use strict;
#use warnings; # sprintf doesn't like nulls as values

my %test = ( ''        => 0,
             '.5'      => 0,
             1         => 0,
             '3.'      => 0,
             100       => 4,
             12.4      => 1,
             12.56     => 0,
             12.45435  => 0,
             123.45678 => 3,
             3.14      => 5,
             1         => 5,
             10        => 5,
             100       => 5,
             1000      => 5,
           );

printf('value|precision'."%12s"x4 ."\n", qw(sprintf Incognito Albannach jeffa));
while (my ($v,$p)= each %test) {
  printf("%14s:","'$v'|$p");
  printf("%12s"x4 ."\n", 
    sprintf("%.${p}f", $v), Incognito($v,$p), Albannach($v,$p), jeffa($v,$p) );
}

sub Albannach {
  my($val, $pre) = @_;
  $val =~ s/(\d*)(\.?)(\d*)/"$1".($pre?'.':'').substr($3.'0'x$pre, 0, $pre)/e;
  $val;
}

sub Incognito {
  my ($strValue,$strPrecision) = @_;

  # Pad the number with a bunch of zeros
  $strValue =~ s/^(\d*)\.?(\d*)$/${1}.${2}000000000/;

  # Remove all but the first '$strPrecision' digits that immediately
  # trail the decimal point.
  my $strDefaultPrecision = 2;
  $strPrecision = ($strPrecision >= 0) ? $strPrecision : $strDefaultPrecision;
  if ($strPrecision == 0) {
    $strValue =~ s/^(\d*)\.?\d*$/$1/;
  } else {
    $strValue =~ s/^(\d*\.\d{$strPrecision})\d*$/$1/;
  }
  $strValue;
}

sub jeffa {
  my ($str,$pad) = @_;
  my ($add,$right);

  ($str,$right) = split('\.',$str,2);
  $right = ($right) ? ".$right" : '';
  $add   = $pad - length($str);

  return $str if $add < 1;
  return ('0' x $add) . $str . $right;
}