Acme-Time-Constant

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lib/Acme/Time/Constant.pm  view on Meta::CPAN

This code contains within it, the golden calf of computer science: The ability to execute any code in constant time.

  use Acme::Time::Constant qw( constant_time );

  my $timestamp = time;

  constant_time( '1' => sub {
    for ( 0 .. 10 ) { }
  } );

  print $timestamp - time;  # 1 second

  constant_time( '1' => sub {
    for ( 0 .. 10_000_000 ) { }
  } );

  print $timestamp - time; # 2 seconds

=head1 BUGS

=head4 General relativity does not hold in the context of this code.

As such, observed time may differ greatly from the time relative to the execution of this code.

B<Workaround:> Get closer to the speed of light.

=head4 Measurements may not be exactly constant.

But Big O is OK with this.  We care not that X takes 1.1 seconds and Y takes 1.2 seconds, as long as the variation
is not subject to the size of Y or X.

Random variation between 0.5 and 1.5 seconds is thus within the range of "constant".

B<Workaround:> Imbibe a minimum of 1 L<< Litre|https://en.wikipedia.org/wiki/Litre >> of your favourite neurotoxic substance
before attempting to code.

=head4 Time::HiRes cannot be trusted.

C<Time::HiRes> is under the influence of the Illuminati and as such is part of a conspiracy to prevent us from experiencing
supernormal time.

Using C<Time::HiRes> in your code will subsequently give the illusion that the code no longer executes in constant time.

lib/Acme/Time/Constant.pm  view on Meta::CPAN

knowledge of.

One may note that this module depends on C<Time::HiRes>, but this is simply our devilish tactic to make the conspirators
think we're willingly playing for them. You know better. ;)

=head1 FUNCTIONS

=head2 C<constant_time>

  constant_time( $time, $callback );
  constant_time( $callback ); # $time defaults to 1 second.

=head1 AUTHOR

Kent Fredric <kentnl@cpan.org>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2017 by Kent Fredric <kentfredric@gmail.com>.

This is free software; you can redistribute it and/or modify it under

t/00-report-prereqs.t  view on Meta::CPAN

    $full_prereqs = _merge_prereqs($full_prereqs, $meta->prereqs);
}
else {
    $source = 'static metadata';
}

my @full_reports;
my @dep_errors;
my $req_hash = $HAS_CPAN_META ? $full_prereqs->as_string_hash : $full_prereqs;

# Add static includes into a fake section
for my $mod (@include) {
    $req_hash->{other}{modules}{$mod} = 0;
}

for my $phase ( qw(configure build test runtime develop other) ) {
    next unless $req_hash->{$phase};
    next if ($phase eq 'develop' and not $ENV{AUTHOR_TESTING});

    for my $type ( qw(requires recommends suggests conflicts modules) ) {
        next unless $req_hash->{$phase}{$type};

t/basic.t  view on Meta::CPAN

my $timestamp = time;
constant_time(
  1 => sub {
    my $j;
    for my $i ( 0 .. 1 ) {
      $j += $i;
    }
  }
);
my $delta = time - $timestamp;
cmp_ok( $delta, '>', 0.5, 'Constant time fixed at at least 0.5 second pass 1' );
cmp_ok( $delta, '<', 1.5, 'Constant time fixed at at most 1.5 second pass 1' );

$timestamp = time;
constant_time(
  1 => sub {
    my $j;
    for my $i ( 0 .. 2_000_000 ) {
      $j += $i;
    }
  }
);
$delta = time - $timestamp;
cmp_ok( $delta, '>', 0.5, 'Constant time fixed at at least 0.5 second pass 2' );
cmp_ok( $delta, '<', 1.5, 'Constant time fixed at at most 1.5 second pass 2' );

done_testing;

t/noargs.t  view on Meta::CPAN

my $timestamp = time;
constant_time(
  sub {
    my $j;
    for my $i ( 0 .. 1 ) {
      $j += $i;
    }
  }
);
my $delta = time - $timestamp;
cmp_ok( $delta, '>', 0.5, 'Constant time fixed at at least 0.5 second pass 1' );
cmp_ok( $delta, '<', 1.5, 'Constant time fixed at at most 1.5 second pass 1' );

done_testing;