# Copyright 2010, 2011, 2013 Kevin Ryde
# This file is part of Math-NumSeq.
#
# Math-NumSeq is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 3, or (at your option) any later
# version.
#
# Math-NumSeq is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
# for more details.
#
# You should have received a copy of the GNU General Public License along
# with Math-NumSeq. If not, see <http://www.gnu.org/licenses/>.
package Math::NumSeq::ChampernowneBinaryLsb;
use 5.004;
use strict;
use vars '$VERSION', '@ISA';
$VERSION = 86;
use Math::NumSeq;
@ISA = ('Math::NumSeq');
use constant name => Math::NumSeq::__('Champernowne Sequence LSB First');
use constant description => Math::NumSeq::__('The 1-bit positions when the integers 1,2,3,4,5 etc are written out concatenated in binary, least significant bit first, 1 01 11 001 101 etc.');
use constant characteristic_increasing => 1;
use constant i_start => 1;
use constant values_min => 0;
# uncomment this to run the ### lines
#use Smart::Comments;
# Champernowne sequence in binary 1s and 0s
# http://oeis.org/
#
# as integer positions
# http://oeis.org/A030310
# http://oeis.org/A030303
#
# 1 10 11 100 101 110 111
# 1 2 4,5 6 9,11 12,13 15,16,17,
#
sub rewind {
my ($self) = @_;
$self->{'i'} = $self->i_start;
$self->{'n'} = 0;
$self->{'val'} = 0;
$self->{'bitmask'} = 1;
}
sub next {
my ($self) = @_;
my $bitmask = $self->{'bitmask'};
for (;;) {
if ($bitmask > $self->{'val'}) {
$self->{'val'}++;
$bitmask = 1;
}
$self->{'n'}++;
if ($bitmask & $self->{'val'}) {
$self->{'bitmask'} = $bitmask << 1;
return ($self->{'i'}++, $self->{'n'});
}
$bitmask <<= 1;
}
}
# sub pred {
# my ($self, $n) = @_;
# return ($n & 1);
# }
1;
__END__