Friend NotInheritable Class StringSplitExtensions
	Private Sub New()
	End Sub
	<System.Runtime.CompilerServices.Extension> _
	Public Shared Function Split(this As [String], isSplitSymbol As Predicate(Of Char)) As String()
		Return Split(this, isSplitSymbol, Integer.MaxValue, StringSplitOptions.None)
	End Function

	<System.Runtime.CompilerServices.Extension> _
	Public Shared Function Split(this As [String], isSplitSymbol As Predicate(Of Char), options As StringSplitOptions) As String()
		Return Split(this, isSplitSymbol, Integer.MaxValue, options)
	End Function

	<System.Runtime.CompilerServices.Extension> _
	Public Shared Function Split(this As [String], isSplitSymbol As Predicate(Of Char), count As Integer, options As StringSplitOptions) As String()
		If count < 0 Then
			Throw New ArgumentOutOfRangeException("count", "Count cannot be less than zero.")
		End If
		If (options < StringSplitOptions.None) OrElse (options > StringSplitOptions.RemoveEmptyEntries) Then
			Throw New ArgumentException([String].Format("Illegal enum value: {0}.", CInt(options)))
		End If

		Dim removeEmptyEntries As Boolean = options = StringSplitOptions.RemoveEmptyEntries
		If (count = 0) OrElse (removeEmptyEntries AndAlso (this.Length = 0)) Then
			Return New String(-1) {}
		End If

		Dim sepList As Integer() = New Integer(this.Length - 1) {}
		Dim numReplaces As Integer = this.MakeSeparatorList(isSplitSymbol, sepList)
		If (numReplaces = 0) OrElse (count = 1) Then
			Return New String() {this}
		End If

		If removeEmptyEntries Then
			Return this.InternalSplitOmitEmptyEntries(sepList, numReplaces, count)
		Else
			Return this.InternalSplitKeepEmptyEntries(sepList, numReplaces, count)
		End If

	End Function

	<System.Runtime.CompilerServices.Extension> _
	Private Shared Function MakeSeparatorList(this As [String], isSplitSymbol As Predicate(Of Char), ByRef sepList As Integer()) As Integer
		Dim numReplaces As Integer = 0

		Dim length As Integer = sepList.Length, j As Integer = 0
		While (j < this.Length) AndAlso (numReplaces < length)
			If isSplitSymbol(this(j)) Then
				sepList(System.Math.Max(System.Threading.Interlocked.Increment(numReplaces),numReplaces - 1)) = j
			End If
			j += 1
		End While

		Return numReplaces
	End Function

	<System.Runtime.CompilerServices.Extension> _
	Private Shared Function InternalSplitKeepEmptyEntries(this As [String], sepList As Integer(), numReplaces As Integer, count As Integer) As String()
		Dim startIndex As Integer = 0
		Dim index As Integer = 0
		count -= 1
		Dim actualCount As Integer = If((numReplaces < count), numReplaces, count)
		Dim strArray As String() = New String(actualCount) {}
		Dim i As Integer = 0
		While (i < actualCount) AndAlso (startIndex < this.Length)
			strArray(System.Math.Max(System.Threading.Interlocked.Increment(index),index - 1)) = this.Substring(startIndex, sepList(i) - startIndex)
			startIndex = sepList(i) + 1
			i += 1
		End While
		If (startIndex < this.Length) AndAlso (actualCount >= 0) Then
			strArray(index) = this.Substring(startIndex)
			Return strArray
		End If
		If index = actualCount Then
			strArray(index) = [String].Empty
		End If
		Return strArray
	End Function

	<System.Runtime.CompilerServices.Extension> _
	Private Shared Function InternalSplitOmitEmptyEntries(this As [String], sepList As Integer(), numReplaces As Integer, count As Integer) As String()
		Dim actualCount As Integer = If((numReplaces < count), (numReplaces + 1), count)
		Dim strArray As String() = New String(actualCount - 1) {}
		Dim startIndex As Integer = 0
		Dim replaceIndex As Integer = 0
		Dim i As Integer = 0
		While (i < numReplaces) AndAlso (startIndex < this.Length)
			If (sepList(i) - startIndex) > 0 Then
				strArray(System.Math.Max(System.Threading.Interlocked.Increment(replaceIndex),replaceIndex - 1)) = this.Substring(startIndex, sepList(i) - startIndex)
			End If
			startIndex = sepList(i) + 1
			If replaceIndex = (count - 1) Then
				While (i < (numReplaces - 1)) AndAlso (startIndex = sepList(System.Threading.Interlocked.Increment(i)))
					startIndex += 1
				End While
				Exit While
			End If
			i += 1
		End While
		If startIndex < this.Length Then
			strArray(System.Math.Max(System.Threading.Interlocked.Increment(replaceIndex),replaceIndex - 1)) = this.Substring(startIndex)
		End If
		Dim strArray2 As String() = strArray
		If replaceIndex <> actualCount Then
			strArray2 = New String(replaceIndex - 1) {}
			For j As Integer = 0 To replaceIndex - 1
				strArray2(j) = strArray(j)
			Next
		End If
		Return strArray2
	End Function
End Class