Re: Extern libmagic output like command File?

[T Lee Davidson <t.lee.davidson@xxxxxxxxx>]

On 9/16/24 09:41, System64 Development wrote:
> Hello
>
> Take the libmagic example from the Italian forum [1] to convert it into a class that returns the file type.
>
> It works, more or less because it returns the file type [2] but not like the file command does [3].
>
> The question: Could someone tell me how to get the same output of the file command but with libmagic?
>
> Regards.
>
> Martin.
>
> [1] https://www.gambas-it.org/wiki/index.php/Conoscere_il_mime-type_di_un_file_mediante_le_funzioni_esterne_del_API_di_libmagic
>
> [2] image/vnd.dwg; charset=binary
>
> [3] "DWG AutoDesk AutoCAD 2018/2019/2020"
>
> ' Gambas class file
>
> Export
>
> Library "libmagic:1"
>
> Private MAGIC_MIME_TYPE As Integer = &10
> Private MAGIC_MIME_ENCODING As Integer = &400
> Private MAGIC_MIME As Integer = MAGIC_MIME_TYPE Or MAGIC_MIME_ENCODING
>
> ' magic_t magic_open(int)
> ' Creates a magic cookie pointer and returns it.
> Private Extern magic_open(mg As Integer) As Pointer
>
> ' int magic_load(magic_t, const char *)
> ' Loads the the colon separated list of database files passed in as file name.
> Private Extern magic_load(magic_t As Pointer, filename As String) As Integer
>
> ' const char *magic_file(magic_t, const char *)
> ' Returns a textual description of the contents of the file.
> Private Extern magic_file(magic_t As Pointer, filename As String) As String
>
> ' void magic_close(magic_t)
> ' Closes the magic database and deallocates any resources used.
> Private Extern magic_close(magic_t As Pointer)
>
> Property Version As String
>
> Private $Version As String
>
> Private Function Version_Read() As String
>
>    Return $Version
>
> End
>
> Private Sub Version_Write(Value As String)
>
>    Dim magic As Pointer
>    Dim err As Integer
>
>    If Exist(Value) Then
>      If Stat(Value).Type = gb.File Then
>        magic = magic_open(MAGIC_MIME)
>        If magic == 0 Then Error.Raise("Impossibile inizializzare la libreria 'magic' !")
>        err = magic_load(magic, Null)
>        If err <> 0 Then
>          ChiudeMagic(magic)
>          Error.Raise("Impossibile caricare il database di 'magic' !")
>        Endif
>        $Version = magic_file(magic, Value)
>        ChiudeMagic(magic)
>      Endif
>    Endif
>
> End
>
> Private Procedure ChiudeMagic(mgc As Pointer)
>
>    magic_close(mgc)
>
> End

Try it with MAGIC_NONE. Also, magic_close frees the string pointer which turns the string stored in $Version to garbage.

[code]
' Gambas module file

Library "libmagic:1"

Public Extern MagicOpen(iFlags As Integer) As Pointer Exec "magic_open"
Public Extern MagicLoad(pMagic As Pointer, sFilename As String) As Exec "magic_load"
Public Extern MagicFile(pMagic As Pointer, sFilename As String) As String Exec "magic_file"
Public Extern MagicClose(pMagic As Pointer) Exec "magic_close"
Public Extern MagicError(pMagic As Pointer) As String Exec "magic_error"


Public Sub Main()

  Dim sPath As String = "filename.dwg"
  Dim pMagic As Pointer
  Dim sContentType, sContentTypeStatic As String

  pMagic = MagicOpen(0) 'MAGIC_NONE
  MagicLoad(pMagic, Null)
  sContentType = MagicFile(pMagic, sPath)
  If IsNull(sContentType) Then
    Print "error"
    Quit
  Endif

  For x As Integer = 0 To Len(sContentType) - 1
    sContentTypeStatic &= sContentType[x]
  Next
  MagicClose(pMagic)

  Print sContentTypeStatic

End
[/code]


--
Lee

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