How to read the last line first from a file???

[Swati Shukla]

Hi,

Is is possible to first read the last line in the file and then read from the first line thru last line - 1?

I need the info that is stored at the last line in the file and I need that before I get any data and do any other manipulation.

Thank you,

Regards,
Swati

[Iouri]

Here are cople of ways to read the last line

Here's a simple way - it uses the 'seek' command in VB to go to an assigned distance from the end
of the file, then reads in the rest of the file and looks for the 'VBCRLF' :

private Function GetLastLine(byval FileName as string) as string
Dim iFile as Integer
Dim lFileLen as Long
Dim sBuffer as string
Dim iPos as Integer
'
' You might need to play with the offset depending on how big
' your 'lines' usually are in the file
'
Const OFFSET as Long = 160
'
' The line delimiter string - in this case I'm using VBCRLF, it
' could just be LF in some cases, again, be careful
'
Const FINDSTR as string = vbCrLf
'
iFile = FreeFile
sBuffer = Space$(OFFSET)
'
Open FileName for binary Access Read as #iFile
seek #iFile, (LOF(iFile) - OFFSET)
get #iFile, , sBuffer
Close #iFile
'
iPos = InStrRev(sBuffer, FINDSTR)
If iPos = 0 then
GetLastLine = sBuffer
else
GetLastLine = mid$(sBuffer, iPos + len(FINDSTR))
End If
'
End Function


'another example using RichTextBox
private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (byval hwnd as Long, byval wMsg as Long, byval wParam as Long, byval lParam as Any) as Long
Const EM_LINEINDEX = &HBB ' get offset of current line


private Sub Command1_Click()
Dim X
rtf.LoadFile "C:\Autoexec.Bat"
rtf.SelStart = len(rtf.Text) - 1
rtf.Refresh
X = rtf.SelStart - SendMessage(rtf.hwnd, EM_LINEINDEX, -1, 0&) + 1
' display last line of text file
MsgBox mid(rtf.Text, len(rtf.Text) - X)
End Sub

private Sub rtf_SelChange()
txtRow = rtf.GetLineFromChar(rtf.SelStart) + 1 ' get the current line
txtcol = rtf.SelStart - SendMessage(rtf.hwnd, EM_LINEINDEX, -1, 0&) + 1
End Sub


But I think it is not what you need. You need to count number of lines in the file and then read all of them but last.




Iouri Boutchkine
iouri@hotsheet.com

[Iouri]

Here is another solution


Dim A$, S$()
Open temp for input as #1
A = input(LOF(1), #1)
Close #1
S = Split(A, vbCrLf)
ReDim Preserve S(UBound(S) - 1)

'now you have all the lines in the array except the last one
'you can write it to the file
Open temp for Output as #1
print #1, Join(S, vbCrLf)
Close #1




Iouri Boutchkine
iouri@hotsheet.com