Custom base number converter.

custom_base_converter.php

<?php

/**
 * Code demo for convert base number with custom base character map.
 * Not support negative number.
 */

// base from toHex on http://hashids.org/
function intToChar($input)
{
    $hash = "";
    $alphabet = BASE_CHARACTER;
    $alphabetLength = strlen($alphabet);

    do {
        $hash = $alphabet[$input % $alphabetLength] . $hash;
        $input = intval($input / $alphabetLength, 10);
    } while ($input);

    return $hash;
}

// My func that will decode it back.
// I write via reverse logic from upper function.
// @author Nimit Suwannagate <ethaizone@hotmail.com>
function charToInt($input)
{

    $dex = 0;
    $alphabet = BASE_CHARACTER;
    $alphabetLength = strlen($alphabet);

    $input = str_split($input);

    do {
        $multiple = count($input)-1;
        $char = array_shift($input);
        $index = strpos($alphabet, $char);
        $dex += pow($alphabetLength, $multiple)*$index;
    } while ($input);

    return $dex;
}


define('BASE_CHARACTER', "fedcba9876543210");

$number = 500;
$char = intToChar($number);
$decoded = charToInt($char);
echo "Number: " . $number .PHP_EOL;
echo "Char: " . $char .PHP_EOL;
echo "Decode: " . $decoded .PHP_EOL;