$Input_File = @ScriptDir & "\test.iso"
$Partial_File = $Input_File & ".parz"

$aZero = _Generate_1_Megabyte_EmptyArray()

;read input file
$v1 = Read_1Megabyte_to_Array($Input_File,0)
;write partial file
Write_File_From_Array($Partial_File,$v1,0)
;write zero to original file
Write_File_From_Array($Input_File,$aZero,0)

MsgBox(0,"recreate original file","recreate original file")

$v1 = Read_1Megabyte_to_Array($Partial_File,0)
Write_File_From_Array($Input_File,$v1,0)
FileDelete($Partial_File)

;**************************************************************************************************
Func Read_1Megabyte_to_Array($Path_Input_File_Func,$Offset_Func)
;**************************************************************************************************
Local $Array_Return[0]

$file = FileOpen($Path_Input_File_Func,16)
if $Offset_Func >= 0 Then
FileSetPos($file, $Offset_Func, 0) ;pos from begin file
Else
FileSetPos($file, $Offset_Func, 2) ;pos from end of file
EndIf

for $i=0 to 512-1
$line = FileRead($file,2048)
If @error Then return -1
ReDim $Array_Return[UBound($Array_Return) + 1]
$Array_Return[$i]=$line
Next
FileClose($file)
Return $Array_Return
EndFunc
;**************************************************************************************************
Func Write_File_From_Array($Path_Input_File_Func,$aInput_Func,$Offset_Func)
;**************************************************************************************************
$file = FileOpen($Path_Input_File_Func,17)
if $Offset_Func >= 0 Then
FileSetPos($file, $Offset_Func, 0) ;pos from begin file
Else
FileSetPos($file, $Offset_Func, 2) ;pos from end of file
EndIf

for $i=0 to UBound($aInput_Func)-1
FileWrite($file,$aInput_Func[$i])
Next
FileClose($file)
EndFunc
;**************************************************************************************************
Func _Generate_1_Megabyte_EmptyArray()
;**************************************************************************************************
$ZeroLine = "0x"
for $i=1 to 41
$ZeroLine &= "0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
Next
$ZeroLine = StringTrimRight($ZeroLine,4)

Local $aReturn[0]
for $i=0 to 512-1
ReDim $aReturn[UBound($aReturn) + 1]
$aReturn[$i]=$ZeroLine
Next
Return $aReturn
EndFunc