Spanky's Place

' Option Public INTENTIONALLY REMOVED
Option Explicit
Use "Utilities"

Public Class StringList
%REM
This class is 256 element array of strings.
The properties and methods allow easy navigation of the array.
%END REM

Private bool_Initialized As Boolean
Private intElements As Integer
Private byteCurrentPos As Byte
Private byteUbound As Byte
Private varElements() As String


' INTERFACE
' PROPERTIES
Public Property Get HasElements As Boolean
 HasElements = (intElements% > 0)
End Property ' Get HasElements

Public Property Get ElementCount As Integer
 ElementCount% = intElements%
End Property ' Get ElementCount

Public Property Get CurrentElementNumber As Integer
 CurrentElementNumber% = Cint(byteCurrentPos) + 1
End Property ' CurrentElementNumber


' METHODS
Public Sub New
 Call Initialize_Class
End Sub ' New


Public Sub Initialize_Class
 
 Redim varElements(0 To 255) As String
 
 intElements% = 0
 byteCurrentPos = 0
 byteUbound = 0
 bool_Initialized = True
End Sub ' Initialize_Class


Public Function AddElement (strSource As String) As Boolean
 ' Returns True if the element is added to the StringList, returns False otherwise.
 
 On Error Goto ErrorTrap
 
 If (intElements% < 256) Then
  If (intElements% <> 0) Then incValue byteUbound, 1
  varElements(byteUbound) = strSource$
  byteCurrentPos = byteUbound
  incValue intElements%, 1
  AddElement = True
 Else
  AddElement = False
 End If ' (intElements% < 256)
 
ExitPoint:
 Exit Function
ErrorTrap:
 AddElement = False
 Resume ExitPoint
End Function ' AddElement


Public Function GetFirst As String
 ' returns the first element of the StringList
 GetFirst = varElements(0)
 byteCurrentPos = 0
End Function ' GetFirst


Public Function GetNext As String
 ' returns the next elment (based on the current position) of the StringList
 If (byteCurrentPos < byteUbound) Then
  incValue byteCurrentPos, 1
  GetNext = varElements(byteCurrentPos)
 Else
  GetNext = ""
 End If ' (byteCurrentPos < byteUbound)
End Function ' GetNext


Public Function GetPrevious As String
 ' returns the previous elment (based on the current position) of the StringList
 If (byteCurrentPos > 0) Then
  incValue byteCurrentPos, -1
  GetPrevious = varElements(byteCurrentPos)
 Else
  GetPrevious = ""
 End If ' (byteCurrentPos > 0)
End Function ' GetPrevious


Public Function GetLast As String
 ' returns the last element of the StringList
 byteCurrentPos = byteUbound
 GetLast = varElements(byteCurrentPos)
End Function ' GetLast


Public Function OrdEntry (bytePos As Byte) As String
 ' returns the entry at the psuedo ordinal position
 
 If Me.HasElements Then
  If (bytePos < intElements) Then
   OrdEntry = varElements(bytePos)
   byteCurrentPos = bytePos
  Else
   OrdEntry = ""
  End If ' (bytePos < intElements)
 Else
  OrdEntry = ""
 End If ' Me.HasElements
End Function ' OrdEntry


Public Function PopLast As String
 ' This function is similar to GetLast,
 ' except it also removes the last element from the StringList
 PopLast = varElements(byteUbound)
 If (intElements% > 0) Then
  varElements(byteUbound) = ""
  incValue intElements%, -1
 End If ' (intElements% > 0)
 
 If byteUbound > 0 Then incValue byteUbound, -1
 byteCurrentPos = byteUbound
End Function ' PopLast


Public Function PopFirst As String
 ' This function is similar to GetFirst,
 ' except it also removes the first element from the StringList and then reorders the StringList
 If (intElements% > 0) Then
  PopFirst = varElements(0)
  If (byteUbound > 0) Then
   For byteCurrentPos = 1 To byteUbound
    varElements(byteCurrentPos -1) = varElements(byteCurrentPos)
   Next ' byteCurrentPos
   varElements(byteUbound) = ""
   incValue byteUbound, -1
  Else
   varElements(0) = ""
  End If ' (byteUbound > 0)
 
  incValue intElements%, -1
 Else
  PopFirst = ""
 End If ' (intElements% > 0)
 
 byteCurrentPos = 0
 
End Function ' PopFirst


Public Sub Delete
 If bool_Initialized Then
  Redim varElements(0) As String
  varElements(0) = ""
 End If ' bool_Initialized
 
 intElements% = 0
 byteCurrentPos = 0
 byteUbound = 0
 bool_Initialized = False
End Sub ' Delete


End Class ' StringList