README.md

December 5, 2022 · View on GitHub

Determine file format using file header, ignoring the extension

Description

Determines the filetype (PE Executable, GIF Image, Word Document, etc) using the file header/contents, as opposed to using the file extension. Supported types: PE Executable, INI File, AVI Movie, WAV Audio, Word document, Access database, GIF Image, MP3 audio, BMP image, TIFF image, ZIP archive, ARJ archive, RAR archive, HTML/HTA docs, JPEG image, Visual Basic files. If it can't determine the filetype, itll try and determine if the file is text or binary.

More Info

Public Function GetFileType(xFile As String)

'xFile is the full path:\filename of the file to test.

Returns a string indicating the filetype, or if the file is an unknown text or unknown binary file.


Submitted On
By	Detonate
Level	Beginner
User Rating	4.4 (22 globes from 5 users)
Compatibility	VB 3.0, VB 4.0 (16-bit), VB 4.0 (32-bit), VB 5.0, VB 6.0, VB Script, ASP (Active Server Pages)
Category	Files/ File Controls/ Input/ Output
World	Visual Basic
Archive File

Source Code

Public Function GetFileType(xFile As String) As String
On Error Resume Next
Dim ID As String * 300
If Dir$(xFile) = "" Then
  GetFileType = "NOT FOUND"
  Exit Function
End If
Open xFile For Binary Access Read As #1
 Get #1, 1, ID
Close #1
If Left(ID, 2) = "MZ" Or Left(ID, 2) = "ZM" Then
  GetFileType = "PE Executable"
  Exit Function
ElseIf Left(ID, 1) = "[" And InStr(1, Left(ID, 100), "]") > 0 Then
  GetFileType = "INI File"
  Exit Function
ElseIf Mid(ID, 9, 8) = "AVI LIST" Then
  GetFileType = "AVI Movie File"
  Exit Function
ElseIf Left(ID, 4) = "RIFF" Then
  GetFileType = "WAV Audio File"
  Exit Function
ElseIf Left(ID, 4) = Chr(208) & Chr(207) & Chr(17) & Chr(224) Then
  GetFileType = "Microsoft Word Document"
  Exit Function
ElseIf Mid(ID, 5, 15) = "Standard Jet DB" Then
  GetFileType = "Microsoft Access Database"
  Exit Function
ElseIf Left(ID, 3) = "GIF" Or InStr(1, ID, "GIF89") > 0 Then
  GetFileType = "GIF Image File"
  Exit Function
ElseIf Left(ID, 1) = Chr(255) And Mid(ID, 5, 1) = Chr(0) Then
  GetFileType = "MP3 Audio File"
  Exit Function
ElseIf Left(ID, 2) = "BM" Then
  GetFileType = "BMP (Bitmap) Image File"
  Exit Function
ElseIf Left(ID, 3) = "II*" Then
  GetFileType = "TIFF Image File"
  Exit Function
ElseIf Left(ID, 2) = "PK" Then
  GetFileType = "ZIP Archive File"
  Exit Function
ElseIf InStr(1, LCase(ID), "<html>") > 0 Or InStr(1, LCase(ID), "<!doctype") > 0 Then
  GetFileType = "HTML Document File"
  Exit Function
ElseIf UCase(Left(ID, 3)) = "RAR" Then
  GetFileType = "RAR Archive File"
  Exit Function
ElseIf Left(ID, 2) = Chr(96) & Chr(234) Then
  GetFileType = "ARJ Archive File"
  Exit Function
ElseIf Left(ID, 3) = Chr(255) & Chr(216) & Chr(255) Then
  GetFileType = "JPEG Image File"
  Exit Function
ElseIf InStr(1, ID, "Type=") > 0 And InStr(1, ID, "Reference=") > 0 Then
  GetFileType = "Visual Basic Project File"
  Exit Function
ElseIf Left(ID, 8) = "VBGROUP " Then
  GetFileType = "Visual Basic Group Project File"
  Exit Function
ElseIf Left(ID, 8) = "VERSION " & InStr(1, ID, vbCrLf & "Begin") > 0 Then
  GetFileType = "Visual Basic Form File"
  Exit Function
Else
 'Unknown file... make a weak attempt to determine if the file is text or binary
 If InStr(1, ID, Chr$(255)) > 0 Or InStr(1, ID, Chr$(1)) > 0 Or InStr(1, ID, Chr$(2)) > 0 Or InStr(1, ID, Chr$(3)) > 0 Then
  GetFileType = "Unknown binary file"
 Else
  GetFileType = "Unknown text file"
 End If
 Exit Function
End If
End Function