38
  39 #include <streambuf>
  40 #include <unistd.h>
  41 #include <cstdio>
  42
  43 #ifdef _GLIBCXX_USE_WCHAR_T
  44 #include <cwchar>
  45 #endif
  46
  47 namespace __gnu_cxx
  48 {
  49   template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
  50     class stdio_sync_filebuf : public std::basic_streambuf<_CharT, _Traits>
  51     {
  52     public:
  53       // Types:
  54       typedef _CharT                                    char_type;
  55       typedef _Traits                                   traits_type;
  56       typedef typename traits_type::int_type            int_type;
  57       typedef typename traits_type::pos_type            pos_type;
  58       typedef typename traits_type::off_type            off_type;
  59
  60     private:
  61       // Underlying stdio FILE
  62       std::__c_file* const _M_file;
  63
  64       // Last character gotten. This is used when pbackfail is
  65       // called from basic_streambuf::sungetc()
  66       int_type _M_unget_buf;
  67
  68     public:
  69       explicit
  70       stdio_sync_filebuf(std::__c_file* __f)
  71       : _M_file(__f), _M_unget_buf(traits_type::eof())
  72       { }
  73
  74     protected:
  75       int_type
  76       syncgetc();
  77
  78       int_type
  79       syncungetc(int_type __c);
  80
  81       int_type
  82       syncputc(int_type __c);
  83
  84       virtual int_type
  85       underflow()
  86       {
  87         int_type __c = this->syncgetc();
  88         return this->syncungetc(__c);
  89       }
  90
  91       virtual int_type
  92       uflow()
  93       {
  94         // Store the gotten character in case we need to unget it.
  95         _M_unget_buf = this->syncgetc();
  96         return _M_unget_buf;
  97       }
  98
  99       virtual int_type
 100       pbackfail(int_type __c = traits_type::eof())
 101       {
 102         int_type __ret;
 103         const int_type __eof = traits_type::eof();
 104
 105         // Check if the unget or putback was requested
 106         if (traits_type::eq_int_type(__c, __eof)) // unget
 107           {
 108             if (!traits_type::eq_int_type(_M_unget_buf, __eof))
 109               __ret = this->syncungetc(_M_unget_buf);
 110             else // buffer invalid, fail.
 111               __ret = __eof;
 112           }
 113         else // putback
 114           __ret = this->syncungetc(__c);
 115
 116         // The buffered character is no longer valid, discard it.
 117         _M_unget_buf = __eof;
 118         return __ret;
 119       }
 120
 121       virtual std::streamsize
 122       xsgetn(char_type* __s, std::streamsize __n);
 123
 124       virtual int_type
 125       overflow(int_type __c = traits_type::eof())
 126       {
 127         int_type __ret;
 128         if (traits_type::eq_int_type(__c, traits_type::eof()))
 129           {
 130             if (std::fflush(_M_file))
 131               __ret = traits_type::eof();
 132             else
 133               __ret = traits_type::not_eof(__c);
 134           }
 135         else
 136           __ret = this->syncputc(__c);
 137         return __ret;
 138       }
 139
 140       virtual std::streamsize
 141       xsputn(const char_type* __s, std::streamsize __n);
 142
 143       virtual int
 144       sync()
 145       { return std::fflush(_M_file); }
 146
 147       virtual std::streampos
 148       seekoff(std::streamoff __off, std::ios_base::seekdir __dir,
 149               std::ios_base::openmode = std::ios_base::in | std::ios_base::out)
 150       {
 151         std::streampos __ret(std::streamoff(-1));
 152         int __whence;
 153         if (__dir == std::ios_base::beg)
 154           __whence = SEEK_SET;
 155         else if (__dir == std::ios_base::cur)
 156           __whence = SEEK_CUR;
 157         else
 158           __whence = SEEK_END;
 159 #ifdef _GLIBCXX_USE_LFS
 160         if (!fseeko64(_M_file, __off, __whence))
 161           __ret = std::streampos(ftello64(_M_file));
 162 #else
 163         if (!fseek(_M_file, __off, __whence))
 164           __ret = std::streampos(std::ftell(_M_file));
 165 #endif
 166         return __ret;
 167       }
 168
 169       virtual std::streampos
 170       seekpos(std::streampos __pos,
 171               std::ios_base::openmode __mode =
 172               std::ios_base::in | std::ios_base::out)
 173       { return seekoff(std::streamoff(__pos), std::ios_base::beg, __mode); }
 174     };
 175
 176   template<>
 177     inline stdio_sync_filebuf<char>::int_type
 178     stdio_sync_filebuf<char>::syncgetc()
 179     { return std::getc(_M_file); }
 180
 181   template<>
 182     inline stdio_sync_filebuf<char>::int_type
 183     stdio_sync_filebuf<char>::syncungetc(int_type __c)
 184     { return std::ungetc(__c, _M_file); }
 185
 186   template<>
 187     inline stdio_sync_filebuf<char>::int_type
 188     stdio_sync_filebuf<char>::syncputc(int_type __c)
 189     { return std::putc(__c, _M_file); }
 190
 191   template<>
 192     inline std::streamsize
 193     stdio_sync_filebuf<char>::xsgetn(char* __s, std::streamsize __n)
 194     {
 195       std::streamsize __ret = std::fread(__s, 1, __n, _M_file);
 196       if (__ret > 0)
 197         _M_unget_buf = traits_type::to_int_type(__s[__ret - 1]);
 198       else
 199         _M_unget_buf = traits_type::eof();
 200       return __ret;
 201     }
 202
 203   template<>
 204     inline std::streamsize
 205     stdio_sync_filebuf<char>::xsputn(const char* __s, std::streamsize __n)
 206     { return std::fwrite(__s, 1, __n, _M_file); }
 207
 208 #ifdef _GLIBCXX_USE_WCHAR_T
 209   template<>
 210     inline stdio_sync_filebuf<wchar_t>::int_type
 211     stdio_sync_filebuf<wchar_t>::syncgetc()
 212     { return std::getwc(_M_file); }
 213
 214   template<>
 215     inline stdio_sync_filebuf<wchar_t>::int_type
 216     stdio_sync_filebuf<wchar_t>::syncungetc(int_type __c)
 217     { return std::ungetwc(__c, _M_file); }
 218
 219   template<>
 220     inline stdio_sync_filebuf<wchar_t>::int_type
 221     stdio_sync_filebuf<wchar_t>::syncputc(int_type __c)
 222     { return std::putwc(__c, _M_file); }
 223
 224   template<>
 225     inline std::streamsize
 226     stdio_sync_filebuf<wchar_t>::xsgetn(wchar_t* __s, std::streamsize __n)
 227     {
 228       std::streamsize __ret = 0;
 229       const int_type __eof = traits_type::eof();
 230       while (__n--)
 231         {
 232           int_type __c = this->syncgetc();
 233           if (traits_type::eq_int_type(__c, __eof))
 234             break;
 235           __s[__ret] = traits_type::to_char_type(__c);
 236           ++__ret;
 237         }
 238
 239       if (__ret > 0)
 240         _M_unget_buf = traits_type::to_int_type(__s[__ret - 1]);
 241       else
 242         _M_unget_buf = traits_type::eof();
 243       return __ret;
 244     }
 245
 246   template<>
 247     inline std::streamsize
 248     stdio_sync_filebuf<wchar_t>::xsputn(const wchar_t* __s,
 249                                         std::streamsize __n)
 250     {
 251       std::streamsize __ret = 0;
 252       const int_type __eof = traits_type::eof();
 253       while (__n--)
 254         {
 255           if (traits_type::eq_int_type(this->syncputc(*__s++), __eof))
 256             break;
 257           ++__ret;
 258         }
 259       return __ret;
 260     }
 261 #endif
 262
 263 #if _GLIBCXX_EXTERN_TEMPLATE
 264   extern template class stdio_sync_filebuf<char>;
 265 #ifdef _GLIBCXX_USE_WCHAR_T
 266   extern template class stdio_sync_filebuf<wchar_t>;
 267 #endif
 268 #endif
 269 } // namespace __gnu_cxx
 270
 271 #endif