p6.p6

# use Benchy;
use nqp;

multi huge_log_10 (Int $n) {
    nqp::if(
      nqp::islt_I($n, 10**300),
      nqp::div_n(nqp::log_n(nqp::tonum_I(nqp::decont($n))), nqp::log_n(10e0)),
      nqp::stmts(
        (my num $ans = 0e0),
        (my $leftovers := nqp::decont($n)),
        nqp::while(
          nqp::isgt_I($leftovers, 10**300),
          ($ans = nqp::add_n($ans,
            nqp::div_n(nqp::log_n(1e300), nqp::log_n(10e0)))),
          $leftovers := nqp::div_I($leftovers, 10**300, Int)),
        nqp::add_n($ans,
          nqp::div_n(nqp::log_n(nqp::tonum_I($leftovers)), nqp::log_n(10e0)) )))
}

# my $v = 10**200;
# b 1000_000,
#     { log10 $v },
#     { huge_log_10 $v };

say huge_log_10 $_ for 10, 10**100, 10**99, 10**1000, 10**10000