tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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Encoder.java (3238B)

      1 package SevenZip.Compression.RangeCoder;
      2 import java.io.IOException;
      3 
      4 public class Encoder
      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 java.io.OutputStream Stream;
     13 
     14 long Low;
     15 int Range;
     16 int _cacheSize;
     17 int _cache;
     18 
     19 long _position;
     20 
     21 public void SetStream(java.io.OutputStream stream)
     22 {
     23 	Stream = stream;
     24 }
     25 
     26 public void ReleaseStream()
     27 {
     28 	Stream = null;
     29 }
     30 
     31 public void Init()
     32 {
     33 	_position = 0;
     34 	Low = 0;
     35 	Range = -1;
     36 	_cacheSize = 1;
     37 	_cache = 0;
     38 }
     39 
     40 public void FlushData() throws IOException
     41 {
     42 	for (int i = 0; i < 5; i++)
     43 		ShiftLow();
     44 }
     45 
     46 public void FlushStream() throws IOException
     47 {
     48 	Stream.flush();
     49 }
     50 
     51 public void ShiftLow() throws IOException
     52 {
     53 	int LowHi = (int)(Low >>> 32);
     54 	if (LowHi != 0 || Low < 0xFF000000L)
     55 	{
     56 		_position += _cacheSize;
     57 		int temp = _cache;
     58 		do
     59 		{
     60 			Stream.write(temp + LowHi);
     61 			temp = 0xFF;
     62 		}
     63 		while(--_cacheSize != 0);
     64 		_cache = (((int)Low) >>> 24);
     65 	}
     66 	_cacheSize++;
     67 	Low = (Low & 0xFFFFFF) << 8;
     68 }
     69 
     70 public void EncodeDirectBits(int v, int numTotalBits) throws IOException
     71 {
     72 	for (int i = numTotalBits - 1; i >= 0; i--)
     73 	{
     74 		Range >>>= 1;
     75 		if (((v >>> i) & 1) == 1)
     76 			Low += Range;
     77 		if ((Range & Encoder.kTopMask) == 0)
     78 		{
     79 			Range <<= 8;
     80 			ShiftLow();
     81 		}
     82 	}
     83 }
     84 
     85 
     86 public long GetProcessedSizeAdd()
     87 {
     88 	return _cacheSize + _position + 4;
     89 }
     90 
     91 
     92 
     93 static final int kNumMoveReducingBits = 2;
     94 public static final int kNumBitPriceShiftBits = 6;
     95 
     96 public static void InitBitModels(short []probs)
     97 {
     98 	for (int i = 0; i < probs.length; i++)
     99 		probs[i] = (kBitModelTotal >>> 1);
    100 }
    101 
    102 public void Encode(short []probs, int index, int symbol) throws IOException
    103 {
    104 	int prob = probs[index];
    105 	int newBound = (Range >>> kNumBitModelTotalBits) * prob;
    106 	if (symbol == 0)
    107 	{
    108 		Range = newBound;
    109 		probs[index] = (short)(prob + ((kBitModelTotal - prob) >>> kNumMoveBits));
    110 	}
    111 	else
    112 	{
    113 		Low += (newBound & 0xFFFFFFFFL);
    114 		Range -= newBound;
    115 		probs[index] = (short)(prob - ((prob) >>> kNumMoveBits));
    116 	}
    117 	if ((Range & kTopMask) == 0)
    118 	{
    119 		Range <<= 8;
    120 		ShiftLow();
    121 	}
    122 }
    123 
    124 private static int[] ProbPrices = new int[kBitModelTotal >>> kNumMoveReducingBits];
    125 
    126 static
    127 {
    128 	int kNumBits = (kNumBitModelTotalBits - kNumMoveReducingBits);
    129 	for (int i = kNumBits - 1; i >= 0; i--)
    130 	{
    131 		int start = 1 << (kNumBits - i - 1);
    132 		int end = 1 << (kNumBits - i);
    133 		for (int j = start; j < end; j++)
    134 			ProbPrices[j] = (i << kNumBitPriceShiftBits) +
    135 					(((end - j) << kNumBitPriceShiftBits) >>> (kNumBits - i - 1));
    136 	}
    137 }
    138 
    139 static public int GetPrice(int Prob, int symbol)
    140 {
    141 	return ProbPrices[(((Prob - symbol) ^ ((-symbol))) & (kBitModelTotal - 1)) >>> kNumMoveReducingBits];
    142 }
    143 static public int GetPrice0(int Prob)
    144 { 
    145 	return ProbPrices[Prob >>> kNumMoveReducingBits]; 
    146 }
    147 static public int GetPrice1(int Prob)
    148 { 
    149 	return ProbPrices[(kBitModelTotal - Prob) >>> kNumMoveReducingBits]; 
    150 }
    151 }