tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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Decoder.java (1916B)

      1 package SevenZip.Compression.RangeCoder;
      2 import java.io.IOException;
      3 
      4 public class Decoder
      5 {
      6 static final int kTopMask = ~((1 << 24) - 1);
      7 
      8 static final int kNumBitModelTotalBits = 11;
      9 static final int kBitModelTotal = (1 << kNumBitModelTotalBits);
     10 static final int kNumMoveBits = 5;
     11 
     12 int Range;
     13 int Code;
     14 
     15 java.io.InputStream Stream;
     16 
     17 public final void SetStream(java.io.InputStream stream)
     18 { 
     19 	Stream = stream; 
     20 }
     21 
     22 public final void ReleaseStream()
     23 { 
     24 	Stream = null; 
     25 }
     26 
     27 public final void Init() throws IOException
     28 {
     29 	Code = 0;
     30 	Range = -1;
     31 	for (int i = 0; i < 5; i++)
     32 		Code = (Code << 8) | Stream.read();
     33 }
     34 
     35 public final int DecodeDirectBits(int numTotalBits) throws IOException
     36 {
     37 	int result = 0;
     38 	for (int i = numTotalBits; i != 0; i--)
     39 	{
     40 		Range >>>= 1;
     41 		int t = ((Code - Range) >>> 31);
     42 		Code -= Range & (t - 1);
     43 		result = (result << 1) | (1 - t);
     44 		
     45 		if ((Range & kTopMask) == 0)
     46 		{
     47 			Code = (Code << 8) | Stream.read();
     48 			Range <<= 8;
     49 		}
     50 	}
     51 	return result;
     52 }
     53 
     54 public int DecodeBit(short []probs, int index) throws IOException
     55 {
     56 	int prob = probs[index];
     57 	int newBound = (Range >>> kNumBitModelTotalBits) * prob;
     58 	if ((Code ^ 0x80000000) < (newBound ^ 0x80000000))
     59 	{
     60 		Range = newBound;
     61 		probs[index] = (short)(prob + ((kBitModelTotal - prob) >>> kNumMoveBits));
     62 		if ((Range & kTopMask) == 0)
     63 		{
     64 			Code = (Code << 8) | Stream.read();
     65 			Range <<= 8;
     66 		}
     67 		return 0;
     68 	}
     69 	else
     70 	{
     71 		Range -= newBound;
     72 		Code -= newBound;
     73 		probs[index] = (short)(prob - ((prob) >>> kNumMoveBits));
     74 		if ((Range & kTopMask) == 0)
     75 		{
     76 			Code = (Code << 8) | Stream.read();
     77 			Range <<= 8;
     78 		}
     79 		return 1;
     80 	}
     81 }
     82 
     83 public static void InitBitModels(short []probs)
     84 {
     85 	for (int i = 0; i < probs.length; i++)
     86 		probs[i] = (kBitModelTotal >>> 1);
     87 }
     88 }