src/ios_state.h

   1 ///
   2 /// \file       ios_state.h
   3 ///             RAII class to save and restore iostream state
   4 ///
   5
   6 /*
   7     Copyright (C) 2011-2013, Net Direct Inc. (http://www.netdirect.ca/)
   8
   9     This program is free software; you can redistribute it and/or modify
  10     it under the terms of the GNU General Public License as published by
  11     the Free Software Foundation; either version 2 of the License, or
  12     (at your option) any later version.
  13
  14     This program is distributed in the hope that it will be useful,
  15     but WITHOUT ANY WARRANTY; without even the implied warranty of
  16     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  17
  18     See the GNU General Public License in the COPYING file at the
  19     root directory of this project for more details.
  20 */
  21
  22 #ifndef __BARRY_IOS_STATE_H__
  23 #define __BARRY_IOS_STATE_H__
  24
  25 #include <ios>
  26 #include <ostream>
  27
  28 namespace Barry {
  29
  30 //
  31 // ios_format_state
  32 //
  33 /// This class saves the following stream settings:
  34 ///     - flags
  35 ///     - precision
  36 ///     - width
  37 ///     - fill character
  38 ///
  39 /// and restores them in the destructor.
  40 ///
  41 class ios_format_state
  42 {
  43 public:
  44         typedef std::ios                stream_type;
  45
  46 private:
  47         stream_type                     &m_stream;
  48         std::ios_base::fmtflags         m_flags;
  49         std::streamsize                 m_precision;
  50         std::streamsize                 m_width;
  51         stream_type::char_type          m_fill;
  52
  53 public:
  54         explicit ios_format_state(stream_type &stream)
  55                 : m_stream(stream)
  56                 , m_flags(stream.flags())
  57                 , m_precision(stream.precision())
  58                 , m_width(stream.width())
  59                 , m_fill(stream.fill())
  60         {
  61         }
  62
  63         ~ios_format_state()
  64         {
  65                 restore();
  66         }
  67
  68         void restore()
  69         {
  70                 m_stream.flags(m_flags);
  71                 m_stream.precision(m_precision);
  72                 m_stream.width(m_width);
  73                 m_stream.fill(m_fill);
  74         }
  75 };
  76
  77 }
  78
  79 #endif
  80