/// <summary>
/// The Previous.
/// </summary>
/// <param name="offsetBase">The offsetBase<see cref="int"/>.</param>
/// <param name="offsetFactor">The offsetFactor<see cref="int"/>.</param>
/// <param name="indexOffset">The indexOffset<see cref="int"/>.</param>
/// <param name="x">The x<see cref="int"/>.</param>
/// <returns>The <see cref="int"/>.</returns>
public override int Previous(int offsetBase, int offsetFactor, int indexOffset, int x)
{
if (max != NULL_KEY && x > max)
{
return(max);
}
BaseSpectrum scopesItem;
int x_highest = highest(x);
int scopesKey;
scopesKey = offsetBase + (indexOffset * parentSqrt) + x_highest;
int minimumLow = NULL_KEY;
if (scopes.TryGet(scopesKey, out scopesItem))
{
minimumLow = scopesItem.IndexMin;
}
if (minimumLow != NULL_KEY && lowest(x) > minimumLow)
{
int _offset = scopesItem.Previous(offsetBase + (offsetFactor * parentSqrt),
(offsetFactor * parentSqrt),
(indexOffset * parentSqrt) + x_highest,
lowest(x));
return(index(x_highest, _offset));
}
if (sigmaNode == null)
{
return(NULL_KEY);
}
//======================//
//from sigmaNode part
//======================//
int predecessorCluster = sigmaNode.Previous(x_highest);
if (predecessorCluster == NULL_KEY)
{
if (min != NULL_KEY && x > min)
{
return(min);
}
return(NULL_KEY);
}
scopesKey = offsetBase + (indexOffset * parentSqrt) + predecessorCluster;
scopes.TryGet(scopesKey, out scopesItem);
int offset = scopesItem.IndexMax;
return(index(predecessorCluster, offset));
}
