//Decompress BitStream into integer array
public static int[] Decompress(ref BitStreamFIFO source)
{
//Read necessary info for decompression
int compressionType = source.ReadInt(2); //The compression technique used
int lengthSaveLength = source.ReadInt(6) * 8; //The amount of bits needed to save the total length in bits of the compressed data
int arrayDataLength = source.ReadInt(lengthSaveLength); //The total length in bits of the compressed data
//Create a new BitStream of correct length from the incoming BitStream
BitStreamFIFO arrayData = new BitStreamFIFO(source.ReadBoolArray(arrayDataLength));
//Decompress using the correct compression type
int[] intArray = new int[0];
switch (compressionType)
{
//Huffmann
case 0:
intArray = HuffmanIntArrayCompressor.DeCompress(arrayData);
break;
//Variable int length
case 1:
intArray = VaryingIntLengthIntArrayCompressor.Decompress(arrayData);
break;
//To add a compression technique, add a new case like the existing ones and increase the length of new byte[??][]
}
//Return the decompressed array of integers
return(intArray);
}
//Compress integer array into BitStream
public static BitStreamFIFO Compress(int[] source)
{
//Compress the array of integers using all different compression techniques, where possible at the same time
BitStreamFIFO[] compressionTechniques = new BitStreamFIFO[2];
Parallel.For(0, compressionTechniques.Length, (i, state) =>
{
switch (i)
{
//Huffmann: generate a dictionary of all used integer values where more frequent values have a code with less bits
case 0:
compressionTechniques[i] = HuffmanIntArrayCompressor.Compress(source);
break;
//Variable int length: save smaller integers with less bits than bigger integers
case 1:
compressionTechniques[i] = VaryingIntLengthIntArrayCompressor.Compress(source);
break;
//To add a compression technique, add a new case like the existing ones and increase the length of new byte[??][]
}
});
//Choose the smallest compression type
//Initialize
int smallestID = 0; //The ID of the smallest compression type
int smallestSize = int.MaxValue; //The size ofthe smallest compression type: int.MaxValue is assigned to make sure that the first compression to be checked will be smaaller than this value
//Loop trough all saved compression techniques
for (int i = 0; i < compressionTechniques.Length; i++)
{
//If the current technique is smaller than the smallest technique which has been checked
if (compressionTechniques[i].Length < smallestSize)
{
//Mark this technique as smallest
smallestSize = compressionTechniques[i].Length;
smallestID = i;
}
}
//Create a new BitStream to write necessary information for the decompressor
BitStreamFIFO compressionInfo = new BitStreamFIFO();
//Calculate the amount of bits needed to save the total length in bits of the compressed data
int lengthSaveLength = (int)Math.Ceiling(Math.Log(smallestSize, 2) / 8);
//Write data to the compression info
compressionInfo.Write(smallestID, 2); //The compression technique used
compressionInfo.Write(lengthSaveLength, 6); //The amount of bits needed to save the total length in bits of the compressed data
compressionInfo.Write(smallestSize, lengthSaveLength * 8); //The total length in bits of the compressed data
//Merge the info about the compression type with the compressed data & return
return(BitStreamFIFO.Merge(compressionInfo, compressionTechniques[smallestID]));
}
