Refactored Sector:: out from under Engine:: and into its own area

[dbsrgits/DBM-Deep.git] / lib / DBM / Deep / Sector / File / Null.pm

diff --git a/lib/DBM/Deep/Sector/File/Null.pm b/lib/DBM/Deep/Sector/File/Null.pm
new file mode 100644 (file)
index 0000000..22632b1
--- /dev/null
+++ b/lib/DBM/Deep/Sector/File/Null.pm
@@ -0,0 +1,46 @@
+package DBM::Deep::Sector::File::Null;
+
+use 5.006_000;
+
+use strict;
+use warnings FATAL => 'all';
+
+use base qw( DBM::Deep::Sector::File::Data );
+
+my $STALE_SIZE = 2;
+
+# Please refer to the pack() documentation for further information
+my %StP = (
+    1 => 'C', # Unsigned char value (no order needed as it's just one byte)
+    2 => 'n', # Unsigned short in "network" (big-endian) order
+    4 => 'N', # Unsigned long in "network" (big-endian) order
+    8 => 'Q', # Usigned quad (no order specified, presumably machine-dependent)
+);
+
+sub type { $_[0]{engine}->SIG_NULL }
+sub data_length { 0 }
+sub data { return }
+
+sub _init {
+    my $self = shift;
+
+    my $engine = $self->engine;
+
+    unless ( $self->offset ) {
+        my $leftover = $self->size - $self->base_size - 1 * $engine->byte_size - 1;
+
+        $self->{offset} = $engine->_request_data_sector( $self->size );
+        $engine->storage->print_at( $self->offset, $self->type ); # Sector type
+        # Skip staleness counter
+        $engine->storage->print_at( $self->offset + $self->base_size,
+            pack( $StP{$engine->byte_size}, 0 ),  # Chain loc
+            pack( $StP{1}, $self->data_length ),  # Data length
+            chr(0) x $leftover,                   # Zero-fill the rest
+        );
+
+        return;
+    }
+}
+
+1;
+__END__