VBA Array Size for CodeReview Question/Answers - Tests Crossing Zero Index...

VbaGenericArraySizeFunctionTests.bas

Public Function f_test()
  Dim blnResult As Boolean

  Dim astrTemp() As String
  
  On Error GoTo NormalExit
  
  ReDim astrTemp(-1 To 1)
  astrTemp(-1) = "A"
  astrTemp(0) = "B"
  astrTemp(1) = "C"
  Debug.Print "1. LBound: " + CStr(LBound(astrTemp))
  Debug.Print "1. UBound: " + CStr(UBound(astrTemp))
  Debug.Assert f_ua_lngSize(astrTemp) = 3
  
  ReDim astrTemp(-2 To 0)
  astrTemp(-2) = "A"
  astrTemp(-1) = "B"
  astrTemp(0) = "C"
  Debug.Print "2. LBound: " + CStr(LBound(astrTemp))
  Debug.Print "2. UBound: " + CStr(UBound(astrTemp))
  Debug.Assert f_ua_lngSize(astrTemp) = 3
  
  ReDim astrTemp(0 To 2)
  astrTemp(0) = "A"
  astrTemp(1) = "B"
  astrTemp(2) = "C"
  Debug.Print "3. LBound: " + CStr(LBound(astrTemp))
  Debug.Print "3. UBound: " + CStr(UBound(astrTemp))
  Debug.Assert f_ua_lngSize(astrTemp) = 3
  
  ReDim astrTemp(-3 To -1)
  astrTemp(-3) = "A"
  astrTemp(-2) = "B"
  astrTemp(-1) = "C"
  Debug.Print "4. LBound: " + CStr(LBound(astrTemp))
  Debug.Print "4. UBound: " + CStr(UBound(astrTemp))
  Debug.Assert f_ua_lngSize(astrTemp) = 3
  
  ReDim astrTemp(1 To 3)
  astrTemp(1) = "A"
  astrTemp(2) = "B"
  astrTemp(3) = "C"
  Debug.Print "5. LBound: " + CStr(LBound(astrTemp))
  Debug.Print "5. UBound: " + CStr(UBound(astrTemp))
  Debug.Assert f_ua_lngSize(astrTemp) = 3
  
  blnResult = True
  
NormalExit:
  f_test = blnResult
End Function

'Return Value:
'   -1 - Not an Array
'    0 - Empty
'  > 0 - Defined
Public Function f_ua_lngSize( _
    ByRef pr_avarValues As Variant _
  , Optional ByVal pv_lngDimensionOneBased As Long = 1 _
) As Long
  Dim lngSize As Long: lngSize = M_UA_SIZE_NOT_ARRAY 'Default to not an Array
  Dim lngLBound As Long
  Dim lngUBound As Long
  
  On Error GoTo Recovery
  
  If (IsArray(pr_avarValues) = True) Then
    lngSize = M_UA_SIZE_EMPTY 'Move default to Empty
    lngLBound = LBound(pr_avarValues, pv_lngDimensionOneBased)
    lngUBound = UBound(pr_avarValues, pv_lngDimensionOneBased)
    If (lngLBound <= lngUBound) Then
      lngSize = lngUBound - lngLBound + 1 'Non-Empty, so return size
    End If
  End If
  
NormalExit:
  f_ua_lngSize = lngSize
  Exit Function
  
Recovery:
  GoTo NormalExit
End Function