/**
* Given a sorted list and value, returns the index of the greatest value in sorted_list that is
* less than value. Ex: List( { 0, 1, 4, 6, 7 } ) Value(5) returns 2, which is the index of value 4.
* If value is less than sorted[0], -1 is returned. If value is greater than sorted[end], sorted.Count-1
* is returned. If an exact match is found, the index prior to that match is returned.
*/
public static int NearestIndexPriorToValue <T>(IList <T> sorted_list, T value) where T : System.IComparable <T>
{
int count = sorted_list.Count;
if (count < 1)
{
return(-1);
}
SearchRange range = new SearchRange(0, count - 1);
if (value.CompareTo(sorted_list[0]) < 0)
{
return(-1);
}
if (value.CompareTo(sorted_list[count - 1]) > 0)
{
return(count - 1);
}
while (range.Valid())
{
if (sorted_list[range.Center()].CompareTo(value) > 0)
{
// sb.AppendLine(sorted_list[range.Center()] + " > " + value + " [" + range.begin + ", " + range.end +"] -> [" + range.begin + ", " + range.Center() + "]");
range.end = range.Center();
}
else
{
// sb.AppendLine(sorted_list[range.Center()] + " < " + value + " [" + range.begin + ", " + range.end +"] -> [" + range.Center() + ", " + range.end + "]");
range.begin = range.Center();
if (sorted_list[range.begin + 1].CompareTo(value) >= 0)
{
return(range.begin);
}
}
}
return(0);
}
