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=head1 NAME |
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|
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Convert::CD::Track - desribe track layout and offer data access methods. |
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|
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=head1 SYNOPSIS |
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|
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use Convert::CD::Track; |
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|
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# to be done |
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|
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=head1 DESCRIPTION |
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|
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Kidding? |
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|
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=head2 EXPORTED CONSTANTS |
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|
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FLAG_DCP digital copy permitted |
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FLAG_FCA four channel audio |
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FLAG_PRE track is pre-emphasized |
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FLAG_SCMS protected by serial copy management system (see DCP) |
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FLAG_DATA disk is data track (automatically set for MODE1) |
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|
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MODE_AUDIO |
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MODE_CDG CD+G (Karaoke) |
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MODE_MODE0 MODE 0 (unused, 2336 bps) |
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MODE_MODE1 MODE 1 (standard yellow book, 2048 bps) |
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MODE_MODE2 MODe 2 (CD/XA, 2336 bps) |
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MODE_CDI CD-i, CD Interactive |
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|
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=cut |
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|
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package Convert::CD::Track; |
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|
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use POSIX qw(ceil); |
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use Carp; |
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|
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use base Exporter; |
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|
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$VERSION = 0.01; |
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|
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@EXPORT = qw( |
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FLAG_DCP FLAG_FCA FLAG_PRE FLAG_SCMS FLAG_DATA |
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MODE_AUDIO MODE_CDG MODE_MODE1 MODE_MODE2 MODE_CDI |
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); |
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|
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sub FLAG_DCP () { 0x0001 } |
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sub FLAG_FCA () { 0x0002 } |
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sub FLAG_PRE () { 0x0004 } |
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sub FLAG_DATA () { 0x0008 } |
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sub FLAG_SCMS () { 0x1000 } |
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|
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sub MODE_MODE0 () { 0 } |
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sub MODE_MODE1 () { 1 } |
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sub MODE_MODE2 () { 2 } |
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sub MODE_AUDIO () { 3 } |
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sub MODE_CDG () { 4 } |
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sub MODE_CDI () { 5 } |
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|
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=head2 Convert::CD::Track METHODS |
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|
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This class is used to repesent single track objects. |
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|
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=over 4 |
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|
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=item new param => value... |
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Create a new track object. Parameters that are not given are usually |
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guess, depending on the mode and other parameters. |
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|
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Parameters: |
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|
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path the file that contains the track |
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offset the offste within the file that contains the first sector |
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(may be negative) |
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rawsize the raw size (in bytes) of the track. (guessed if missing) |
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mode a mode string (MODE1, MODE2, AUDIO, CDI, CDG....) |
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datasize size of the data part of the sector (e.g. 2048). |
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dataoffset offset of data part within sector |
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secsize size of a sector in disk image |
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index an array of index times (0 is pregap start, 1 is track start) |
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|
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=cut |
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|
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sub new { |
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my $class = shift; |
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my $self = bless { |
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@_, |
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}, $class; |
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|
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$self->{rawsize} ||= (-s $self->{path}) - $self->{offset}; |
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|
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$self->{flags} ||= FLAG_DATA if $self->{mode} == MODE_MODE1; |
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$self->{datasize} ||= $self->{mode} == MODE_MODE1 ? 2048 |
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: $self->{mode} == MODE_MODE2 ? 2336 |
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: $self->{mode} == MODE_AUDIO ? 2352 |
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: $self->{secsize}; |
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|
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$self->{datasize} = $self->{secsize} |
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if $self->{secsize} < $self->{datasize}; |
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|
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# guess offset by type OR datasize |
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|
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$self; |
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} |
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|
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# create and cache a filehandle of the given mode |
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sub fh { |
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my ($self, $mode) = @_; |
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|
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$self->{fh}{$mode} ||= do { |
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open my $fh, $mode, $self->{path} |
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or croak "$self->{path}: $!"; |
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binmode $fh; # *seufz* |
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$fh; |
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}; |
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} |
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|
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=item $track->read ($offset, $length) |
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|
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Reads and returns a part of the track. C<$offset> should be a multiple of |
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the datasize. |
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|
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=cut |
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|
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sub read { |
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my ($self, $offset, $length) = @_; |
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my $buf; |
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|
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my $fh = $self->fh ("<"); |
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|
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$offset = $offset / $self->{secsize} * $self->{secsize}; |
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$offset += $self->{offset} + $self->{dataoffset}; |
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|
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while ($length > 0) { |
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if ($offset < 0) { |
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$buf .= "\x00" x $self->{datasize}; |
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} else { |
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sysseek $fh, $offset, 0 |
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or croak "seek($self->{path}): $!"; |
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sysread $fh, $buf, ($length < $self->{datasize} ? $length : $self->{datasize}), length $buf |
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or croak "read($self->{path}): $!"; |
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} |
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|
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$length -= $self->{datasize}; |
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$offset += $self->{secsize}; |
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} |
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|
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$buf; |
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} |
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|
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=item $track->size |
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|
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Returns the (cooked) size of the track in bytes, i.e. logical size of the |
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track without any ECC etc. information. |
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|
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=cut |
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|
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sub size { |
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my ($self) = @_; |
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|
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ceil ($self->{rawsize} / $self->{secsize}) * $self->{datasize}; |
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} |
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|
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=item $track->as_string |
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|
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Returns a single-line, textual description of the track. |
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|
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=cut |
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|
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sub as_string { |
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my ($self) = @_; |
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my %data = %$self; |
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|
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$data{index} = "<" . (join "|", @{$data{index}}) .">"; |
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|
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sprintf "%s %08x+%08x %s/%d (%s)", |
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delete @data{qw(path offset rawsize mode secsize)}, |
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join " ", %data; |
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} |
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|
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=item $track->to_msf ($offset) |
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|
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Converts the given byte offste into M:S:F format. |
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|
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=cut |
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|
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sub to_msf { |
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my ($self, $offset) = @_; |
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|
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my $frame = $offset / $self->{datasize}; |
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|
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sprintf "%02d:%02d:%02d", $frame / (60 * 75), |
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$frame / 75 % 60, |
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$frame % 75; |
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} |
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|
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1; |
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|
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=back |
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|
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=head1 AUTHOR |
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|
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Marc Lehmann <schmorp@schmorp.de> |
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|
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=cut |
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|
