Attacker Success Probability function

AttackerSuccessProbability.js

// Function extracted from http://web.archive.org/web/20200502141047/https://people.xiph.org/~greg/attack_success.html
// $q: Porportion of hash power, 0.0 to 1.0
// $z: Number of confirmations
function _AttackerSuccessProbability($q, $z) {
  var label = 0;
  label = 2;
  while (1) switch (label) {
   case 2:
    var $1 = 1 - $q;
    var $2 = $z | 0;
    var $3 = $q / $1;
    var $4 = $2 * $3;
    var $5 = $q > .5;
    var $6 = ($z | 0) < 0;
    var $or_cond = $5 | $6;
    if ($or_cond) {
      var $_0 = 1;
      label = 7;
      break;
    } else {
      label = 3;
      break;
    }
   case 3:
    var $7 = -$4;
    var $8 = Math.exp($7);
    var $9 = $z + 1 | 0;
    var $sum_019 = 1;
    var $k_020 = 0;
    var $indvars_iv = 1;
    label = 4;
    break;
   case 4:
    var $indvars_iv;
    var $k_020;
    var $sum_019;
    var $11 = ($k_020 | 0) < 1;
    if ($11) {
      var $poisson_0_lcssa = $8;
      label = 6;
      break;
    } else {
      var $i_017 = 1;
      var $poisson_018 = $8;
      label = 5;
      break;
    }
   case 5:
    var $poisson_018;
    var $i_017;
    var $12 = $i_017 | 0;
    var $13 = $4 / $12;
    var $14 = $poisson_018 * $13;
    var $15 = $i_017 + 1 | 0;
    var $exitcond = ($15 | 0) == ($indvars_iv | 0);
    if ($exitcond) {
      var $poisson_0_lcssa = $14;
      label = 6;
      break;
    } else {
      var $i_017 = $15;
      var $poisson_018 = $14;
      label = 5;
      break;
    }
   case 6:
    var $poisson_0_lcssa;
    var $16 = $z - $k_020 | 0;
    var $17 = $16 | 0;
    var $18 = Math.pow($3, $17);
    var $19 = 1 - $18;
    var $20 = $poisson_0_lcssa * $19;
    var $21 = $sum_019 - $20;
    var $22 = $k_020 + 1 | 0;
    var $indvars_iv_next = $indvars_iv + 1 | 0;
    var $exitcond24 = ($22 | 0) == ($9 | 0);
    if ($exitcond24) {
      var $_0 = $21;
      label = 7;
      break;
    } else {
      var $sum_019 = $21;
      var $k_020 = $22;
      var $indvars_iv = $indvars_iv_next;
      label = 4;
      break;
    }
   case 7:
    var $_0;
    return $_0;
  }
}