PureBoard

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quell$="Diese Prozedur sucht nicht von hinten, sondern fängt in der Mitte an. Deshalb ist diese Prozedur in vielen Fällen schneller als der Originalcode von Edel und auch schneller als die meisten hier vorgestellten Prozeduren."

such$ ="Edel"


Procedure.l FindLastString(heuhaufen.s, nadel.s, CaseSensitive=1) 

Protected pos = 0
Protected lastpos=0
Protected start=Len(heuhaufen)/2 ; <-- im 1.Repeat ab Mitte suchen

If CaseSensitive = 0 
   heuhaufen = LCase(heuhaufen) 
   nadel = LCase(nadel) 
EndIf 
  
Repeat 
  lastpos = pos 
  pos = FindString(heuhaufen,nadel,start+pos+1) 
  start=0
Until pos = 0 

If lastpos
    ProcedureReturn lastpos
Else
    pos = 0
    lastpos=0    
    Repeat 
      lastpos = pos 
      pos = FindString(heuhaufen,nadel,start+pos+1) 
    Until pos = 0 
EndIf

ProcedureReturn lastpos

EndProcedure

p=FindLastString(quell$, such$)
Debug p

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Procedure FindLastString(String$, StringToFind$, CaseInSensitive=0)
	Protected length=Len(StringToFind$), *position=@String$+(Len(String$)-length)<<#PB_Compiler_Unicode
	If StringToFind$
		While *position >= @String$
			If CompareMemoryString(*position, @StringToFind$, CaseInSensitive, length) = #PB_String_Equal
				ProcedureReturn (*position-@String$)>>#PB_Compiler_Unicode+1
			EndIf
			*position-SizeOf(Character)
		Wend
	EndIf
EndProcedure

Debug FindLastString("berthold", "hold")

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mem = StrRStrI_(@"Ich liebe PureBasic! Du auch?",0,@"liebe")

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Procedure FindLastString(String$, StringToFind$) 
  For i=1 To CountString(String$, StringToFind$)
    temp$=StringField(String$, i, StringToFind$)
    pos=pos+Len(temp$)+1
  Next i
  ProcedureReturn pos
EndProcedure

Debug FindLastString("anna", "a")

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Procedure.l inMemStrRev(StartPos, *Source, strStr.s)
  
  ; naiver Algorithmus überprüft ein gesuchtes Muster rückwärts 
  ; an allen Positionen i eines Speicherbereichs beginnend bei 
  ; StartPos, Ende der Suche bei *Source
  
  result.l
  PatLen = Len(strStr)
  
  ;init pointers etc.
  MOV Ebx,strStr    ; Ebx = Pointer to first Char in string
  MOV Edx,*Source
  MOV Ecx,Edx   ; Ecx = Pointer to akt. Char in source
  ADD Ecx,StartPos  ; set source-pointer to startposition
  SUB Ecx, PatLen
  DEC Edx
  ;INC Ecx      ; StartPos - 1
  
  ! rpt_SrcRev:        ; startpoint for loop scanning through the source
  MOV al,[Ecx]
  DEC Ecx           ; Ecx + 1
  CMP Ecx,Edx          ; if null (end of source-string)
  JS endProcRev        ; -> end Procedure, Result=0
  
  CMP byte[Ebx],al  ; if found first Char of strStr look for the rest
  JNE rpt_SrcRev       ; else go on with next Char in source
  
  ;found the first Char of strStr in source
  ;now look if the rest does match
  Xor Edi,Edi             ; Edi = 0, Edi = Pointer to akt. Char in strStr
  ! rpt_StrRev:              ; startpoint for loop pounding the string
  INC Edi                 ; Edi + 1 (the first Char in string is already found)
  
  CMP byte[Ebx+Edi],0     ; if 0 (end of strStr) 
  JE got_itRev               ; -> got it, all Chars of the string did match
  MOV al,byte[Ecx+Edi+1]  ; move actual Char in source to accumulator, have 
  ; to add 1 cause Ecx already decreased before
  
  CMP byte[Ebx+Edi],al    ; if actual Char in source (Ebx+Edi) = act Char in string (al)
  JE rpt_StrRev              ; then take next Char
  JMP rpt_SrcRev             ; and go on with scanning source
  
  ! got_itRev:
  ;Result = Ecx - Source, to get the place in the source-string
  SUB Ecx,Edx
  INC Ecx
  MOV result,Ecx
  
  ! endProcRev:
  ProcedureReturn result
EndProcedure

; und zum testen 

Macro FindReport()
  PrintN ("pattern found at position: " + Str(a) + " in " + Str(timeGetTime_()-StartTime ) + " milliseconds")
  PrintN (" ")
  a=0
EndMacro

Text.s="axbbaaxbbaaxbbabbal axbbaaxbbaaxbbabbal axbbaaxbbaaxbbabbalaxbbaaxbbaaxbbabbal This is any Text of any number of characters With no content"

findstr.s= "many"

OpenConsole()

For i = 1 To 20;8
  Text=Text+"|"+Text
Next
Text=findstr+Text

loopcount = 10;2;5000

PrintN ("starting to search " + Str(loopcount) + " times, in " + Str(Len(Text)) + " characters, for '" + findstr + "'")
PrintN (" ")


PrintN ("Search inMemStrRev")
lentxt=Len(Text)
lenfindstr=Len(findstr)
StartTime = timeGetTime_()
For i = 1 To loopcount
  a=inMemStrRev(lentxt, @Text, findstr)
Next i
FindReport()