sub funpack {
    my ($template, $source) = @_;
    my %hash = map { reverse split /:/, $_, 2 } split " ", $template;
    local $" = ' ';
    @hash{keys %hash} = unpack "@{[ values %hash ]}", $source;
    return \%hash;
}

my $data = funpack 'A20:name A1:sex A3:age A8:salary A12:sign', $foo;
[download]

(Field names may start with a digit with this data format. I also find it easier on the eye.)

Update: D'oh. Always test before posting.. Of course the above code doesn't preserve the order of fields, which is crucial.

sub funpack {
    my ($template, $source) = @_;

    my ($i, @field, @format) = 0;
    push @{ (\@format, \@field)[$i++ & 1] }, $_
        for map /^([^:]+):(.*)/, split " ", $template;

    local $" = " ";
    return { map +(shift(@format) => $_), unpack "@format", $source };
}

my $data = funpack 'A20:name A1:sex A3:age A8:salary A12:sign', $foo;
[download]

Makeshifts last the longest.