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| 4 | (C) Copyright 2002-4 Robert Ramey - http://www.rrsd.com . |
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| 5 | Use, modification and distribution is subject to the Boost Software |
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| 6 | License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
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| 11 | <link rel="stylesheet" type="text/css" href="../../../boost.css"> |
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| 13 | <title>Serialization - <code style="white-space: normal">state_saver</code></title> |
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| 15 | <body link="#0000ff" vlink="#800080"> |
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| 16 | <table border="0" cellpadding="7" cellspacing="0" width="100%" summary="header"> |
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| 17 | <tr> |
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| 18 | <td valign="top" width="300"> |
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| 19 | <h3><a href="../../../index.htm"><img height="86" width="277" alt="C++ Boost" src="../../../boost.png" border="0"></a></h3> |
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| 20 | </td> |
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| 21 | <td valign="top"> |
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| 22 | <h1 align="center">Serialization</h1> |
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| 23 | <h2 align="center"><code style="white-space: normal">state_saver</code</h2> |
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| 24 | </td> |
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| 25 | </tr> |
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| 26 | </table> |
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| 27 | <hr> |
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| 28 | <p> |
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| 29 | Sometimes a certain value has to change only for a limited scope. |
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| 30 | This class wrapper saves a copy of the current state of some object, |
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| 31 | and resets the object's state at destruction time, undoing any change the object |
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| 32 | may have gone through. Here is the interface: |
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| 33 | |
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| 34 | <pre><code> |
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| 35 | template<class T> |
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| 36 | // T requirements: |
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| 37 | // - POD or object semantic (cannot be reference, function, ...) |
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| 38 | // - copy constructor |
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| 39 | // - operator = (no-throw one preferred) |
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| 40 | class state_saver : private boost::noncopyable |
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| 41 | { |
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| 42 | private: |
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| 43 | ... // implementation |
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| 44 | |
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| 45 | public: |
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| 46 | state_saver(T & object); |
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| 47 | ~state_saver(); |
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| 48 | }; |
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| 49 | </code></pre> |
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| 50 | |
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| 51 | The complete implementation can be found |
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| 52 | <a target="state_saver" href="../../../boost/state_saver.hpp">here</a> |
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| 53 | |
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| 54 | The following illustrates how this is expected to be used. |
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| 55 | |
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| 56 | <pre><code> |
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| 57 | #include <boost/state_saver.hpp> |
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| 58 | |
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| 59 | void func(A & a) |
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| 60 | boost::state_saver<A> s(a); |
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| 61 | ... // alter state of a by calling non-const functions |
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| 62 | ... // call other functions |
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| 63 | // original state of a automatically restored on exit |
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| 64 | } |
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| 65 | </pre></code> |
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| 66 | |
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| 67 | <h3>History</h3> |
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| 68 | This is a generalization of Daryle Walker's |
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| 69 | <a href="../../../libs/io/doc/ios_state.html">io_state_saver</a> library. |
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| 70 | <p> |
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| 71 | Robert Ramey made an initial version for the serialization library. |
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| 72 | <p> |
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| 73 | Pavel Vozenilek made several non-obvious refinements to make it more |
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| 74 | secure and boost friendly |
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| 75 | |
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| 76 | <hr> |
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| 77 | <p><i>© Copyright <a href="http://www.rrsd.com">Robert Ramey</a> 2002-2004. |
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| 78 | Distributed under the Boost Software License, Version 1.0. (See |
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| 79 | accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
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| 80 | </i></p> |
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| 81 | </body> |
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| 82 | </html> |
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