use strict;
use warnings;

my @time_str_list = ( "abc", "1abc", ":", ":,", "5:29,11", "29,11", "29:00", "29:00,3", "29:00,303", "9:13,07",  ",11", "0:11", "5:29" );
my $seconds;

for my $time_str ( @time_str_list )
{        
    &convertTimeStrToSeconds($time_str, \$seconds);
	next unless defined $seconds;
	print("$time_str\n");
    print("$seconds\n");
    
    &convertSecondsToTimeStr($seconds, \$time_str);
	next unless defined $time_str;
    print("$time_str\n");

    print("\n");
}

sub convertTimeStrToSeconds
{
    my ($time_str, $ref_seconds) = @_;
    
    # 1) min:sec,frac  e.g. "5:29,11"
    # 2) sec,frac      e.g. "29,11"
    # 3) sec           e.g. "29"
    # 4) ,frac         e.g. ",11"
    # 5) min:sec       e.g. "5:29"
    # 6) someth. else  e.g. "abc"

    $$ref_seconds = undef; # 6)

    # remove leading and trailing whitespace characters
    $time_str =~ s/^\s+|\s+$//g;

    # valid time string
    if( ($time_str =~ m/^(?<min>\d+):(?<sec>\d+),(?<frac>\d+)$/) ||# 1)
		($time_str =~ m/^(?<sec>\d+),(?<frac>\d+)$/) ||          # 2)
		($time_str =~ m/^(?<sec>\d+)$/) ||                       # 3)
		($time_str =~ m/^,(?<frac>\d+)$/) ||                     # 4)
		($time_str =~ m/^(?<min>\d+):(?<sec>\d+)$/) )            # 5)
		
    {
		no warnings 'uninitialized'; # intention: undef treated as zero
		$$ref_seconds = ($+{'min'} * 60.0) + $+{'sec'} + ($+{'frac'}/(10**length($+{'frac'})));    
    }
}


sub convertSecondsToTimeStr
{
    my ($seconds, $ref_time_str) = @_;

    $$ref_time_str = undef;

    if( $seconds > 0 )
    {
		my $min = int($seconds / 60.0);
		my $sec = $seconds % 60.0;
		my $frac = int(sprintf("%.2f", ($seconds - int($seconds))*100.0));
		
		$$ref_time_str = "$min:" if( $min > 0 );
		$$ref_time_str .= sprintf("%02d", $sec) if ( ($min > 0) || ($sec > 0) );
		$$ref_time_str .= ",$frac" if ( $frac > 0 );
    }
}