Convert/CD/Track.pm

=head1 NAME

Convert::CD::Track - desribe track layout and offer data access methods.

=head1 SYNOPSIS

 use Convert::CD::Track;

 # to be done

=head1 DESCRIPTION

Kidding?

=head2 EXPORTED CONSTANTS

   FLAG_DCP    digital copy permitted
   FLAG_FCA    four channel audio
   FLAG_PRE    track is pre-emphasized
   FLAG_SCMS   protected by serial copy management system (see DCP)
   FLAG_DATA   disk is data track (automatically set for MODE1)

   MODE_AUDIO
   MODE_CDG    CD+G (Karaoke)
   MODE_MODE1  MODE 1 CD (standard yellow book, 2048 bps)
   MODE_MODE2  MODe 2 CD (CD/XA, 2336 bps)
   MODE_CDI    CD-i, CD Interactive

=cut

package Convert::CD::Track;

use POSIX qw(ceil);
use Carp;

use base Exporter;

$VERSION = 0.01;

@EXPORT = qw(
   FLAG_DCP FLAG_FCA FLAG_PRE FLAG_SCMS FLAG_DATA
   MODE_AUDIO MODE_CDG MODE_MODE1 MODE_MODE2 MODE_CDI
);

sub FLAG_DCP   () { 0x0001 } # digital copy permitted
sub FLAG_FCA   () { 0x0002 } # four channel audio
sub FLAG_PRE   () { 0x0004 } # track is pre-emphasized
sub FLAG_DATA  () { 0x0008 } # disk is data track (not usually set)
sub FLAG_SCMS  () { 0x1000 } # protected by serial copy management system (see DCP)

sub MODE_AUDIO () { 0x0001 }
sub MODE_CDG   () { 0x0002 } # CD+G (Karaoke)
sub MODE_MODE1 () { 0x0004 } # MODE 1 CD (standard yellow book, 2048 bps)
sub MODE_MODE2 () { 0x0008 } # MODe 2 CD (CD/XA, 2336 bps)
sub MODE_CDI   () { 0x0010 } # CD-i, CD Interactive

=head2 Convert::CD::Track METHODS

This class is used to repesent single track objects.

=over 4

=item new param => value...

Create a new track object. Parameters that are not given are usually
guess, depending on the mode and other parameters.

Parameters:

 path        the file that contains the track
 offset      the offste within the file that contains the first sector
             (may be negative)
 rawsize     the raw size (in bytes) of the track. (guessed if missing)
 mode        a mode string (MODE1, MODE2, AUDIO, CDI, CDG....)
 datasize    size of the data part of the sector (e.g. 2048).
 secsize     size of a sector in disk image
 index       an array of index times (0 is pregap start, 1 is track start)

=cut

sub new {
   my $class = shift;
   my $self = bless {
      @_,
   }, $class;

   $self->{rawsize}  ||= (-s $self->{path}) - $self->{offset};

   $self->{flags}    ||= FLAG_DATA if $self->{mode} == MODE_MODE1;
   $self->{datasize} ||= $self->{mode} == MODE_MODE1 ? 2048
                       : $self->{mode} == MODE_MODE2 ? 2336
                       : $self->{mode} == MODE_AUDIO ? 2352
                       : $self->{secsize};

   $self->{datasize} = $self->{secsize}
      if $self->{secsize} < $self->{datasize};

   $self;
}

# create and cache a filehandle of the given mode
sub fh {
   my ($self, $mode) = @_;

   $self->{fh}{$mode} ||= do {
      open my $fh, $mode, $self->{path}
         or croak "$self->{path}: $!";
      binmode $fh; # *seufz*
      $fh;
   };
}

=item $track->read ($offset, $length)

Reads and returns a part of the track. C<$offset> should be a multiple of
the datasize.

=cut

sub read {
   my ($self, $offset, $length) = @_;
   my $buf;

   my $fh = $self->fh ("<");

   $offset = $offset / $self->{secsize} * $self->{secsize};

   while ($length > 0) {
      sysseek $fh, $self->{offset} + $offset, 0
         or croak "seek($self->{path}): $!";
      sysread $fh, $buf, ($length < $self->{datasize} ? $length : $self->{datasize}), length $buf
         or croak "read($self->{path}): $!";

      $length -= $self->{datasize};
      $offset += $self->{secsize};
   }

   $buf;
}

=item $track->size

Returns the (cooked) size of the track in bytes, i.e. logical size of the
track without any ECC etc. information.

=cut

sub size {
   my ($self) = @_;

   ceil ($self->{rawsize} / $self->{secsize}) * $self->{datasize};
}

=item $track->as_string

Returns a single-line, textual description of the track.

=cut

sub as_string {
   my ($self) = @_;
   my %data = %$self;

   $data{index} = "<" . (join "|", @{$data{index}}) .">";

   sprintf "%s %08x+%08x %s/%d (%s)",
           delete @data{qw(path offset rawsize mode secsize)},
           join " ", %data;
}

=item $track->to_msf ($offset)

Converts the given byte offste into M:S:F format.

=cut

sub to_msf {
   my ($self, $offset) = @_;

   my $frame = $offset / $self->{datasize};

   sprintf "%02d:%02d:%02d", $frame / (60 * 75),
                             $frame / 75 % 60,
                             $frame % 75;
}

1;

=back

=head1 AUTHOR

 Marc Lehmann <pcg@goof.com>

=cut

Revision:	1.1
Committed:	Tue Jun 10 15:54:26 2003 UTC (23 years, 3 months ago) by root
Branch:	MAIN
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			Convert::CD::Track - desribe track layout and offer data access methods.
4
5			=head1 SYNOPSIS
6
7			use Convert::CD::Track;
8
9			# to be done
10
11			=head1 DESCRIPTION
12
13			Kidding?
14
15			=head2 EXPORTED CONSTANTS
16
17			FLAG_DCP digital copy permitted
18			FLAG_FCA four channel audio
19			FLAG_PRE track is pre-emphasized
20			FLAG_SCMS protected by serial copy management system (see DCP)
21			FLAG_DATA disk is data track (automatically set for MODE1)
22
23			MODE_AUDIO
24			MODE_CDG CD+G (Karaoke)
25			MODE_MODE1 MODE 1 CD (standard yellow book, 2048 bps)
26			MODE_MODE2 MODe 2 CD (CD/XA, 2336 bps)
27			MODE_CDI CD-i, CD Interactive
28
29			=cut
30
31			package Convert::CD::Track;
32
33			use POSIX qw(ceil);
34			use Carp;
35
36			use base Exporter;
37
38			$VERSION = 0.01;
39
40			@EXPORT = qw(
41			FLAG_DCP FLAG_FCA FLAG_PRE FLAG_SCMS FLAG_DATA
42			MODE_AUDIO MODE_CDG MODE_MODE1 MODE_MODE2 MODE_CDI
43			);
44
45			sub FLAG_DCP () { 0x0001 } # digital copy permitted
46			sub FLAG_FCA () { 0x0002 } # four channel audio
47			sub FLAG_PRE () { 0x0004 } # track is pre-emphasized
48			sub FLAG_DATA () { 0x0008 } # disk is data track (not usually set)
49			sub FLAG_SCMS () { 0x1000 } # protected by serial copy management system (see DCP)
50
51			sub MODE_AUDIO () { 0x0001 }
52			sub MODE_CDG () { 0x0002 } # CD+G (Karaoke)
53			sub MODE_MODE1 () { 0x0004 } # MODE 1 CD (standard yellow book, 2048 bps)
54			sub MODE_MODE2 () { 0x0008 } # MODe 2 CD (CD/XA, 2336 bps)
55			sub MODE_CDI () { 0x0010 } # CD-i, CD Interactive
56
57			=head2 Convert::CD::Track METHODS
58
59			This class is used to repesent single track objects.
60
61			=over 4
62
63			=item new param => value...
64
65			Create a new track object. Parameters that are not given are usually
66			guess, depending on the mode and other parameters.
67
68			Parameters:
69
70			path the file that contains the track
71			offset the offste within the file that contains the first sector
72			(may be negative)
73			rawsize the raw size (in bytes) of the track. (guessed if missing)
74			mode a mode string (MODE1, MODE2, AUDIO, CDI, CDG....)
75			datasize size of the data part of the sector (e.g. 2048).
76			secsize size of a sector in disk image
77			index an array of index times (0 is pregap start, 1 is track start)
78
79			=cut
80
81			sub new {
82			my $class = shift;
83			my $self = bless {
84			@_,
85			}, $class;
86
87			$self->{rawsize} \|\|= (-s $self->{path}) - $self->{offset};
88
89			$self->{flags} \|\|= FLAG_DATA if $self->{mode} == MODE_MODE1;
90			$self->{datasize} \|\|= $self->{mode} == MODE_MODE1 ? 2048
91			: $self->{mode} == MODE_MODE2 ? 2336
92			: $self->{mode} == MODE_AUDIO ? 2352
93			: $self->{secsize};
94
95			$self->{datasize} = $self->{secsize}
96			if $self->{secsize} < $self->{datasize};
97
98			$self;
99			}
100
101			# create and cache a filehandle of the given mode
102			sub fh {
103			my ($self, $mode) = @_;
104
105			$self->{fh}{$mode} \|\|= do {
106			open my $fh, $mode, $self->{path}
107			or croak "$self->{path}: $!";
108			binmode $fh; # seufz
109			$fh;
110			};
111			}
112
113			=item $track->read ($offset, $length)
114
115			Reads and returns a part of the track. C<$offset> should be a multiple of
116			the datasize.
117
118			=cut
119
120			sub read {
121			my ($self, $offset, $length) = @_;
122			my $buf;
123
124			my $fh = $self->fh ("<");
125
126			$offset = $offset / $self->{secsize} * $self->{secsize};
127
128			while ($length > 0) {
129			sysseek $fh, $self->{offset} + $offset, 0
130			or croak "seek($self->{path}): $!";
131			sysread $fh, $buf, ($length < $self->{datasize} ? $length : $self->{datasize}), length $buf
132			or croak "read($self->{path}): $!";
133
134			$length -= $self->{datasize};
135			$offset += $self->{secsize};
136			}
137
138			$buf;
139			}
140
141			=item $track->size
142
143			Returns the (cooked) size of the track in bytes, i.e. logical size of the
144			track without any ECC etc. information.
145
146			=cut
147
148			sub size {
149			my ($self) = @_;
150
151			ceil ($self->{rawsize} / $self->{secsize}) * $self->{datasize};
152			}
153
154			=item $track->as_string
155
156			Returns a single-line, textual description of the track.
157
158			=cut
159
160			sub as_string {
161			my ($self) = @_;
162			my %data = %$self;
163
164			$data{index} = "<" . (join "\|", @{$data{index}}) .">";
165
166			sprintf "%s %08x+%08x %s/%d (%s)",
167			delete @data{qw(path offset rawsize mode secsize)},
168			join " ", %data;
169			}
170
171			=item $track->to_msf ($offset)
172
173			Converts the given byte offste into M:S:F format.
174
175			=cut
176
177			sub to_msf {
178			my ($self, $offset) = @_;
179
180			my $frame = $offset / $self->{datasize};
181
182			sprintf "%02d:%02d:%02d", $frame / (60 * 75),
183			$frame / 75 % 60,
184			$frame % 75;
185			}
186
187			1;
188
189			=back
190
191			=head1 AUTHOR
192
193			Marc Lehmann <pcg@goof.com>
194
195			=cut
196