private static int LastIndexOfSliceExperimental <A>(this IEnumerable <A> source, IEnumerable <A> that, int end, IEqualityComparer <A> comparer)
{
if (source == null)
{
throw Error.ArgumentNull("source");
}
if (that == null)
{
throw Error.ArgumentNull("that");
}
if (comparer == null)
{
comparer = EqualityComparer <A> .Default;
}
// ReSharper disable PossibleMultipleEnumeration
var l = source.Count();
var tl = that.Count();
var clippedEnd = Math.Min(l - tl, end);
if (end < 0)
{
return(-1);
}
if (tl < 1)
{
return(clippedEnd);
}
if (l < tl)
{
return(-1);
}
return(KmpSearchUtilities.KmpSearch(source, 0, clippedEnd + tl, that, 0, tl, comparer, forward: false));
// ReSharper restore PossibleMultipleEnumeration
}
private static int IndexOfSliceExperimental <A>(this IEnumerable <A> source, IEnumerable <A> that, int from, IEqualityComparer <A> comparer)
{
if (source == null)
{
throw Error.ArgumentNull("source");
}
if (that == null)
{
throw Error.ArgumentNull("that");
}
if (comparer == null)
{
comparer = EqualityComparer <A> .Default;
}
var sourceList = source as IList <A>;
var thatList = that as IList <A>;
var clippedFrom = Math.Max(0, from);
if (sourceList != null && thatList != null)
{
var l = sourceList.Count;
var tl = thatList.Count;
if (from > l)
{
return(-1);
}
if (tl < 1)
{
return(clippedFrom);
}
if (l < tl)
{
return(-1);
}
return(KmpSearchUtilities.KmpSearch(sourceList, clippedFrom, l, thatList, 0, tl, comparer, forward: true));
}
// ReSharper disable PossibleMultipleEnumeration
if (that.IsEmpty())
{
var sourceLength = source.Count();
return((clippedFrom <= sourceLength) ? clippedFrom : -1);
}
var index = clippedFrom;
var seq = source.Skip(clippedFrom);
for (; ;)
{
if (seq.IsEmpty())
{
return(-1);
}
if (seq.StartsWith(that, comparer))
{
return(index);
}
seq = seq.Tail();
index++;
}
// ReSharper restore PossibleMultipleEnumeration
}
