[RESOLVED] Convert Hex String to a normal String

[Merri]

StrConv in itself isn't slow... but you can limit the amount of calls into it. Simply remove the first StrConv and adjust the rest of your calculation to match it -> a lot more speed. Also Dim hBv(1) As Byte doesn't need to be an array: if you use two variables instead you again get more speed.


Updated!
This function now fully validates given input. It also allows any invalid character from range 0 to 127 to work as a separator that gets ignored. The formatting can be anything as long as two consecutive characters make up a valid hex pair.

Option Explicit

Private Declare Function ArrayPtr Lib "msvbvm60" Alias "VarPtr" (Arr() As Any) As Long
Private Declare Sub PutMem4 Lib "msvbvm60" (ByVal Ptr As Long, ByVal Value As Long)

Public Function HexANSIToStringFast3(ByVal Hex As String) As String
    Dim Char() As Byte, Header(0 To 5) As Long, Ptr As Long
    Dim B As Byte, I As Long, J As Long, TL(0 To 255) As Byte, TU(0 To 255) As Byte, TI(0 To 255) As Byte
    For I = 0 To 127: TI(I) = 1: Next I
    For I = I To 255: TI(I) = 2: Next I
    For B = 48 To 57: TL(B) = B - 48: TU(B) = TL(B) * 16: TI(B) = 0: Next
    For B = 65 To 70: TL(B) = B - 55: TU(B) = TL(B) * 16: TL(B + 32) = TL(B): TU(B + 32) = TU(B): TI(B) = 0: TI(B + 32) = 0: Next
    Header(0) = 1: Header(1) = 1: Header(3) = StrPtr(Hex): Header(4) = LenB(Hex)
    Ptr = ArrayPtr(Char): PutMem4 Ptr, VarPtr(Header(0))
    For I = 0 To Header(4) - 4 Step 4
        B = TI(Char(I))
        If B = 0 Then
            Char(J) = TU(Char(I)) Or TL(Char(I + 2))
            J = J + 1
        ElseIf B = 1 Then
            I = I - 2
        Else
            J = 0
            Exit For
        End If
    Next I
    PutMem4 Ptr, 0
    If J Then
        HexANSIToStringFast3 = StrConv(LeftB$(Hex, J), vbUnicode)
    Else
        Err.Raise 5
    End If
End Function

Just to show what you can do:
Debug.Print HexANSIToStringFast3("[48] [45] [6c] - [6C] [6f]")