83 lines
2.7 KiB
HTML
83 lines
2.7 KiB
HTML
<!doctype HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<!--
|
|
(C) Copyright 2002-4 Robert Ramey - http://www.rrsd.com .
|
|
Use, modification and distribution is subject to the Boost Software
|
|
License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
|
|
http://www.boost.org/LICENSE_1_0.txt)
|
|
-->
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
|
|
<link rel="stylesheet" type="text/css" href="../../../boost.css">
|
|
<link rel="stylesheet" type="text/css" href="style.css">
|
|
<title>Serialization - <code style="white-space: normal">state_saver</code></title>
|
|
</head>
|
|
<body link="#0000ff" vlink="#800080">
|
|
<table border="0" cellpadding="7" cellspacing="0" width="100%" summary="header">
|
|
<tr>
|
|
<td valign="top" width="300">
|
|
<h3><a href="../../../index.htm"><img height="86" width="277" alt="C++ Boost" src="../../../boost.png" border="0"></a></h3>
|
|
</td>
|
|
<td valign="top">
|
|
<h1 align="center">Serialization</h1>
|
|
<h2 align="center"><code style="white-space: normal">state_saver</code</h2>
|
|
</td>
|
|
</tr>
|
|
</table>
|
|
<hr>
|
|
<p>
|
|
Sometimes a certain value has to change only for a limited scope.
|
|
This class wrapper saves a copy of the current state of some object,
|
|
and resets the object's state at destruction time, undoing any change the object
|
|
may have gone through. Here is the interface:
|
|
|
|
<pre><code>
|
|
template<class T>
|
|
// T requirements:
|
|
// - POD or object semantic (cannot be reference, function, ...)
|
|
// - copy constructor
|
|
// - operator = (no-throw one preferred)
|
|
class state_saver : private boost::noncopyable
|
|
{
|
|
private:
|
|
... // implementation
|
|
|
|
public:
|
|
state_saver(T & object);
|
|
~state_saver();
|
|
};
|
|
</code></pre>
|
|
|
|
The complete implementation can be found
|
|
<a target="state_saver" href="../../../boost/serialization/state_saver.hpp">here</a>
|
|
|
|
The following illustrates how this is expected to be used.
|
|
|
|
<pre><code>
|
|
#include <boost/state_saver.hpp>
|
|
|
|
void func(A & a)
|
|
boost::state_saver<A> s(a);
|
|
... // alter state of a by calling non-const functions
|
|
... // call other functions
|
|
// original state of a automatically restored on exit
|
|
}
|
|
</pre></code>
|
|
|
|
<h3>History</h3>
|
|
This is a generalization of Daryle Walker's
|
|
<a href="../../../libs/io/doc/ios_state.html">io_state_saver</a> library.
|
|
<p>
|
|
Robert Ramey made an initial version for the serialization library.
|
|
<p>
|
|
Pavel Vozenilek made several non-obvious refinements to make it more
|
|
secure and boost friendly
|
|
|
|
<hr>
|
|
<p><i>© Copyright <a href="http://www.rrsd.com">Robert Ramey</a> 2002-2004.
|
|
Distributed under the Boost Software License, Version 1.0. (See
|
|
accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
|
</i></p>
|
|
</body>
|
|
</html>
|