;==========================================================================================================================================
;   How to extract specified line from text file?
;
;   Detlev Dalitz.20040327.20090506.
;==========================================================================================================================================
;
;   Assuming the given text file is a DOS standard text file
;   with each line delimited by a sequence of two bytes @CR@LF,
;   we are able to extract a line by the line number.
;   There exist different techniques to fetch a line out of a text file.
;
;------------------------------------------------------------------------------------------------------------------------------------------
;   Contents
;
;   1. Using FileRead.
;   2. Using Binary Buffer functions.
;   3. Using Fileget and ItemExtract.
;   4. Using Fileget and ItemExtract (one line code).
;
;------------------------------------------------------------------------------------------------------------------------------------------
;
;   1. Using FileRead.


strFilename = IntControl (1004, 0, 0, 0, 0) ; We use this script as test input file.
intLineToExtract = 10

intLine = 0
strLine = ""
hdlFR = FileOpen (strFilename, "READ")
While @TRUE
   strLine = FileRead (hdlFR)
   If strLine == "*EOF*" Then Break
   intLine = intLine + 1
   If intLine == intLineToExtract Then Break
EndWhile
hdlFR = FileClose (hdlFR)

If intLine == intLineToExtract
   Message (StrCat ("1: This is Line #", intLineToExtract), strLine)
Else
   Message ("Warning", StrCat ("Line not found #", intLineToExtract))
EndIf
;Exit

;------------------------------------------------------------------------------------------------------------------------------------------
;
;   2. Using Binary Buffer functions.


strFilename = IntControl (1004, 0, 0, 0, 0) ; We use this script as test input file.
intLineToExtract = 10

intLine = 0
strLine = ""
intFilesize = FileSize (strFilename)
If !!intFilesize
   hdlBB = BinaryAlloc (1 + intFilesize)
   intResult = BinaryPokeStr (hdlBB, 0, @LF)
   intResult = BinaryReadEx (hdlBB, 1, strFilename, 0, intFilesize)
   strBBTag = BinaryTagInit (hdlBB, @LF, @CR)
   While @TRUE
      strBBTag = BinaryTagFind (strBBTag)
      If strBBTag == "" Then Break
      intLine = intLine + 1
      If intLine == intLineToExtract
         strLine = BinaryTagExtr (strBBTag, 0)
         Break
      EndIf
   EndWhile
   hdlBB = BinaryFree (hdlBB)
EndIf

If intLine == intLineToExtract
   Message (StrCat ("2: This is Line #", intLineToExtract), strLine)
Else
   Message ("Warning", StrCat ("Line not found #", intLineToExtract))
EndIf
;Exit


;------------------------------------------------------------------------------------------------------------------------------------------
;
;   3. Using Fileget and ItemExtract.


strFilename = IntControl (1004, 0, 0, 0, 0) ; We use this script as test input file.
intLineToExtract = 10

strString = FileGet (strFilename)
strString = StrReplace (strString, @CRLF, @LF)

If ItemCount (strString, @LF) >= intLineToExtract
   strLine = ItemExtract (intLineToExtract, strString, @LF)
   Message (StrCat ("3: This is Line #", intLineToExtract), strLine)
Else
   Message ("Warning", StrCat ("Line not found #", intLineToExtract))
EndIf
;Exit


;------------------------------------------------------------------------------------------------------------------------------------------
;
;   4. Using Fileget and ItemExtract (one line code).
;
;   Almost the same as method 3, but condensed into one code line:

strFilename = IntControl (1004, 0, 0, 0, 0) ; We use this script as test input file.
intLineToExtract = 10

strLine = ItemExtract (1, ItemExtract (intLineToExtract, FileGet (strFilename), @LF), @CR)

Message (StrCat ("4: This is Line #", intLineToExtract), strLine)

Exit
;------------------------------------------------------------------------------------------------------------------------------------------
;==========================================================================================================================================