Это алгоритм поиска Бойера-Мура-Хорспула для поиска подстроки в строке. Так же в коде есть небольшая процедура прямого поиска. Код написан мною для последующего его перевода на ASM , что и было потом сделано. Но поскольку код ASM здесь мало кому интересен , то выкладываю только код FB:
Код
Function DirectSearch(_
start As Integer, _
pszBuf As Zstring Ptr,_
pszTemplate As Zstring Ptr,_
iLenBuf As Integer,_
iLenTemplate As Integer) As Integer
Dim As Integer iTemp
For i As Integer = start-1 To iLenBuf-1
If (*pszBuf)[i] = (*pszTemplate)[iTemp] Then
iTemp+=1
If iTemp >= iLenTemplate Then
Return i - iLenTemplate +2
Endif
Else
iTemp = 0
Endif
Next
End Function
Function Search (iStart As Integer , pszBuf As Zstring Ptr, pszTemplate As Zstring Ptr , iLenBuf As Integer , iLenTemplate As Integer) As Integer
Dim As Ubyte bTable(255)
Dim As Integer iPointer = iLenTemplate - 1 + (iStart-1)
Dim As Integer iPointerTemplate = iLenTemplate - 1
Dim As Integer iBackPointer = iPointer
Dim As Integer iRet
For i As Integer = 0 To 255
bTable(i) = iLenTemplate
Next
Dim iDistance As Byte = 1
For i As Integer = iLenTemplate-2 To 0 Step -1
Dim bChar As Ubyte = (*pszTemplate)[i]
If bTable(bChar) = iLenTemplate Then
bTable(bChar) = iDistance
Endif
iDistance +=1
Next
Do
Dim As Ubyte bCharBuf = (*pszBuf)[iPointer]
Dim As Ubyte bCharTemplate = (*pszTemplate)[iPointerTemplate]
If bCharBuf = bCharTemplate Then
iRet = iPointer+1
iPointer-=1
iPointerTemplate-=1
If iPointerTemplate < 0 Then
Exit Do
Endif
Else
Dim As Ubyte bChar = (*pszBuf)[iBackPointer]
Dim As Integer iDistance = bTable(bChar)
iPointerTemplate = iLenTemplate - 1
iPointer = iBackPointer + iDistance
iBackPointer = iPointer
iRet = 0
Endif
If iPointer >= iLenBuf Then
Exit Do
Endif
Loop
Return iRet
End Function
Dim As Zstring Ptr psz0 = @"Hello world"
Dim As Zstring Ptr psz1 = @"ld"
? DirectSearch(1, psz0 , psz1 , Len(*psz0) , Len(*psz1))
? Search(1 , psz0 , psz1 , Len(*psz0) , Len(*psz1))
