Differential D413 Diff 1621 source/lib/res/h_mgr.cpp

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source/lib/res/h_mgr.cpp

	/* Copyright (c) 2013 Wildfire Games			/* Copyright (c) 2017 Wildfire Games
	*			*
	* Permission is hereby granted, free of charge, to any person obtaining			* Permission is hereby granted, free of charge, to any person obtaining
	* a copy of this software and associated documentation files (the			* a copy of this software and associated documentation files (the
	* "Software"), to deal in the Software without restriction, including			* "Software"), to deal in the Software without restriction, including
	* without limitation the rights to use, copy, modify, merge, publish,			* without limitation the rights to use, copy, modify, merge, publish,
	* distribute, sublicense, and/or sell copies of the Software, and to			* distribute, sublicense, and/or sell copies of the Software, and to
	* permit persons to whom the Software is furnished to do so, subject to			* permit persons to whom the Software is furnished to do so, subject to
	* the following conditions:			* the following conditions:
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	// (field width determines maximum currently open handles)			// (field width determines maximum currently open handles)
	#define IDX_BITS 16			#define IDX_BITS 16
	static const u64 IDX_MASK = (1l << IDX_BITS) - 1;			static const u64 IDX_MASK = (1l << IDX_BITS) - 1;

	// - tag (1-based) ensures the handle references a certain resource instance.			// - tag (1-based) ensures the handle references a certain resource instance.
	// (field width determines maximum unambiguous resource allocs)			// (field width determines maximum unambiguous resource allocs)
	typedef i64 Tag;			typedef i64 Tag;
	#define TAG_BITS 48			#define TAG_BITS 48
	static const u64 TAG_MASK = 0xFFFFFFFF; // safer than (1 << 32) - 1

	// make sure both fields fit within a Handle variable			// make sure both fields fit within a Handle variable
	cassert(IDX_BITS + TAG_BITS <= sizeof(Handle)*CHAR_BIT);			cassert(IDX_BITS + TAG_BITS <= sizeof(Handle)*CHAR_BIT);


	// return the handle's index field (always non-negative).			// return the handle's index field (always non-negative).
	// no error checking!			// no error checking!
	static inline size_t h_idx(const Handle h)			static inline size_t h_idx(const Handle h)
	{			{
	return (size_t)(h & IDX_MASK) - 1;			return (size_t)(h & IDX_MASK) - 1;
	}			}

	// return the handle's tag field.
	// no error checking!
	static inline Tag h_tag(Handle h)
	{
	return h >> IDX_BITS;
	}

	// build a handle from index and tag.			// build a handle from index and tag.
	// can't fail.			// can't fail.
	static inline Handle handle(size_t idx, u64 tag)			static inline Handle handle(size_t idx, u64 tag)
	{			{
	const size_t idxPlusOne = idx+1;			const size_t idxPlusOne = idx+1;
	ENSURE(idxPlusOne <= IDX_MASK);			ENSURE(idxPlusOne <= IDX_MASK);
	ENSURE((tag & IDX_MASK) == 0);			ENSURE((tag & IDX_MASK) == 0);
	Handle h = tag \| idxPlusOne;			Handle h = tag \| idxPlusOne;
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