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Lib/Include/ZSTL/ZSTLInvalidPos.hpp

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+/*
+	ZSTLInvalidPos.hpp
+	Author: James Russell <jcrussell@762studios.com>
+	Created: 12/27/2012
+
+	Purpose: 
+
+	Header file for ZSTL::InvalidPos, which includes only a single definition for
+	the 'InvalidPos' structure.  This acts as a common return value for most containers
+	wherein the return would be an invalid index or iterator.
+
+	License:
+
+	This program is free software. It comes without any warranty, to
+	the extent permitted by applicable law. You can redistribute it
+	and/or modify it under the terms of the Do What The Fuck You Want
+	To Public License, Version 2, as published by Sam Hocevar. See
+	http://sam.zoy.org/wtfpl/COPYING for more details.
+
+*/
+
+#pragma once
+
+#ifndef _ZSTLINVALIDPOS_HPP
+#define _ZSTLINVALIDPOS_HPP
+
+#include <stdlib.h> // size_t, NULL
+
+//Predeclare ZListIterator type
+template <typename T> class ZListIterator;
+
+/* The ZSTL namespace */
+namespace ZSTL
+{
+	//Invalid Object structure, used to indicate an invalid position on many different types of containers
+	struct _InvalidObject
+	{
+		//Implicit cast to size_t
+		operator size_t () const 
+			{ return ((size_t)-1); }
+
+		//Implicit (and templated) cast to ZListIterator<T>
+		template <typename T>
+		operator ZListIterator<T> () const
+			{ return ZListIterator<T>(NULL, NULL); }
+	};
+
+	/*
+	Indicator used to check when an algorithm has returned an invalid position or iterator.  
+	Many algorithms return an index or iterator that needs to be checked against an 'invalid'
+	return, such as 'FindFirstOf' returning a size_t value for arrays and an iterator
+	for lists.
+
+	This structure can be used to check against all types of returns. 
+
+		if (ZArrayAlgo::FindFirstOf(...) != ZSTL::InvalidPos)
+			...
+
+		if (ZListAlgo::FindFirstOf(...) != ZSTL::InvalidPos)
+			...
+	*/
+	const static _InvalidObject InvalidPos = _InvalidObject();
+}
+
+#endif
+