How to determine file type from header record?

[8MaRk4]

I need to search all files on a netware server for a particular file type, ie WordPerfect files, however there are a number of these files which do not have the .wpd extension. Is there a way to read the file header record and test for the file type?

Mark.

 

[chiph]

If you know the format of WordPerfect files, you can certainly read x bytes and try and determine if the file is a match or not.

Chip H.

 

[Alt255]

I believe that WordPerfect files begin with an ASCII 255 followed by "WPC" (I kinda like that...). You might have decent results if you....
[tt]
Search$ = Chr$(255) & "WPC"
Test$ = String$(4, 0)
ff = FreeFile
Fi$ = "C:\MyFile.WPG"
Open Fi$ For Binary As #ff
Get #ff, 1, Test$
Close #ff
If Search$ = Test$ Then
MsgBox "This is a WordPerfect file."
End If
[/tt]

 

[8MaRk4]

Thanks Chip, I guess my question is a bit more basic. How would I manage to read the header record in the first place is what I am trying to determine. Any suggestions?

Mark.

 

[8MaRk4]

Thanks Alt255, That is exactly what I needed. Works great!

 

[chiph]

Do like Alt255 suggests and open the file as binary. Read the first 4 bytes to see if they're equal to hex 255, followed by "WPC". You can easily do this by reading a Long (a 4-byte value), and comparing it to:
[tt]
255[tab]= &hff x 16777216 = 4278190080
W [tab]= &h57 x 65536 = 5701632
P [tab]= &h50 x 256 = 20480
C [tab]= &h43 x 1 = 67
---------------
= 4283912259
[/tt]
But since VB only knows about signed Longs, that becomes:
-2136428612

Complicated, but it will make things faster.

Chip H.

 

[Alt255]

Interesting. I had always assumed that the VB Get statement would retrieve a 4-byte string at the same approximate speed as a 4-byte number.

In any case, reading a string may allow a slight advantage by providing additional information:

Test$ = String$(10, 0)
ff = FreeFile
Fi$ = "c:\MyFile.doc"
Open Fi$ For Binary As #ff
Get #ff, 1, Test$
Close #ff
If Left$(Test$, 4) <> Chr$(255) & &quot;WPC&quot; Then
    Exit Sub
End If
FileType% = Asc(Right$(Test$, 1))
Select Case FileType%
    Case 1: Ret$ = &quot;macro file&quot;
    Case 2: Ret$ = &quot;help file&quot;
    Case 3: Ret$ = &quot;keyboard definition file&quot;
    Case 10: Ret$ = &quot;document file&quot;
    Case 11: Ret$ = &quot;dictionary file&quot;
    Case 12: Ret$ = &quot;thesaurus file&quot;
    Case 13: Ret$ = &quot;block&quot;
    Case 14: Ret$ = &quot;rectangular block&quot;
    Case 15: Ret$ = &quot;column block&quot;
    Case 16: Ret$ = &quot;printer resource file&quot;
    Case 17: Ret$ = &quot;setup file&quot;
    Case 18: Ret$ = &quot;prefix information file&quot;
    Case 19: Ret$ = &quot;printer resource file&quot;
    Case 20: Ret$ = &quot;display resource file&quot;
    Case 21: Ret$ = &quot;overlay file&quot;
    Case 22: Ret$ = &quot;graphics file&quot;
    Case 23: Ret$ = &quot;hyphenation code module&quot;
    Case 24: Ret$ = &quot;hyphenation data module&quot;
    Case 25: Ret$ = &quot;macro resource file&quot;
    Case 26: Ret$ = &quot;graphics driver&quot;
    Case 27: Ret$ = &quot;hyphenation lex module&quot;
    Case Else: Ret$ = &quot;(??) WordPerfect file&quot;
End Select
MsgBox Fi$ & &quot; is a &quot; & Ret$ & &quot;.&quot;

Naturally, in the absence of a requirement for additional information, the fastest way is the way to go.