sub funpack {
    my ($template, $source) = @_;
    my @fields;
    push @fields, $2 while $template =~ s/(\D\d+)(\S+)/$1/;
    my $hash = {};
    @$hash{@fields} = unpack $template, $source;
    return $hash
}

my $data = funpack 'A20name A1sex A3age A8salary A12sign', $foo;