/// <summary>
/// UnShuffle the data that has been shuffled
/// </summary>
/// <param name="data">The shuffled data</param>
/// <returns>The UnShuffled data</returns>
public T[] UnShuffle <T>(T[] data, int ChunkSize = 255, ShuffleStatusCallback callback = null)
{
if (data.Length <= 1)
{
return(data);
}
lock (UnshuffleRnd)
{
T[] UnShuffledData = new T[data.Length];
List <DataShuffleInfo> NewPos = new List <DataShuffleInfo>();
GetNewPos(ref NewPos, data, ref UnshuffleRnd, ChunkSize, callback);
for (int i = 0; i < NewPos.Count; i++)
{
if (NewPos[i].Length == 1)
{
UnShuffledData[NewPos[i].OldIndex] = data[NewPos[i].NewIndex];
}
else
{
Buffer.BlockCopy(data, NewPos[i].NewIndex, UnShuffledData, NewPos[i].OldIndex, NewPos[i].Length);
}
}
NewPos.Clear();
return(UnShuffledData);
}
}
private void GetNewPos <T>(ref List <DataShuffleInfo> NewPos, T[] data, ref Random rnd, int ChunkSize, ShuffleStatusCallback callback)
{
lock (rnd)
{
bool isOneByte = ChunkSize >= data.Length;
int size = isOneByte ? 1 : ChunkSize;
int MaxSize = (int)Math.Floor((float)data.Length / (float)size);
int BytesLeft = data.Length - (size * MaxSize);
int BytesLeftIndex = -1;
int[] Indexes = new int[MaxSize];
ProgressHelper progressHelper = new ProgressHelper((ulong)MaxSize);
//lets pre-generate the indexes
for (int i = 0; i < Indexes.Length; i++)
{
Indexes[i] = i;
}
int prevProgress = 0;
for (int i = Indexes.Length, j = 0; i > 1; i--, j++)
{
int pos = rnd.Next(i); // 0 <= j <= i-1
int tmp = Indexes[pos];
Indexes[pos] = Indexes[i - 1];
Indexes[i - 1] = tmp;
progressHelper.Update(1);
if (callback != null)
{
double progress = progressHelper.Progress;
if (prevProgress != progress)
{
callback(progress, progressHelper.TimeLeft, (int)progressHelper.Speed);
prevProgress = progressHelper.Progress;
}
}
}
/*for (int i = 0; i < MaxSize; i++)
* {
* decimal tmp = rnd.NextDecimal();
* while (Indexes.ContainsKey(tmp))
* tmp = rnd.NextDecimal();
* Indexes.Add(tmp, i);
* }*/
//lets generate where the data needs to be
for (int i = 0, j = 0; i < data.Length; i += size, j++)
{
if (i + size > data.Length)
{
BytesLeftIndex = i;
break;
}
DataShuffleInfo inf = new DataShuffleInfo()
{
OldIndex = i,
NewIndex = Indexes[j] * size,
Length = size
};
if (inf.OldIndex + size > data.Length)
{
inf.Length = (inf.OldIndex + size) - data.Length;
}
if (inf.NewIndex + size > data.Length)
{
inf.Length = (inf.NewIndex + size) - data.Length;
}
NewPos.Add(inf);
}
if (BytesLeft > 0 && BytesLeftIndex >= 0)
{
//need some improvement
NewPos.Add(new DataShuffleInfo()
{
OldIndex = BytesLeftIndex, NewIndex = BytesLeftIndex, Length = BytesLeft
});
}
Indexes = null;
}
}
