Raw content of Bio::DB::GFF::Adaptor::memory_iterator
<![CDATA[=head1 NAME
Bio::DB::GFF::Adaptor::memory_iterator - iterator for Bio::DB::GFF::Adaptor::memory
=head1 SYNOPSIS
For internal use only
=head1 DESCRIPTION
This is an internal module that is used by the Bio::DB::GFF in-memory
adaptor to return an iterator across a sequence feature query. The
object has a single method, next_feature(), that returns the next
feature from the query. The method next_seq() is an alias for
next_feature().
=head1 BUGS
None known yet.
=head1 SEE ALSO
L<Bio::DB::GFF>,
=head1 AUTHOR
Lincoln Stein E<lt>lstein@cshl.orgE<gt>.
Copyright (c) 2001 Cold Spring Harbor Laboratory.
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut
package Bio::DB::GFF::Adaptor::memory_iterator;
use strict;
# $Id: memory_iterator.pm,v 1.4.2.1 2003/07/05 00:52:31 lstein Exp $
# this module needs to be cleaned up and documented
#use constant STH => 0;
#use constant CALLBACK => 1;
#use constant CACHE => 2;
*next_seq = \&next_feature;
sub new {
my $class = shift;
my ($data,$callback) = @_;
my $pos = 0;
return bless {data => $data,
pos => $pos,
callback => $callback,
cache => []},$class;
#return bless [$sth,$callback,[]],$class;
}
sub next_feature {
my $self = shift;
return shift @{$self->{cache}} if @{$self->{cache}};
my $data = $self->{data} or return;
my $callback = $self->{callback};
my $features;
while (1) {
my $feature = $data->[$self->{pos}++];
if ($feature) {
$features = $callback->(@{$feature});
last if $features;
} else {
$features = $callback->();
undef $self->{pos};
undef $self->{data};
undef $self->{cache};
last;
}
}
$self->{cache} = $features or return;
shift @{$self->{cache}};
}
1;
]]>