physxCAPI/physxCDLL/include/foundation/PxBitMap.h

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#ifndef PX_BITMAP_H
#define PX_BITMAP_H

#include "foundation/PxAssert.h"
#include "foundation/PxMath.h"
#include "foundation/PxMemory.h"
#include "foundation/PxAllocator.h"
#include "foundation/PxUserAllocated.h"
#include "foundation/PxIntrinsics.h"
#include "foundation/PxBitUtils.h"

#if !PX_DOXYGEN
namespace physx
{
#endif
	/*!
	Hold a bitmap with operations to set,reset or test given bit.

	We inhibit copy to prevent unintentional copies. If a copy is desired copy() should be used or
	alternatively a copy constructor implemented.
	*/
	template<class PxAllocator>
	class PxBitMapBase : public PxUserAllocated
	{
		//= ATTENTION! =====================================================================================
		// Changing the data layout of this class breaks the binary serialization format.  See comments for 
		// PX_BINARY_SERIAL_VERSION.  If a modification is required, please adjust the getBinaryMetaData 
		// function.  If the modification is made on a custom branch, please change PX_BINARY_SERIAL_VERSION
		// accordingly.
		//==================================================================================================

		PX_NOCOPY(PxBitMapBase)

	public:

		// PX_SERIALIZATION
		/* todo: explicit */ PxBitMapBase(const PxEMPTY)
		{
			if (mMap)
				mWordCount |= PX_SIGN_BITMASK;
		}
		//~PX_SERIALIZATION

		PX_INLINE PxBitMapBase(const PxAllocator& allocator) : mMap(0), mWordCount(0), mAllocator(allocator) {}

		PX_INLINE PxBitMapBase() : mMap(0), mWordCount(0) {}

		PX_INLINE ~PxBitMapBase()
		{
			release();
		}

		PX_INLINE void release()
		{
			if (mMap && !isInUserMemory())
				mAllocator.deallocate(mMap);
			mMap = NULL;
		}

		PX_INLINE PxAllocator&	getAllocator() { return mAllocator; }

		PX_INLINE void growAndSet(PxU32 index)
		{
			extend(index + 1);
			mMap[index >> 5] |= 1 << (index & 31);
		}

		PX_INLINE void growAndReset(PxU32 index)
		{
			extend(index + 1);
			mMap[index >> 5] &= ~(1 << (index & 31));
		}

		PX_INLINE PxIntBool boundedTest(PxU32 index) const
		{
			return PxIntBool(index >> 5 >= getWordCount() ? PxIntFalse : (mMap[index >> 5] & (1 << (index & 31))));
		}

		PX_INLINE void boundedReset(PxU32 index)
		{
			if((index >> 5) < getWordCount())
				mMap[index >> 5] &= ~(1 << (index & 31));
		}

		// Special optimized versions, when you _know_ your index is in range
		PX_INLINE void set(PxU32 index)
		{
			PX_ASSERT(index<getWordCount() * 32);
			mMap[index >> 5] |= 1 << (index & 31);
		}

		PX_INLINE void reset(PxU32 index)
		{
			PX_ASSERT(index<getWordCount() * 32);
			mMap[index >> 5] &= ~(1 << (index & 31));
		}

		PX_INLINE PxIntBool test(PxU32 index) const
		{
			PX_ASSERT(index<getWordCount() * 32);
			return PxIntBool(mMap[index >> 5] & (1 << (index & 31)));
		}

		// nibble == 4 bits
		PX_INLINE PxU32 getNibbleFast(PxU32 nibIndex) const
		{
			const PxU32 bitIndex = nibIndex << 2;
			PX_ASSERT(bitIndex < getWordCount() * 32);
			return (mMap[bitIndex >> 5] >> (bitIndex & 31)) & 0xf;
		}

		PX_INLINE void andNibbleFast(PxU32 nibIndex, PxU32 mask)
		{
			//TODO: there has to be a faster way...
			const PxU32 bitIndex = nibIndex << 2;
			const PxU32 shift = (bitIndex & 31);
			const PxU32 nibMask = (0xfu << shift);

			PX_ASSERT(bitIndex < getWordCount() * 32);

			mMap[bitIndex >> 5] &= ((mask << shift) | ~nibMask);
		}

		PX_INLINE void orNibbleFast(PxU32 nibIndex, PxU32 mask)
		{
			PX_ASSERT(!(mask & ~0xfu)); //check extra bits are not set

			const PxU32 bitIndex = nibIndex << 2;
			const PxU32 shift = bitIndex & 31;

			PX_ASSERT(bitIndex < getWordCount() * 32);

			mMap[bitIndex >> 5] |= (mask << shift);
		}

		void clear()
		{
			PxMemSet(mMap, 0, getWordCount() * sizeof(PxU32));
		}

		void resizeAndClear(PxU32 newBitCount)
		{
			extendUninitialized(newBitCount);
			PxMemSet(mMap, 0, getWordCount() * sizeof(PxU32));
		}

		void setEmpty()
		{
			mMap = NULL;
			mWordCount = 0;
		}

		void setWords(PxU32* map, PxU32 wordCount)
		{
			mMap = map;
			mWordCount = wordCount;
			mWordCount |= PX_SIGN_BITMASK;
		}

		// !!! only sets /last/ bit to value
		void resize(PxU32 newBitCount, bool value = false)
		{
			PX_ASSERT(!value); // only new class supports this
			PX_UNUSED(value);
			extend(newBitCount);
		}

		PxU32 size() const { return getWordCount() * 32; }

		void copy(const PxBitMapBase& a)
		{
			extendUninitialized(a.getWordCount() << 5);
			PxMemCopy(mMap, a.mMap, a.getWordCount() * sizeof(PxU32));
			if (getWordCount() > a.getWordCount())
				PxMemSet(mMap + a.getWordCount(), 0, (getWordCount() - a.getWordCount()) * sizeof(PxU32));
		}

		PX_INLINE PxU32 count()		const
		{
			// NOTE: we can probably do this faster, since the last steps in PxcBitCount32 can be defered to
			// the end of the seq. + 64/128bits at a time + native bit counting instructions(360 is fast non micro code).
			PxU32 count = 0;
			const PxU32 wordCount = getWordCount();
			for (PxU32 i = 0; i<wordCount; i++)
				count += PxBitCount(mMap[i]);

			return count;
		}

		PX_INLINE PxU32 count(PxU32 start, PxU32 length) const
		{
			const PxU32 end = PxMin(getWordCount() << 5, start + length);
			PxU32 count = 0;
			for (PxU32 i = start; i<end; i++)
				count += (test(i) != 0);
			return count;
		}

		//! returns 0 if no bits set (!!!)
		PxU32 findLast() const
		{
			const PxU32 wordCount = getWordCount();
			for (PxU32 i = wordCount; i-- > 0;)
			{
				if (mMap[i])
					return (i << 5) + PxHighestSetBit(mMap[i]);
			}
			return PxU32(0);
		}

		// the obvious combiners and some used in the SDK

		struct OR { PX_INLINE PxU32 operator()(PxU32 a, PxU32 b) { return a | b; } };
		struct AND { PX_INLINE PxU32 operator()(PxU32 a, PxU32 b) { return a&b; } };
		struct XOR { PX_INLINE PxU32 operator()(PxU32 a, PxU32 b) { return a^b; } };

		// we use auxiliary functions here so as not to generate combiners for every combination
		// of allocators

		template<class Combiner, class _>
		PX_INLINE void combineInPlace(const PxBitMapBase<_>& b)
		{
			combine1<Combiner>(b.mMap, b.getWordCount());
		}

		template<class Combiner, class _1, class _2>
		PX_INLINE void combine(const PxBitMapBase<_1>& a, const PxBitMapBase<_2>& b)
		{
			combine2<Combiner>(a.mMap, a.getWordCount(), b.mMap, b.getWordCount());
		}

		PX_FORCE_INLINE const PxU32*	getWords()			const	{ return mMap; }
		PX_FORCE_INLINE PxU32*			getWords()					{ return mMap; }

		// PX_SERIALIZATION
		PX_FORCE_INLINE PxU32			getWordCount()		const	{ return mWordCount & ~PX_SIGN_BITMASK; }

		// We need one bit to mark arrays that have been deserialized from a user-provided memory block.
		PX_FORCE_INLINE	PxU32			isInUserMemory()	const	{ return mWordCount & PX_SIGN_BITMASK; }
		//~PX_SERIALIZATION

		/*!
		Iterate over indices in a bitmap

		This iterator is good because it finds the set bit without looping over the cached bits upto 31 times.
		However it does require a variable shift.
		*/

		class Iterator
		{
		public:
			static const PxU32 DONE = 0xffffffff;

			PX_INLINE Iterator(const PxBitMapBase &map) : mBitMap(map)
			{
				reset();
			}

			PX_INLINE Iterator& operator=(const Iterator& other)
			{
				PX_ASSERT(&mBitMap == &other.mBitMap);
				mBlock = other.mBlock;
				mIndex = other.mIndex;
				return *this;
			}

			PX_INLINE PxU32	getNext()
			{
				if (mBlock)
				{
					PxU32 bitIndex = mIndex << 5 | PxLowestSetBit(mBlock);
					mBlock &= mBlock - 1;
					PxU32 wordCount = mBitMap.getWordCount();
					while (!mBlock && ++mIndex < wordCount)
						mBlock = mBitMap.mMap[mIndex];
					return bitIndex;
				}
				return DONE;
			}

			PX_INLINE void reset()
			{
				mIndex = mBlock = 0;
				PxU32 wordCount = mBitMap.getWordCount();
				while (mIndex < wordCount && ((mBlock = mBitMap.mMap[mIndex]) == 0))
					++mIndex;
			}
		private:
			PxU32 mBlock, mIndex;
			const PxBitMapBase& mBitMap;
		};

		// DS: faster but less general: hasBits() must be true or getNext() is illegal so it is the calling code's responsibility to ensure that getNext() is not called illegally.
		class PxLoopIterator
		{
			PX_NOCOPY(PxLoopIterator)

		public:
			PX_FORCE_INLINE PxLoopIterator(const PxBitMapBase &map) : mMap(map.getWords()), mBlock(0), mIndex(-1), mWordCount(PxI32(map.getWordCount())) {}

			PX_FORCE_INLINE bool hasBits()
			{
				PX_ASSERT(mIndex<mWordCount);
				while (mBlock == 0)
				{
					if (++mIndex == mWordCount)
						return false;
					mBlock = mMap[mIndex];
				}
				return true;
			}

			PX_FORCE_INLINE PxU32 getNext()
			{
				PX_ASSERT(mIndex<mWordCount && mBlock != 0);
				PxU32 result = PxU32(mIndex) << 5 | PxLowestSetBit(mBlock);	// will assert if mask is zero
				mBlock &= (mBlock - 1);
				return result;
			}

		private:
			const PxU32*const mMap;
			PxU32 mBlock;		// the word we're currently scanning
			PxI32 mIndex;		// the index of the word we're currently looking at
			PxI32 mWordCount;
		};

		//Class to iterate over the bitmap from a particular start location rather than the beginning of the list
		class PxCircularIterator
		{
		public:
			static const PxU32 DONE = 0xffffffff;

			PX_INLINE PxCircularIterator(const PxBitMapBase &map, PxU32 index) : mBitMap(map)
			{
				mIndex = mBlock = mStartIndex = 0;
				const PxU32 wordCount = mBitMap.getWordCount();
				if ((index << 5) < wordCount)
				{
					mIndex = index << 5;
					mStartIndex = mIndex;
				}

				if (mIndex < wordCount)
				{
					mBlock = mBitMap.mMap[mIndex];
					if (mBlock == 0)
					{
						mIndex = (mIndex + 1) % wordCount;
						while (mIndex != mStartIndex && (mBlock = mBitMap.mMap[mIndex]) == 0)
							mIndex = (mIndex + 1) % wordCount;
					}
				}
			}

			PX_INLINE PxU32	getNext()
			{
				if (mBlock)
				{
					PxU32 bitIndex = mIndex << 5 | PxLowestSetBit(mBlock);
					mBlock &= mBlock - 1;
					PxU32 wordCount = mBitMap.getWordCount();
					while (!mBlock && (mIndex = ((mIndex + 1) % wordCount)) != mStartIndex)
						mBlock = mBitMap.mMap[mIndex];
					return bitIndex;
				}
				return DONE;
			}

		private:
			PxU32 mBlock, mIndex;
			PxU32 mStartIndex;
			const PxBitMapBase& mBitMap;

			PX_NOCOPY(PxCircularIterator)
		};

	protected:
		PxU32*		mMap;			//one bit per index
		PxU32		mWordCount;
		PxAllocator	mAllocator;
		PxU8		mPadding[3];	// PT: "mAllocator" is empty but consumes 1 byte

		void extend(PxU32 size)
		{
			const PxU32 newWordCount = (size + 31) >> 5;
			if (newWordCount > getWordCount())
			{
				PxU32* newMap = reinterpret_cast<PxU32*>(mAllocator.allocate(newWordCount * sizeof(PxU32), __FILE__, __LINE__));
				if (mMap)
				{
					PxMemCopy(newMap, mMap, getWordCount() * sizeof(PxU32));
					if (!isInUserMemory())
						mAllocator.deallocate(mMap);
				}
				PxMemSet(newMap + getWordCount(), 0, (newWordCount - getWordCount()) * sizeof(PxU32));
				mMap = newMap;
				// also resets the isInUserMemory bit
				mWordCount = newWordCount;
			}
		}

		void extendUninitialized(PxU32 size)
		{
			PxU32 newWordCount = (size + 31) >> 5;
			if (newWordCount > getWordCount())
			{
				if (mMap && !isInUserMemory())
					mAllocator.deallocate(mMap);
				// also resets the isInUserMemory bit
				mWordCount = newWordCount;
				mMap = reinterpret_cast<PxU32*>(mAllocator.allocate(mWordCount * sizeof(PxU32), __FILE__, __LINE__));
			}
		}

		template<class Combiner>
		void combine1(const PxU32* words, PxU32 length)
		{
			extend(length << 5);
			PxU32 combineLength = PxMin(getWordCount(), length);
			for (PxU32 i = 0; i<combineLength; i++)
				mMap[i] = Combiner()(mMap[i], words[i]);
		}

		template<class Combiner>
		void combine2(const PxU32* words1, PxU32 length1,
			const PxU32* words2, PxU32 length2)
		{
			extendUninitialized(PxMax(length1, length2) << 5);

			PxU32 commonSize = PxMin(length1, length2);

			for (PxU32 i = 0; i<commonSize; i++)
				mMap[i] = Combiner()(words1[i], words2[i]);

			for (PxU32 i = commonSize; i<length1; i++)
				mMap[i] = Combiner()(words1[i], 0);

			for (PxU32 i = commonSize; i<length2; i++)
				mMap[i] = Combiner()(0, words2[i]);
		}

		friend class Iterator;
	};

	typedef PxBitMapBase<PxAllocator> PxBitMap;
	typedef PxBitMapBase<PxVirtualAllocator> PxBitMapPinned;
#if !PX_DOXYGEN
} // namespace physx
#endif

#endif