This file is indexed.

/usr/share/perl5/Bio/Map/PositionI.pm is in libbio-perl-perl 1.6.924-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
#
# BioPerl module for Bio::Map::PositionI
#
# Please direct questions and support issues to <bioperl-l@bioperl.org> 
#
# Cared for by Sendu Bala <bix@sendu.me.uk>
#
# Copyright Jason Stajich
#
# You may distribute this module under the same terms as perl itself

# POD documentation - main docs before the code

=head1 NAME

Bio::Map::PositionI - Abstracts the notion of a position having a value in the context of a marker and a Map

=head1 SYNOPSIS

    # do not use this module directly
    # See Bio::Map::Position for an example of
    # implementation.

=head1 DESCRIPTION

This object stores one of the postions that a mappable object
(e.g. Marker) may have in a map.

Positions can have non-numeric values or other methods to store the locations,
so they have a method numeric() which does the conversion. numeric()
returns the position in a form that can be compared between other positions of
the same type. It is not necessarily a value suitable for sorting positions (it
may be the distance from the previous position); for that purpose the result of
sortable() should be used.

A 'position', in addition to being a single point, can also be an area and so
can be imagined as a range and compared with other positions on the basis of
overlap, intersection etc.

=head1 FEEDBACK

=head2 Mailing Lists

User feedback is an integral part of the evolution of this and other
Bioperl modules. Send your comments and suggestions preferably to
the Bioperl mailing list.  Your participation is much appreciated.

  bioperl-l@bioperl.org                  - General discussion
  http://bioperl.org/wiki/Mailing_lists  - About the mailing lists

=head2 Support 

Please direct usage questions or support issues to the mailing list:

I<bioperl-l@bioperl.org>

rather than to the module maintainer directly. Many experienced and 
reponsive experts will be able look at the problem and quickly 
address it. Please include a thorough description of the problem 
with code and data examples if at all possible.

=head2 Reporting Bugs

Report bugs to the Bioperl bug tracking system to help us keep track
of the bugs and their resolution. Bug reports can be submitted via the
web:

  https://github.com/bioperl/bioperl-live/issues

=head1 AUTHOR - Jason Stajich

Email jason-at-bioperl.org

=head1 CONTRIBUTORS

Lincoln Stein, lstein-at-cshl.org
Heikki Lehvaslaiho, heikki-at-bioperl-dot-org
Sendu Bala, bix@sendu.me.uk

=head1 APPENDIX

The rest of the documentation details each of the object methods.
Internal methods are usually preceded with a _

=cut

# Let the code begin...

package Bio::Map::PositionI;
use strict;
use Bio::Map::PositionHandler;
use Bio::Map::Mappable;
use Scalar::Util qw(looks_like_number);

use base qw(Bio::Map::EntityI Bio::RangeI);

=head2 EntityI methods

 These are fundamental to coordination of Positions and other entities, so are
 implemented at the interface level

=cut

=head2 get_position_handler

 Title   : get_position_handler
 Usage   : my $position_handler = $entity->get_position_handler();
 Function: Gets a PositionHandlerI that $entity is registered with.
 Returns : Bio::Map::PositionHandlerI object
 Args    : none

=cut

sub get_position_handler {
    my $self = shift;
    unless (defined $self->{_eh}) {
        my $ph = Bio::Map::PositionHandler->new(-self => $self);
        $self->{_eh} = $ph;
        $ph->register;
    }
    return $self->{_eh};
}

=head2 PositionHandlerI-related methods

 These are fundamental to coordination of Positions and other entities, so are
 implemented at the interface level

=cut

=head2 map

 Title   : map
 Usage   : my $map = $position->map();
           $position->map($map);
 Function: Get/Set the map the position is in.
 Returns : L<Bio::Map::MapI>
 Args    : none to get
           new L<Bio::Map::MapI> to set

=cut

sub map {
    my ($self, $map) = @_;
    return $self->get_position_handler->map($map);
}

=head2 element

 Title   : element
 Usage   : my $element = $position->element();
           $position->element($element);
 Function: Get/Set the element the position is for.
 Returns : L<Bio::Map::MappableI>
 Args    : none to get
           new L<Bio::Map::MappableI> to set

=cut

sub element {
    my ($self, $element) = @_;
    return $self->get_position_handler->element($element);
}

=head2 marker

 Title   : marker
 Function: This is a synonym of the element() method
 Status  : deprecated, will be removed in the next version

=cut

*marker = \&element;

=head2 PositionI-specific methods

=cut

=head2 value

 Title   : value
 Usage   : my $pos = $position->value();
 Function: Get/Set the value for this position
 Returns : scalar, value
 Args    : [optional] new value to set

=cut

sub value {
    my $self = shift;
    $self->throw_not_implemented();
}

=head2 numeric

 Title   : numeric
 Usage   : my $num = $position->numeric;
 Function: Read-only method that is guaranteed to return a numeric 
           representation of the start of this position. 
 Returns : scalar numeric
 Args    : none to get the co-ordinate normally (see absolute() method), OR
           Bio::Map::RelativeI to get the co-ordinate converted to be
           relative to what this Relative describes.

=cut

sub numeric {
    my $self = shift;
    $self->throw_not_implemented();
}

=head2 sortable

 Title   : sortable
 Usage   : my $num = $position->sortable();
 Function: Read-only method that is guaranteed to return a value suitable
           for correctly sorting this kind of position amongst other positions
           of the same kind on the same map. Note that sorting different kinds
           of position together is unlikely to give sane results.
 Returns : numeric
 Args    : none

=cut

sub sortable {
    my $self = shift;
    $self->throw_not_implemented();
}

=head2 relative

  Title   : relative
  Usage   : my $relative = $position->relative();
            $position->relative($relative);
  Function: Get/set the thing this Position's coordinates (numerical(), start(),
            end()) are relative to, as described by a Relative object.
  Returns : Bio::Map::RelativeI (default is one describing "relative to the
            start of the Position's map")
  Args    : none to get, OR
            Bio::Map::RelativeI to set

=cut

sub relative {
    my $self = shift;
    $self->throw_not_implemented();
}

=head2 absolute

  Title   : absolute
  Usage   : my $absolute = $position->absolute();
            $position->absolute($absolute);
  Function: Get/set how this Position's co-ordinates (numerical(), start(),
            end()) are reported. When absolute is off, co-ordinates are
            relative to the thing described by relative(). Ie. the value
            returned by start() will be the same as the value you set start()
            to. When absolute is on, co-ordinates are converted to be relative
            to the start of the map.

            So if relative() currently points to a Relative object describing
            "relative to another position which is 100 bp from the start of
            the map", this Position's start() had been set to 50 and absolute()
            returns 1, $position->start() will return 150. If absolute() returns
            0 in the same situation, $position->start() would return 50.

  Returns : boolean (default 0)
  Args    : none to get, OR
            boolean to set

=cut

sub absolute {
    my $self = shift;
    $self->throw_not_implemented();
}

=head2 RangeI-based methods

=cut

=head2 start

  Title   : start
  Usage   : my $start = $position->start();
            $position->start($start);
  Function: Get/set the start co-ordinate of this position.
  Returns : the start of this position
  Args    : scalar numeric to set, OR
            none to get the co-ordinate normally (see absolute() method), OR
            Bio::Map::RelativeI to get the co-ordinate converted to be
            relative to what this Relative describes.

=cut

=head2 end

  Title   : end
  Usage   : my $end = $position->end();
            $position->end($end);
  Function: Get/set the end co-ordinate of this position.
  Returns : the end of this position
  Args    : scalar numeric to set, OR
            none to get the co-ordinate normally (see absolute() method), OR
            Bio::Map::RelativeI to get the co-ordinate converted to be
            relative to what this Relative describes.

=cut

=head2 length

  Title   : length
  Usage   : $length = $position->length();
  Function: Get the length of this position.
  Returns : the length of this position
  Args    : none

=cut

=head2 strand

  Title   : strand
  Usage   : $strand = $position->strand();
  Function: Get the strand of this position; it is always 1 since maps to not
            have strands.
  Returns : 1
  Args    : none

=cut

sub strand {
    return 1;
}

=head2 toString

  Title   : toString
  Usage   : print $position->toString(), "\n";
  Function: stringifies this range
  Returns : a string representation of the range of this Position
  Args    : optional Bio::Map::RelativeI to have the co-ordinates reported
            relative to the thing described by that Relative

=cut

sub toString {
    my $self = shift;
    $self->throw_not_implemented();
}

=head1 RangeI-related methods

These methods work by considering only the values of start() and end(), as
modified by considering every such co-ordinate relative to the start of the map
(ie. absolute(1) is set temporarily during the calculation), or any supplied
Relative. For the boolean methods, when the comparison Position is on the same
map as the calling Position, there is no point supplying a Relative since the
answer will be the same as without. Relative is most useful when comparing
Positions on different maps and you have a Relative that describes some special
place on each map like 'the start of the gene', where the actual start of the
gene relative to the start of the map is different for each map.

The methods do not consider maps during their calculations - things on different
maps can overlap/contain/intersect/etc. each other.

The geometrical methods (intersect, union etc.) do things to the geometry of
ranges, and return Bio::Map::PositionI compliant objects or triplets (start,
stop, strand) from which new positions could be built. When a PositionI is made
it will have a map transferred to it if all the arguments shared the same map.
If a Relative was supplied the result will have that same Relative.

Note that the strand-testing args are there for compatibility with the RangeI
interface. They have no meaning when only using PositionI objects since maps do
not have strands. Typically you will just set the argument to undef if you want
to supply the argument after it.

=head2 equals

  Title   : equals
  Usage   : if ($p1->equals($p2)) {...}
  Function: Test whether $p1 has the same start, end, length as $p2.
  Returns : true if they are describing the same position (regardless of map)
  Args    : arg #1 = a Bio::RangeI (eg. a Bio::Map::Position) to compare this
                     one to (mandatory)
            arg #2 = optional strand-testing arg ('strong', 'weak', 'ignore')
            arg #3 = optional Bio::Map::RelativeI to ask if the Positions
                     equal in terms of their relative position to the thing
                     described by that Relative

=cut

sub equals {
    # overriding the RangeI implementation so we can handle Relative
    my ($self, $other, $so, $rel) = @_;
    
    my ($own_start, $own_end) = $self->_pre_rangei($self, $rel);
    my ($other_start, $other_end) = $self->_pre_rangei($other, $rel);
    
    return ($self->_testStrand($other, $so) and
            $own_start == $other_start and $own_end == $other_end);
}


=head2 less_than

 Title   : less_than
 Usage   : if ($position->less_than($other_position)) {...}
 Function: Ask if this Position ends before another starts.
 Returns : boolean
 Args    : arg #1 = a Bio::RangeI (eg. a Bio::Map::Position) to compare this
                    one to (mandatory)
           arg #2 = optional Bio::Map::RelativeI to ask if the Position is less
                    in terms of their relative position to the thing described
                    by that Relative

=cut

sub less_than {
    my ($self, $other, $rel) = @_;
    
    my ($own_start, $own_end) = $self->_pre_rangei($self, $rel);
    my ($other_start, $other_end) = $self->_pre_rangei($other, $rel);
    
    return $own_end < $other_start;
}

=head2 greater_than

 Title   : greater_than
 Usage   : if ($position->greater_than($other_position)) {...}
 Function: Ask if this Position starts after another ends.
 Returns : boolean
 Args    : arg #1 = a Bio::RangeI (eg. a Bio::Map::Position) to compare this
                    one to (mandatory)
           arg #2 = optional Bio::Map::RelativeI to ask if the Position is
                    greater in terms of their relative position to the thing
                    described by that Relative

=cut

sub greater_than {
    my ($self, $other, $rel) = @_;
    
    my ($own_start, $own_end) = $self->_pre_rangei($self, $rel);
    my ($other_start, $other_end) = $self->_pre_rangei($other, $rel);
    
    return $own_start > $other_end;
}

=head2 overlaps

  Title   : overlaps
  Usage   : if ($p1->overlaps($p2)) {...}
  Function: Tests if $p1 overlaps $p2.
  Returns : True if the positions overlap (regardless of map), false otherwise
  Args    : arg #1 = a Bio::RangeI (eg. a Bio::Map::Position) to compare this
                     one to (mandatory)
            arg #2 = optional strand-testing arg ('strong', 'weak', 'ignore')
            arg #3 = optional Bio::Map::RelativeI to ask if the Positions
                     overlap in terms of their relative position to the thing
                     described by that Relative
            arg #4 = optional minimum percentage length of the overlap before
                     reporting an overlap exists (default 0)

=cut

sub overlaps {
    # overriding the RangeI implementation so we can handle Relative
    my ($self, $other, $so, $rel, $min_percent) = @_;
    $min_percent ||= 0;
    
    my ($own_min, $other_min) = (0, 0);
    if ($min_percent > 0) {
        $own_min = (($self->length / 100) * $min_percent) - 1;
        $other_min = (($other->length / 100) * $min_percent) - 1;
    }
    
    my ($own_start, $own_end) = $self->_pre_rangei($self, $rel);
    my ($other_start, $other_end) = $self->_pre_rangei($other, $rel);
    
    return ($self->_testStrand($other, $so) and not
            (($own_start + $own_min > $other_end or $own_end - $own_min < $other_start) ||
             ($own_start > $other_end - $other_min or $own_end < $other_start + $other_min)));
}

=head2 contains

  Title   : contains
  Usage   : if ($p1->contains($p2)) {...}
  Function: Tests whether $p1 totally contains $p2.
  Returns : true if the argument is totally contained within this position
            (regardless of map), false otherwise
  Args    : arg #1 = a Bio::RangeI (eg. a Bio::Map::Position) to compare this
                     one to, or scalar number (mandatory)
            arg #2 = optional strand-testing arg ('strong', 'weak', 'ignore')
            arg #3 = optional Bio::Map::RelativeI to ask if the Position
                     is contained in terms of their relative position to the
                     thing described by that Relative

=cut

sub contains {
    # overriding the RangeI implementation so we can handle Relative
    my ($self, $other, $so, $rel) = @_;
    
    my ($own_start, $own_end) = $self->_pre_rangei($self, $rel);
    my ($other_start, $other_end) = $self->_pre_rangei($other, $rel);
    
    return ($self->_testStrand($other, $so) and
			$other_start >= $own_start and $other_end <= $own_end);
}

=head2 intersection

 Title   : intersection
 Usage   : ($start, $stop, $strand) = $p1->intersection($p2)
           ($start, $stop, $strand) = Bio::Map::Position->intersection(\@positions);
           $mappable = $p1->intersection($p2, undef, $relative);
           $mappable = Bio::Map::Position->intersection(\@positions);
 Function: gives the range that is contained by all ranges
 Returns : undef if they do not overlap, OR
           Bio::Map::Mappable object who's positions are the
           cross-map-calculated intersection of the input positions on all the
           maps that the input positions belong to, OR, in list context, a three
           element array (start, end, strand)
 Args    : arg #1 = [REQUIRED] a Bio::RangeI (eg. a Bio::Map::Position) to
                    compare this one to, or an array ref of Bio::RangeI
           arg #2 = optional strand-testing arg ('strong', 'weak', 'ignore')
           arg #3 = optional Bio::Map::RelativeI to ask how the Positions
                    intersect in terms of their relative position to the thing
                    described by that Relative

=cut

sub intersection {
    # overriding the RangeI implementation so we can transfer map and handle
    # Relative
    my ($self, $given, $so, $rel) = @_;
	$self->throw("missing arg: you need to pass in another argument") unless $given;
    
    my @positions;
    if ($self eq "Bio::Map::PositionI") {
		$self = "Bio::Map::Position";
		$self->warn("calling static methods of an interface is deprecated; use $self instead");
	}
	if (ref $self) {
		push(@positions, $self);
	}
    ref($given) eq 'ARRAY' ? push(@positions, @{$given}) : push(@positions, $given);
    $self->throw("Need at least 2 Positions") unless @positions >= 2;
    
    my ($intersect, $i_start, $i_end, $c_start, $c_end, %known_maps);
    while (@positions > 0) {
        unless ($intersect) {
            $intersect = shift(@positions);
            ($i_start, $i_end) = $self->_pre_rangei($intersect, $rel);
            my $map = $intersect->map;
            $known_maps{$map->unique_id} = $map;
        }
        
        my $compare = shift(@positions);
        ($c_start, $c_end) = $self->_pre_rangei($compare, $rel);
        return unless $compare->_testStrand($intersect, $so);
        if ($compare->isa('Bio::Map::PositionI')) {
            my $this_map = $compare->map;
            if ($this_map) {
                $known_maps{$this_map->unique_id} = $this_map;
            }
        }
        else {
            $self->throw("Only Bio::Map::PositionI objects are supported, not [$compare]");
        }
        
        my @starts = sort {$a <=> $b} ($i_start, $c_start);
        my @ends   = sort {$a <=> $b} ($i_end, $c_end);
        
        my $start = pop @starts; # larger of the 2 starts
        my $end = shift @ends;   # smaller of the 2 ends
        
        my $intersect_strand;    # strand for the intersection
        if (defined($intersect->strand) && defined($compare->strand) && $intersect->strand == $compare->strand) {
            $intersect_strand = $compare->strand;
        }
        else {
            $intersect_strand = 0;
        }
        
        if ($start > $end) {
            return;
        }
        else {
            $intersect = $self->new(-start  => $start,
                                    -end    => $end,
                                    -strand => $intersect_strand);
        }
    }
    
    $intersect || return;
    my ($start, $end, $strand) = ($intersect->start, $intersect->end, $intersect->strand);
    
    my @intersects;
    foreach my $known_map (values %known_maps) {
        my $new_intersect = $intersect->new(-start => $start,
                                            -end => $end,
                                            -strand => $strand,
                                            -map => $known_map);
        $new_intersect->relative($rel) if $rel;
        push(@intersects, $new_intersect);
    }
    unless (@intersects) {
        $intersect->relative($rel) if $rel;
        @intersects = ($intersect);
    }
    
    my $result = Bio::Map::Mappable->new();
    $result->add_position(@intersects); # sneaky, add_position can take a list of positions
    return $result;
}

=head2 union

 Title   : union
 Usage   : ($start, $stop, $strand) = $p1->union($p2);
           ($start, $stop, $strand) = Bio::Map::Position->union(@positions);
           my $mappable = $p1->union($p2);
           my $mappable = Bio::Map::Position->union(@positions);
 Function: finds the minimal position/range that contains all of the positions
 Returns : Bio::Map::Mappable object who's positions are the
           cross-map-calculated union of the input positions on all the maps
           that the input positions belong to, OR, in list context, a three
           element array (start, end, strand)
 Args    : a Bio::Map::PositionI to compare this one to, or a list of such
           OR
           a single Bio::Map::PositionI or array ref of such AND a
           Bio::Map::RelativeI to ask for the Position's union in terms of their
           relative position to the thing described by that Relative

=cut

sub union {
    # overriding the RangeI implementation so we can transfer map and handle
    # Relative
    my ($self, @args) = @_;
    $self->throw("Not enough arguments") unless @args >= 1;
    
    my @positions;
    my $rel;
    if ($self eq "Bio::Map::PositionI") {
		$self = "Bio::Map::Position";
		$self->warn("calling static methods of an interface is deprecated; use $self instead");
	}
	if (ref $self) {
		push(@positions, $self);
	}
    if (ref $args[0] eq 'ARRAY') {
        push(@positions, @{shift(@args)});
    }
    else {
        push(@positions, shift(@args));
    }
    if ($args[0] && $args[0]->isa('Bio::Map::RelativeI')) {
        $rel = shift(@args);
    }
    foreach my $arg (@args) {
        # avoid pushing undefined values into @positions
        push(@positions, $arg) if $arg;
    }
    $self->throw("Need at least 2 Positions") unless @positions >= 2;
    
    my (@starts, @ends, %known_maps, $union_strand);
    foreach my $compare (@positions) {
        # RangeI union allows start or end to be undefined; however _pre_rangei
        # will throw
        my ($start, $end) = $self->_pre_rangei($compare, $rel);
        
        if ($compare->isa('Bio::Map::PositionI')) {
            my $this_map = $compare->map;
            if ($this_map) {
                $known_maps{$this_map->unique_id} = $this_map;
            }
        }
        else {
            $self->throw("Only Bio::Map::PositionI objects are supported, not [$compare]");
        }
        
        if (! defined $union_strand) {
			$union_strand = $compare->strand;
		}
        else {
			if (! defined $compare->strand or $union_strand ne $compare->strand) {
				$union_strand = 0;
			}
		}
        
        push(@starts, $start);
        push(@ends, $end);
    }
    
	@starts = sort { $a <=> $b } @starts;
	@ends   = sort { $a <=> $b } @ends;
	my $start = shift @starts;
	my $end = pop @ends;
    
    my @unions;
    foreach my $known_map (values %known_maps) {
        my $new_union = $self->new(-start => $start,
                                   -end => $end,
                                   -strand => $union_strand,
                                   -map => $known_map);
        $new_union->relative($rel) if $rel;
        push(@unions, $new_union);
    }
    unless (@unions) {
        @unions = ($self->new(-start => $start,
                         -end => $end,
                         -strand => $union_strand));
        $unions[0]->relative($rel) if $rel;
    }
    
    my $result = Bio::Map::Mappable->new();
    $result->add_position(@unions); # sneaky, add_position can take a list of positions
    return $result;
}

=head2 overlap_extent

 Title   : overlap_extent
 Usage   : ($a_unique,$common,$b_unique) = $a->overlap_extent($b)
 Function: Provides actual amount of overlap between two different
           positions
 Example :
 Returns : array of values containing the length unique to the calling 
           position, the length common to both, and the length unique to 
           the argument position
 Args    : a position

=cut

#*** should this be overridden from RangeI?

=head2 disconnected_ranges

 Title   : disconnected_ranges
 Usage   : my @disc_ranges = Bio::Map::Position->disconnected_ranges(@ranges);
 Function: Creates the minimal set of positions such that each input position is
           fully contained by at least one output position, and none of the
           output positions overlap.
 Returns : Bio::Map::Mappable with the calculated disconnected ranges
 Args    : a Bio::Map::PositionI to compare this one to, or a list of such,
           OR
           a single Bio::Map::PositionI or array ref of such AND a
           Bio::Map::RelativeI to consider all Position's co-ordinates in terms
           of their relative position to the thing described by that Relative,
           AND, optionally, an int for the minimum percentage of overlap that
           must be present before considering two ranges to be overlapping
           (default 0)

=cut

sub disconnected_ranges {
    # overriding the RangeI implementation so we can transfer map and handle
    # Relative
    my ($self, @args) = @_;
    $self->throw("Not enough arguments") unless @args >= 1;
    
    my @positions;
    my $rel;
    my $overlap = 0;
    if ($self eq "Bio::Map::PositionI") {
		$self = "Bio::Map::Position";
		$self->warn("calling static methods of an interface is deprecated; use $self instead");
	}
	if (ref $self) {
		push(@positions, $self);
	}
    if (ref $args[0] eq 'ARRAY') {
        push(@positions, @{shift(@args)});
    }
    else {
        push(@positions, shift(@args));
    }
    if ($args[0] && $args[0]->isa('Bio::Map::RelativeI')) {
        $rel = shift(@args);
        $overlap = shift(@args);
    }
    foreach my $arg (@args) {
        push(@positions, $arg) if $arg;
    }
    $self->throw("Need at least 2 Positions") unless @positions >= 2;
    
    my %known_maps;
    foreach my $pos (@positions) {
        $pos->isa('Bio::Map::PositionI') || $self->throw("Must supply only Bio::Map::PositionI objects, not [$pos]");
        my $map = $pos->map || next;
        $known_maps{$map->unique_id} = $map;
    }
    my %prior_positions;
    foreach my $map (values %known_maps) {
        foreach my $pos ($map->get_positions) {
            $prior_positions{$pos} = 1;
        }
    }
    
    my @outranges = ();
    foreach my $inrange (@positions) {
        my @outranges_new = ();
        my %overlapping_ranges = ();
        
        for (my $i=0; $i<@outranges; $i++) {
            my $outrange = $outranges[$i];
            if ($inrange->overlaps($outrange, undef, $rel, $overlap)) {
                my $union_able = $inrange->union($outrange, $rel); # using $inrange->union($outrange, $rel); gives >6x speedup,
                                                                   # but different answer, not necessarily incorrect...
                foreach my $pos ($union_able->get_positions) {
                    $overlapping_ranges{$pos->toString} = $pos; # we flatten down to a result on a single map
                                                                # to avoid creating 10s of thousands of positions during this process;
                                                                # we then apply the final answer to all maps at the very end
                    last;
                }
            }
            else {
                push(@outranges_new, $outrange);
            }
        }
        
        @outranges = @outranges_new;
        
        my @overlappers = values %overlapping_ranges;
        if (@overlappers) {
            if (@overlappers > 1) {
                my $merged_range_able = shift(@overlappers)->union(\@overlappers, $rel);
                push(@outranges, $merged_range_able->get_positions);
            }
            else {
                push(@outranges, @overlappers);
            }
        }
        else {
            push(@outranges, $self->new(-start => $inrange->start($rel), -end => $inrange->end($rel), -strand => $inrange->strand, -map => $inrange->map, -relative => $rel));
        }
    }
    
    # purge positions that were created whilst calculating the answer, but
    # aren't the final answer and weren't there previously
    my %answers = map { $_ => 1 } @outranges;
    foreach my $map (values %known_maps) {
        foreach my $pos ($map->get_positions) {
            if (! exists $prior_positions{$pos} && ! exists $answers{$pos}) {
                $map->purge_positions($pos);
            }
        }
    }
    
    my %post_positions;
    foreach my $map (values %known_maps) {
        foreach my $pos ($map->get_positions) {
            $post_positions{$pos} = 1;
        }
    }
    
    @outranges || return;
    
    # make an outrange on all known maps
    my @final_positions;
    foreach my $map (values %known_maps) {
        foreach my $pos (@outranges) {
            if ($pos->map eq $map) {
                push(@final_positions, $pos);
            }
            else {
                push(@final_positions, $pos->new(-start => $pos->start,
                                                 -end => $pos->end,
                                                 -relative => $pos->relative,
                                                 -map => $map));
            }
        }
    }
    
    # assign the positions to a result mappable
    my $result = Bio::Map::Mappable->new();
    $result->add_position(@final_positions); # sneaky, add_position can take a list of positions
    return $result;
}

# get start & end suitable for rangeI methods, taking relative into account
sub _pre_rangei {
    my ($self, $other, $rel) = @_;
    $self->throw("Must supply an object") unless $other;
    if ($rel) {
        $self->throw("Must supply an object for the Relative argument") unless ref($rel);
        $self->throw("This is [$rel], not a Bio::Map::RelativeI") unless $rel->isa('Bio::Map::RelativeI');
    }
    
    my ($other_start, $other_end);
    if (ref($other)) {
        if (ref($other) eq 'ARRAY') {
            $self->throw("_pre_rangei got an array");
        }
        $self->throw("This is [$other], not a Bio::RangeI object") unless defined $other && $other->isa('Bio::RangeI');
        
        if ($other->isa('Bio::Map::PositionI')) {
            # to get the desired start/end we need the position to be on a map;
            # if it isn't on one temporarily place it on self's map
            # - this lets us have 'generic' positions that aren't on any map
            # but have a relative defined and can thus be usefully compared to
            # positions that /are/ on maps
            my $other_map = $other->map;
            unless ($other_map) {
                my $self_map = $self->map || $self->throw("Trying to compare two positions but neither had been placed on a map");
                $other->map($self_map);
            }
            
            # want start and end positions relative to the supplied rel or map start
            $rel ||= $other->absolute_relative;
            $other_start = $other->start($rel);
            $other_end = $other->end($rel);
            
            unless ($other_map) {
                $self->map->purge_positions($other);
            }
        }
        else {
            $other_start = $other->start;
            $other_end = $other->end;
        }
    }
    else {
        $self->throw("not a number") unless looks_like_number($other);
        $other_start = $other_end = $other;
    }
    
	$other->throw("start is undefined") unless defined $other_start;
	$other->throw("end is undefined") unless defined $other_end;
    
    return ($other_start, $other_end);
}

1;