1 files changed, 88 insertions, 0 deletions
diff --git a/other-licenses/7zstub/src/Java/SevenZip/Compression/RangeCoder/Decoder.java b/other-licenses/7zstub/src/Java/SevenZip/Compression/RangeCoder/Decoder.java
new file mode 100644
index 000000000..745338348
--- /dev/null
+++ b/other-licenses/7zstub/src/Java/SevenZip/Compression/RangeCoder/Decoder.java
@@ -0,0 +1,88 @@
+package SevenZip.Compression.RangeCoder;
+import java.io.IOException;
+
+public class Decoder
+{
+	static final int kTopMask = ~((1 << 24) - 1);
+	
+	static final int kNumBitModelTotalBits = 11;
+	static final int kBitModelTotal = (1 << kNumBitModelTotalBits);
+	static final int kNumMoveBits = 5;
+	
+	int Range;
+	int Code;
+
+	java.io.InputStream Stream;
+	
+	public final void SetStream(java.io.InputStream stream)
+	{ 
+		Stream = stream; 
+	}
+	
+	public final void ReleaseStream()
+	{ 
+		Stream = null; 
+	}
+	
+	public final void Init() throws IOException
+	{
+		Code = 0;
+		Range = -1;
+		for (int i = 0; i < 5; i++)
+			Code = (Code << 8) | Stream.read();
+	}
+	
+	public final int DecodeDirectBits(int numTotalBits) throws IOException
+	{
+		int result = 0;
+		for (int i = numTotalBits; i != 0; i--)
+		{
+			Range >>>= 1;
+			int t = ((Code - Range) >>> 31);
+			Code -= Range & (t - 1);
+			result = (result << 1) | (1 - t);
+			
+			if ((Range & kTopMask) == 0)
+			{
+				Code = (Code << 8) | Stream.read();
+				Range <<= 8;
+			}
+		}
+		return result;
+	}
+	
+	public int DecodeBit(short []probs, int index) throws IOException
+	{
+		int prob = probs[index];
+		int newBound = (Range >>> kNumBitModelTotalBits) * prob;
+		if ((Code ^ 0x80000000) < (newBound ^ 0x80000000))
+		{
+			Range = newBound;
+			probs[index] = (short)(prob + ((kBitModelTotal - prob) >>> kNumMoveBits));
+			if ((Range & kTopMask) == 0)
+			{
+				Code = (Code << 8) | Stream.read();
+				Range <<= 8;
+			}
+			return 0;
+		}
+		else
+		{
+			Range -= newBound;
+			Code -= newBound;
+			probs[index] = (short)(prob - ((prob) >>> kNumMoveBits));
+			if ((Range & kTopMask) == 0)
+			{
+				Code = (Code << 8) | Stream.read();
+				Range <<= 8;
+			}
+			return 1;
+		}
+	}
+	
+	public static void InitBitModels(short []probs)
+	{
+		for (int i = 0; i < probs.length; i++)
+			probs[i] = (kBitModelTotal >>> 1);
+	}
+}