Split string by substring without using String.Split()

The Aim

Since I very rarely write code to do things other than business logic anymore I've set myself a challenge:

Split a string into a list of substrings by splitting on a matching string, without using string.Split() or similar methods of string (substring, indexof, etc) or LINQ methods (edit or regex /edit).

The method must also accept a parameter stating whether the return list is allowed to contain empty strings (only excludes string.Empty, not whitespace).

The Code

```
private static IList SplitString(string toSplit, string splitOn, bool allowEmptyResults = true)
{
int cursorPosition = 0;
int innerCursor = 0;
var strings = new List();

while (cursorPosition < toSplit.Length)
{
bool match = false;

for (int i = 0; i < splitOn.Length ; i++)
{
match = toSplit[innerCursor] == splitOn[i];

if ((i < splitOn.Length - 1 && innerCursor == toSplit.Length - 1) || !match)
{
match = false;
break;
}

innerCursor++;
}

if (match)
{
var result = StringFromCursor(toSplit, cursorPosition, innerCursor - splitOn.Length);

if (result != string.Empty || allowEmptyResults)
{
strings.Add(result);
}

cursorPosition = innerCursor;
}
else
{
if (innerCursor < toSplit.Length - 1)
{
innerCursor++;
}
else
{
var result = StringFromCursor(toSplit, cursorPosition, toSplit.Length);

if (result != string.Empty || allowEmptyResults)
{
strings.Add(result);
}

break;
}
}
}

return strings;
}

private static string StringFromCursor(string toSplit, int cursorPosition, int matchStart)
{
string result = string.Empty;

for (int

private static string StringFromCursor(string toSplit, int cursorPosition, int matchStart)
{
    string result = string.Empty;

    for (int i = cursorPosition; i < matchStart; i++)
    {
        result += toSplit[i].ToString();
    }

    return result;
}

This is a bad idea. Since C# string is immutable, the only way to support an append or += operation is to throw the old string away and build a new one. Doing this repeatedly leads to an \$O(n^2)\$ running time. What you really need is a StringBuilder which does support building up strings piece by piece.

StackExchange Code Review Q#87119, answer score: 5