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version 1.1, 2006/06/30 20:52:52
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version 1.2, 2006/07/11 18:39:28
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//%2006//////////////////////////////////////////////////////////////////////// |
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// |
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// Copyright (c) 2000, 2001, 2002 BMC Software; Hewlett-Packard Development |
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// Company, L.P.; IBM Corp.; The Open Group; Tivoli Systems. |
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// Copyright (c) 2003 BMC Software; Hewlett-Packard Development Company, L.P.; |
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// IBM Corp.; EMC Corporation, The Open Group. |
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// Copyright (c) 2004 BMC Software; Hewlett-Packard Development Company, L.P.; |
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// IBM Corp.; EMC Corporation; VERITAS Software Corporation; The Open Group. |
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// Copyright (c) 2005 Hewlett-Packard Development Company, L.P.; IBM Corp.; |
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// EMC Corporation; VERITAS Software Corporation; The Open Group. |
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// Copyright (c) 2006 Hewlett-Packard Development Company, L.P.; IBM Corp.; |
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// EMC Corporation; Symantec Corporation; The Open Group. |
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// |
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// Permission is hereby granted, free of charge, to any person obtaining a copy |
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// of this software and associated documentation files (the "Software"), to |
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// deal in the Software without restriction, including without limitation the |
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// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or |
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// sell copies of the Software, and to permit persons to whom the Software is |
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// furnished to do so, subject to the following conditions: |
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// |
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// THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN |
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// ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED |
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// "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT |
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// LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR |
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// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT |
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// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
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// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION |
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// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
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// |
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//============================================================================== |
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// |
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//%///////////////////////////////////////////////////////////////////////////// |
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#ifndef Pegasus_Magic_h |
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#define Pegasus_Magic_h |
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#include <Pegasus/Common/Config.h> |
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PEGASUS_NAMESPACE_BEGIN |
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/** The Magic class implements a convenient way to use magic numbers in |
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user-defined classes. Magic numbers help detect use of uninitialized, |
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destructed, or corrupted objects. |
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To instrument a class to use magic numbers simply add a class member |
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of type Magic<> as shown in thsi example: |
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\code |
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class MyClass |
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{ |
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public: |
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MyClass(); |
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~MyClass(); |
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void foo(); |
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private: |
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Magic<0xC531B144> _magic; |
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}; |
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\endcode |
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Choose whatever number you like for a magic number. The number above was |
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generated by the Linux uuidgen utility (Windows has a utility with the |
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same name). |
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To test magic number, add the following expression wherever necessary |
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(usually as the first line of every member function). |
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\code |
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PEGASUS_ASSERT_DEBUG(_magic); |
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\endcode |
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Here's a typical example: |
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\code |
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MyClass::~MyClass() |
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{ |
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PEGASUS_ASSERT_DEBUG(_magic); |
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} |
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\endcode |
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This tests whether the magic number is 0xC531B144 and asserts if it is |
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not. |
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Note that using a magic number makes the user-defined class 4 bytes larger |
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but there is no run-time overhead unless you compile with PEGASUS_DEBUG. |
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The Magic constructor and destructor are empty without PEGASUS_DEBUG and |
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are discarded by the compiler. |
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CAUTION: You may be tempted to compile out the magic member when |
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PEGASUS_DEBUG undefined. However, this will causes unpredictable |
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behavior when debug libraries are mixed with non-debug libraries. The |
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structure alignment and size will be different and will lead to crashes. |
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This is only safe if a class is internal to a library. |
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*/ |
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template<Uint32 MAGIC_NUMBER> |
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class Magic |
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{ |
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public: |
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/** Default constructor. Sets the magic number. |
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*/ |
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Magic() |
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{ |
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#ifdef PEGASUS_DEBUG |
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_magic = MAGIC_NUMBER; |
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#endif |
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} |
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/** Destructor. Clears the magic number (with the pattern 0xDDDDDDDD). |
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*/ |
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~Magic() |
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{ |
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#ifdef PEGASUS_DEBUG |
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_magic = 0xDDDDDDDD; |
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#endif |
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} |
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/** Allows magic number to be used as a boolean expression. This function |
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tests the magic number and return true if valid. |
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*/ |
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operator bool() const |
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{ |
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#ifdef PEGASUS_DEBUG |
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return _magic == MAGIC_NUMBER; |
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#else |
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return true; |
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#endif |
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} |
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private: |
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Uint32 _magic; |
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}; |
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PEGASUS_NAMESPACE_END |
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#endif /* Pegasus_Magic_h */ |
Return to
Magic.h
CVS log
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