internal BwtModel Encode(List <byte> bytes)
{
_bytes = bytes;
var initialValue = 0;
var indexes = Enumerable.Range(0, _bytes.Count).Select(i => initialValue++).ToList();
indexes.Sort(Comparer);
var originalIndex = indexes.IndexOf(0);
var encodedBytes = new List <byte>(_bytes.Count);
for (int i = 0; i < _bytes.Count; i++)
{
encodedBytes.Add(_bytes[(indexes[i] + _bytes.Count - 1) % _bytes.Count]);
}
var model = new BwtModel(originalIndex, encodedBytes);
return(model);
}
internal List <byte> Decode(BwtModel model)
{
var byteLength = 256;
var counts = Enumerable.Range(0, byteLength).Select(i => 0).ToList();
foreach (var element in model.Bytes)
{
counts[element]++;
}
var sum = 0;
for (int i = 0; i < byteLength; i++)
{
sum += counts[i];
counts[i] = sum - counts[i];
}
var invertVector = Enumerable.Range(0, model.Bytes.Count).Select(i => 0).ToList();
for (int i = 0; i < model.Bytes.Count; i++)
{
invertVector[counts[model.Bytes[i]]] = i;
counts[model.Bytes[i]]++;
}
var currentIndex = invertVector[model.OriginalIndex];
var decodedBytes = new List <byte>(model.Bytes.Count);
for (int i = 0; i < model.Bytes.Count; i++)
{
decodedBytes.Add(model.Bytes[currentIndex]);
currentIndex = invertVector[currentIndex];
}
return(decodedBytes);
}