- strpos: documentation ( source)
<?php
function base58_encode($num) {
$alphabet = '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ';
$base_count = strlen($alphabet);
$encoded = '';
while ($num >= $base_count) {
$div = $num / $base_count;
$mod = ($num - ($base_count * intval($div)));
$encoded = $alphabet[$mod] . $encoded;
$num = intval($div);
}
if ($num) {
$encoded = $alphabet[$num] . $encoded;
}
return $encoded;
}
function base58_decode($num) {
$alphabet = '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ';
$len = strlen($num);
$decoded = 0;
$multi = 1;
for ($i = $len - 1; $i >= 0; $i--) {
$decoded += $multi * strpos($alphabet, $num[$i]);
$multi = $multi * strlen($alphabet);
}
return $decoded;
}
echo base58_decode("3jf");