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

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

diff --git a/lib/DBM/Deep/Sector/File/Index.pm b/lib/DBM/Deep/Sector/File/Index.pm
new file mode 100644 (file)
index 0000000..de0fa73
--- /dev/null
+++ b/lib/DBM/Deep/Sector/File/Index.pm
@@ -0,0 +1,95 @@
+package DBM::Deep::Sector::File::Index;
+
+use base qw( DBM::Deep::Sector::File );
+
+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 _init {
+    my $self = shift;
+
+    my $engine = $self->engine;
+
+    unless ( $self->offset ) {
+        my $leftover = $self->size - $self->base_size;
+
+        $self->{offset} = $engine->_request_index_sector( $self->size );
+        $engine->storage->print_at( $self->offset, $engine->SIG_INDEX ); # Sector type
+        # Skip staleness counter
+        $engine->storage->print_at( $self->offset + $self->base_size,
+            chr(0) x $leftover, # Zero-fill the rest
+        );
+    }
+
+    return $self;
+}
+
+#XXX Change here
+sub size {
+    my $self = shift;
+    unless ( $self->{size} ) {
+        my $e = $self->engine;
+        $self->{size} = $self->base_size + $e->byte_size * $e->hash_chars;
+    }
+    return $self->{size};
+}
+
+sub free_meth { return '_add_free_index_sector' }
+
+sub free {
+    my $self = shift;
+    my $e = $self->engine;
+
+    for my $i ( 0 .. $e->hash_chars - 1 ) {
+        my $l = $self->get_entry( $i ) or next;
+        DBM::Deep::Sector::File->load( $e, $l )->free;
+    }
+
+    $self->SUPER::free();
+}
+
+sub _loc_for {
+    my $self = shift;
+    my ($idx) = @_;
+    return $self->offset + $self->base_size + $idx * $self->engine->byte_size;
+}
+
+sub get_entry {
+    my $self = shift;
+    my ($idx) = @_;
+
+    my $e = $self->engine;
+
+    DBM::Deep->_throw_error( "get_entry: Out of range ($idx)" )
+        if $idx < 0 || $idx >= $e->hash_chars;
+
+    return unpack(
+        $StP{$e->byte_size},
+        $e->storage->read_at( $self->_loc_for( $idx ), $e->byte_size ),
+    );
+}
+
+sub set_entry {
+    my $self = shift;
+    my ($idx, $loc) = @_;
+
+    my $e = $self->engine;
+
+    DBM::Deep->_throw_error( "set_entry: Out of range ($idx)" )
+        if $idx < 0 || $idx >= $e->hash_chars;
+
+    $self->engine->storage->print_at(
+        $self->_loc_for( $idx ),
+        pack( $StP{$e->byte_size}, $loc ),
+    );
+}
+
+1;
+__END__