private bool SwapOut(T[] entries)
{
// if (Median.CompareTo(entries[Left]) == 0) Swap(entries, LeftMedian++, Left);
var leftCompare = Median.AbstractCompareTo(entries[Left]);
if (!leftCompare.ComparisonSucceeded)
{
return(false);
}
if (leftCompare.ComparisonResult == 0)
{
Swap(entries, LeftMedian++, Left);
}
// if (Median.CompareTo(entries[Right]) == 0) Swap(entries, Right, RightMedian--);
var rightCompare = Median.AbstractCompareTo(entries[Right]);
if (!rightCompare.ComparisonSucceeded)
{
return(false);
}
if (rightCompare.ComparisonResult == 0)
{
Swap(entries, Right, RightMedian--);
}
return(true);
}
private SortResult <T> Partition(T[] entries)
{
var first = Left;
var last = Right;
LeftMedian = first;
RightMedian = last;
while (true)
{
//[Assert]There exists some index >= Left where entries[index] >= Median
//[Assert]There exists some index <= Right where entries[index] <= Median
// So, there is no need for Left or Right bound checks
// while (Median.CompareTo(entries[Left]) > 0) Left++;
while (true)
{
var compareResult = Median.AbstractCompareTo(entries[Left]);
if (!compareResult.ComparisonSucceeded)
{
return(new SortResult <T>(entries, entries[Left], Median));
}
if (compareResult.ComparisonResult > 0)
{
Left++;
}
else
{
break;
}
}
//while (Median.CompareTo(entries[Right]) < 0) Right--;
while (true)
{
var compareResult = Median.AbstractCompareTo(entries[Right]);
if (!compareResult.ComparisonSucceeded)
{
return(new SortResult <T>(entries, entries[Right], Median));
}
if (compareResult.ComparisonResult < 0)
{
Right--;
}
else
{
break;
}
}
//[Assert]entries[Right] <= Median <= entries[Left]
if (Right <= Left)
{
break;
}
Swap(entries, Left, Right);
if (!SwapOut(entries))
{
return(new SortResult <T>(entries, entries[Left], entries[Right]));
}
Left++;
Right--;
//[Assert]entries[first:Left - 1] <= Median <= entries[Right + 1:last]
}
if (Left == Right)
{
Left++;
Right--;
}
//[Assert]Right < Left
SwapIn(entries, first, last);
//[Assert]entries[first:Right] <= Median <= entries[Left:last]
//[Assert]entries[Right + 1:Left - 1] == Median when non-empty
return(new SortResult <T>(entries));
}