C# DataPacket.ReadBit方法代码示例

            protected override void Init(DataPacket packet)
            {
                var submapCount = 1;
                if (packet.ReadBit()) submapCount += (int)packet.ReadBits(4);

                // square polar mapping
                var couplingSteps = 0;
                if (packet.ReadBit())
                {
                    couplingSteps = (int)packet.ReadBits(8) + 1;
                }

                var couplingBits = Utils.ilog(_vorbis._channels - 1);
                CouplingSteps = new CouplingStep[couplingSteps];
                for (int j = 0; j < couplingSteps; j++)
                {
                    var magnitude = (int)packet.ReadBits(couplingBits);
                    var angle = (int)packet.ReadBits(couplingBits);
                    if (magnitude == angle || magnitude > _vorbis._channels - 1 || angle > _vorbis._channels - 1)
                        throw new Exception();
                    CouplingSteps[j] = new CouplingStep { Angle = angle, Magnitude = magnitude };
                }

                // reserved bits
                if (packet.ReadBits(2) != 0UL) throw new Exception();

                // channel multiplex
                var mux = new int[_vorbis._channels];
                if (submapCount > 1)
                {
                    for (int c = 0; c < ChannelSubmap.Length; c++)
                    {
                        mux[c] = (int)packet.ReadBits(4);
                        if (mux[c] >= submapCount) throw new Exception();
                    }
                }

                // submaps
                Submaps = new Submap[submapCount];
                for (int j = 0; j < submapCount; j++)
                {
                    packet.ReadBits(8); // unused placeholder
                    var floorNum = (int)packet.ReadBits(8);
                    if (floorNum >= _vorbis.Floors.Length) throw new Exception();
                    var residueNum = (int)packet.ReadBits(8);
                    if (residueNum >= _vorbis.Residues.Length) throw new Exception();

                    Submaps[j] = new Submap
                    {
                        Floor = _vorbis.Floors[floorNum],
                        Residue = _vorbis.Residues[floorNum]
                    };
                }

                ChannelSubmap = new Submap[_vorbis._channels];
                for (int c = 0; c < ChannelSubmap.Length; c++)
                {
                    ChannelSubmap[c] = Submaps[mux[c]];
                }
            }

 protected override void Init(DataPacket packet)
 {
   int length1 = 1;
   if (packet.ReadBit())
     length1 += (int) packet.ReadBits(4);
   int length2 = 0;
   if (packet.ReadBit())
     length2 = (int) packet.ReadBits(8) + 1;
   int count = Utils.ilog(this._vorbis._channels - 1);
   this.CouplingSteps = new VorbisMapping.CouplingStep[length2];
   for (int index = 0; index < length2; ++index)
   {
     int num1 = (int) packet.ReadBits(count);
     int num2 = (int) packet.ReadBits(count);
     if (num1 == num2 || num1 > this._vorbis._channels - 1 || num2 > this._vorbis._channels - 1)
       throw new InvalidDataException();
     this.CouplingSteps[index] = new VorbisMapping.CouplingStep()
     {
       Angle = num2,
       Magnitude = num1
     };
   }
   if ((long) packet.ReadBits(2) != 0L)
     throw new InvalidDataException();
   int[] numArray = new int[this._vorbis._channels];
   if (length1 > 1)
   {
     for (int index = 0; index < this.ChannelSubmap.Length; ++index)
     {
       numArray[index] = (int) packet.ReadBits(4);
       if (numArray[index] >= length1)
         throw new InvalidDataException();
     }
   }
   this.Submaps = new VorbisMapping.Submap[length1];
   for (int index1 = 0; index1 < length1; ++index1)
   {
     long num = (long) packet.ReadBits(8);
     int index2 = (int) packet.ReadBits(8);
     if (index2 >= this._vorbis.Floors.Length)
       throw new InvalidDataException();
     if ((int) packet.ReadBits(8) >= this._vorbis.Residues.Length)
       throw new InvalidDataException();
     this.Submaps[index1] = new VorbisMapping.Submap()
     {
       Floor = this._vorbis.Floors[index2],
       Residue = this._vorbis.Residues[index2]
     };
   }
   this.ChannelSubmap = new VorbisMapping.Submap[this._vorbis._channels];
   for (int index = 0; index < this.ChannelSubmap.Length; ++index)
     this.ChannelSubmap[index] = this.Submaps[numArray[index]];
 }

 internal static VorbisMode Init(VorbisStreamDecoder vorbis, DataPacket packet)
 {
   VorbisMode vorbisMode = new VorbisMode(vorbis);
   vorbisMode.BlockFlag = packet.ReadBit();
   vorbisMode.WindowType = (int) packet.ReadBits(16);
   vorbisMode.TransformType = (int) packet.ReadBits(16);
   int index = (int) packet.ReadBits(8);
   if (vorbisMode.WindowType != 0 || vorbisMode.TransformType != 0 || index >= vorbis.Maps.Length)
     throw new InvalidDataException();
   vorbisMode.Mapping = vorbis.Maps[index];
   vorbisMode.BlockSize = vorbisMode.BlockFlag ? vorbis.Block1Size : vorbis.Block0Size;
   if (vorbisMode.BlockFlag)
   {
     vorbisMode._windows = new float[4][];
     vorbisMode._windows[0] = new float[vorbis.Block1Size];
     vorbisMode._windows[1] = new float[vorbis.Block1Size];
     vorbisMode._windows[2] = new float[vorbis.Block1Size];
     vorbisMode._windows[3] = new float[vorbis.Block1Size];
   }
   else
   {
     vorbisMode._windows = new float[1][];
     vorbisMode._windows[0] = new float[vorbis.Block0Size];
   }
   vorbisMode.CalcWindows();
   return vorbisMode;
 }

        internal static VorbisMode Init(VorbisStreamDecoder vorbis, DataPacket packet)
        {
            var mode = new VorbisMode(vorbis);
            mode.BlockFlag = packet.ReadBit();
            mode.WindowType = (int)packet.ReadBits(16);
            mode.TransformType = (int)packet.ReadBits(16);
            var mapping = (int)packet.ReadBits(8);

            if (mode.WindowType != 0 || mode.TransformType != 0 || mapping >= vorbis.Maps.Length) throw new InvalidDataException();

            mode.Mapping = vorbis.Maps[mapping];
            mode.BlockSize = mode.BlockFlag ? vorbis.Block1Size : vorbis.Block0Size;

            // now pre-calc the window(s)...
            if (mode.BlockFlag)
            {
                // long block
                mode._windows = new float[4][];
                mode._windows[0] = new float[vorbis.Block1Size];
                mode._windows[1] = new float[vorbis.Block1Size];
                mode._windows[2] = new float[vorbis.Block1Size];
                mode._windows[3] = new float[vorbis.Block1Size];
            }
            else
            {
                // short block
                mode._windows = new float[1][];
                mode._windows[0] = new float[vorbis.Block0Size];
            }
            mode.CalcWindows();

            return mode;
        }

 protected override void Init(DataPacket packet)
 {
   this._begin = (int) packet.ReadBits(24);
   this._end = (int) packet.ReadBits(24);
   this._partitionSize = (int) packet.ReadBits(24) + 1;
   this._classifications = (int) packet.ReadBits(6) + 1;
   this._classBookNum = (int) packet.ReadBits(8);
   this._classBook = this._vorbis.Books[this._classBookNum];
   this._cascade = new int[this._classifications];
   int length = 0;
   int val2 = 0;
   for (int index = 0; index < this._classifications; ++index)
   {
     int num1 = 0;
     int num2 = (int) packet.ReadBits(3);
     if (packet.ReadBit())
       num1 = (int) packet.ReadBits(5);
     this._cascade[index] = num1 << 3 | num2;
     length += VorbisResidue.Residue0.icount(this._cascade[index]);
     val2 = Math.Max(Utils.ilog(this._cascade[index]), val2);
   }
   this._maxPasses = val2;
   int[] numArray = new int[length];
   for (int index = 0; index < length; ++index)
     numArray[index] = (int) packet.ReadBits(8);
   int num3 = 0;
   this._books = new VorbisCodebook[this._classifications][];
   this._bookNums = new int[this._classifications][];
   for (int index1 = 0; index1 < this._classifications; ++index1)
   {
     this._books[index1] = new VorbisCodebook[8];
     this._bookNums[index1] = new int[8];
     int num1 = 1;
     int index2 = 0;
     while (num1 < 256)
     {
       if ((this._cascade[index1] & num1) == num1)
       {
         int index3 = numArray[num3++];
         this._books[index1][index2] = this._vorbis.Books[index3];
         this._bookNums[index1][index2] = index3;
         if (this._books[index1][index2].MapType == 0)
           throw new InvalidDataException();
       }
       num1 <<= 1;
       ++index2;
     }
   }
   this._classWordsPerCodeWord = this._classBook.Dimensions;
   this._nToRead = this._end - this._begin;
   this._partsToRead = this._nToRead / this._partitionSize;
   this._partWords = (this._partsToRead + this._classWordsPerCodeWord - 1) / this._classWordsPerCodeWord;
 }

        bool LoadBooks(DataPacket packet)
        {
            bool equal = true;
            byte[] sequence = new byte[] { 0x05, 0x76, 0x6f, 0x72, 0x62, 0x69, 0x73 };
            byte[] packets  = packet.ReadBytes(7);

            for (int i = 0; i < 7; i++)
            {
                if (packets[i] != sequence[i])
                {
                    equal = false;
                    break;
                }
            }

            if (!equal)
            {
                return false;
            }

            if (!_pagesSeen.Contains((_lastPageSeen = packet.PageSequenceNumber))) _pagesSeen.Add(_lastPageSeen);

            var bits = packet.BitsRead;

            _glueBits += packet.BitsRead;

            // get books
            Books = new VorbisCodebook[packet.ReadByte() + 1];
            for (int i = 0; i < Books.Length; i++)
            {
                Books[i] = VorbisCodebook.Init(this, packet, i);
            }

            _bookBits += packet.BitsRead - bits;
            bits = packet.BitsRead;

            // get times
            Times = new VorbisTime[(int)packet.ReadBits(6) + 1];
            for (int i = 0; i < Times.Length; i++)
            {
                Times[i] = VorbisTime.Init(this, packet);
            }

            _timeHdrBits += packet.BitsRead - bits;
            bits = packet.BitsRead;

            // get floor
            Floors = new VorbisFloor[(int)packet.ReadBits(6) + 1];
            for (int i = 0; i < Floors.Length; i++)
            {
                Floors[i] = VorbisFloor.Init(this, packet);
            }

            _floorHdrBits += packet.BitsRead - bits;
            bits = packet.BitsRead;

            // get residue
            Residues = new VorbisResidue[(int)packet.ReadBits(6) + 1];
            for (int i = 0; i < Residues.Length; i++)
            {
                Residues[i] = VorbisResidue.Init(this, packet);
            }

            _resHdrBits += packet.BitsRead - bits;
            bits = packet.BitsRead;

            // get map
            Maps = new VorbisMapping[(int)packet.ReadBits(6) + 1];
            for (int i = 0; i < Maps.Length; i++)
            {
                Maps[i] = VorbisMapping.Init(this, packet);
            }

            _mapHdrBits += packet.BitsRead - bits;
            bits = packet.BitsRead;

            // get mode settings
            Modes = new VorbisMode[(int)packet.ReadBits(6) + 1];
            for (int i = 0; i < Modes.Length; i++)
            {
                Modes[i] = VorbisMode.Init(this, packet);
            }

            _modeHdrBits += packet.BitsRead - bits;

            // check the framing bit
            if (!packet.ReadBit()) throw new InvalidDataException();

            ++_glueBits;

            _wasteHdrBits += 8 * packet.Length - packet.BitsRead;

            _modeFieldBits = Utils.ilog(Modes.Length - 1);

            return true;
        }

        bool UnpackPacket(DataPacket packet)
        {
            // make sure we're on an audio packet
            if (packet.ReadBit())
            {
                // we really can't do anything... count the bits as waste
                return false;
            }

            // get mode and prev/next flags
            var modeBits = _modeFieldBits;
            _mode = Modes[(int)packet.ReadBits(_modeFieldBits)];
            if (_mode.BlockFlag)
            {
                _prevFlag = packet.ReadBit();
                _nextFlag = packet.ReadBit();
                modeBits += 2;
            }
            else
            {
                _prevFlag = _nextFlag = false;
            }

            if (packet.IsShort) return false;

            var startBits = packet.BitsRead;

            var halfBlockSize = _mode.BlockSize / 2;

            // read the noise floor data (but don't decode yet)
            for (int i = 0; i < _channels; i++)
            {
                _floorData[i] = _mode.Mapping.ChannelSubmap[i].Floor.UnpackPacket(packet, _mode.BlockSize, i);
                _noExecuteChannel[i] = !_floorData[i].ExecuteChannel;

                // go ahead and clear the residue buffers
                Array.Clear(_residue[i], 0, halfBlockSize);
            }

            // make sure we handle no-energy channels correctly given the couplings...
            foreach (var step in _mode.Mapping.CouplingSteps)
            {
                if (_floorData[step.Angle].ExecuteChannel || _floorData[step.Magnitude].ExecuteChannel)
                {
                    _floorData[step.Angle].ForceEnergy = true;
                    _floorData[step.Magnitude].ForceEnergy = true;
                }
            }

            var floorBits = packet.BitsRead - startBits;
            startBits = packet.BitsRead;

            foreach (var subMap in _mode.Mapping.Submaps)
            {
                for (int j = 0; j < _channels; j++)
                {
                    if (_mode.Mapping.ChannelSubmap[j] != subMap)
                    {
                        _floorData[j].ForceNoEnergy = true;
                    }
                }

                var rTemp = subMap.Residue.Decode(packet, _noExecuteChannel, _channels, _mode.BlockSize);
                for (int c = 0; c < _channels; c++)
                {
                    var r = _residue[c];
                    var rt = rTemp[c];
                    for (int i = 0; i < halfBlockSize; i++)
                    {
                        r[i] += rt[i];
                    }
                }
            }

            _glueBits += 1;
            _modeBits += modeBits;
            _floorBits += floorBits;
            _resBits += packet.BitsRead - startBits;
            _wasteBits += 8 * packet.Length - packet.BitsRead;

            _packetCount += 1;

            return true;
        }

        void LoadBooks(DataPacket packet)
        {
            packet.SkipBits(8);
            if ( !packet.ReadBytes ( 6 ).SequenceEqual ( new byte [] { 0x76, 0x6f, 0x72, 0x62, 0x69, 0x73 } ) ) throw new ArgumentException ( "Corrupted book header!" );

            var bits = packet.BitsRead;

            _glueBits += packet.BitsRead;

            // get books
            Books = new VorbisCodebook[packet.ReadByte() + 1];
            for (int i = 0; i < Books.Length; i++)
            {
                Books[i] = VorbisCodebook.Init(this, packet, i);
            }

            _bookBits += packet.BitsRead - bits;
            bits = packet.BitsRead;

            // get times
            Times = new VorbisTime[(int)packet.ReadBits(6) + 1];
            for (int i = 0; i < Times.Length; i++)
            {
                Times[i] = VorbisTime.Init(this, packet);
            }

            _timeHdrBits += packet.BitsRead - bits;
            bits = packet.BitsRead;

            // get floor
            Floors = new VorbisFloor[(int)packet.ReadBits(6) + 1];
            for (int i = 0; i < Floors.Length; i++)
            {
                Floors[i] = VorbisFloor.Init(this, packet);
            }

            _floorHdrBits += packet.BitsRead - bits;
            bits = packet.BitsRead;

            // get residue
            Residues = new VorbisResidue[(int)packet.ReadBits(6) + 1];
            for (int i = 0; i < Residues.Length; i++)
            {
                Residues[i] = VorbisResidue.Init(this, packet);
            }

            _resHdrBits += packet.BitsRead - bits;
            bits = packet.BitsRead;

            // get map
            Maps = new VorbisMapping[(int)packet.ReadBits(6) + 1];
            for (int i = 0; i < Maps.Length; i++)
            {
                Maps[i] = VorbisMapping.Init(this, packet);
            }

            _mapHdrBits += packet.BitsRead - bits;
            bits = packet.BitsRead;

            // get mode settings
            Modes = new VorbisMode[(int)packet.ReadBits(6) + 1];
            for (int i = 0; i < Modes.Length; i++)
            {
                Modes[i] = VorbisMode.Init(this, packet);
            }

            _modeHdrBits += packet.BitsRead - bits;

            // check the framing bit
            if ( !packet.ReadBit () ) throw new ArgumentException ();

            ++_glueBits;

            _wasteHdrBits += 8 * packet.Length - packet.BitsRead;

            _modeFieldBits = Utils.ilog(Modes.Length - 1);
        }

        internal int GetPacketLength(DataPacket curPacket, DataPacket lastPacket)
        {
            // if we don't have a previous packet, or we're re-syncing, this packet has no audio data to return
            if (lastPacket == null || curPacket.IsResync) return 0;

            // make sure they are audio packets
            if (curPacket.ReadBit()) return 0;
            if (lastPacket.ReadBit()) return 0;

            // get the current packet's information
            var modeIdx = (int)curPacket.ReadBits(_modeFieldBits);
            if (modeIdx < 0 || modeIdx >= Modes.Length) return 0;
            var mode = Modes[modeIdx];

            // get the last packet's information
            modeIdx = (int)lastPacket.ReadBits(_modeFieldBits);
            if (modeIdx < 0 || modeIdx >= Modes.Length) return 0;
            var prevMode = Modes[modeIdx];

            // now calculate the totals...
            return mode.BlockSize / 4 + prevMode.BlockSize / 4;
        }

            internal override PacketData UnpackPacket(DataPacket packet, int blockSize, int channel)
            {
                var data = _reusablePacketData[channel];
                data.BlockSize = blockSize;
                data.ForceEnergy = false;
                data.ForceNoEnergy = false;
                data.PostCount = 0;
                Array.Clear(data.Posts, 0, 64);

                // hoist ReadPosts to here since that's all we're doing...
                if (packet.ReadBit())
                {
                    var postCount = 2;
                    data.Posts[0] = (int)packet.ReadBits(_yBits);
                    data.Posts[1] = (int)packet.ReadBits(_yBits);

                    for (int i = 0; i < _partitionClass.Length; i++)
                    {
                        var clsNum = _partitionClass[i];
                        var cdim = _classDimensions[clsNum];
                        var cbits = _classSubclasses[clsNum];
                        var csub = (1 << cbits) - 1;
                        var cval = 0U;
                        if (cbits > 0)
                        {
                            if ((cval = (uint)_classMasterbooks[clsNum].DecodeScalar(packet)) == uint.MaxValue)
                            {
                                // we read a bad value...  bail
                                postCount = 0;
                                break;
                            }
                        }
                        for (int j = 0; j < cdim; j++)
                        {
                            var book = _subclassBooks[clsNum][cval & csub];
                            cval >>= cbits;
                            if (book != null)
                            {
                                if ((data.Posts[postCount] = book.DecodeScalar(packet)) == -1)
                                {
                                    // we read a bad value... bail
                                    postCount = 0;
                                    i = _partitionClass.Length;
                                    break;
                                }
                            }
                            ++postCount;
                        }
                    }

                    data.PostCount = postCount;
                }

                return data;
            }

 private void InitLookupTable(DataPacket packet)
 {
   this.MapType = (int) packet.ReadBits(4);
   if (this.MapType == 0)
     return;
   float num1 = Utils.ConvertFromVorbisFloat32(packet.ReadUInt32());
   float num2 = Utils.ConvertFromVorbisFloat32(packet.ReadUInt32());
   int count = (int) packet.ReadBits(4) + 1;
   bool flag = packet.ReadBit();
   int length = this.Entries * this.Dimensions;
   float[] numArray1 = new float[length];
   if (this.MapType == 1)
     length = this.lookup1_values();
   uint[] numArray2 = new uint[length];
   for (int index = 0; index < length; ++index)
     numArray2[index] = (uint) packet.ReadBits(count);
   if (this.MapType == 1)
   {
     for (int index1 = 0; index1 < this.Entries; ++index1)
     {
       double num3 = 0.0;
       int num4 = 1;
       for (int index2 = 0; index2 < this.Dimensions; ++index2)
       {
         int index3 = index1 / num4 % length;
         double num5 = (double) numArray2[index3] * (double) num2 + (double) num1 + num3;
         numArray1[index1 * this.Dimensions + index2] = (float) num5;
         if (flag)
           num3 = num5;
         num4 *= length;
       }
     }
   }
   else
   {
     for (int index1 = 0; index1 < this.Entries; ++index1)
     {
       double num3 = 0.0;
       int index2 = index1 * this.Dimensions;
       for (int index3 = 0; index3 < this.Dimensions; ++index3)
       {
         double num4 = (double) numArray2[index2] * (double) num2 + (double) num1 + num3;
         numArray1[index1 * this.Dimensions + index3] = (float) num4;
         if (flag)
           num3 = num4;
         ++index2;
       }
     }
   }
   this.LookupTable = numArray1;
 }

 internal int GetPacketLength(DataPacket curPacket, DataPacket lastPacket)
 {
   if (lastPacket == null || curPacket.IsResync || (curPacket.ReadBit() || lastPacket.ReadBit()))
     return 0;
   int index1 = (int) curPacket.ReadBits(this._modeFieldBits);
   if (index1 < 0 || index1 >= this.Modes.Length)
     return 0;
   VorbisMode vorbisMode1 = this.Modes[index1];
   int index2 = (int) lastPacket.ReadBits(this._modeFieldBits);
   if (index2 < 0 || index2 >= this.Modes.Length)
     return 0;
   VorbisMode vorbisMode2 = this.Modes[index2];
   return vorbisMode1.BlockSize / 4 + vorbisMode2.BlockSize / 4;
 }

 private void LoadBooks(DataPacket packet)
 {
   packet.SkipBits(8);
   if (!Enumerable.SequenceEqual<byte>((IEnumerable<byte>) packet.ReadBytes(6), (IEnumerable<byte>) new byte[6]
   {
     (byte) 118,
     (byte) 111,
     (byte) 114,
     (byte) 98,
     (byte) 105,
     (byte) 115
   }))
     throw new InvalidDataException("Corrupted book header!");
   long bitsRead1 = packet.BitsRead;
   this._glueBits += packet.BitsRead;
   this.Books = new VorbisCodebook[(int) packet.ReadByte() + 1];
   for (int number = 0; number < this.Books.Length; ++number)
     this.Books[number] = VorbisCodebook.Init(this, packet, number);
   this._bookBits += packet.BitsRead - bitsRead1;
   long bitsRead2 = packet.BitsRead;
   this.Times = new VorbisTime[(int) packet.ReadBits(6) + 1];
   for (int index = 0; index < this.Times.Length; ++index)
     this.Times[index] = VorbisTime.Init(this, packet);
   this._timeHdrBits += packet.BitsRead - bitsRead2;
   long bitsRead3 = packet.BitsRead;
   this.Floors = new VorbisFloor[(int) packet.ReadBits(6) + 1];
   for (int index = 0; index < this.Floors.Length; ++index)
     this.Floors[index] = VorbisFloor.Init(this, packet);
   this._floorHdrBits += packet.BitsRead - bitsRead3;
   long bitsRead4 = packet.BitsRead;
   this.Residues = new VorbisResidue[(int) packet.ReadBits(6) + 1];
   for (int index = 0; index < this.Residues.Length; ++index)
     this.Residues[index] = VorbisResidue.Init(this, packet);
   this._resHdrBits += packet.BitsRead - bitsRead4;
   long bitsRead5 = packet.BitsRead;
   this.Maps = new VorbisMapping[(int) packet.ReadBits(6) + 1];
   for (int index = 0; index < this.Maps.Length; ++index)
     this.Maps[index] = VorbisMapping.Init(this, packet);
   this._mapHdrBits += packet.BitsRead - bitsRead5;
   long bitsRead6 = packet.BitsRead;
   this.Modes = new VorbisMode[(int) packet.ReadBits(6) + 1];
   for (int index = 0; index < this.Modes.Length; ++index)
     this.Modes[index] = VorbisMode.Init(this, packet);
   this._modeHdrBits += packet.BitsRead - bitsRead6;
   if (!packet.ReadBit())
     throw new InvalidDataException();
   ++this._glueBits;
   this._wasteHdrBits += (long) (8 * packet.Length) - packet.BitsRead;
   this._modeFieldBits = Utils.ilog(this.Modes.Length - 1);
 }

 private void InitTree(DataPacket packet)
 {
   int num1 = 0;
   bool flag;
   if (packet.ReadBit())
   {
     int num2 = (int) packet.ReadBits(5) + 1;
     int num3 = 0;
     while (num3 < this.Entries)
     {
       int num4 = (int) packet.ReadBits(Utils.ilog(this.Entries - num3));
       while (--num4 >= 0)
         this.Lengths[num3++] = num2;
       ++num2;
     }
     num1 = 0;
     flag = false;
   }
   else
   {
     flag = packet.ReadBit();
     for (int index = 0; index < this.Entries; ++index)
     {
       if (!flag || packet.ReadBit())
       {
         this.Lengths[index] = (int) packet.ReadBits(5) + 1;
         ++num1;
       }
       else
         this.Lengths[index] = -1;
     }
   }
   this.MaxBits = Enumerable.Max((IEnumerable<int>) this.Lengths);
   int[] numArray1 = (int[]) null;
   if (flag && num1 >= this.Entries >> 2)
   {
     numArray1 = new int[this.Entries];
     Array.Copy((Array) this.Lengths, (Array) numArray1, this.Entries);
     flag = false;
   }
   int length = !flag ? 0 : num1;
   int[] numArray2 = (int[]) null;
   int[] codeList = (int[]) null;
   if (!flag)
     codeList = new int[this.Entries];
   else if (length != 0)
   {
     numArray1 = new int[length];
     codeList = new int[length];
     numArray2 = new int[length];
   }
   VorbisCodebook vorbisCodebook = this;
   int[] numArray3 = this.Lengths;
   int num5 = this.Entries;
   int[] numArray4 = numArray2;
   int num6 = flag ? 1 : 0;
   int sortedEntries = length;
   int[] codewords = codeList;
   int[] codewordLengths = numArray1;
   int[] len = numArray3;
   int n = num5;
   int[] values = numArray4;
   if (!vorbisCodebook.ComputeCodewords(num6 != 0, sortedEntries, codewords, codewordLengths, len, n, values))
     throw new InvalidDataException();
   this.LTree = Huffman.BuildLinkedList<int>(numArray2 ?? Enumerable.ToArray<int>(Enumerable.Range(0, codeList.Length)), numArray1 ?? this.Lengths, codeList);
 }

            protected override void Init(DataPacket packet)
            {
                // this is pretty well stolen directly from libvorbis...  BSD license
                _begin = (int)packet.ReadBits(24);
                _end = (int)packet.ReadBits(24);
                _partitionSize = (int)packet.ReadBits(24) + 1;
                _classifications = (int)packet.ReadBits(6) + 1;
                _classBook = _vorbis.Books[(int)packet.ReadBits(8)];

                _cascade = new int[_classifications];
                var acc = 0;
                for (int i = 0; i < _classifications; i++)
                {
                    var low_bits = (int)packet.ReadBits(3);
                    if (packet.ReadBit())
                    {
                        _cascade[i] = (int)packet.ReadBits(5) << 3 | low_bits;
                    }
                    else
                    {
                        _cascade[i] = low_bits;
                    }
                    acc += icount(_cascade[i]);
                }

                var bookNums = new int[acc];
                for (var i = 0; i < acc; i++)
                {
                    bookNums[i] = (int)packet.ReadBits(8);
                    if (_vorbis.Books[bookNums[i]].MapType == 0) throw new Exception();
                }

                var entries = _classBook.Entries;
                var dim = _classBook.Dimensions;
                var partvals = 1;
                while (dim > 0)
                {
                    partvals *= _classifications;
                    if (partvals > entries) throw new Exception();
                    --dim;
                }

                // now the lookups
                dim = _classBook.Dimensions;

                _books = new VorbisCodebook[_classifications][];

                acc = 0;
                var maxstage = 0;
                int stages;
                for (int j = 0; j < _classifications; j++)
                {
                    stages = Utils.ilog(_cascade[j]);
                    _books[j] = new VorbisCodebook[stages];
                    if (stages > 0)
                    {
                        maxstage = Math.Max(maxstage, stages);
                        for (int k = 0; k < stages; k++)
                        {
                            if ((_cascade[j] & (1 << k)) > 0)
                            {
                                _books[j][k] = _vorbis.Books[bookNums[acc++]];
                            }
                        }
                    }
                }
                _maxStages = maxstage;

                _decodeMap = new int[partvals][];
                for (int j = 0; j < partvals; j++)
                {
                    var val = j;
                    var mult = partvals / _classifications;
                    _decodeMap[j] = new int[_classBook.Dimensions];
                    for (int k = 0; k < _classBook.Dimensions; k++)
                    {
                        var deco = val / mult;
                        val -= deco * mult;
                        mult /= _classifications;
                        _decodeMap[j][k] = deco;
                    }
                }

                _entryCache = new int[_partitionSize];

                _partWordCache = new int[_vorbis._channels][][];
                var maxPartWords = ((_end - _begin) / _partitionSize + _classBook.Dimensions - 1) / _classBook.Dimensions;
                for (int ch = 0; ch < _vorbis._channels; ch++)
                {
                    _partWordCache[ch] = new int[maxPartWords][];
                }
            }