Comparing Two Version Numbers

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Author: comperio (talk, contrib)


Description

Please note that this function has been superseded by the VersionCompare function.

I was searching for a function that could compare two version numbers.

I was having a hard time stepping through the existing code, so I decided to write my own variation. I've tested every possible scenerio I could think of and could not make it fail. It will handle from 1 to up to 4 sections (ex: "1.2.3.4") as long as the version number string consists of strictly numbers (no letters).

The Script

The code is below. The documentation throughout the code should make it easy enough to follow: 

;  Created 1/5/05 by Comperio
;
;	Usage:
;	${VersionCheck} "Version1" "Version2" "outputVar"
;		Version1 = 1st version number
;		Version2 = 2nd version number
;		outputVar = Variable used to store the ouput
;
;	Return values:
;		0 = both versions are equal
;		1 = Version 1 is NEWER than version 2
;		2 = Version1 is OLDER than version 2
;	Rules for Version Numbers:
;		Version numbers must always be a string of numbers only.  (A dot
;		in the name is optional). 
;
;	[Variables]
var P1	; file pointer, used to "remember" the position in the Version1 string
var P2	; file pointer, used to "remember" the position in the Version2 string
var V1	;version number from Version1
var V2	;version number from Version2
Var Reslt	; holds the return flag
 
 
;	[Macros]
!macro VersionCheck Ver1 Ver2 OutVar
	;	To make this work, one character must be added to the version string:
	Push "x${Ver2}"
	Push "x${Ver1}"
	Call VersionCheckF
	Pop ${OutVar}
 
!macroend
 
;	[Defines]
!define VersionCheck "!insertmacro VersionCheck"
 
;	[Functions]
Function VersionCheckF
	Exch $1 ; $1 contains Version 1
	Exch
	Exch $2 ; $2 contains Version 2
	Exch
	Push $R0
	;	initialize Variables
	StrCpy $V1 ""
	StrCpy $V2 ""
	StrCpy $P1 ""
	StrCpy $P2 ""
	StrCpy $Reslt ""
	;	Set the file pointers:
	IntOp $P1 $P1 + 1
	IntOp $P2 $P2 + 1
	;  ******************* Get 1st version number for Ver1 **********************
	V11:
	;	I use $1 and $2 to help keep identify "Ver1" vs. "Ver2"
	StrCpy $R0 $1 1 $P1 ;$R0 contains the character at position $P1
	IntOp $P1 $P1 + 1 	;increments the file pointer for the next read
	StrCmp $R0 "" V11end 0	;check for empty string
	strCmp $R0 "." v11end 0
	strCpy $V1 "$V1$R0"
	Goto V11
	V11End:
	StrCmp $V1 "" 0 +2
	StrCpy $V1 "0"	
	;  ******************* Get 1st version number for Ver2 **********************
	V12:
	StrCpy $R0 $2 1 $P2 ;$R0 contains the character at position $P1
	IntOp $P2 $P2 + 1 	;increments the file pointer for the next read
	StrCmp $R0 "" V12end 0	;check for empty string
	strCmp $R0 "." v12end 0
	strCpy $V2 "$V2$R0"
	Goto V12
	V12End:
	StrCmp $V2 "" 0 +2
	StrCpy $V2 "0"	
	;	At this point, we can compare the results.  If the numbers are not
	;		equal, then we can exit
	IntCmp $V1 $V2 cont1 older1 newer1
	older1: ; Version 1 is older (less than) than version 2
	StrCpy $Reslt 2
	Goto ExitFunction
	newer1:	; Version 1 is newer (greater than) Version 2
	StrCpy $Reslt 1
	Goto ExitFunction
	Cont1: ;Versions are the same.  Continue searching for differences
	;	Reset $V1 and $V2
	StrCpy $V1 ""
	StrCpy $V2 ""
 
	;  ******************* Get 2nd version number for Ver1 **********************	
	V21:
	StrCpy $R0 $1 1 $P1 ;$R0 contains the character at position $P1
	IntOp $P1 $P1 + 1 	;increments the file pointer for the next read
	StrCmp $R0 "" V21end 0	;check for empty string
	strCmp $R0 "." v21end 0
	strCpy $V1 "$V1$R0"
	Goto V21
	V21End:
	StrCmp $V1 "" 0 +2
	StrCpy $V1 "0"	
	;  ******************* Get 2nd version number for Ver2 **********************
	V22:
	StrCpy $R0 $2 1 $P2 ;$R0 contains the character at position $P1
	IntOp $P2 $P2 + 1 	;increments the file pointer for the next read
	StrCmp $R0 "" V22end 0	;check for empty string
	strCmp $R0 "." V22end 0
	strCpy $V2 "$V2$R0"
	Goto V22
	V22End:
	StrCmp $V2 "" 0 +2
	StrCpy $V2 "0"	
	;	At this point, we can compare the results.  If the numbers are not
	;		equal, then we can exit
	IntCmp $V1 $V2 cont2 older2 newer2
	older2: ; Version 1 is older (less than) than version 2
	StrCpy $Reslt 2 
	Goto ExitFunction
	newer2:	; Version 1 is newer (greater than) Version 2
	StrCpy $Reslt 1
	Goto ExitFunction
	Cont2: ;Versions are the same.  Continue searching for differences
	;	Reset $V1 and $V2
	StrCpy $V1 ""
	StrCpy $V2 ""	
	;  ******************* Get 3rd version number for Ver1 **********************	
	V31:
	StrCpy $R0 $1 1 $P1 ;$R0 contains the character at position $P1
	IntOp $P1 $P1 + 1 	;increments the file pointer for the next read
	StrCmp $R0 "" V31end 0	;check for empty string
	strCmp $R0 "." v31end 0
	strCpy $V1 "$V1$R0"
	Goto V31
	V31End:
	StrCmp $V1 "" 0 +2
	StrCpy $V1 "0"	
	;  ******************* Get 3rd version number for Ver2 **********************
	V32:
	StrCpy $R0 $2 1 $P2 ;$R0 contains the character at position $P1
	IntOp $P2 $P2 + 1 	;increments the file pointer for the next read
	StrCmp $R0 "" V32end 0	;check for empty string
	strCmp $R0 "." V32end 0
	strCpy $V2 "$V2$R0"
	Goto V32
	V32End:
	StrCmp $V2 "" 0 +2
	StrCpy $V2 "0"	
	;	At this point, we can compare the results.  If the numbers are not
	;		equal, then we can exit
	IntCmp $V1 $V2 cont3 older3 newer3
	older3: ; Version 1 is older (less than) than version 2
	StrCpy $Reslt 2
	Goto ExitFunction
	newer3:	; Version 1 is newer (greater than) Version 2
	StrCpy $Reslt 1
	Goto ExitFunction
	Cont3: ;Versions are the same.  Continue searching for differences
	;	Reset $V1 and $V2
	StrCpy $V1 ""
	StrCpy $V2 ""
	;  ******************* Get 4th version number for Ver1 **********************	
	V41:
	StrCpy $R0 $1 1 $P1 ;$R0 contains the character at position $P1
	IntOp $P1 $P1 + 1 	;increments the file pointer for the next read
	StrCmp $R0 "" V41end 0	;check for empty string
	strCmp $R0 "." v41end 0
	strCpy $V1 "$V1$R0"
	Goto V41
	V41End:
	StrCmp $V1 "" 0 +2
	StrCpy $V1 "0"	
	;  ******************* Get 4th version number for Ver2 **********************
	V42:
	StrCpy $R0 $2 1 $P2 ;$R0 contains the character at position $P1
	IntOp $P2 $P2 + 1 	;increments the file pointer for the next read
	StrCmp $R0 "" V42end 0	;check for empty string
	strCmp $R0 "." V42end 0
	strCpy $V2 "$V2$R0"
	Goto V42
	V42End:
	StrCmp $V2 "" 0 +2
	StrCpy $V2 "0"	
	;	At this point, we can compare the results.  If the numbers are not
	;		equal, then we can exit
	IntCmp $V1 $V2 cont4 older4 newer4
	older4: ; Version 1 is older (less than) than version 2
	StrCpy $Reslt 2
	Goto ExitFunction
	newer4:	; Version 1 is newer (greater than) Version 2
	StrCpy $Reslt 1
	Goto ExitFunction
	Cont4: 
	;Versions are the same.  We've reached the end of the version
	;	strings, so set the function to 0 (equal) and exit
	StrCpy $Reslt 0
	ExitFunction:
	Pop $R0
	Pop $1
	Pop $2
	Push $Reslt
FunctionEnd
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