This simple class makes it very easy to typecast a String into an Integer array. Treating a String as an array enables some kinds of String processing to be done much quicker than is possible with VB's intrinsic String functions.
clsStrToIntArray.cls
modMain.bas
clsStrToIntArray.cls
Code:
Option Explicit
Private Const FADF_AUTO As Integer = &H1 'An array that is allocated on the stack.
Private Const FADF_FIXEDSIZE As Integer = &H10 'An array that may not be resized or reallocated.
Private Type SAFEARRAY1D 'Represents a safe array. (One Dimensional)
cDims As Integer 'The count of dimensions.
fFeatures As Integer 'Flags used by the SafeArray.
cbElements As Long 'The size of an array element.
cLocks As Long 'The number of times the array has been locked without a corresponding unlock.
pvData As Long 'Pointer to the data.
cElements As Long 'The number of elements in the dimension.
lLbound As Long 'The lower bound of the dimension.
End Type 'http://msdn.microsoft.com/en-us/library/ms221482(v=vs.85).aspx
Private Declare Function VarPtrArray Lib "msvbvm60.dll" Alias "VarPtr" (ByRef ArrayVar() As Any) As Long
Private Declare Sub PutMem4 Lib "msvbvm60.dll" (ByVal Addr As Long, ByVal NewVal As Long)
Private Ptr As Long
Private SA1D As SAFEARRAY1D
Private Sub Class_Initialize()
With SA1D
.cDims = 1
.fFeatures = FADF_AUTO Or FADF_FIXEDSIZE
.cbElements = 2&
.cLocks = 1&
.lLbound = 1&
End With
End Sub
'This should be the first method called right after instantiating
'the class and should be invoked only once per class instance.
'Pass the Integer array that will substitute for the String.
Public Sub InitArray(ByRef IntArray_OUT() As Integer)
Erase IntArray_OUT
Ptr = VarPtrArray(IntArray_OUT())
PutMem4 Ptr, VarPtr(SA1D)
End Sub
'This function typecasts the passed String into an Integer array.
'That is, the characters of the String can be treated as elements
'of the Integer array. Any number of Strings can be typecast to
'the Integer array by calling this function repeatedly. However,
'the array should not be Erased when assigning another String.
'This function fails (returns False) if passed an empty string.
Public Function CastString(ByRef String_IN As String) As Boolean
Dim StrLen As Long
If Ptr Then
StrLen = Len(String_IN)
If StrLen Then
With SA1D
.pvData = StrPtr(String_IN)
.cElements = StrLen
CastString = .pvData <> 0&
End With
End If
End If
End Function
Private Sub Class_Terminate()
If Ptr Then PutMem4 Ptr, 0&
End Sub
Code:
Option Explicit
Private Sub Main()
Dim aintChars() As Integer, i As Long
Dim sControlChars As String, sPrintableChars As String
sControlChars = Space$(31&)
sPrintableChars = String$(224&, 0)
With New clsStrToIntArray
.InitArray aintChars()
If .CastString(sPrintableChars) Then
For i = LBound(aintChars) To UBound(aintChars)
aintChars(i) = i + 31&
Next
Debug.Print """" & sPrintableChars & """"
End If
If .CastString(sControlChars) Then
For i = LBound(aintChars) To UBound(aintChars)
aintChars(i) = i
Next
Debug.Print """" & sControlChars & """"
End If
End With
End Sub