File Coverage

blib/lib/Math/Prime/Util/PrimeIterator.pm

Criterion	Covered	Total	%
statement	65	72	90.2
branch	9	12	75.0
condition	2	3	66.6
subroutine	25	28	89.2
pod	21	21	100.0
total	122	136	89.7

package Math::Prime::Util::PrimeIterator;
use strict;
use warnings;

BEGIN {
  $Math::Prime::Util::PrimeIterator::AUTHORITY = 'cpan:DANAJ';
  $Math::Prime::Util::PrimeIterator::VERSION = '0.73';
}

use base qw( Exporter );
our @EXPORT_OK = qw( );
our %EXPORT_TAGS = (all => [ @EXPORT_OK ]);


use Math::Prime::Util qw/next_prime prev_prime is_prime prime_count nth_prime/;

# We're going to use a scalar rather than a hash because there is currently
# only one data object (the current value) and this makes it little faster.

sub new {
  my ($class, $start) = @_;
  my $p = 2;
  my $self = bless \$p, $class;
  $self->rewind($start) if defined $start;
  return $self;
}

# To make Iterator::Simple happy.
sub __iter__ {
  my $self = shift;
  require Iterator::Simple;
  return Iterator::Simple::iterator(sub { $self->iterate });
  $self;
}

sub value { ${$_[0]}; }
sub next {
  #my $self = shift;  $$self = next_prime($$self);  return $self;
  ${$_[0]} = next_prime(${$_[0]});
  return $_[0];
}
sub prev {
  my $self = shift;
  my $p = $$self;
  $$self = ($p <= 2) ? 2 : prev_prime($p);
  return $self;
}
sub iterate {
  #my $self = shift;  my $p = $$self;  $$self = next_prime($p);  return $p;
  my $p = ${$_[0]};
  ${$_[0]} = next_prime(${$_[0]});
  return $p;
}

sub rewind {
  my ($self, $start) = @_;
  $$self = 2;
  if (defined $start && $start ne '2') {
    Math::Prime::Util::_validate_num($start)
      || Math::Prime::Util::_validate_positive_integer($start);
    $$self = next_prime($start-1) if $start > 2;
  }
  return $self;
}

sub peek {
  return next_prime(${$_[0]});
}

# Some methods to match Math::NumSeq
sub tell_i {
  return prime_count(${$_[0]});
}
sub pred {
  my($self, $n) = @_;
  return is_prime($n);
}
sub ith {
  my($self, $n) = @_;
  return nth_prime($n);
}
sub seek_to_i {
  my($self, $n) = @_;
  $self->rewind( nth_prime($n) );
}
sub seek_to_value {
  my($self, $n) = @_;
  $self->rewind($n);
}
sub value_to_i {
  my($self, $n) = @_;
  return unless is_prime($n);
  return prime_count($n);
}
sub value_to_i_ceil {
  my($self, $n) = @_;
  return prime_count(next_prime($n-1));
}
sub value_to_i_floor {
  my($self, $n) = @_;
  return prime_count($n);
}
sub value_to_i_estimate {
  my($self, $n) = @_;
  return Math::Prime::Util::prime_count_approx($n);
}
sub i_start     { 1 }
sub description { "The prime numbers 2, 3, 5, 7, 11, 13, 17, etc." }
sub values_min  { 2 }
sub values_max  { undef }
sub oeis_anum   { "A000040" }
1;

__END__