encoder.java

lzma算法的源码,这个算法的简写请google一把,仅用于学习之用.

					}
				}
			}

			if (newLen > numAvailableBytes)
			{
				newLen = numAvailableBytes;
				for (numDistancePairs = 0; newLen > _matchDistances[numDistancePairs]; numDistancePairs += 2) ;
				_matchDistances[numDistancePairs] = newLen;
				numDistancePairs += 2;
			}
			if (newLen >= startLen)
			{
				normalMatchPrice = matchPrice + SevenZip.Compression.RangeCoder.Encoder.GetPrice0(_isRep[state]);
				while (lenEnd < cur + newLen)
					_optimum[++lenEnd].Price = kIfinityPrice;

				int offs = 0;
				while (startLen > _matchDistances[offs])
					offs += 2;

				for (int lenTest = startLen; ; lenTest++)
				{
					int curBack = _matchDistances[offs + 1];
					int curAndLenPrice = normalMatchPrice + GetPosLenPrice(curBack, lenTest, posState);
					Optimal optimum = _optimum[cur + lenTest];
					if (curAndLenPrice < optimum.Price)
					{
						optimum.Price = curAndLenPrice;
						optimum.PosPrev = cur;
						optimum.BackPrev = curBack + Base.kNumRepDistances;
						optimum.Prev1IsChar = false;
					}

					if (lenTest == _matchDistances[offs])
					{
						if (lenTest < numAvailableBytesFull)
						{
							int t = Math.min(numAvailableBytesFull - 1 - lenTest, _numFastBytes);
							int lenTest2 = _matchFinder.GetMatchLen(lenTest, curBack, t);
							if (lenTest2 >= 2)
							{
								int state2 = Base.StateUpdateMatch(state);

								int posStateNext = (position + lenTest) & _posStateMask;
								int curAndLenCharPrice = curAndLenPrice +
									SevenZip.Compression.RangeCoder.Encoder.GetPrice0(_isMatch[(state2 << Base.kNumPosStatesBitsMax) + posStateNext]) +
									_literalEncoder.GetSubCoder(position + lenTest,
									_matchFinder.GetIndexByte(lenTest - 1 - 1)).
									GetPrice(true,
									_matchFinder.GetIndexByte(lenTest - (curBack + 1) - 1),
									_matchFinder.GetIndexByte(lenTest - 1));
								state2 = Base.StateUpdateChar(state2);
								posStateNext = (position + lenTest + 1) & _posStateMask;
								int nextMatchPrice = curAndLenCharPrice + SevenZip.Compression.RangeCoder.Encoder.GetPrice1(_isMatch[(state2 << Base.kNumPosStatesBitsMax) + posStateNext]);
								int nextRepMatchPrice = nextMatchPrice + SevenZip.Compression.RangeCoder.Encoder.GetPrice1(_isRep[state2]);

								int offset = lenTest + 1 + lenTest2;
								while (lenEnd < cur + offset)
									_optimum[++lenEnd].Price = kIfinityPrice;
								curAndLenPrice = nextRepMatchPrice + GetRepPrice(0, lenTest2, state2, posStateNext);
								optimum = _optimum[cur + offset];
								if (curAndLenPrice < optimum.Price)
								{
									optimum.Price = curAndLenPrice;
									optimum.PosPrev = cur + lenTest + 1;
									optimum.BackPrev = 0;
									optimum.Prev1IsChar = true;
									optimum.Prev2 = true;
									optimum.PosPrev2 = cur;
									optimum.BackPrev2 = curBack + Base.kNumRepDistances;
								}
							}
						}
						offs += 2;
						if (offs == numDistancePairs)
							break;
					}
				}
			}
		}
	}

	boolean ChangePair(int smallDist, int bigDist)
	{
		int kDif = 7;
		return (smallDist < (1 << (32 - kDif)) && bigDist >= (smallDist << kDif));
	}

	void WriteEndMarker(int posState) throws IOException
	{
		if (!_writeEndMark)
			return;

		_rangeEncoder.Encode(_isMatch, (_state << Base.kNumPosStatesBitsMax) + posState, 1);
		_rangeEncoder.Encode(_isRep, _state, 0);
		_state = Base.StateUpdateMatch(_state);
		int len = Base.kMatchMinLen;
		_lenEncoder.Encode(_rangeEncoder, len - Base.kMatchMinLen, posState);
		int posSlot = (1 << Base.kNumPosSlotBits) - 1;
		int lenToPosState = Base.GetLenToPosState(len);
		_posSlotEncoder[lenToPosState].Encode(_rangeEncoder, posSlot);
		int footerBits = 30;
		int posReduced = (1 << footerBits) - 1;
		_rangeEncoder.EncodeDirectBits(posReduced >> Base.kNumAlignBits, footerBits - Base.kNumAlignBits);
		_posAlignEncoder.ReverseEncode(_rangeEncoder, posReduced & Base.kAlignMask);
	}

	void Flush(int nowPos) throws IOException
	{
		ReleaseMFStream();
		WriteEndMarker(nowPos & _posStateMask);
		_rangeEncoder.FlushData();
		_rangeEncoder.FlushStream();
	}

	public void CodeOneBlock(long[] inSize, long[] outSize, boolean[] finished) throws IOException
	{
		inSize[0] = 0;
		outSize[0] = 0;
		finished[0] = true;

		if (_inStream != null)
		{
			_matchFinder.SetStream(_inStream);
			_matchFinder.Init();
			_needReleaseMFStream = true;
			_inStream = null;
		}

		if (_finished)
			return;
		_finished = true;


		long progressPosValuePrev = nowPos64;
		if (nowPos64 == 0)
		{
			if (_matchFinder.GetNumAvailableBytes() == 0)
			{
				Flush((int)nowPos64);
				return;
			}

			ReadMatchDistances();
			int posState = (int)(nowPos64) & _posStateMask;
			_rangeEncoder.Encode(_isMatch, (_state << Base.kNumPosStatesBitsMax) + posState, 0);
			_state = Base.StateUpdateChar(_state);
			byte curByte = _matchFinder.GetIndexByte(0 - _additionalOffset);
			_literalEncoder.GetSubCoder((int)(nowPos64), _previousByte).Encode(_rangeEncoder, curByte);
			_previousByte = curByte;
			_additionalOffset--;
			nowPos64++;
		}
		if (_matchFinder.GetNumAvailableBytes() == 0)
		{
			Flush((int)nowPos64);
			return;
		}
		while (true)
		{

			int len = GetOptimum((int)nowPos64);
			int pos = backRes;
			int posState = ((int)nowPos64) & _posStateMask;
			int complexState = (_state << Base.kNumPosStatesBitsMax) + posState;
			if (len == 1 && pos == -1)
			{
				_rangeEncoder.Encode(_isMatch, complexState, 0);
				byte curByte = _matchFinder.GetIndexByte((int)(0 - _additionalOffset));
				LiteralEncoder.Encoder2 subCoder = _literalEncoder.GetSubCoder((int)nowPos64, _previousByte);
				if (!Base.StateIsCharState(_state))
				{
					byte matchByte = _matchFinder.GetIndexByte((int)(0 - _repDistances[0] - 1 - _additionalOffset));
					subCoder.EncodeMatched(_rangeEncoder, matchByte, curByte);
				}
				else
					subCoder.Encode(_rangeEncoder, curByte);
				_previousByte = curByte;
				_state = Base.StateUpdateChar(_state);
			}
			else
			{
				_rangeEncoder.Encode(_isMatch, complexState, 1);
				if (pos < Base.kNumRepDistances)
				{
					_rangeEncoder.Encode(_isRep, _state, 1);
					if (pos == 0)
					{
						_rangeEncoder.Encode(_isRepG0, _state, 0);
						if (len == 1)
							_rangeEncoder.Encode(_isRep0Long, complexState, 0);
						else
							_rangeEncoder.Encode(_isRep0Long, complexState, 1);
					}
					else
					{
						_rangeEncoder.Encode(_isRepG0, _state, 1);
						if (pos == 1)
							_rangeEncoder.Encode(_isRepG1, _state, 0);
						else
						{
							_rangeEncoder.Encode(_isRepG1, _state, 1);
							_rangeEncoder.Encode(_isRepG2, _state, pos - 2);
						}
					}
					if (len == 1)
						_state = Base.StateUpdateShortRep(_state);
					else
					{
						_repMatchLenEncoder.Encode(_rangeEncoder, len - Base.kMatchMinLen, posState);
						_state = Base.StateUpdateRep(_state);
					}
					int distance = _repDistances[pos];
					if (pos != 0)
					{
						for (int i = pos; i >= 1; i--)
							_repDistances[i] = _repDistances[i - 1];
						_repDistances[0] = distance;
					}
				}
				else
				{
					_rangeEncoder.Encode(_isRep, _state, 0);
					_state = Base.StateUpdateMatch(_state);
					_lenEncoder.Encode(_rangeEncoder, len - Base.kMatchMinLen, posState);
					pos -= Base.kNumRepDistances;
					int posSlot = GetPosSlot(pos);
					int lenToPosState = Base.GetLenToPosState(len);
					_posSlotEncoder[lenToPosState].Encode(_rangeEncoder, posSlot);

					if (posSlot >= Base.kStartPosModelIndex)
					{
						int footerBits = (int)((posSlot >> 1) - 1);
						int baseVal = ((2 | (posSlot & 1)) << footerBits);
						int posReduced = pos - baseVal;

						if (posSlot < Base.kEndPosModelIndex)
							BitTreeEncoder.ReverseEncode(_posEncoders,
									baseVal - posSlot - 1, _rangeEncoder, footerBits, posReduced);
						else
						{
							_rangeEncoder.EncodeDirectBits(posReduced >> Base.kNumAlignBits, footerBits - Base.kNumAlignBits);
							_posAlignEncoder.ReverseEncode(_rangeEncoder, posReduced & Base.kAlignMask);
							_alignPriceCount++;
						}
					}
					int distance = pos;
					for (int i = Base.kNumRepDistances - 1; i >= 1; i--)
						_repDistances[i] = _repDistances[i - 1];
					_repDistances[0] = distance;
					_matchPriceCount++;
				}
				_previousByte = _matchFinder.GetIndexByte(len - 1 - _additionalOffset);
			}
			_additionalOffset -= len;
			nowPos64 += len;
			if (_additionalOffset == 0)
			{
				// if (!_fastMode)
				if (_matchPriceCount >= (1 << 7))
					FillDistancesPrices();
				if (_alignPriceCount >= Base.kAlignTableSize)
					FillAlignPrices();
				inSize[0] = nowPos64;
				outSize[0] = _rangeEncoder.GetProcessedSizeAdd();
				if (_matchFinder.GetNumAvailableBytes() == 0)
				{
					Flush((int)nowPos64);
					return;
				}

				if (nowPos64 - progressPosValuePrev >= (1 << 12))
				{
					_finished = false;
					finished[0] = false;
					return;
				}
			}
		}
	}

	void ReleaseMFStream()
	{
		if (_matchFinder != null && _needReleaseMFStream)
		{
			_matchFinder.ReleaseStream();
			_needReleaseMFStream = false;
		}
	}

	void SetOutStream(java.io.OutputStream outStream)
	{ _rangeEncoder.SetStream(outStream); }
	void ReleaseOutStream()
	{ _rangeEncoder.ReleaseStream(); }

	void ReleaseStreams()
	{
		ReleaseMFStream();
		ReleaseOutStream();
	}

	void SetStreams(java.io.InputStream inStream, java.io.OutputStream outStream,
			long inSize, long outSize)
	{
		_inStream = inStream;
		_finished = false;
		Create();
		SetOutStream(outStream);
		Init();

		// if (!_fastMode)
		{
			FillDistancesPrices();
			FillAlignPrices();
		}

		_lenEncoder.SetTableSize(_numFastBytes + 1 - Base.kMatchMinLen);
		_lenEncoder.UpdateTables(1 << _posStateBits);
		_repMatchLenEncoder.SetTableSize(_numFastBytes + 1 - Base.kMatchMinLen);
		_repMatchLenEncoder.UpdateTables(1 << _posStateBits);

		nowPos64 = 0;
	}

	long[] processedInSize = new long[1]; long[] processedOutSize = new long[1]; boolean[] finished = new boolean[1];
	public void Code(java.io.InputStream inStream, java.io.OutputStream outStream,
			long inSize, long outSize, ICodeProgress progress) throws IOException
	{
		_needReleaseMFStream = false;
		try
		{
			SetStreams(inStream, outStream, inSize, outSize);
			while (true)
			{



				CodeOneBlock(processedInSize, processedOutSize, finished);
				if (finished[0])
					return;
				if (progress != null)
				{
					progress.SetProgress(processedInSize[0], processedOutSize[0]);
				}
			}
		}
		finally
		{
			ReleaseStreams();
		}
	}

	public static final int kPropSize = 5;
	byte[] properties = new byte[kPropSize];

	public void WriteCoderProperties(java.io.OutputStream outStream) throws IOException
	{
		properties[0] = (byte)((_posStateBits * 5 + _numLiteralPosStateBits) * 9 + _numLiteralContextBits);
		for (int i = 0; i < 4; i++)
			properties[1 + i] = (byte)(_dictionarySize >> (8 * i));
		outStream.write(properties, 0, kPropSize);
	}

	int[] tempPrices = new int[Base.kNumFullDistances];
	int _matchPriceCount;

	void FillDistancesPrices()
	{
		for (int i = Base.kStartPosModelIndex; i < Base.kNumFullDistances; i++)
		{
			int posSlot = GetPosSlot(i);
			int footerBits = (int)((posSlot >> 1) - 1);
			int baseVal = ((2 | (posSlot & 1)) << footerBits);
			tempPrices[i] = BitTreeEncoder.ReverseGetPrice(_posEncoders,
				baseVal - posSlot - 1, footerBits, i - baseVal);
		}

		for (int lenToPosState = 0; lenToPosState < Base.kNumLenToPosStates; lenToPosState++)
		{
			int posSlot;
			BitTreeEncoder encoder = _posSlotEncoder[lenToPosState];

			int st = (lenToPosState << Base.kNumPosSlotBits);
			for (posSlot = 0; posSlot < _distTableSize; posSlot++)
				_posSlotPrices[st + posSlot] = encoder.GetPrice(posSlot);
			for (posSlot = Base.kEndPosModelIndex; posSlot < _distTableSize; posSlot++)
				_posSlotPrices[st + posSlot] += ((((posSlot >> 1) - 1) - Base.kNumAlignBits) << SevenZip.Compression.RangeCoder.Encoder.kNumBitPriceShiftBits);

			int st2 = lenToPosState * Base.kNumFullDistances;
			int i;
			for (i = 0; i < Base.kStartPosModelIndex; i++)
				_distancesPrices[st2 + i] = _posSlotPrices[st + i];
			for (; i < Base.kNumFullDistances; i++)
				_distancesPrices[st2 + i] = _posSlotPrices[st + GetPosSlot(i)] + tempPrices[i];
		}
		_matchPriceCount = 0;
	}

	void FillAlignPrices()
	{
		for (int i = 0; i < Base.kAlignTableSize; i++)
			_alignPrices[i] = _posAlignEncoder.ReverseGetPrice(i);
		_alignPriceCount = 0;
	}


	public boolean SetAlgorithm(int algorithm)
	{
		/*
		_fastMode = (algorithm == 0);
		_maxMode = (algorithm >= 2);
		*/
		return true;
	}

	public boolean SetDictionarySize(int dictionarySize)
	{
		int kDicLogSizeMaxCompress = 29;
		if (dictionarySize < (1 << Base.kDicLogSizeMin) || dictionarySize > (1 << kDicLogSizeMaxCompress))
			return false;
		_dictionarySize = dictionarySize;
		int dicLogSize;
		for (dicLogSize = 0; dictionarySize > (1 << dicLogSize); dicLogSize++) ;
		_distTableSize = dicLogSize * 2;
		return true;
	}

	public boolean SetNumFastBytes(int numFastBytes)
	{
		if (numFastBytes < 5 || numFastBytes > Base.kMatchMaxLen)
			return false;
		_numFastBytes = numFastBytes;
		return true;
	}

	public boolean SetMatchFinder(int matchFinderIndex)
	{
		if (matchFinderIndex < 0 || matchFinderIndex > 2)
			return false;
		int matchFinderIndexPrev = _matchFinderType;
		_matchFinderType = matchFinderIndex;
		if (_matchFinder != null && matchFinderIndexPrev != _matchFinderType)
		{
			_dictionarySizePrev = -1;
			_matchFinder = null;
		}
		return true;
	}

	public boolean SetLcLpPb(int lc, int lp, int pb)
	{
		if (
				lp < 0 || lp > Base.kNumLitPosStatesBitsEncodingMax ||
				lc < 0 || lc > Base.kNumLitContextBitsMax ||
				pb < 0 || pb > Base.kNumPosStatesBitsEncodingMax)
			return false;
		_numLiteralPosStateBits = lp;
		_numLiteralContextBits = lc;
		_posStateBits = pb;
		_posStateMask = ((1) << _posStateBits) - 1;
		return true;
	}

	public void SetEndMarkerMode(boolean endMarkerMode)
	{
		_writeEndMark = endMarkerMode;
	}
}