49 lines
1.8 KiB
C
49 lines
1.8 KiB
C
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//========= Copyright <20> 1996-2005, Valve Corporation, All rights reserved. ============//
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//
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// Purpose: Macros for defining branching singletons.
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//
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// A branching singleton defines a singleton class within another class, and subclasses
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// of the outer class can automatically expand on that singleton at their node in the
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// class branching tree with the confidence that changes will be reflected in all
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// subclasses.
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//
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// The primary reason to have a branching singleton is to centralize management code
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// without being tied explicitly to one interface. The interface can possibly change
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// vastly as it gets passed down the tree to the point where all the original functions
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// are stubs and the interface uses an entirely different set of functions.
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//
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// $NoKeywords: $
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//=============================================================================//
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#ifndef BRANCHINGSINGLETON_H
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#define BRANCHINGSINGLETON_H
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#ifdef _WIN32
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#pragma once
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#endif
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#define START_BRANCHING_SINGLETON_DEFINITION_NOBASE( classname ) class classname
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#define START_BRANCHING_SINGLETON_DEFINITION( classname ) class classname : public Base##classname
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#define _END_BRANCHING_SINGLETON_DEFINITION( classname );\
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static classname *Get_##classname##_Static( void )\
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{\
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static classname s_Singleton;\
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return &s_Singleton;\
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}\
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\
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virtual Root##classname *Get_##classname##( void )\
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{\
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return Get_##classname##_Static();\
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}\
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typedef classname Base##classname;
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#define END_BRANCHING_SINGLETON_DEFINITION( classname ) _END_BRANCHING_SINGLETON_DEFINITION( classname )
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#define END_BRANCHING_SINGLETON_DEFINITION_NOBASE( classname );\
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typedef classname Root##classname;\
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_END_BRANCHING_SINGLETON_DEFINITION( classname );
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#endif //#ifndef BRANCHINGSINGLETON_H
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