/usr/share/perl5/Math/Calc/Units/Convert.pm is in libmath-calc-units-perl 1.07-1.
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 | package Math::Calc::Units::Convert;
use base 'Exporter';
use strict;
use vars qw(@EXPORT_OK);
BEGIN { @EXPORT_OK = qw(convert reduce canonical find_top construct); };
use Math::Calc::Units::Convert::Multi qw(to_canonical);
# convert : value x unit -> value
#
# The lower-level conversion routines really only know how to convert
# things to canonical units. But this routine may be called with eg
# 120 minutes -> hours. So we convert both the current and target to
# canonical units, and divide the first by the second. (Doesn't work
# for adding units that aren't multiples of each other, but that's not
# what this tool is for anyway.)
sub convert {
my ($from, $unit) = @_;
my $to = [ 1, $unit ];
my $canon_from = canonical($from);
my $canon_to = canonical($to);
die "conversion between incompatible units"
if not same_units($canon_from->[1], $canon_to->[1]);
return [ $canon_from->[0] / $canon_to->[0], $unit ];
}
# Are the (canonical) units compatible? (They must have exactly the
# same base units, and each must be raised to exactly the same power.)
sub same_units {
my ($u1, $u2) = @_;
return if keys %$u1 != keys %$u2;
while (my ($bu1, $bp1) = each %$u1) {
return if ! exists $u2->{$bu1};
return if $bp1 != $u2->{$bu1};
}
return 1;
}
sub canonical {
my ($v) = @_;
my $c = to_canonical($v->[1]);
my $w = [ $v->[0] * $c->[0], $c->[1] ];
return $w;
}
sub reduce {
my ($v) = @_;
return canonical($v, 'reduce, please');
}
sub construct {
my ($constructor, $args) = @_;
return Math::Calc::Units::Convert::Multi::construct($constructor, $args);
}
1;
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