public static byte[] Decode(byte[] encodedData, ConcurrentDictionary <BitsWithLength, byte> decodeTable,
long bitsCount, int degreeOfParallelism)
{
var result = new List <byte>();
var sample = new BitsWithLength {
Bits = 0, BitsCount = 0
};
for (var byteNum = 0; byteNum < encodedData.Length; byteNum++)
{
var b = encodedData[byteNum];
for (var bitNum = 0; bitNum < 8 && byteNum * 8 + bitNum < bitsCount; bitNum++)
{
sample.Bits = (sample.Bits << 1) + ((b & (1 << (8 - bitNum - 1))) != 0 ? 1 : 0);
sample.BitsCount++;
byte decodedByte;
if (decodeTable.TryGetValue(sample, out decodedByte))
{
result.Add(decodedByte);
sample.BitsCount = 0;
sample.Bits = 0;
}
}
}
return(result.ToArray());
}
public static byte[] Encode(byte[] data, out ConcurrentDictionary <BitsWithLength, byte> decodeTable,
out long bitsCount, int degreeOfParallelism)
{
var frequences = CalcFrequences(data, degreeOfParallelism);
var root = BuildHuffmanTree(frequences);
var encodeTable = new BitsWithLength[byte.MaxValue + 1];
FillEncodeTable(root, encodeTable);
var dataSize = data.Length;
var chunkLength = dataSize / degreeOfParallelism;
ParallelEnumerable.Range(0, degreeOfParallelism + 1)
.AsOrdered()
.WithDegreeOfParallelism(degreeOfParallelism)
.Select(
i =>
{
var chunk = new BitsBuffer();
var lower = chunkLength * i;
var upper = Math.Min(chunkLength * (i + 1), dataSize);
for (var j = lower; j < upper; j++)
{
chunk.Add(encodeTable[data[j]]);
}
return(chunk);
})
.ForEach(AddRange);
decodeTable = CreateDecodeTable(encodeTable, degreeOfParallelism);
return(globalBuffer.ToArray(out bitsCount));
}
public void Add(BitsWithLength bitsWithLength, int bitsCount = 0)
{
if (bitsCount == 0)
{
bitsCount = bitsWithLength.BitsCount;
}
var bits = bitsWithLength.Bits;
var neededBits = 8 - unfinishedBits.BitsCount;
while (bitsCount >= neededBits)
{
bitsCount -= neededBits;
buffer.Add((byte)((unfinishedBits.Bits << neededBits) + (bits >> bitsCount)));
bits = bits & ((1 << bitsCount) - 1);
unfinishedBits.Bits = 0;
unfinishedBits.BitsCount = 0;
neededBits = 8;
}
unfinishedBits.BitsCount += bitsCount;
unfinishedBits.Bits = (unfinishedBits.Bits << bitsCount) + bits;
}
public static byte[] EncodeSequential(byte[] data, out ConcurrentDictionary <BitsWithLength, byte> decodeTable,
out long bitsCount, int degreeOfParallelism)
{
var frequences = CalcFrequences(data, degreeOfParallelism);
var root = BuildHuffmanTree(frequences);
var encodeTable = new BitsWithLength[byte.MaxValue + 1];
FillEncodeTable(root, encodeTable);
var bitsBuffer = new BitsBuffer();
foreach (var b in data)
{
bitsBuffer.Add(encodeTable[b]);
}
decodeTable = CreateDecodeTable(encodeTable, degreeOfParallelism);
return(bitsBuffer.ToArray(out bitsCount));
}
