fdstream.h

   1 /* Copyright (C) 2004 and 2005 Chris Vine
   2
   3
   4  The following code declares classes to read from and write to
   5  Unix file descriptors.
   6
   7    This library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public License
   9    as published by the Free Software Foundation; either version 2.1 of
  10    the License, or (at your option) any later version.
  11
  12    This library is distributed in the hope that it will be useful, but
  13    WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with this library (see the file LGPL.TXT which came
  19    with this source code package); if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  21    02111-1307, USA.
  22 */
  23
  24 #ifndef FDSTREAM_H
  25 #define FDSTREAM_H
  26
  27 #include <istream>
  28 #include <ostream>
  29 #include <streambuf>
  30 #include <cstdio>
  31
  32
  33 struct fdstream_error {
  34   bool error;
  35   enum {dup, open, flush, eof} code;
  36 };
  37
  38
  39 class fdoutbuf: public std::streambuf {
  40
  41   fdstream_error error_condition;
  42   std::FILE* stream_p;
  43
  44   void reset();
  45 protected:
  46   virtual int sync();
  47   virtual int_type overflow(int_type);
  48   virtual std::streamsize xsputn(const char*, std::streamsize);
  49 public:
  50   int attach_fd(int fd, bool manage = true);
  51   void close_filestream();
  52   int get_fd() const;
  53   fdstream_error get_error() const {return error_condition;}
  54   fdoutbuf(int fd, bool manage = true);
  55   fdoutbuf();
  56   virtual ~fdoutbuf();
  57 };
  58
  59 class fdostream: public std::ostream {
  60   fdoutbuf buf;
  61 public:
  62   int attach(int fd, bool manage = true) {return buf.attach_fd(fd, manage);}
  63   void close() {buf.close_filestream();}
  64   int filedesc() const {return buf.get_fd();}
  65   fdstream_error get_error() const {return buf.get_error();}
  66   fdostream(int fd, bool manage = true);
  67   fdostream();
  68 };
  69
  70 class fdinbuf: public std::streambuf {
  71
  72   fdstream_error error_condition;
  73   std::FILE* stream_p;
  74
  75   // putback_buffer does not do any buffering: it reserves one character
  76   // for putback and one character for a peek() and/or for bumping
  77   // with sbumpc/uflow() - buffering is done by the underlying C stream
  78   char_type putback_buffer[2];
  79
  80   void reset();
  81 protected:
  82   virtual int_type underflow();
  83   virtual std::streamsize xsgetn(char*, std::streamsize);
  84 public:
  85   int attach_fd(int fd, bool manage = true);
  86   void close_filestream();
  87   int get_fd() const;
  88   fdstream_error get_error() const {return error_condition;}
  89   fdinbuf(int fd, bool manage = true);
  90   fdinbuf();
  91   virtual ~fdinbuf();
  92 };
  93
  94 class fdistream: public std::istream {
  95   fdinbuf buf;
  96 public:
  97   int attach(int fd, bool manage = true) {return buf.attach_fd(fd, manage);}
  98   void close() {buf.close_filestream();}
  99   int filedesc() const {return buf.get_fd();}
 100   fdstream_error get_error() const {return buf.get_error();}
 101   fdistream(int fd, bool manage = true);
 102   fdistream();
 103 };
 104
 105 #endif /*FDSTREAM_H*/