$nlen) {
throw new Exception("Invalid source base: " . $frombase . ". Must be in the range [2, " . $nlen . "]");
}
if ($tobase < 2 || $tobase > $nlen) {
throw new Exception("Invalid destination base: " . $tobase . ". Must be in the range [2, " . $nlen . "]");
}
$length = strlen($numstring);
$result = '';
$number = array();
for ($i = 0; $i < $length; $i++) {
$number[$i] = strpos($chars, $numstring{$i});
if ($number[$i] === FALSE)
throw new Exception("Invalid notation: " . $number[$i]);
if ($number[$i] >= $frombase)
throw new Exception("Number value '" . $number[$i] . "' too big for base" . $frombase . " notation!");
}
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;
}
$title = 'Base Convert';
$header = 'Base Convert';
$number = "";
$frombase = "";
$tobase = "";
if (isset($_POST['convert'])) {
try {
$number = $_POST['number'];
$frombase = (int)$_POST['frombase'];
$tobase = (int)$_POST['tobase'];
$result = big_base_convert($number, $frombase, $tobase);
$title = $number . '(' . $frombase . ') = ' . $result . '(' . $tobase . ')';
$header = $number . '(' . $frombase . ') = ' . $result . '(' . $tobase . ')';
} catch (Exception $e) {
$error = $e->getMessage();
}
}
require_once(dirname(__FILE__) . '/header.php');
// Verification
/*$binary="11010101001111010001110101000100011110010110110001111000010001010001111001100011010110110010010011010001011010000001001011111110001010101101101011010101010000100011101110010110010100111110001010010111010110011001111111100011001011011001110001111110000101011010010";
echo '';
print("6A9E8EA23CB63C228F31AD9268B4097F156D6AA11DCB29F14BACCFF196CE3F0AD2\n");
print(strtoupper(base_convert($binary, 2, 16))) . "\n";
print(strtoupper(big_base_convert($binary, 2, 16))) ."\n";
echo '
';*/
// Stress test
/*$chars = "0123456789abcdefghijklmnopqrstuvwxyz";
$clen = strlen($chars);
for ($i = 0; $i < 10; $i++) {
$frombase = rand(2, $clen);
$tobase = rand(2, $clen);
$rchars = substr($chars, 0, $frombase);
$rclen = strlen($rchars);
$rnum = "";
for ($j = 0; $j < 100; $j++) {
$v = rand(0, $rclen-1);
$rnum .= $rchars{$v};
}
$n1 = big_base_convert($rnum, $frombase, $tobase);
$n2 = big_base_convert($n1, $tobase, $frombase);
if ($n2 != $rnum) {
echo "FAILED ON $rnum()->$n2
";
}
}*/
?>