MalwareSourceCode/MSIL/Trojan-Ransom/Win32/G/Trojan-Ransom.Win32.Gimemo.ayt-624a52079bf1703bcd3bcc9d2d3716b6126fd05655e25289d19142f9aae02eb5/Compression/RangeCoder/BitEncoder.cs

// Decompiled with JetBrains decompiler
// Type: SevenZip.Compression.RangeCoder.BitEncoder
// Assembly: P4CTEMP, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null
// MVID: 7BE4E538-8555-4C2E-974B-99E556F5462C
// Assembly location: C:\Users\Administrateur\Downloads\Virusshare-00000-msil\Trojan-Ransom.Win32.Gimemo.ayt-624a52079bf1703bcd3bcc9d2d3716b6126fd05655e25289d19142f9aae02eb5.exe

using System;

namespace SevenZip.Compression.RangeCoder
{
  internal struct BitEncoder
  {
    public const int kNumBitModelTotalBits = 11;
    public const uint kBitModelTotal = 2048;
    private const int kNumMoveBits = 5;
    private const int kNumMoveReducingBits = 2;
    public const int kNumBitPriceShiftBits = 6;
    private uint Prob;
    private static uint[] ProbPrices = new uint[new IntPtr(512)];

    public void Init() => this.Prob = 1024U;

    public void UpdateModel(uint symbol)
    {
      if (symbol == 0U)
        this.Prob += 2048U - this.Prob >> 5;
      else
        this.Prob -= this.Prob >> 5;
    }

    public void Encode(Encoder encoder, uint symbol)
    {
      uint num = (encoder.Range >> 11) * this.Prob;
      if (symbol == 0U)
      {
        encoder.Range = num;
        this.Prob += 2048U - this.Prob >> 5;
      }
      else
      {
        encoder.Low += (ulong) num;
        encoder.Range -= num;
        this.Prob -= this.Prob >> 5;
      }
      if (encoder.Range >= 16777216U)
        return;
      encoder.Range <<= 8;
      encoder.ShiftLow();
    }

    static BitEncoder()
    {
      for (int index1 = 8; index1 >= 0; --index1)
      {
        uint num1 = (uint) (1 << 9 - index1 - 1);
        uint num2 = (uint) (1 << 9 - index1);
        for (uint index2 = num1; index2 < num2; ++index2)
          BitEncoder.ProbPrices[(IntPtr) index2] = (uint) (index1 << 6) + ((uint) ((int) num2 - (int) index2 << 6) >> 9 - index1 - 1);
      }
    }

    public uint GetPrice(uint symbol) => BitEncoder.ProbPrices[(((long) (this.Prob - symbol) ^ (long) -(int) symbol) & 2047L) >> 2];

    public uint GetPrice0() => BitEncoder.ProbPrices[(IntPtr) (this.Prob >> 2)];

    public uint GetPrice1() => BitEncoder.ProbPrices[(IntPtr) (2048U - this.Prob >> 2)];
  }
}