| 1 |
package Tape; |
| 2 |
|
| 3 |
# Dobrica Pavlinusic, <dpavlin@rot13.org> 08/03/07 11:11:56 CEST |
| 4 |
|
| 5 |
use strict; |
| 6 |
use warnings; |
| 7 |
|
| 8 |
use base qw/Class::Accessor/; |
| 9 |
__PACKAGE__->mk_accessors(qw(tape tape_path tape_pos trace)); |
| 10 |
|
| 11 |
use File::Slurp; |
| 12 |
use Carp qw/confess/; |
| 13 |
|
| 14 |
=head1 NAME |
| 15 |
|
| 16 |
Tape - implement tape reader/recorder |
| 17 |
|
| 18 |
=cut |
| 19 |
|
| 20 |
=head2 read_tape |
| 21 |
|
| 22 |
my $byte = $self->read_tape; |
| 23 |
|
| 24 |
=cut |
| 25 |
|
| 26 |
my $last_warn = ''; |
| 27 |
|
| 28 |
sub _warn { |
| 29 |
my $msg = shift; |
| 30 |
if ( $msg ne $last_warn ) { |
| 31 |
warn "$msg\n"; |
| 32 |
$last_warn = $msg; |
| 33 |
} |
| 34 |
} |
| 35 |
|
| 36 |
my $c_0 = 0; |
| 37 |
my $c_1 = 0; |
| 38 |
my $mask = 1; |
| 39 |
|
| 40 |
sub read_tape { |
| 41 |
my $self = shift; |
| 42 |
if ( ! $self->tape ) { |
| 43 |
_warn "please load tape!"; |
| 44 |
return 0; |
| 45 |
} |
| 46 |
my $pos = $self->tape_pos; |
| 47 |
my $tape = $self->tape; |
| 48 |
if ( $pos > length( $tape ) ) { |
| 49 |
_warn "end of tape [$pos]"; |
| 50 |
return -1; |
| 51 |
} |
| 52 |
|
| 53 |
if ( $c_0 ) { |
| 54 |
$c_0--; |
| 55 |
return 0; |
| 56 |
} |
| 57 |
if ( $c_1 ) { |
| 58 |
$c_1--; |
| 59 |
return 255; |
| 60 |
} |
| 61 |
|
| 62 |
$mask = $mask << 1; |
| 63 |
if ( $mask > 0x80 ) { |
| 64 |
$pos++; |
| 65 |
$self->tape_pos( $pos ); |
| 66 |
$mask = 1; |
| 67 |
}; |
| 68 |
|
| 69 |
my $byte = ord( substr($self->tape,$pos,1) ); |
| 70 |
my $bit = $byte & $mask; |
| 71 |
# warn sprintf("## tape pos %d 0x%04x mask %02x and %02x = %d\n", $pos, $pos, $mask, $byte, $bit); # if $self->trace; |
| 72 |
|
| 73 |
( $c_0, $c_1 ) = ( 0x17, 0x17 ); |
| 74 |
( $c_0, $c_1 ) = ( 0x30, 0x30 ) if $bit; |
| 75 |
|
| 76 |
return 0; |
| 77 |
} |
| 78 |
|
| 79 |
=head2 write_tape |
| 80 |
|
| 81 |
$self->write_tape( $byte ); |
| 82 |
|
| 83 |
=cut |
| 84 |
|
| 85 |
|
| 86 |
sub write_tape { |
| 87 |
my ( $self, $byte ) = @_; |
| 88 |
|
| 89 |
$self->append_to_file( 'tape.dmp', $byte ); |
| 90 |
|
| 91 |
return $byte; |
| 92 |
} |
| 93 |
|
| 94 |
=head2 load_tape |
| 95 |
|
| 96 |
$self->load_tape( '/path/to/file' ); |
| 97 |
|
| 98 |
=cut |
| 99 |
|
| 100 |
sub load_tape { |
| 101 |
my $self = shift; |
| 102 |
my $path = shift || return; |
| 103 |
|
| 104 |
my $tape = read_file( $path ) || confess "can't load $path: $!"; |
| 105 |
$self->tape_path( $path ); |
| 106 |
|
| 107 |
$self->tape_pos( 0 ); |
| 108 |
$self->tape( $tape ); |
| 109 |
warn "loaded tape $path ", -s $path, " bytes\n"; |
| 110 |
return 1; |
| 111 |
} |
| 112 |
|
| 113 |
=head2 tape_status |
| 114 |
|
| 115 |
print $self->tape_status; |
| 116 |
|
| 117 |
=cut |
| 118 |
|
| 119 |
sub tape_status { |
| 120 |
my $self = shift; |
| 121 |
|
| 122 |
return "No tape in (simulated) drive" unless $self->tape; |
| 123 |
|
| 124 |
my $size = length( $self->tape ); |
| 125 |
|
| 126 |
return sprintf( |
| 127 |
"tape file: %s with %d 0x%x bytes, current position: %d 0x%x", |
| 128 |
$self->tape_path, $size, $size, $self->pos, $self->pos, |
| 129 |
); |
| 130 |
} |
| 131 |
|
| 132 |
=head1 SEE ALSO |
| 133 |
|
| 134 |
L<VRac> |
| 135 |
|
| 136 |
=cut |
| 137 |
|
| 138 |
1; |
Parent Directory
| 
Revision Log