private static int Binary <T>(Get <T> get, int index, int length, CompareToExpectedValue <T> compare)
{
int low = index;
int hi = index + length - 1;
while (low <= hi)
{
int median = low + (hi - low >> 1);
switch (compare(get(median)))
{
case Comparison.Equal:
return(median);
case Comparison.Less:
low = median + 1;
break;
case Comparison.Greater:
hi = median - 1;
break;
default:
throw new NotImplementedException();
}
}
return(~low);
}
/// <summary>Performs a binary search to find the index where a specific value fits in indexed, sorted items.</summary>
/// <param name="get">Indexer delegate.</param>
/// <param name="length">The number of indexed items.</param>
/// <param name="compare">Comparison delegate.</param>
/// <returns>The index where the specific value fits into the index, sorted items.</returns>
public static int BinarySearch(Get <T> get, int length, CompareToExpectedValue <T> compare)
{
if (get == null)
{
throw new System.ArgumentNullException("get");
}
if (compare == null)
{
throw new System.ArgumentNullException("compare");
}
return(BinarySearch(get, 0, length, compare));
}
/// <summary>Performs a binary search to find the index where a specific value fits in indexed, sorted items.</summary>
/// <param name="get">Indexer delegate.</param>
/// <param name="length">The number of indexed items.</param>
/// <param name="compare">Comparison delegate.</param>
/// <returns>The index where the specific value fits into the index, sorted items.</returns>
public static int Binary <T>(Get <T> get, int length, CompareToExpectedValue <T> compare)
{
if (get is null)
{
throw new ArgumentNullException(nameof(get));
}
if (compare is null)
{
throw new ArgumentNullException(nameof(compare));
}
if (length <= 0)
{
throw new ArgumentOutOfRangeException(nameof(length), length, "!(" + nameof(length) + " > 0)");
}
return(Binary(get, 0, length, compare));
}
