StrStr: Difference between revisions

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{{PageAuthor|sunjammer}}
{{PageAuthor|deguix}}


== Description ==
== Description ==
This function searches for a substring on a string, and returns itself plus the remaining of the string. Doesn't work with Unicode.


== The Function ==
'''Requires:''' [[LogicLib]].
<highlight-nsis>; StrStr
 
; input, top of stack = string to search for
'''Version:''' 2.0.
;       top of stack-1 = string to search in
 
; output, top of stack (replaces with the portion of the string remaining)
This function searches for a substring on a string, and returns itself plus the remaining part of the string on the right of the substring.
; modifies no other variables.
 
;
== How To Use ==
; Usage:
 
;   Push "this is a long ass string"
=== Syntax ===
;   Push "ass"
 
;   Call StrStr
<highlight-nsis>
;   Pop $R0
${StrLoc} "ResultVar" "String" "SubString"
;  ($R0 at this point is "ass string")
</highlight-nsis>
or
<highlight-nsis>
Push "SubString"
Push "String"
Call StrLoc
Pop "ResultVar"
</highlight-nsis>
 
=== Parameters ===
 
; ResultVar
: Variable where the part on the right and including the ''SubString'' found on ''String'' is returned. If ''SubString'' is not found, an empty value is returned.
 
; String
: String where to search for ''SubString''.
 
; SubString
: String to search in ''String''.
 
=== Example ===
 
<highlight-nsis>
${StrStr} $0 "This is just an example" "just"
;$0 = "just an example"
</highlight-nsis>
 
== Function Code ==
 
<highlight-nsis>
!define StrStr "!insertmacro StrStr"
 
!macro StrStr ResultVar String SubString
   Push "${SubString}"
   Push "${String}"
   Call StrStr
   Pop "${ResultVar}"
!macroend


Function StrStr
Function StrStr
   Exch $R1 ; st=haystack,old$R1, $R1=needle
/*After this point:
   Exch    ; st=old$R1,haystack
  ------------------------------------------
   Exch $R2 ; st=old$R1,old$R2, $R2=haystack
  $R0 = SubString (input)
   $R1 = String (input)
  $R2 = SubStringLen (temp)
  $R3 = StrLen (temp)
   $R4 = StartCharPos (temp)
  $R5 = TempStr (temp)*/
 
  ;Get input from user
   Exch $R0
  Exch
  Exch $R1
  Push $R2
   Push $R3
   Push $R3
   Push $R4
   Push $R4
   Push $R5
   Push $R5
  ;Get "String" and "SubString" length
  StrLen $R2 $R0
   StrLen $R3 $R1
   StrLen $R3 $R1
  ;Start "StartCharPos" counter
   StrCpy $R4 0
   StrCpy $R4 0
   ; $R1=needle
 
   ; $R2=haystack
   ;Loop until "SubString" is found or "String" reaches its end
  ; $R3=len(needle)
   ${Do}
  ; $R4=cnt
    ;Remove everything before and after the searched part ("TempStr")
  ; $R5=tmp
    StrCpy $R5 $R1 $R2 $R4
  loop:
 
     StrCpy $R5 $R2 $R3 $R4
    ;Compare "TempStr" with "SubString"
    StrCmp $R5 $R1 done
    ${IfThen} $R5 == $R0 ${|} ${ExitDo} ${|}
     StrCmp $R5 "" done
    ;If not "SubString", this could be "String"'s end
     ${IfThen} $R4 >= $R3 ${|} ${ExitDo} ${|}
     ;If not, continue the loop
     IntOp $R4 $R4 + 1
     IntOp $R4 $R4 + 1
    Goto loop
  ${Loop}
   done:
 
   StrCpy $R1 $R2 "" $R4
/*After this point:
  ------------------------------------------
  $R0 = OutVar (output)*/
 
   ;Remove part before "SubString" on "String" (if there has one)
   StrCpy $R0 $R1 `` $R4
 
  ;Return output to user
   Pop $R5
   Pop $R5
   Pop $R4
   Pop $R4
   Pop $R3
   Pop $R3
   Pop $R2
   Pop $R2
   Exch $R1
  Pop $R1
   Exch $R0
FunctionEnd
FunctionEnd
</highlight-nsis>
</highlight-nsis>
== Credits ==
Version 2.0 - Diego Pedroso ([[User:deguix|deguix]]).
Version 1.0 - Ximon Eighteen ([[User:sunjammer|sunjammer]]).


[[Category:String Functions]]
[[Category:String Functions]]

Revision as of 21:16, 2 July 2005

Author: deguix (talk, contrib)


Description

Requires: LogicLib.

Version: 2.0.

This function searches for a substring on a string, and returns itself plus the remaining part of the string on the right of the substring.

How To Use

Syntax

${StrLoc} "ResultVar" "String" "SubString"

or

Push "SubString"
Push "String"
Call StrLoc
Pop "ResultVar"

Parameters

ResultVar
Variable where the part on the right and including the SubString found on String is returned. If SubString is not found, an empty value is returned.
String
String where to search for SubString.
SubString
String to search in String.

Example

${StrStr} $0 "This is just an example" "just"
;$0 = "just an example"

Function Code

!define StrStr "!insertmacro StrStr"
 
!macro StrStr ResultVar String SubString
  Push "${SubString}"
  Push "${String}"
  Call StrStr
  Pop "${ResultVar}"
!macroend
 
Function StrStr
/*After this point:
  ------------------------------------------
  $R0 = SubString (input)
  $R1 = String (input)
  $R2 = SubStringLen (temp)
  $R3 = StrLen (temp)
  $R4 = StartCharPos (temp)
  $R5 = TempStr (temp)*/
 
  ;Get input from user
  Exch $R0
  Exch
  Exch $R1
  Push $R2
  Push $R3
  Push $R4
  Push $R5
 
  ;Get "String" and "SubString" length
  StrLen $R2 $R0
  StrLen $R3 $R1
  ;Start "StartCharPos" counter
  StrCpy $R4 0
 
  ;Loop until "SubString" is found or "String" reaches its end
  ${Do}
    ;Remove everything before and after the searched part ("TempStr")
    StrCpy $R5 $R1 $R2 $R4
 
    ;Compare "TempStr" with "SubString"
    ${IfThen} $R5 == $R0 ${|} ${ExitDo} ${|}
    ;If not "SubString", this could be "String"'s end
    ${IfThen} $R4 >= $R3 ${|} ${ExitDo} ${|}
    ;If not, continue the loop
    IntOp $R4 $R4 + 1
  ${Loop}
 
/*After this point:
  ------------------------------------------
  $R0 = OutVar (output)*/
 
  ;Remove part before "SubString" on "String" (if there has one)
  StrCpy $R0 $R1 `` $R4
 
  ;Return output to user
  Pop $R5
  Pop $R4
  Pop $R3
  Pop $R2
  Pop $R1
  Exch $R0
FunctionEnd

Credits

Version 2.0 - Diego Pedroso (deguix). Version 1.0 - Ximon Eighteen (sunjammer).