[TUTORIAL] Extern: Uso de la libreria C TagLib, id3.module, libtag_c, TagLib

Código:
' Gambas module file



Export

Library "libtag_c"



Public Struct TagLib_File

  dummy As Integer

End Struct



Public Struct TagLib_Tag

  dummy As Integer

End Struct



Public Struct TagLib_AudioProperties

  dummy As Integer

End Struct



' void taglib_set_strings_unicode(BOOL unicode)

' By default all strings coming into or out of TagLib's C API are in UTF8.

' However, it may be desirable For TagLib To operate On Latin1(ISO - 8859 - 1) strings In which Case this should be set To FALSE.

Private Extern taglib_set_strings_unicode(unicode As Boolean)



' TagLib_File *taglib_file_new_type(const char *filename)

' Creates a TagLib file based on \a filename.

Private Extern taglib_file_new(filename As String) As TagLib_File



' TagLib_Tag *taglib_file_tag(const TagLib_File *file)

' Returns a pointer to the tag associated with this file.

Private Extern taglib_file_tag(_file As TagLib_File) As TagLib_Tag



' char *taglib_tag_title(const TagLib_Tag *tag)

' Returns a string with this tag's title.

Private Extern taglib_tag_title(tag As TagLib_Tag) As String



' char *taglib_tag_artist(const TagLib_Tag *tag)

' Returns a string with this tag's artist.

Private Extern taglib_tag_artist(tag As TagLib_Tag) As String



' char *taglib_tag_album(const TagLib_Tag *tag)

' Returns a string with this tag's album name.

Private Extern taglib_tag_album(tag As TagLib_Tag) As String



' unsigned int taglib_tag_year(const TagLib_Tag *tag)

' Returns the tag's year or 0 if year is not set.

Private Extern taglib_tag_year(tag As TagLib_Tag) As Integer



' char *taglib_tag_comment(const TagLib_Tag *tag)

' Returns a string with this tag's comment.

Private Extern taglib_tag_comment(tag As TagLib_Tag) As String



' unsigned int taglib_tag_track(const TagLib_Tag *tag)

' Returns the tag's track number or 0 if track number is not set.

Private Extern taglib_tag_track(tag As TagLib_Tag) As Integer



'Private Extern taglib_tag_encoder(tag As TagLib_Tag) As String

'Private Extern taglib_tag_volume_number(tag As TagLib_Tag) As Integer



' char *taglib_tag_genre(const TagLib_Tag *tag)

' Returns a string with this tag's genre.

Private Extern taglib_tag_genre(tag As TagLib_Tag) As String



' const TagLib_AudioProperties *taglib_file_audioproperties(const TagLib_File *file)

' Returns a pointer to the the audio properties associated with this file.

Private Extern taglib_file_audioproperties(_file As TagLib_File) As TagLib_AudioProperties



' int taglib_audioproperties_length(const TagLib_AudioProperties *audioProperties)

' Returns the length of the file in seconds.

Private Extern taglib_audioproperties_length(audioProperties As TagLib_AudioProperties) As Integer



' int taglib_audioproperties_bitrate(const TagLib_AudioProperties *audioProperties)

' Returns the bitrate of the file in kb/s.

Private Extern taglib_audioproperties_bitrate(audioProperties As TagLib_AudioProperties) As Integer



' int taglib_audioproperties_samplerate(const TagLib_AudioProperties *audioProperties)

' Returns the sample rate of the file in Hz.

Private Extern taglib_audioproperties_samplerate(audioProperties As TagLib_AudioProperties) As Integer



' int taglib_audioproperties_channels(const TagLib_AudioProperties *audioProperties)

' Returns the number of channels in the audio stream.

Private Extern taglib_audioproperties_channels(audioProperties As TagLib_AudioProperties) As Integer



' void taglib_tag_free_strings(void)

' Frees all of the strings that have been created by the tag.

Private Extern taglib_tag_free_strings()



' void taglib_file_free(TagLib_File *file)

' Frees and closes the file.

Private Extern taglib_file_free(_file As TagLib_File)



Public Function Info(fileaudio As String) As Collection



  Dim fl As TagLib_File

  Dim autag As TagLib_Tag

  Dim auprop As TagLib_AudioProperties

  '  Dim secondi, minuti As Integer

  '

  Dim inf As New Collection



  taglib_set_strings_unicode(False)

  taglib_set_strings_unicode(True)



  fl = taglib_file_new(fileaudio)

  If IsNull(fl) Then Error.Raise("Impossibile caricare il file audio: " & fileaudio)



  autag = taglib_file_tag(fl)

  If IsNull(autag) Then Error.Raise("Impossibile ottenere i tag dal file audio: " & fileaudio)



  inf.Add(taglib_tag_album(autag), "album")

  inf.Add(taglib_tag_artist(autag), "artist")

  inf.Add(taglib_tag_track(autag), "track")

  inf.Add(taglib_tag_title(autag), "title")

  inf.Add(taglib_tag_year(autag), "year")

  inf.Add(taglib_tag_genre(autag), "genre")

  inf.Add(taglib_tag_comment(autag), "comment")



  inf.Add(File.Ext(fileaudio), "format")



  ' Mostra le proprietà del file audio:

  auprop = taglib_file_audioproperties(fl)



  If IsNull(auprop) Then

    inf.Add(True, "audioerror")

  Else

    inf.Add(taglib_audioproperties_length(auprop), "length")

    inf.Add(taglib_audioproperties_bitrate(auprop), "bitrate")

    inf.Add(taglib_audioproperties_samplerate(auprop), "frequency")

    inf.Add(taglib_audioproperties_channels(auprop), "channels")

  Endif

  inf.Add(taglib_tag_comment(autag), "comment")

  ' Va in chiusura:

  taglib_tag_free_strings()

  taglib_file_free(fl)



  Return inf



End