DummyFile_Create

[jaberwacky]

If you ever find yourself in need of a dummy file for testing then this function may be what you need.

Feed the function a size in megabytes and give it a location to store the dummy file and you're done.

Large files may take a while depending on your system.

[update: April 28, 2011] -- Now you can create UNICODE files!

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#include-once

Func DummyFile_Create( Const $iTotalB , Const $fileSaveLoc , Const $alphaNumeric = 1 )
    Local $string
    Local Const $mode = 2 + 8
    Local Const $binary = 16
    Local Const $utf16 = 32

    Switch $alphaNumeric
        Case 0 ; numeric data
            FileOpen( $fileSaveLoc , $mode )
            If @error = -1 Then Return SetError( 1 , 0 , 1 )

            For $i = 1 To $iTotalB
                $string &= Random( 0 , 9 , 1 )
            Next

            FileWrite( 1 , $string )

        Case 1 ; ASCII alphanumeric data
            FileOpen( $fileSaveLoc , $mode )
            If @error = -1 Then SetError( 1 , 0 , 1 )

            For $i = 1 To $iTotalB
                $string &= Chr( Random( 0 , 255 , 1 ) )
            Next

            FileWrite( 1 , $string )

        Case 2 ; dummy file with no data
            ; trancexx
            FileOpen( $fileSaveLoc , $mode + $binary )
            If @error = -1 Then SetError( 1 , 0 , 1 )

            FileSetPos( 1 , $iTotalB - 1 , 0 )

            FileWrite( 1 , Chr( 32 ) ) ; Chr( 32 ) = NUL

        Case 3 ; UNICODE data
            FileOpen( $fileSaveLoc , $mode + $utf16 )
            If @error = -1 Then SetError( 1 , 0 , 1 )

            For $i = 1 To $iTotalB
                $string &= ChrW( Random( 256 , 65535 , 1 ) )
            Next

            FileWrite( 1 , $string )
    EndSwitch

    FileClose( 1 )
EndFunc

Edited May 2, 2011 by LaCastiglione

[FuryCell]

Why the 1028 instead of 1024?

[jaberwacky]

lulz, that's why it wasn't coming out right, sheesh.

Thanks FuryCell!

[Ascend4nt]

If you just need a dummy file, period (without random #'s), you could easily quicken the routine by using a DLLStruct:

Func _FileCreateDummyInMB($sFilename,$iTotalMB)
    Local $stData=DllStructCreate("byte[1048576]"),$binData=DllStructGetData($stData,1)
    Local $hFile=FileOpen($sFilename,2)
    For $i=1 To $iTotalMB
        FileWrite($hFile,$binData)
    Next
    FileClose($hFile)
EndFunc

_FileCreateDummyInMB(@DesktopDir&"\dummyfile.bin",10)

[trancexx]

Or something like this:

Func _FileCreateDummyInMB($sFilename, $iTotalMB)
    Local $hFile = FileOpen($sFilename, 18)
    FileSetPos($hFile, $iTotalMB * 1048576 - 4, 0)
    FileWrite($hFile, 0)
    FileClose($hFile)
EndFunc

[Ascend4nt]

Very clever, trancexx. I didn't know you could set a position on a newly created file that is past the current position. Good to know

[jaberwacky]

Hmmm, what I use one of the two methods posted above to create a file of predetermined size. Then create a huge string that would fit snug into the file and just write it all at once?

Edited August 8, 2010 by jaberwocky6669

[FuryCell]

Hmmm, what I use one of the two methods posted above to create a file of predetermined size. Then create a huge string that would fit snug into the file and just write it all at once?

Depending on your definition of 'Huge' RAM usage might go through the roof.

[jaberwacky]

I always forget to take that into account.