Boyer–Moore–Horspool search algorithm

				
'**************************************
' Name: Boyer–Moore–Horspool search algorithm
' Description:I've produced this from looking at the Wikipedia article etc. as I couldn't find a VB version anywhere. Kept as simple as possible, no error checks or anything.
' By: Je.
'
'This code is copyrighted and has' limited warranties.Please see http://www.Planet-Source-Code.com/vb/scripts/ShowCode.asp?txtCodeId=74520&lngWId=1'for details.'**************************************

Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
Function BMHSearch(start As Long, stin() As Integer, stfind() As Integer) As Long
Const MaxChar = 32767 'keeping it simple - just allowing positive values
Dim f As Long, skip(MaxChar) As Integer, UbIn As Long, UbFi As Long, tmp As String
UbIn = UBound(stin): UbFi = UBound(stfind) + 1: BMHSearch = -1
If UbIn < start + UbFi - 1 Then Exit Function
'build skip table
tmp = String(MaxChar, UbFi): CopyMemory skip(0), ByVal StrPtr(tmp), 2& * MaxChar
UbFi = UbFi - 1
For f = 0 To UbFi
skip(stfind(f)) = UbFi - f
Next
'search
 inpos = start + UbFi
Do While (inpos <= UbIn)
f = UbFi
Do
If stin(inpos) <> stfind(f) Then Exit Do
If f = 0 Then BMHSearch = inpos: Exit Function
f = f - 1: inpos = inpos - 1
Loop
inpos = inpos + skip(stin(inpos))
Loop
End Function