CDDB::File - Parse a CDDB/freedb data file

  my $disc = CDDB::File->new("rock/f4109511");

  print $disc->id, $disc->all_ids;
  print $disc->artist, $disc->title;
  print $disc->year, $disc->genre, $disc->extd;
  print $disc->length, $disc->track_count;

  print $disc->revision, $disc->submitted_via, $disc->processed_by;

  foreach my $track ($disc->tracks) {
    print $track->number, $track->title, $track->artist;
    print $track->length, $track->extd;
  }

  my $disc = CDDB::File->new("rock/f4109511");

  my $discid = $disc->id;
  my @discid = $disc->all_ids;

  foreach my $track ($disc->tracks) {
    print $track->number, $track->title, $track->artist;
    print $track->length, $track->extd;
  }

  Copyright (C) 2001-2005 Tony Bowden. All rights reserved.

  This program is free software; you can redistribute it and/or modify it under
  the terms of the GNU General Public License; either version 2 of the License,
  or (at your option) any later version.

  This program is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  FOR A PARTICULAR PURPOSE.

package CDDB::File;

$VERSION = '1.05';

use strict;
use IO::File;

sub new {
  my ($class, $file) = @_;
  my $fh = new IO::File $file, "r" or die "Can't read $file\n";
  chomp(my @data = <$fh>);
  bless {
    _data => \@data,
  }, $class;
}

sub _data { @{shift->{_data}} }

sub id            { (shift->all_ids)[0]                     }
sub all_ids       { split /,/, shift->_get_lines("DISCID=") }
sub year          { shift->_get_lines("DYEAR=")             }
sub genre         { shift->_get_lines("DGENRE=")            }
sub extd          { shift->_get_lines("EXTD=")              }
sub revision      { shift->_get_lines("# Revision: ")       }
sub submitted_via { shift->_get_lines("# Submitted via: ")  }
sub processed_by  { shift->_get_lines("# Processed by: ")   }

sub _offsets {
  my $self = shift;
  my $from = $self->_offset_line;
  ((grep s/^#\s*//, ($self->_data)[$from + 1 .. $from + $self->track_count]), 
   $self->length * 75);
}

sub _offset_line {
  my $self = shift;
  my @data = $self->_data;
  foreach (0 .. $#data) {
    return $_ if $data[$_] =~ /^# Track frame offsets/;
  }
  return 2;
}

sub length     { 
  my $length = shift->_get_lines("# Disc length: ");
     $length =~ s/ sec(ond)?s//;
  return $length;
}

sub _title_line { 
  my $self = shift;
  $self->{_title_line} ||= $self->_get_lines("DTITLE=") 
}

sub _split_title {
  my $self = shift;
  ($self->{_artist}, $self->{_title}) = split /\s+\/\s+/, $self->_title_line, 2;
  $self->{_title} ||= $self->{_artist};
}

sub title {
  my $self = shift;
  $self->_split_title unless defined $self->{_title};
  $self->{_title};
}

sub artist {
  my $self = shift;
  $self->_split_title unless defined $self->{_artist};
  $self->{_artist};
}

sub tracks { 
  my $self = shift;
  my @title  = $self->_get_multi_lines("TTITLE");
  my @extd   = $self->_get_multi_lines("EXTT");
  my @offset = $self->_offsets;
  return map {
    bless { 
      _cd     => $self,
      _number => $_+1,
      _tline  => $title[$_],
      _extd   => $extd[$_],
      _offset => $offset[$_],
      _length => int(($offset[$_+1] - $offset[$_]) / 75),
    }, 'CDDB::File::Track'
  } 0 .. $self->_highest_track_no;
}

sub _get_lines {
  my ($self, $keyword) = @_;
  join "", grep s/^${keyword}//, $self->_data;
}

sub _get_multi_lines {
  my ($self, $keyword) = @_;
  map $self->_get_lines("${keyword}$_="), 0 .. $self->_highest_track_no;
}

sub _highest_track_no { 
  my $self = shift;
  $self->{_high} ||= pop @{[ map /^TTITLE(\d+)=/, $self->_data ]}
}

sub track_count { shift->_highest_track_no + 1 }

# ==================================================================== #

package CDDB::File::Track;

use overload 
  '""'  => 'title';

sub cd     { shift->{_cd} }
sub extd   { shift->{_extd}  }
sub length { shift->{_length}}
sub number { shift->{_number}}
sub offset { shift->{_offset}}

sub _split_title {
  my $self = shift;
  if ($self->cd->artist eq "Various") {
    ($self->{_artist}, $self->{_title}) = split /\s+\/\s+/, $self->{_tline}, 2
  } else {
    $self->{_title}  = $self->{_tline};
    $self->{_artist} = $self->cd->artist;
  }

  unless ($self->{_title}) {
    $self->{_title} = $self->{_artist};
    $self->{_artist} = $self->cd->artist;
  }
}

sub title {
  my $self = shift;
  $self->_split_title unless defined $self->{_title};
  $self->{_title};
}

sub artist {
  my $self = shift;
  $self->_split_title unless defined $self->{_artist};
  $self->{_artist};
}

1;