public CompressedChunk(XlBinaryReader Data)
{
this.CompressedChunkStart = Data.i;
this.CompressedHeader = new CompressedChunkHeader(Data);
this.CompressedData = new CompressedChunkData(this.CompressedHeader, Data);
}
//protected TokenSequence _TokenSequence;
public CompressedChunkData(CompressedChunkHeader header, XlBinaryReader Data)
{
this.header = header;
if (header.CompressedChunkFlag == (Byte)0x00)
{
// page 57: CompressedChunkData contains an array of CompressedChunkHeader.CompressedChunkSize
// elements plus 3 bytes of uncompressed data
int ArraySize = header.CompressedChunkSize + 3;
this.Data = new Byte[ArraySize];
int CopySize = header.CompressedChunkSize; // todo: this is my fix...
Array.Copy(Data.ReadBytes(CopySize), 0, this.Data, 0, CopySize);
//Array.Copy(Data, ArrayIndex, this.Data, 0, CopySize);
//ArrayIndex += header.CompressedChunkSize;
this.Decompress = (buffer, state) => DecompressRawChunk(buffer, state, this.Data);
}
else if (header.CompressedChunkFlag == (Byte)0x01)
{
// TODO: DO something like when compressedcurrent < compressedend -> add a new tokensequence
// page 57: CompressedChunkData contains an array of TokenSequence elements
var size = Math.Min(header.CompressedChunkSize, Data.Length - Data.i);
var tokenSequences = new List <TokenSequence>();
int processedBytes = 0;
while (processedBytes < size)
{
int remainingBytes = size - processedBytes;
var tokenSequence = new TokenSequence(Data, remainingBytes);
tokenSequences.Add(tokenSequence);
processedBytes += tokenSequence.GetSizeInBytes();
}
//var tokenSequenceBytes = tokenSequence.GetDataInRawBytes();
//this.Data = tokenSequenceBytes;
//var tokenSequenceSize = tokenSequenceBytes.Count();
//if(tokenSequenceSize != header.CompressedChunkSize+3)
//{
//throw new InvalidOperationException(String.Format("CompressedChunkData Data-array size expected {0}, but was {1}", header.CompressedChunkSize+3, tokenSequenceSize));
//}
this.Decompress = (buffer, state) => DecompressTokenSequence(buffer, state, tokenSequences);
}
else
{
throw new Exception();
}
//this._TokenSequence = new TokenSequence(ref Data);
//Data = Data.Skip(N);
}
// 2.4.1.3.7 Compressing a DecompressedChunk
// page 62
private static void CompressDecompressedChunk(byte[] Data, CompressedBuffer resultBuffer, DecompressionState state)
{
var CompressedEnd = state.CompressedChunkStart + 4098;
state.CompressedCurrent = state.CompressedChunkStart + 2;
var DecompressedEnd = Math.Min(state.DecompressedChunkStart + 4096, state.DecompressedBufferEnd);
while (state.DecompressedCurrent < DecompressedEnd && state.CompressedCurrent < CompressedEnd)
{
CompressTokenSequence(Data, resultBuffer, state, CompressedEnd, DecompressedEnd);
}
UInt16 CompressedFlag;
if (state.DecompressedCurrent < DecompressedEnd)
{
CompressRawChunk(Data, resultBuffer, state, DecompressedEnd - 1);
CompressedFlag = 0;
}
else
{
CompressedFlag = 1;
}
UInt16 size = Convert.ToUInt16(state.CompressedCurrent - state.CompressedChunkStart);
var header = new CompressedChunkHeader(0x0000);
PackCompressedChunkSize(Data, state, size, header);
PackCompressedChunkFlag(Data, state, CompressedFlag, header);
PackCompressedChunkSignature(Data, state, header);
// SET the CompressedChunkHeader (section 2.4.1.1.5) located at CompressedChunkStart TO Header
var bytes = BitConverter.GetBytes(header.AsUInt16());
resultBuffer.SetByte(state.CompressedChunkStart, bytes.First());
resultBuffer.SetByte(state.CompressedChunkStart + 1, bytes.Skip(1).Single());
}
// Section 2.4.1.3.16
private static void PackCompressedChunkFlag(byte[] Data, DecompressionState state, UInt16 CompressedFlag, CompressedChunkHeader header)
{
if (CompressedFlag != 0 && CompressedFlag != 1)
{
throw new ArgumentOutOfRangeException("CompressedFlag", "CompressedFlag must be 0 or 1");
}
UInt16 temp1 = (UInt16)(header.AsUInt16() & (ushort)0x7FFF);
UInt16 temp2 = (UInt16)(CompressedFlag << 15);
UInt16 result = (UInt16)(temp1 | temp2);
header.SetFrom(result);
}
// Section 2.4.1.3.14
private static void PackCompressedChunkSignature(byte[] Data, DecompressionState state, CompressedChunkHeader header)
{
UInt16 temp = (UInt16)(header.AsUInt16() & (ushort)0x8FFF);
UInt16 result = (UInt16)(temp | (ushort)0x3000);
header.SetFrom(result);
}
// Section 2.4.1.3.13
// page 66
private static void PackCompressedChunkSize(byte[] Data, DecompressionState state, UInt16 size, CompressedChunkHeader header)
{
if (size > 4098 || size < 3)
{
throw new ArgumentOutOfRangeException("size", "Size must be between 3 - 4098");
}
UInt16 temp1 = (UInt16)(header.AsUInt16() & (ushort)(0xF000));
UInt16 temp2 = (UInt16)(size - 3);
UInt16 result = (UInt16)(temp1 | temp2);
header.SetFrom(result);
}
