Testing base conversion

convert.php

<?php

// $foo = "12524176338753030162";
// $foo = "12524176338";
$foo = $argv[1];

function bcdechex($dec) {
    $hex = '';
    do {
        $last = bcmod($dec, 16);
        $hex = dechex($last).$hex;
        $dec = bcdiv(bcsub($dec, $last), 16);
    } while($dec>0);
    return $hex;
}

function my_base_convert($numstring, $frombase, $tobase)
{
  $chars = "0123456789abcdefghijklmnopqrstuvwxyz";
  $tostring = substr($chars, 0, $tobase);

  $length = strlen($numstring);
  $result = '';
  for ($i = 0; $i < $length; $i++)
  {
      $number[$i] = strpos($chars, $numstring{$i});
  }
  do
  {
    $divide = 0;
    $newlen = 0;
    for ($i = 0; $i < $length; $i++)
    {
        $divide = $divide * $frombase + $number[$i];
        if ($divide >= $tobase)
        {
            $number[$newlen++] = (int)($divide / $tobase);
            $divide = $divide % $tobase;
        } elseif ($newlen > 0)
        {
            $number[$newlen++] = 0;
        }
    }
    $length = $newlen;
    $result = $tostring{$divide} . $result;
  } while ($newlen != 0);
  return $result;
}

function time_function(callable $func, $times = 1000) {
    $c = new HRTime\StopWatch();
    $results = [];
    for ($i = 0; $i < $times; $i++) {
        $c->start();
        $res = $func();
        $c->stop();
        $results[] = $c->getLastElapsedTime(HRTime\Unit::NANOSECOND);
    }
    echo 'average: ' . array_sum($results) / count($results) . PHP_EOL;
    var_dump($res);
}

echo "dechex\n";
time_function(function () use ($foo) {
    return dechex($foo);
});

echo "bcchex\n";
time_function(function () use ($foo) {
    return bcdechex($foo);
});

echo "custom\n";
time_function(function () use ($foo) {
    return my_base_convert($foo, 10, 16);
});