File Coverage

lib/Spreadsheet/Engine/Function/NPER.pm

Criterion	Covered	Total	%
statement	23	23	100.0
branch	7	10	70.0
condition	5	8	62.5
subroutine	5	5	100.0
pod	2	2	100.0
total	42	48	87.5

package Spreadsheet::Engine::Function::NPER;

use strict;
use warnings;

use base 'Spreadsheet::Engine::Fn::investment';

sub result_type { Spreadsheet::Engine::Value->new(type => 'n') }

sub calculate {
  my ($self, $rate, $payment, $pv, $fv, $type) = @_;
  $fv ||= 0;
  $type = $type ? 1 : 0;

  die Spreadsheet::Engine::Value->num if $rate == 0 && $payment == 0;
  return ($pv + $fv) / (-$payment) if $rate == 0;

  my $part1 = $payment * (1 + $rate * $type) / $rate;
  my $part2 = $pv + $part1;
  die Spreadsheet::Engine::Value->num if $part2 == 0 || $rate <= -1;

  my $part3 = ($part1 - $fv) / $part2;
  die Spreadsheet::Engine::Value->num if $part3 <= 0;

  my $part4 = log($part3);
  my $part5 = log(1 + $rate);    # rate > -1
  return $part4 / $part5;
}

1;

__END__