PHP function to implement decimal and hexadecimal conversion

/**
* Base conversion: decimal, hexadecimal conversion
* by bbs.it-home.org
*/
$dic = array(
    0 => '0', 1 => '1', 2 => '2', 3 => '3', 4 => '4', 5 => '5', 6 => '6', 7 => '7', 8 => '8', 9 => '9',
    10 => 'A', 11 => 'B', 12 => 'C', 13 => 'D', 14 => 'E', 15 => 'F', 16 => 'G', 17 => 'H', 18 => 'I',
    19 => 'J', 20 => 'K', 21 => 'L', 22 => 'M', 23 => 'N', 24 => 'O', 25 => 'P', 26 => 'Q', 27 => 'R',
    28 => 'S', 29 => 'T', 30 => 'U', 31 => 'V', 32 => 'W', 33 => 'X', 34 => 'Y', 35 => 'Z'
    );

 //十进制转换三十六进制
function enid($int, $format = 8) {
    global $dic;
    $arr = array();
    $loop = true;
    while ($loop)
    {
        $arr[] = $dic[bcmod($int, 36)];
        $int = floor(bcdiv($int, 36));
        if ($int == 0) {
            $loop = false;
        }
    }
    array_pad($arr, $format, $dic[0]);
    return implode('', array_reverse($arr));
}

//三十六进制转换十进制
function deid($id) {
    global $dic;
    // 键值交换
    $dedic = array_flip($dic);
    // 去零
    $id = ltrim($id, $dic[0]);
    // 反转
    $id = strrev($id);
    $v = 0;
    for($i = 0, $j = strlen($id); $i < $j; $i++)
    {
        $v = bcadd(bcmul($dedic[$id{$i}] , bcpow(36, $i)) , $v);
    }
    return $v;
}

// 遍历三位所有的三十六进制数
$i = deid('ZZZ');
$b = array();
while ($i > 0) {
    $id_dym = str_pad(enid($i), 3, 0, STR_PAD_LEFT);
    echo strtolower($id_dym), '';
    $i--;
}