/// <summary>
/// Build the specified seq, sigma and t.
/// </summary>
public void Build(IList<int> seq, int sigma, short t = 16, IIEncoder32 rl2_coder = null, short rl2_block_size = 127)
{
// A counting sort construction of the permutation
var counters = new int[sigma];
foreach (var s in seq) {
if (s + 1 < sigma) {
counters [s + 1]++;
}
}
for (int i = 1; i < sigma; i++) {
counters [i] += counters [i - 1];
}
var n = seq.Count;
var P = new int[n];
for (int i = 0; i < n; i++) {
var sym = seq [i];
var pos = counters [sym];
P [pos] = i;
counters [sym] = pos + 1;
}
// the bitmap to save the lengths
var lens = new BitStream32 ();
int prevc = 0;
foreach (var c in counters) {
var len = c - prevc;
prevc = c;
lens.Write (true);
lens.Write (false, len);
}
// an additional 1 to the end, to simplify source code
lens.Write (true);
var bb_lens = new FakeBitmap (lens);
this.LENS = BitmapBuilder (bb_lens);
this.PERM = new SuccRL2CyclicPerms_MRRR ();
if (rl2_coder == null) {
rl2_coder = new EliasGamma32 ();
}
var build_params = new SuccRL2CyclicPerms_MRRR.BuildParams (rl2_coder, rl2_block_size);
this.PERM.Build (P, t, build_params);
}
