Write null (00H) to file

[Guest tanewha]

Can anyone tell me how I can use AutoIt 3 to write a null (00H) to file? Any nulls in the "line" string of the WriteFile command seem to be ignored.

Thanks in anticipation.

[Valik 478]

You can't read or write NULL characters. If reading, you can read up to the first NULL, but not beyond (At least not without reading character by character). It's not possible to write NULL characters.

[ezzetabi 3]

About writing there is a workaround using XVI:

Simply write in the file a character you can write and that is unique and after, using this UDF, you can change it in NULLs.

In the example it creates a small file where I want to write NULLs, the nulls value are wrote as pipes and changed.

Here the UDF:

FileWrite("Test.txt", "Some text ||, some other text");It is just a test.
;The pipes must become 00

_ReplaceWith00h("Test.txt", "7c");7c is the HEX value of the pipe


Func _ReplaceWith00h($FILENAME, $ORIG);$Orig must be in the HEX value to change in 00
   If Not FileExists($FILENAME) Then Return -1;Returns -1 if the file do not exists.
   $FILENAME = FileGetLongName($FILENAME)

   
  ;Download http://www.handshake.de/user/chmaas/delphi/download/xvi32.zip and unpack
  ;XVI32.exe in c:\XVI32 before compiling.

   DirCreate(@ScriptDir & "\tmp")   
   FileInstall("C:\XVI32\XVI32.exe", @ScriptDir & "\tmp\")
   
   FileWrite(@ScriptDir & "\tmp\x.xsc", "ADR 0" & @CRLF & "REPLACEALL " & $ORIG & " BY 00")
  ;It creates the istructions file for XVI
   
   RunWait(@ScriptDir & '\tmp\xvi32.exe "' & $FILENAME & '" /s=x.xsc', _
         @ScriptDir & "\tmp", @SW_HIDE)
   DirRemove(@ScriptDir & "\tmp", 1)
   Return 0
EndFunc  ;==>_ReplaceWith00h

Edited July 26, 2004 by ezzetabi

[ezzetabi 3]

Otherwise you can just add the 00 chars using XVI if you know the exatly place wher to put them.

[Guest tanewha]

Thanks ezzetabi, that looks like it should do the trick.

Sorry it took so long to acknowlrdge your reply, I was having trouble with my log-on.

I haven't tried your solution yet but I'm just about to .... so fingers crossed.

Thanks again

[seanhart 3]

I also had a similar issue, needed to write NULL data to a file from within AutoIt, and ended up creating a little external utility to do this. Thought I would share this with the group for anyone who is interested.

The tiny utility (18K) is called "BINWRITE" and is designed to write binary data to a file (provided in either binary, hex, or string format).

E.g.:

binwrite.exe file.bin hex 00

binwrite.exe file.bin hex ff1a3f002c

binwrite.exe file.bin bin 10010110

binwrite.exe file.bin asc "This is some normal text."

Obviously this can be called with a RunWait command in AutoIt.

Hope someone else finds this useful.

Sean

binwrite.zip