VERSION 1.0 CLASS
BEGIN
  MultiUse = -1  'True
  Persistable = 0  'NotPersistable
  DataBindingBehavior = 0  'vbNone
  DataSourceBehavior  = 0  'vbNone
  MTSTransactionMode  = 0  'NotAnMTSObject
END
Attribute VB_Name = "StringIndex"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Option Explicit
Private Const NOT_FOUND = -1
Private Where_ As String
Private What_ As String
Private Index_ As Long

Private Sub Class_Initialize()
    Index_ = NOT_FOUND
End Sub

Friend Property Let Where(ByVal Value As String)
    Where_ = Value
End Property

Friend Property Let What(ByVal Value As String)
    What_ = Value
End Property

Friend Property Let Index(ByVal Value As Long)
    Index_ = Value
End Property

Private Function Validate(ByVal Name As String, ByVal Value As Long) As Long
    If Value < 0 Then Err.Raise "[" & Value & "] cannot be negative!"
    Validate = Value
End Function

Public Property Get Found() As Boolean
Attribute Found.VB_UserMemId = 0
    Found = Index_ <> NOT_FOUND
End Property

Public Property Get What() As String
    If Index_ = NOT_FOUND Then Exit Property
    What = Mid$(Where_, Index_, Len(What_))
End Property

Public Function Before() As String
    If Index_ = NOT_FOUND Then Exit Function
    Before = Mid$(Where_, 1, Index_ - 1)
End Function

Public Function After() As String
    If Index_ = NOT_FOUND Then Exit Function
    Dim Start As Long: Start = Len(What_) + Index_
    If Start > Len(Where_) Then Exit Function
    After = Mid$(Where_, Start)
End Function

Public Function TakeBackward(ByVal Count As Long, Optional ByVal Skip As Long) As String
    Count = Validate("count", Count)
    Skip = Validate("skip", Skip)
    If Count = 0 Or Index_ = NOT_FOUND Then Exit Function
    Dim Start As Long: Start = Index_ - Count - Skip
    If Start < 1 Then Start = 1
    Count = Index_ - Start - Skip
    If Count <= 0 Then Exit Function
    If Start + Count >= Len(Where_) Then Count = Len(Where_) - Start
    TakeBackward = Mid$(Where_, Start, Count)
End Function

Public Function TakeForward(ByVal Count As Long, Optional ByVal Skip As Long) As String
    Count = Validate("count", Count)
    Skip = Validate("skip", Skip)
    If Count = 0 Or Index_ = NOT_FOUND Then Exit Function
    Dim Start As Long: Start = Index_ + Len(What_) + Skip
    If Start >= Len(Where_) Then Exit Function
    If Start + Count >= Len(Where_) Then Count = Len(Where_) - Start
    TakeForward = Mid$(Where_, Start, Count)
End Function