File Coverage

blib/lib/MP3/TAG/ID3v1.pm

Criterion	Covered	Total	%
statement	52	111	46.8
branch	13	44	29.5
condition	4	12	33.3
subroutine	8	13	61.5
pod	5	8	62.5
total	82	188	43.6

package MP3::TAG::ID3v1;

# reads ID3v1 and ID3v1.1 mp3-tags
# writes ID3v1.1 mp3-tags

use strict;
use vars qw /@mp3_genres @winamp_genres $AUTOLOAD %ok_length/;
# allowed fields in ID3v1.1 and max length of this fields (expect for track and genre which are coded later)
%ok_length = (song => 30, artist => 30, album => 30, comment => 28, track => 3, genre => 30, year=>4, genreID=>1);

=pod

=head1 NAME

MP3::TAG::ID3v1 - Perl extension for reading / writing ID3v1 tags of mp3-files

=head1 SYNOPSIS

MP3::TAG::ID3v2 is designed to be called from the MP3::Tag module.
It then returns a ID3v2-tag-object, which can be used in a users
program.

  use MP3::TAG::ID3v1;
  $id3v1 = MP3::TAG::ID3v1->new($mp3obj);

C<$mp3obj> is a object from MP3::Tag. See according documentation.
C<$tag> is undef when no tag is found in the C<$mp3obj>.

* Reading the tag

    print "   Song: " .$id3v1->song . "\n";
    print " Artist: " .$id3v1->artist . "\n";
    print "  Album: " .$id3v1->album . "\n";
    print "Comment: " .$id3v1->comment . "\n";
    print "   Year: " .$id3v1->year . "\n";
    print "  Genre: " .$id3v1->genre . "\n";
    print "  Track: " .$id3v1->track . "\n";
    @tagdata = $mp3->all();
    foreach (@tagdata) {
      print $_;
    }

* Changing / Writing the tag

      $id3v1->comment("This is only a Test Tag");
      $id3v1->song("testing");
      $id3v1->artist("Artest");
      $id3v1->album("Test it");
      $id3v1->year("1965");
      $id3v1->track("5");
      $id3v1->genre("Blues");
      # or at once
      $id3v1->all("song title","artist","album","1900","comment",10,"Ska");#
      $id3v1->writeTag;

=head1 AUTHOR

Thomas Geffert, [e-mail]

=head1 DESCRIPTION

=item new()

  $id3v1 = MP3::TAG::ID3v1->new($mp3obj[, $create]);

Generally called from MP3::TAG, because a $mp3obj is needed.
If $create is true, a new tag is created. Otherwise undef is
returned, if now ID3v1 tag is found in the $mp3obj.

=cut

# create a ID3v1 object
sub new {
  my ($class, $mp3obj, $create) = @_;
  my $self={mp3=>$mp3obj};
  my $buffer;

  if (defined $create && $create) {
    $self->{new} = 1;
  } else {
    $mp3obj->seek(-128,2);
    $mp3obj->read(\$buffer, 128);
  }

  if ($create || substr ($buffer,0,3) eq "TAG") {
    bless $self, $class;
    $self->readTag($buffer);

    return $self;
  } else {
    return undef;
  }
}

=pod

=item song(), artist(), album(), year(), comment(), track(), genre()

  $artist  = $id3v1->artist;
  $artist  = $id3v1->artist($artist);
  $album   = $id3v1->album;
  $album   = $id3v1->album($album);
  $year    = $id3v1->year;
  $year    = $id3v1->year($year);
  $comment = $id3v1->comment;
  $comment = $id3v1->comment($comment);
  $track   = $id3v1->track;
  $track   = $id3v1->track($track);
  $genre   = $id3v1->genre;
  $genre   = $id3v1->genre($genre);

Use these functions to retrieve the date of these fields,
or to set the data.

$genre can be a string with the name of the genre, or a number
describing the genre.

=cut

sub AUTOLOAD {
  my $self = shift;
  my $attr = $AUTOLOAD;

  # is it an allowed field
  $attr =~ s/.*:://;
  return unless $attr =~ /[^A-Z]/;
  warn "invalid field: ->$attr()" unless $ok_length{$attr};

  if (my $new = shift) {
    $new =~ s/ *$//;
    $new = substr  $new, 0, $ok_length{$attr};
    if ($attr eq "genre") {
      if ($new =~ /^\d+$/) {
	$self->{genreID} = $new;
      } else {
	$self->{genreID} = genre2id($new);
      }
      $new = id2genre($self->{genreID});
    }
    $self->{$attr}=$new;
    $self->{changed} = 1;
  }
  return $self->{$attr};
}

=pod

=item all()

  @tagdata = $id3v1->all;
  @tagdata = $id3v1->all($song, $artist, $album, $year, $comment, $track, $genre);

Returns all information of the tag in a list.
You can use this sub also to set the data of the complete tag.

The order of the data is always song, artist, album, year, comment, track, and  genre.
genre has to be a string with the name of the genre, or a number identifying the genre.

=cut

sub all {
  my $self=shift;
  if ($#_ == 6) {
    my $new;
    for (qw/song artist album year comment track genre/) {
      $new = shift;
      $new =~ s/ *$//;
      $new = substr  $new, 0, $ok_length{$_};
      $self->{$_}=$new;
    }
    if ($self->{genre} =~ /^\d+$/) {
      $self->{genreID} = $self->{genre};
    } else {
      $self->{genreID} = genre2id($self->{genre});
    }
    $self->{genre} = id2genre($self->{genreID});
    $self->{changed} = 1;
  }
  return ($self->{song},$self->{artist},$self->{album},
	  $self->{year},$self->{genre},
	  $self->{track}, $self->{comment});
}

=pod

=item writeTag()

  $id3v1->writeTag;

Writes the ID3v1 tag to the file.

=cut

sub writeTag {
  my $self = shift;
  return undef unless exists $self->{song} && exists $self->{changed};
  my $data = pack("a30a30a30a4a28xCC",$self->{song},$self->{artist},$self->{album},
		  $self->{year}, $self->{comment}, $self->{track}, $self->{genreID});
  my $mp3obj = $self->{mp3};
  my $mp3tag;
  $mp3obj->close;
  if ($mp3obj->open("+<")) {
    $mp3obj->seek(-128,2);
    $mp3obj->read(\$mp3tag, 3);
    if ($mp3tag eq "TAG") {
      $mp3obj->write($data);
    } else {
      $mp3obj->seek(0,2);
      $mp3obj->write("TAG$data");
    }
  }
  return 1;
}

=pod

=item removeTag()

  $id3v1->removeTag;

Removes the ID3v1 tag from the file.

=cut

sub removeTag {
  my $self = shift;
  my $mp3obj = $self->{mp3};
  my $mp3tag;
  $mp3obj->seek(-128,2);
  $mp3obj->read(\$mp3tag, 3);
  if ($mp3tag eq "TAG") {
    $mp3obj->close;
    if ($mp3obj->open("+<")) {
      $mp3obj->truncate(-128);
      $self->all("","","","","",0,255);
      $mp3obj->close;
      $self->{changed} = 1;
      return 1;
    }
    return -1;
  }
  return 0;
}

=pod

=item genres()

  @allgenres = $id3v1->genres;
  $genreName = $id3v1->genres($genreID);
  $genreID   = $id3v1->genres($genreName);

Returns a list of all genres, or the according name or id to
a given id or name.

=cut

sub genres {
  # return an array with all genres, of if a parameter is given, the according genre
  my $genre = shift;
  return \@winamp_genres unless defined $genre;
  return $winamp_genres[$genre] if $genre =~ /^\d+$/;
  my $r;
  foreach (@winamp_genres) {
    if ($_ eq $genre) {
      $r=$_;
      last;
    }
  }
  return $r;
}

#################
##
## internal subs

# actually read the tag data
sub readTag {
  my ($self, $buffer) = @_;
  my $mp3obj = $self->{mp3};
  my $id3v1;

  if ($self->{new}) {
    ($self->{song}, $self->{artist}, $self->{album}, $self->{year},
     $self->{comment}, $self->{track}, $self->{genre}, $self->{genreID}) = ("","","","","",0,"",255);
    $self->{changed} = 1;
  } else {
    (undef, $self->{song}, $self->{artist}, $self->{album}, $self->{year},
     $self->{comment}, $id3v1, $self->{track}, $self->{genreID}) =
       unpack ("a3Z30Z30Z30Z4Z28CCC", $buffer);

    if ($id3v1!=0) { # ID3v1 tag found: track is not valid, comment two chars longer
      $self->{comment} .= chr($id3v1);
      $self->{comment} .= chr($self->{track}) if $self->{track}!=32;
      $self->{track} = 0;
    };
    $self->{genre} = id2genre($self->{genreID});
  }
}

# convert one byte id to genre name
sub id2genre {
  my $id=shift;
  return "" unless defined $id && $id<$#winamp_genres;
  return $winamp_genres[$id];
}

# convert genre name to one byte id
sub genre2id {
  my $genre = shift;
  my $i=0;
  foreach (@winamp_genres) {
    if (uc $genre eq uc $_) {
      return $i;
    }
    $i++,
  }
  return 255;
}

# nothing to do for destroy
sub DESTROY {
}

1;

######## define all the genres

BEGIN { @mp3_genres = ( 'Blues', 'Classic Rock', 'Country', 'Dance',
			'Disco', 'Funk', 'Grunge', 'Hip-Hop', 'Jazz', 'Metal', 'New Age',
			'Oldies', 'Other', 'Pop', 'R&B', 'Rap', 'Reggae', 'Rock', 'Techno',
			'Industrial', 'Alternative', 'Ska', 'Death Metal', 'Pranks',
			'Soundtrack', 'Euro-Techno', 'Ambient', 'Trip-Hop', 'Vocal',
			'Jazz+Funk', 'Fusion', 'Trance', 'Classical', 'Instrumental', 'Acid',
			'House', 'Game', 'Sound Clip', 'Gospel', 'Noise', 'AlternRock',
			'Bass', 'Soul', 'Punk', 'Space', 'Meditative', 'Instrumental Pop',
			'Instrumental Rock', 'Ethnic', 'Gothic', 'Darkwave',
			'Techno-Industrial', 'Electronic', 'Pop-Folk', 'Eurodance', 'Dream',
			'Southern Rock', 'Comedy', 'Cult', 'Gangsta', 'Top 40',
			'Christian Rap', 'Pop/Funk', 'Jungle', 'Native American', 'Cabaret', 'New Wave',
			'Psychadelic', 'Rave', 'Showtunes', 'Trailer', 'Lo-Fi', 'Tribal',
			'Acid Punk', 'Acid Jazz', 'Polka', 'Retro', 'Musical', 'Rock & Roll',
			'Hard Rock', );

  	@winamp_genres = ( @mp3_genres, 'Folk', 'Folk-Rock',
			   'National Folk', 'Swing', 'Fast Fusion', 'Bebob', 'Latin', 'Revival',
			   'Celtic', 'Bluegrass', 'Avantgarde', 'Gothic Rock',
			   'Progressive Rock', 'Psychedelic Rock', 'Symphonic Rock',
			   'Slow Rock', 'Big Band', 'Chorus', 'Easy Listening',
			   'Acoustic', 'Humour', 'Speech', 'Chanson', 'Opera',
			   'Chamber Music', 'Sonata', 'Symphony', 'Booty Bass', 'Primus',
			   'Porn Groove', 'Satire', 'Slow Jam', 'Club', 'Tango', 'Samba',
			   'Folklore', 'Ballad', 'Power Ballad', 'Rhythmic Soul',
			   'Freestyle', 'Duet', 'Punk Rock', 'Drum Solo', 'Acapella',
			   'Euro-House', 'Dance Hall', );
}

=pod

=head1 SEE ALSO

MP3::Tag, MP3::TAG::ID3v2

ID3v1 standard - http://www.id3.org

=cut