Whats the most efficient way of adding milliseconds to this code?

Question

#-----------------------------------------------------------------------------
#
# Get time string
#
#-----------------------------------------------------------------------------
#
sub formatTime
    {
    my ( $seconds )  = @_;

    my( $sec, $min, $hour, $mday, $mon, $year, $wday, $yday, $isdst ) =
                                localtime( $seconds );
    $year += 1900;
    $mon += 1;

    return ( sprintf "%02d/%02d/%04d %02d:%02d:%02d",
                $mday,$mon,$year,$hour,$min,$sec );
    }

#-----------------------------------------------------------------------------
#
# Extract time from the string
#
#-----------------------------------------------------------------------------
#
sub extractTime
    {
    my ( $edate, $time ) = @_;

    my $date =  $1 if ($edate =~ /(\d+\/\d+\/\d+)/);    # remove leading '[' etc.
    my ( $mday, $mon, $year ) = split( /\//, $date );
    my ( $hour,$min, $sec ) = split( /:/, $time );

    return (timelocal( $sec, $min, $hour, $mday, ($mon - 1), ($year - 1900 )));
    }

Answer 1

In order to to get a higher precision for you function formatTime, you need to take in miliseconds, rather than seconds. You can't take rounded seconds and make it more precise.

Since localtime() only accepts seconds since epoch, you will need to convert the miliseconds passed in and convert it to seconds. Here is an example:

use POSIX qw(floor);

sub formatTime {
    my ( $milliseconds )  = @_;

    my $seconds = floor($milliseconds / 1000);
    my $msec = $milliseconds % 1000;

    my( $sec, $min, $hour, $mday, $mon, $year, $wday, $yday, $isdst ) =
                                localtime( $seconds );
    $year += 1900;
    $mon += 1;

    return ( sprintf "%02d/%02d/%04d %02d:%02d:%02d:%04d",
                $mday,$mon,$year,$hour,$min,$sec,$msec );
}

The other option would be to use the DateTime. If you pass in seconds as a decimal, it can create a DateTime object with greater precision:

use DateTime;

sub formatTime {
    my ( $seconds ) = @_;
    my $dt = DateTime->from_epoch( epoch => $seconds );
    # ....
}