Binary or Text file?

[josemauricio]

Hey guys!

How can I know if a file is a binary or a text file?

Thanx.

Zé Maurício.

 

[chiph]

There's no reliable way to determine this.

The file could be a UTF-8 Unicode file with a byte-order-mark (three byte flag) at the front of it, and that could cause you to think it's a binary file, when it really is text, just not plain ascii text.

A technique I've seen used is to scan through the first 1000 bytes, counting up printable characters vs. non-printing characters (carriage-returns, etc fall into the non-printing category). You'd then decide on a percentage of non-printing characters to mark your tipping point -- above that quantity, the file is assumed to be binary. Below that amount, you assume it's text.

Chip H.


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[kevinf2349]

Would just checking the file extension give you what you want? If so I use

Dim filename as String

Filename = "test.txt"

filename = filename.Substring(filename.LastIndexOf(".") + 1, filename.Length - filename.LastIndexOf(".") - 1)
filename = filename.ToUpper
Select Case filename
Case "TXT"
Binary = False
Return
Case Else
Binary = True
Return
End Select

 

[josemauricio]

Thank you both for reply!!

Kevin, I'd like to know the sort of data of the file. htm, xml, txt, and others are text files extensions.

José Maurício.

 

[kevinf2349]

Thats fine just add another CASE for those that you know are text. i.e

Case "HTML"
Binary = False
Return
Case "XML"
Binary = False
Return
Case "HTM"
Binary = False
Return

etc.