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version 1.1.2.2, 2006/06/30 21:11:03
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version 1.1.2.3, 2006/06/30 22:37:52
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| //%2006//////////////////////////////////////////////////////////////////////// | //%2006//////////////////////////////////////////////////////////////////////// |
| // | // |
| // Copyright (c) 2000, 2001, 2002 BMC Software; Hewlett-Packard Development | // Copyright (c) 2000, 2001, 2002 BMC Software; Hewlett-Packard Development |
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| PEGASUS_NAMESPACE_BEGIN | PEGASUS_NAMESPACE_BEGIN |
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| /** Implements a simple magic number that is set on construction and cleared |
/** The Magic class implements a convenient way to use magic numbers in |
| on destruction. |
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. |
| */ | */ |
| template<Uint32 MAGIC_NUMBER> | template<Uint32 MAGIC_NUMBER> |
| class Magic | class Magic |
| { | { |
| public: | public: |
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/** Default constructor. Sets the magic number. |
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*/ |
| Magic() | Magic() |
| { | { |
| #ifdef PEGASUS_DEBUG | #ifdef PEGASUS_DEBUG |
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| #endif | #endif |
| } | } |
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/** Destructor. Clears the magic number (with the pattern 0xDDDDDDDD). |
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*/ |
| ~Magic() | ~Magic() |
| { | { |
| #ifdef PEGASUS_DEBUG | #ifdef PEGASUS_DEBUG |
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| #endif | #endif |
| } | } |
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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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*/ |
| operator bool() const | operator bool() const |
| { | { |
| #ifdef PEGASUS_DEBUG | #ifdef PEGASUS_DEBUG |
Return to
Magic.h
CVS log
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