Entonces, esta es una necesidad de nicho, pero recientemente fui parte de una discusión en la que un usuario quería recuperar algunos archivos que insistía que eran xlsx, pero se informó que Excel no era válido.
Proporcionó un archivo de muestra y estaba en lo cierto: Excel no lo abrió. Comencé a investigar y decidí examinar el archivo con más detalle y descubrí que NO era un archivo xlsx, independientemente de la extensión, de hecho era un archivo de video mp4.
Ahora, hice lo anterior manualmente y pensé si VBA podría hacer dicho análisis automáticamente.
Alerta de spoiler, la respuesta es sí. Sigue leyendo.
El concepto básico: firmas de archivos
La idea básica es que «la mayoría» de los archivos contienen una sección de «encabezado» (normalmente al comienzo del archivo) que incluye varios bits de información y normalmente incluye un identificador único que permite identificar el tipo de archivo.
Así que no se trata simplemente de mirar la extensión del archivo. Eso podría ser incorrecto. En lugar de ello, leemos parte del contenido real del archivo, el encabezado, y lo utilizamos para determinar correctamente el tipo de archivo.
El código
Entonces comencé a incursionar con VBA para leer esta sección de ‘encabezado’ y desglosar las distintas firmas de archivos.
A continuación se muestra mi primera prueba (probablemente el 80-85% del camino). Todavía quiero perfeccionar la identificación del documento de Office (sé que se puede hacer, sólo necesito tener tiempo para hacerlo), pero lo publicaré «tal cual» con la esperanza de que pueda ser útil para alguien más. Todavía es difícil, necesita un manejo adecuado de errores…, pero funciona.
Funciones auxiliares
Como es habitual, tengo un par de funciones auxiliares:
'Helper function to read a file's signature
Function GetFilesSignature(filePath As String) As String
Dim fileNum As Integer
Dim sSignature As String
fileNum = FreeFile
Open filePath For Binary Access Read As fileNum
'sSignature = Space$(16)
sSignature = Space$(500) 'increased significantly for files like .tar
Get fileNum, 1, sSignature
Close fileNum
GetFilesSignature = sSignature
End Function
' Helper function to convert binary string to hex for debugging
Function ConvertToHex(binaryStr As String) As String
Dim i As Integer
Dim hexStr As String
For i = 1 To Len(binaryStr)
hexStr = hexStr & " " & Right("0" & Hex(Asc(Mid(binaryStr, i, 1))), 2)
Next i
ConvertToHex = Trim(hexStr)
End FunctionProcedimientos principales
'Main function!
Function IdentifyFileType(ByVal filePath As String, _
ByRef sFileType As String, _
ByRef sFileExtension As String, _
ByRef sSignature As String, _
ByRef sHEXsSignature As String) As Boolean
Static vTestArray As Variant
Dim sTestHEXSignature As String
Dim sTestSignature As String
Dim lArrayRow As Long
Dim sOutput As String
Dim sTestSignatureStart As String
Dim sTestSignatureEnd As String
Dim lTestSignatureEndOffset As Long
sSignature = GetFilesSignature(filePath)
sHEXsSignature = ConvertToHex(sSignature)
'Debug.Print "File sSignature: '" & sSignature & "'", , sHEXsSignature
If IsEmpty(vTestArray) Then vTestArray = BuildTestArray 'Small performance boost
'vTestArray = BuildTestArray '*** For Development purposes
For lArrayRow = LBound(vTestArray, 1) To UBound(vTestArray, 1)
sTestSignature = vTestArray(lArrayRow, 0)
sTestHEXSignature = ConvertToHex(Mid(sSignature, vTestArray(lArrayRow, 3) + 1, UBound(Split(sTestSignature)) + 1))
If InStr(sTestSignature, "?") = 0 Then 'Most cases
'If Left(sHEXsSignature, Len(vTestArray(lArrayRow, 0))) = vTestArray(lArrayRow, 0) Then
If sTestHEXSignature = vTestArray(lArrayRow, 0) Then
sFileType = vTestArray(lArrayRow, 1)
sFileExtension = vTestArray(lArrayRow, 2)
Exit For
End If
Else 'Exceptions like webp, jpg, wav, avi, ... with patterns rather than a single signature
sTestSignatureStart = Left(sTestSignature, InStr(sTestSignature, "?") - 2)
sTestSignatureEnd = Mid(sTestSignature, InStrRev(sTestSignature, "?") + 2)
'sTestSignatureEndOffset = UBound(Split(Trim(Replace(Replace(sTestSignature, sTestSignatureStart, ""), sTestSignatureEnd, "")), " ")) + 1
lTestSignatureEndOffset = Len(Replace(Replace(sTestSignature, sTestSignatureStart, ""), sTestSignatureEnd, ""))
If Left(sTestHEXSignature, Len(sTestSignatureStart)) = sTestSignatureStart And Mid(sTestHEXSignature, Len(sTestSignatureStart) + lTestSignatureEndOffset + 1, Len(sTestSignatureEnd)) = sTestSignatureEnd Then
sFileType = vTestArray(lArrayRow, 1)
sFileExtension = vTestArray(lArrayRow, 2)
Exit For
End If
End If
Next lArrayRow
End Function
'Function to build an array of file signatures, this can further be expanded as I've just included 64 file types to date
'I used an array, but you could use a table, worksheet, ...
Function BuildTestArray() As Variant
Dim vFileSignatures(63, 3) As String ' 9->rows, 2->columns
Dim lCounter As Long
vFileSignatures(lCounter, 0) = "00 01 00 00 53 74 61 6E 64 61 72 64 20 4A 65 74 20 44 42"
vFileSignatures(lCounter, 1) = "Microsoft Access Database"
vFileSignatures(lCounter, 2) = "mdb"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "00 01 00 00 53 74 61 6E 64 61 72 64 20 41 43 45 20 44 42"
vFileSignatures(lCounter, 1) = "Microsoft Access 2007+ Database"
vFileSignatures(lCounter, 2) = "accdb"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "00 01 00 00 4D 53 49 53 41 4D 20 44 61 74 61 62 61 73 65"
vFileSignatures(lCounter, 1) = "Microsoft Money file"
vFileSignatures(lCounter, 2) = "mny"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "53 51 4C 69 74 65 20 66 6F 72 6D 61 74 20 33 00"
vFileSignatures(lCounter, 1) = "SQLite Database"
vFileSignatures(lCounter, 2) = "sqlitedb, sqlite, db"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "D0 CF 11 E0 A1 B1 1A E1"
vFileSignatures(lCounter, 1) = "Compound File Binary Format, a container format defined by Microsoft COM"
vFileSignatures(lCounter, 2) = "doc, xls, ppt, msi, msg"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "25 50 44 46 2D"
vFileSignatures(lCounter, 1) = "PDF document"
vFileSignatures(lCounter, 2) = "pdf"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "7B 5C 72 74 66 31"
vFileSignatures(lCounter, 1) = "Rich Text Format"
vFileSignatures(lCounter, 2) = "rtf"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "52 65 63 65 69 76 65 64 3A"
vFileSignatures(lCounter, 1) = "Email Message var5"
vFileSignatures(lCounter, 2) = "eml"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "21 42 44 4E"
vFileSignatures(lCounter, 1) = "Microsoft Outlook Personal Storage Table file"
vFileSignatures(lCounter, 2) = "pst"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "25 21 50 53 2D 41 64 6F 62 65 2D 33 2E 30 20 45 50 53 46 2D 33 2E 30"
vFileSignatures(lCounter, 1) = "Encapsulated PostScript file version 3.0"
vFileSignatures(lCounter, 2) = "eps, epsf"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "25 21 50 53 2D 41 64 6F 62 65 2D 33 2E 31 20 45 50 53 46 2D 33 2E 30"
vFileSignatures(lCounter, 1) = "Encapsulated PostScript file version 3.1"
vFileSignatures(lCounter, 2) = "eps, epsf"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "49 54 53 46 03 00 00 00 60 00 00 00"
vFileSignatures(lCounter, 1) = "MS Windows HtmlHelp Data"
vFileSignatures(lCounter, 2) = "chm"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "3F 5F"
vFileSignatures(lCounter, 1) = "Windows 3.x/95/98 Help file"
vFileSignatures(lCounter, 2) = "hlp"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "25 21 50 53"
vFileSignatures(lCounter, 1) = "PostScript document"
vFileSignatures(lCounter, 2) = "ps"
vFileSignatures(lCounter, 3) = 0
' Images
' //////////////////////////////////////////////////////////////////////////////
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "42 4D"
vFileSignatures(lCounter, 1) = "BMP file, a bitmap format used mostly in the Windows world"
vFileSignatures(lCounter, 2) = "bmp, dib"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "47 49 46 38 37 61"
vFileSignatures(lCounter, 1) = "Image file encoded in the Graphics Interchange Format (GIF87a)"
vFileSignatures(lCounter, 2) = "gif"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "47 49 46 38 39 61"
vFileSignatures(lCounter, 1) = "Image file encoded in the Graphics Interchange Format (GIF89a)"
vFileSignatures(lCounter, 2) = "gif"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "66 74 79 70 68 65 69 63"
vFileSignatures(lCounter, 1) = "High Efficiency Image Container (HEIC)"
vFileSignatures(lCounter, 2) = "heic"
vFileSignatures(lCounter, 3) = 4
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "00 00 01 00"
vFileSignatures(lCounter, 1) = "Computer icon encoded in ICO file format"
vFileSignatures(lCounter, 2) = "ico"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "FF D8 FF DB"
vFileSignatures(lCounter, 1) = "JPEG raw or in the JFIF or Exif file format"
vFileSignatures(lCounter, 2) = "jpg"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "FF D8 FF E0 00 10 4A 46 49 46 00 01"
vFileSignatures(lCounter, 1) = "JPEG raw or in the JFIF or Exif file format"
vFileSignatures(lCounter, 2) = "jpg"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "FF D8 FF EE"
vFileSignatures(lCounter, 1) = "JPEG raw or in the JFIF or Exif file format"
vFileSignatures(lCounter, 2) = "jpg"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "FF D8 FF E1 ?? ?? 45 78 69 66 00 00"
vFileSignatures(lCounter, 1) = "JPEG raw or in the JFIF or Exif file format"
vFileSignatures(lCounter, 2) = "jpg"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "FF D8 FF E0"
vFileSignatures(lCounter, 1) = "JPEG raw or in the JFIF or Exif file format"
vFileSignatures(lCounter, 2) = "jpg"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "00 00 00 0C 6A 50 20 20 0D 0A 87 0A"
vFileSignatures(lCounter, 1) = "JPEG 2000 format"
vFileSignatures(lCounter, 2) = "jp2, j2k, jpf, jpm, jpg2, j2c, jpc, jpx, mj2"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "4F 67 67 53"
vFileSignatures(lCounter, 1) = "Ogg, an open source media container format"
vFileSignatures(lCounter, 2) = "ogg, oga, ogv"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "89 50 4E 47 0D 0A 1A 0A"
vFileSignatures(lCounter, 1) = "Image encoded in the Portable Network Graphics format"
vFileSignatures(lCounter, 2) = "png"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "38 42 50 53"
vFileSignatures(lCounter, 1) = "Photoshop Document file, Adobe Photoshop's native file format"
vFileSignatures(lCounter, 2) = "psd"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "49 49 2A 00"
vFileSignatures(lCounter, 1) = "Tagged Image File Format (TIFF - little-endian)"
vFileSignatures(lCounter, 2) = "tif, tiff"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "4D 4D 00 2A"
vFileSignatures(lCounter, 1) = "Tagged Image File Format (TIFF - big-endian)"
vFileSignatures(lCounter, 2) = "tif, tiff"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "49 49 2B 00"
vFileSignatures(lCounter, 1) = "BigTIFF (little-endian)"
vFileSignatures(lCounter, 2) = "tif, tiff"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "4D 4D 00 2B"
vFileSignatures(lCounter, 1) = "BigTIFF (big-endian)"
vFileSignatures(lCounter, 2) = "tif, tiff"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "52 49 46 46 ?? ?? ?? ?? 57 45 42 50"
vFileSignatures(lCounter, 1) = "Google WebP image file"
vFileSignatures(lCounter, 2) = "webp"
vFileSignatures(lCounter, 3) = 0
' Audio
' //////////////////////////////////////////////////////////////////////////////
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "66 4C 61 43"
vFileSignatures(lCounter, 1) = "Free Lossless Audio Codec"
vFileSignatures(lCounter, 2) = "flac"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "4D 54 68 64"
vFileSignatures(lCounter, 1) = "MIDI sound file"
vFileSignatures(lCounter, 2) = "mid, midi"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "FF FB"
vFileSignatures(lCounter, 1) = "MPEG-1 Layer 3 file without an ID3 tag or with an ID3v1 tag (which is appended at the end of the file)"
vFileSignatures(lCounter, 2) = "mp3"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "FF F3"
vFileSignatures(lCounter, 1) = "MPEG-1 Layer 3 file without an ID3 tag or with an ID3v1 tag (which is appended at the end of the file)"
vFileSignatures(lCounter, 2) = "mp3"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "FF F2"
vFileSignatures(lCounter, 1) = "MPEG-1 Layer 3 file without an ID3 tag or with an ID3v1 tag (which is appended at the end of the file)"
vFileSignatures(lCounter, 2) = "mp3"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "49 44 33"
vFileSignatures(lCounter, 1) = "MP3 file with an ID3v2 container "
vFileSignatures(lCounter, 2) = "mp3"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "52 49 46 46 ?? ?? ?? ?? 57 41 56 45"
vFileSignatures(lCounter, 1) = "Waveform Audio File Format"
vFileSignatures(lCounter, 2) = "wav"
vFileSignatures(lCounter, 3) = 0
' Video
' //////////////////////////////////////////////////////////////////////////////
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "52 49 46 46 ?? ?? ?? ?? 41 56 49 20"
vFileSignatures(lCounter, 1) = "Audio Video Interleave video format"
vFileSignatures(lCounter, 2) = "avi"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "46 4C 56"
vFileSignatures(lCounter, 1) = "Flash Video file"
vFileSignatures(lCounter, 2) = "flv"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "66 74 79 70 69 73 6F 6D"
vFileSignatures(lCounter, 1) = "ISO Base Media file (MPEG-4)"
vFileSignatures(lCounter, 2) = "mp4"
vFileSignatures(lCounter, 3) = 4
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "66 74 79 70 4D 53 4E 56"
vFileSignatures(lCounter, 1) = "MPEG-4 video file"
vFileSignatures(lCounter, 2) = "mp4"
vFileSignatures(lCounter, 3) = 4
lCounter = lCounter + 1 'generic entry until I figure out other isom values
vFileSignatures(lCounter, 0) = "66 74 79 70"
vFileSignatures(lCounter, 1) = "MPEG-4 video file"
vFileSignatures(lCounter, 2) = "mp4"
vFileSignatures(lCounter, 3) = 4
' Archives
' //////////////////////////////////////////////////////////////////////////////
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "37 7A BC AF 27 1C"
vFileSignatures(lCounter, 1) = "7-Zip File Format"
vFileSignatures(lCounter, 2) = "7z"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "42 5A 68"
vFileSignatures(lCounter, 1) = "Compressed file using Bzip2 algorithm"
vFileSignatures(lCounter, 2) = "gbz2"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "1F 8B"
vFileSignatures(lCounter, 1) = "GZIP compressed file"
vFileSignatures(lCounter, 2) = "gz, tar.gz"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "4C 5A 49 50"
vFileSignatures(lCounter, 1) = "lzip compressed file"
vFileSignatures(lCounter, 2) = "lz"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "52 61 72 21 1A 07 00"
vFileSignatures(lCounter, 1) = "Roshal ARchive compressed archive v1.50 onwards"
vFileSignatures(lCounter, 2) = "rar"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "52 61 72 21 1A 07 01 00"
vFileSignatures(lCounter, 1) = "Roshal ARchive compressed archive v5.00 onwards"
vFileSignatures(lCounter, 2) = "rar"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "75 73 74 61 72 00 30 30"
vFileSignatures(lCounter, 1) = "tar archive"
vFileSignatures(lCounter, 2) = "tar"
vFileSignatures(lCounter, 3) = 257
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "75 73 74 61 72 20 20 00"
vFileSignatures(lCounter, 1) = "tar archive"
vFileSignatures(lCounter, 2) = "tar"
vFileSignatures(lCounter, 3) = 257
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "50 4B 03 04"
vFileSignatures(lCounter, 1) = "zip file format and formats based on it, such as EPUB, JAR, ODF, OOXML"
vFileSignatures(lCounter, 2) = "zip"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "50 4B 05 06"
vFileSignatures(lCounter, 1) = "zip file format and formats based on it, such as EPUB, JAR, ODF, OOXML (empty archive)"
vFileSignatures(lCounter, 2) = "zip"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "50 4B 07 08"
vFileSignatures(lCounter, 1) = "zip file format and formats based on it, such as EPUB, JAR, ODF, OOXML (spanned archive)"
vFileSignatures(lCounter, 2) = "zip"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "4D 53 43 46"
vFileSignatures(lCounter, 1) = "Microsoft Cabinet file"
vFileSignatures(lCounter, 2) = "cab"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "49 53 63 28"
vFileSignatures(lCounter, 1) = "InstallShield CAB Archive File"
vFileSignatures(lCounter, 2) = "cab"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "3C 3C 3C 20 4F 72 61 63 6C 65 20 56 4D 20 56 69 72 74 75 61 6C 42 6F 78 20 44 69 73 6B 20 49 6D 61 67 65 20 3E 3E 3E"
vFileSignatures(lCounter, 1) = "VirtualBox Virtual Hard Disk file format"
vFileSignatures(lCounter, 2) = "vdi"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "63 6F 6E 65 63 74 69 78"
vFileSignatures(lCounter, 1) = "Windows Virtual PC Virtual Hard Disk file format"
vFileSignatures(lCounter, 2) = "vhd"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "4B 44 4D"
vFileSignatures(lCounter, 1) = "VMDK files"
vFileSignatures(lCounter, 2) = "vmdk"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "23 20 44 69 73 6B 20 44 65 73 63 72 69 70 74 6F"
vFileSignatures(lCounter, 1) = "VMware 4 Virtual Disk description file (split disk)"
vFileSignatures(lCounter, 2) = "vmdk"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "00 01 00 00 00"
vFileSignatures(lCounter, 1) = "TrueType font"
vFileSignatures(lCounter, 2) = "ttf, tte, dfont"
vFileSignatures(lCounter, 3) = 0
lCounter = lCounter + 1
vFileSignatures(lCounter, 0) = "4F 54 54 4F"
vFileSignatures(lCounter, 1) = "OpenType font"
vFileSignatures(lCounter, 2) = "otf"
vFileSignatures(lCounter, 3) = 0
BuildTestArray = vFileSignatures
End FunctionEjemplo de uso
A continuación se muestra un ejemplo sencillo de cómo se puede utilizar el código anterior.
Sub Test()
Dim sFileType As String
Dim sFileExtension As String
Dim sSignature As String
Dim sHEXsSignature As String
Const sFile = "C:\temp\img01.jpg"
Call IdentifyFileType(sFile, sFileType, sFileExtension, sSignature, sHEXsSignature)
Debug.Print sFile, sFileType, sFileExtension
Debug.Print
Debug.Print sSignature
Debug.Print
Debug.Print sHEXsSignature
End Sub
