1 mike  1.1.2.1 //%2006////////////////////////////////////////////////////////////////////////
  2               //
  3               // Copyright (c) 2000, 2001, 2002 BMC Software; Hewlett-Packard Development
  4               // Company, L.P.; IBM Corp.; The Open Group; Tivoli Systems.
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  6               // IBM Corp.; EMC Corporation, The Open Group.
  7               // Copyright (c) 2004 BMC Software; Hewlett-Packard Development Company, L.P.;
  8               // IBM Corp.; EMC Corporation; VERITAS Software Corporation; The Open Group.
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 10               // EMC Corporation; VERITAS Software Corporation; The Open Group.
 11               // Copyright (c) 2006 Hewlett-Packard Development Company, L.P.; IBM Corp.;
 12               // EMC Corporation; Symantec Corporation; The Open Group.
 13               //
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 22 mike  1.1.2.1 // ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
 23               // "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
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 30               //==============================================================================
 31               //
 32               //%/////////////////////////////////////////////////////////////////////////////
 33               
 34               #ifndef Pegasus_Magic_h
 35               #define Pegasus_Magic_h
 36               
 37               #include <Pegasus/Common/Config.h>
 38               #include <Pegasus/Common/Mutex.h>
 39               #include <Pegasus/Common/Stack.h>
 40               
 41               PEGASUS_NAMESPACE_BEGIN
 42               

 43 mike  1.1.2.3 /** The Magic class implements a convenient way to use magic numbers in
 44                   user-defined classes. Magic numbers help detect use of uninitialized, 
 45                   destructed, or corrupted objects.
 46               
 47                   To instrument a class to use magic numbers simply add a class member 
 48                   of type Magic<> as shown in thsi example:
 49               
 50               	\code
 51               	class MyClass
 52               	{
 53               	public:
 54               
 55               	    MyClass();
 56               
 57               	    ~MyClass();
 58               
 59               	    void foo();
 60               
 61               	private:
 62               	    Magic<0xC531B144> _magic;
 63               	};
 64 mike  1.1.2.3 	\endcode
 65               
 66                   Choose whatever number you like for a magic number. The number above was
 67                   generated by the Linux uuidgen utility (Windows has a utility with the 
 68                   same name).
 69               
 70                   To test magic number, add the following expression wherever necessary
 71                   (usually as the first line of every member function).
 72               
 73               	\code
 74               	PEGASUS_ASSERT_DEBUG(_magic);
 75               	\endcode
 76               
 77                   Here's a typical example:
 78               
 79               	\code
 80               	MyClass::~MyClass()
 81               	{
 82               	    PEGASUS_ASSERT_DEBUG(_magic);
 83               	}
 84               	\endcode
 85 mike  1.1.2.3 
 86                   This tests whether the magic number is 0xC531B144 and asserts if it is
 87                   not.
 88               
 89                   Note that using a magic number makes the user-defined class 4 bytes larger
 90                   but there is no run-time overhead unless you compile with PEGASUS_DEBUG.
 91                   The Magic constructor and destructor are empty without PEGASUS_DEBUG and
 92                   are discarded by the compiler.
 93               
 94                   CAUTION: You may be tempted to compile out the magic member when
 95                   PEGASUS_DEBUG undefined. However, this will causes unpredictable
 96                   behavior when debug libraries are mixed with non-debug libraries. The
 97                   structure alignment and size will be different and will lead to crashes.
 98                   This is only safe if a class is internal to a library.

 99 mike  1.1.2.1 */
100               template<Uint32 MAGIC_NUMBER>
101               class Magic
102               {
103               public:
104               

105 mike  1.1.2.3     /** Default constructor. Sets the magic number.
106                   */

107 mike  1.1.2.2     Magic() 
108                   {
109               #ifdef PEGASUS_DEBUG
110               	_magic = MAGIC_NUMBER;
111               #endif
112                   }
113               

114 mike  1.1.2.3     /** Destructor. Clears the magic number (with the pattern 0xDDDDDDDD).
115                   */

116 mike  1.1.2.2     ~Magic() 

117 mike  1.1.2.3     {

118 mike  1.1.2.2 #ifdef PEGASUS_DEBUG
119               	_magic = 0xDDDDDDDD; 
120               #endif
121                   }
122               

123 mike  1.1.2.3     /** Allows magic number to be used as a boolean expression. This function
124               	tests the magic number and return true if valid.
125                   */

126 mike  1.1.2.2     operator bool() const 
127                   { 
128               #ifdef PEGASUS_DEBUG
129               	return _magic == MAGIC_NUMBER; 
130               #else
131               	return true;
132               #endif
133                   }

134 mike  1.1.2.1 
135               private:
136                   Uint32 _magic;
137               };
138               
139               PEGASUS_NAMESPACE_END
140               
141               #endif /* Pegasus_Magic_h */