Why not adopt me?
NAME
Set::IntSpan::Fast - Fast handling of sets containing integer spans.
VERSION
This document describes Set::IntSpan::Fast version 0.0.8
SYNOPSIS
use Set::IntSpan::Fast;
my $set = Set::IntSpan::Fast->new();
$set->add(1, 3, 5, 7, 9);
$set->add_range(100, 1_000_000);
print $set->as_string(), "\n"; # prints 1,3,5,7,9,100-1000000
DESCRIPTION
The Set::IntSpan
module represents sets of integers as a number of inclusive ranges, for example '1-10,19-23,45-48'. Because many of its operations involve linear searches of the list of ranges its overall performance tends to be proportional to the number of distinct ranges. This is fine for small sets but suffers compared to other possible set representations (bit vectors, hash keys) when the number of ranges grows large.
This module also represents sets as ranges of values but stores those ranges in order and uses a binary search for many internal operations so that overall performance tends towards O log N where N is the number of ranges.
The internal representation used by this module is extremely simple: a set is represented as a list of integers. Integers in even numbered positions (0, 2, 4 etc) represent the start of a run of numbers while those in odd numbered positions represent the ends of runs. As an example the set (1, 3-7, 9, 11, 12) would be represented internally as (1, 2, 3, 8, 11, 13).
Sets may be infinite - assuming you're prepared to accept that infinity is actually no more than a fairly large integer. Specifically the constants Set::IntSpan::Fast::NEGATIVE_INFINITY
and Set::IntSpan::Fast::POSITIVE_INFINITY
are defined to be -(2^31-1) and (2^31-2) respectively. To create an infinite set invert an empty one:
my $inf = Set::IntSpan::Fast->new()->complement();
Sets need only be bounded in one direction - for example this is the set of all positive integers (assuming you accept the slightly feeble definition of infinity we're using):
my $pos_int = Set::IntSpan::Fast->new();
$pos_int->add_range(1, $pos_int->POSITIVE_INFINITY);
INTERFACE
new()
-
Create a new, empty set.
copy()
-
Return an identical copy of the set.
my $new_set = $set->copy();
add( $number ... )
-
Add the specified integers to the set. Any number of arguments may be specified in any order. All arguments must be integers between
Set::IntSpan::NEGATIVE_INFINITY
andSet::IntSpan::POSITIVE_INFINITY
inclusive. remove( $number ... )
-
Remove the specified integers from the set. It is not an error to remove non-members. Any number of arguments may be specified.
add_range($from, $to)
-
Add the inclusive range of integers to the set. Multiple ranges may be specified:
$set->add_range(1, 10, 20, 22, 15, 17);
Each pair of arguments constitute a range. The second argument in each pair must be greater than or equal to the first.
add_from_string($string)
-
Add items to a set from a string representation, of the same form as
as_string
. Multiple strings may be supplied:$set->add_from_string( '1-10, 30-40', '100-200' );
is equivalent to
$set->add_from_string( '1-10, 30-40, 100-200' );
By default items are separated by ',' and ranges delimited by '-'. You may select different punctuation like this:
$set->add_from_string( { sep => ';', range => ':' }, '1;3;5;7:11;19:27' );
When supplying an options hash in this way the
sep
andrange
option may be either a regular expression or a literal string.$set->add_from_string( { sep => qr/:+/, range => qr/[.]+/ }, '1::3::5:7...11:19..27' );
And embedded whitespace in the string will be ignored.
remove_range($from, $to)
-
Remove the inclusive range of integers from the set. Multiple ranges may be specified:
$set->remove_range(1, 10, 20, 22, 15, 17);
Each pair of arguments constitute a range. The second argument in each pair must be greater than or equal to the first.
remove_from_string($string)
-
Remove items to a set from a string representation, of the same form as
as_string
. As withadd_from_string
the punctuation characters may be specified. invert()
-
Complement the set. Because our notion of infinity is actually disappointingly finite inverting a finite set results in another finite set. For example inverting the empty set makes it contain all the integers between
NEGATIVE_INFINITY
andPOSITIVE_INFINITY
inclusive.As noted above
NEGATIVE_INFINITY
andPOSITIVE_INFINITY
are actually just big integers. merge( $set ... )
-
Merge the members of the supplied sets into this set. Any number of sets may be supplied as arguments.
Operators
complement()
-
Returns a new set that is the complement of this set. See the comments about our definition of infinity above.
union( $set ... )
-
Return a new set that is the union of this set and all of the supplied sets. May be called either as a method:
$un = $set->union($other_set);
or as a function:
$un = Set::IntSpan::Fast::union( $set1, $set2, $set3 );
intersection()
-
Return a new set that is the intersection of this set and all the supplied sets. May be called either as a method:
$in = $set->intersection($other_set);
or as a function:
$in = Set::IntSpan::Fast::intersection( $set1, $set2, $set3 );
xor()
-
Return a new set that contains all of the members that are in this set or the supplied set but not both. Can actually handle more than two sets in which case it returns a set that contains all the members that are in some of the sets but not all of the sets.
Can be called as a method or a function.
diff( $set )
-
Return a set containing all the elements that are in this set but not the supplied set.
Tests
is_empty()
-
Return true if the set is empty.
contains($number)
-
Return true if the specified number is contained in the set.
contains_any($number, $number, $number ...)
-
Return true if the set contains any of the specified numbers.
contains_all($number, $number, $number ...)
-
Return true if the set contains all of the specified numbers.
cardinality()
-
Returns the number of members in the set.
superset( $set )
-
Returns true if this set is a superset of the supplied set. A set is always a superset of itself, or in other words
$set->superset($set)
returns true.
subset( $set )
-
Returns true if this set is a subset of the supplied set. A set is always a subset of itself, or in other words
$set->subset($set)
returns true.
equals( $set )
-
Returns true if this set is identical to the supplied set.
Getting set contents
as_array()
-
Return an array containing all the members of the set in ascending order.
as_string()
-
Return a string representation of the set.
my $set = Set::IntSpan::Fast->new(); $set->add(1, 3, 5, 7, 9); $set->add_range(100, 1_000_000); print $set->as_string(), "\n"; # prints 1,3,5,7,9,100-1000000
You may optionally supply a hash containing
sep
andrange
options:print $set->as_string({ sep => ';', range => '*' ), "\n"; # prints 1;3;5;7;9;100*1000000
iterate_runs()
-
Returns an iterator that returns each run of integers in the set in ascending order. To iterate all the members of the set do something like this:
my $iter = $set->iterate_runs(); while (my ($from, $to) = $iter->()) { for my $member ($from .. $to) { print "$member\n"; } }
Constants
The constants NEGATIVE_INFINITY
and POSITIVE_INFINITY
are exposed. As noted above these are infinitely smaller than infinity but they're the best we've got. They're not exported into the caller's namespace so if you want to use them you'll have to use their fully qualified names:
$set->add_range(1, Set::IntSpan::Fast::POSITIVE_INFINITY);
DIAGNOSTICS
Range list must have an even number of elements
-
The lists of ranges passed to
add_range
andremove_range
consist of a number of pairs of integers each of which specify the start and end of a range. Range limits must be integers
-
You may only add integers to sets.
Range limits must be in ascending order
-
When specifying a range in a call to
add_range
orremove_range
the range bounds must be in ascending order. Multiple ranges don't need to be in any particular order. Value out of range
-
Sets may only contain values in the range
NEGATIVE_INFINITY
toPOSITIVE_INFINITY
inclusive. That's very kind of you - but I expect you meant complement()
-
The method that complements a set is called
complement
. I need two sets to compare
-
superset
andsubset
need two sets to compare. They may be called either as a function:$ss = Set::IntSpan::Fast::subset( $s1, $s2 )
or as a method:
$ss = $s1->subset($s2);
Invalid Range String
-
The range string must only contain a comma separated list of ranges, with a hyphen used as the range limit separator. e.g. "1,5,8-12,15-29".
CONFIGURATION AND ENVIRONMENT
Set::IntSpan::Fast requires no configuration files or environment variables.
DEPENDENCIES
Data::Types
List::Util
INCOMPATIBILITIES
Although this module was conceived as a replacement for Set::IntSpan
it isn't a drop-in replacement.
BUGS AND LIMITATIONS
No bugs have been reported.
Please report any bugs or feature requests to bug-set-intspan-fast@rt.cpan.org
, or through the web interface at http://rt.cpan.org.
AUTHOR
Andy Armstrong <andy@hexten.net>
CREDITS
K. J. Cheetham http://www.shadowcatsystems.co.uk/ for add_from_string, remove_from_string. I butchered his code so any errors are mine.
LICENCE AND COPYRIGHT
Copyright (c) 2006, Andy Armstrong <andy@hexten.net>
. All rights reserved.
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.
DISCLAIMER OF WARRANTY
BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.