; #FUNCTION# ;===============================================================================
;
; Name...........: _NaturalCompare
; Description ...: Compare two strings using Natural (Alphabetical) sorting.
; Syntax.........: _NaturalCompare($s1, $s2, $iCase = 0)
; Parameters ....: $s1, $s2 - Strings to compare
;                  $iCase   - Case sensitive or insensitive comparison
;                  |0 - Case insensitive (default)
;                  |1 - Case sensitive
; Return values .: Success - One of the following:
;                  |0  - Strings are equal
;                  |-1 - $s1 comes before $s2
;                  |1  - $s1 goes after $s2
;                  Failure - Returns -2 and Sets @Error:
;                  |1 - $s1 or $s2 is not a string
;                  |2 - $iCase is invalid
; Author ........: Erik Pilsits
; Modified.......:
; Remarks .......: Original algorithm by Dave Koelle
; Related .......: StringCompare
; Link ..........: http://www.davekoelle.com/alphanum.html
; Example .......: Yes
;
; ;==========================================================================================
Func _NaturalCompare($s1, $s2, $iCase = 0)
    If (Not IsString($s1)) Or (Not IsString($s2)) Then Return SetError(1, 0, -2)
    If $iCase <> 0 And $iCase <> 1 Then Return SetError(2, 0, -2)

    Local $n = 0, $iLen = 1
    Local $s1chunk, $s2chunk

    While $n = 0 ; get next chunk
        ; STRING 1
        $iLen = 1
        If StringIsDigit(StringLeft($s1, 1)) Then
            ; chunk of digits
            For $i = 2 To StringLen($s1)
                If StringIsDigit(StringMid($s1, $i, 1)) Then
                    $iLen += 1
                Else
                    ExitLoop
                EndIf
            Next
        Else
            ; chunk of letters
            For $i = 2 To StringLen($s1)
                If Not StringIsDigit(StringMid($s1, $i, 1)) Then
                    $iLen += 1
                Else
                    ExitLoop
                EndIf
            Next
        EndIf
        $s1chunk = StringLeft($s1, $iLen)

        ; STRING 2
        $iLen = 1
        If StringIsDigit(StringLeft($s2, 1)) Then
            ; chunk of digits
            For $i = 2 To StringLen($s2)
                If StringIsDigit(StringMid($s2, $i, 1)) Then
                    $iLen += 1
                Else
                    ExitLoop
                EndIf
            Next
        Else
            ; chunk of letters
            For $i = 2 To StringLen($s2)
                If Not StringIsDigit(StringMid($s2, $i, 1)) Then
                    $iLen += 1
                Else
                    ExitLoop
                EndIf
            Next
        EndIf
        $s2chunk = StringLeft($s2, $iLen)

        ; ran out of chunks, strings are the same, return 0
        If $s1chunk = "" And $s2chunk = "" Then Return 0

        ; remove chunks from strings
        $s1 = StringMid($s1, StringLen($s1chunk) + 1)
        $s2 = StringMid($s2, StringLen($s2chunk) + 1)

        ; Case 1: both chunks contain letters
        If (Not StringIsDigit($s1chunk)) And (Not StringIsDigit($s2chunk)) Then
            $n = StringCompare($s1chunk, $s2chunk, $iCase)
        Else
            ; Case 2: both chunks contain numbers
            If StringIsDigit($s1chunk) And StringIsDigit($s2chunk) Then
                Local $i1chunk = Int($s1chunk)
                Local $i2chunk = Int($s2chunk)
                If $i1chunk > $i2chunk Then
                    Return 1
                ElseIf $i1chunk < $i2chunk Then
                    Return -1
                EndIf
            Else
                ; Case 3: one chunk has letters, the other has numbers; or one is empty
                ; if we get here, this should be the last and deciding test, so return the result
                Return StringCompare($s1chunk, $s2chunk, $iCase)
            EndIf
        EndIf
    WEnd

    Return $n
EndFunc