Custom implementation of Base32 or Base64

Question

I need custom implementation (library or set of classes/functions) of Base32 or Base64 in PHP

Function should return URL safe strings.

Why not http://php.net/manual/fr/function.base64-encode.php ? — David Bélanger, Apr 16 '12 at 16:13
And there is http://php.net/base_convert - and all the notes everywhere in the manual, dum-te-dum. — hakre, Apr 16 '12 at 16:20
I need custom implementation, because my host don't provide me with base64_* functions — I-M-JM, Apr 17 '12 at 16:46
See my answer, you got what you want and you won't get more I think — David Bélanger, Apr 17 '12 at 19:28

score 2 · Answer 1 · answered Apr 17 '12 at 19:28

Since you don't have access to base64 build in function I suggest you this :

<?php

echo bencode("Gabriel Malca");
// R2FicmllbCBNYWxjYQ==

function bencode($string='') {
    $binval = convert_binary_str($string);
    $final = "";
    $start = 0;
    while ($start < strlen($binval)) {
        if (strlen(substr($binval,$start)) < 6)
            $binval .= str_repeat("0",6-strlen(substr($binval,$start)));
        $tmp = bindec(substr($binval,$start,6));
        if ($tmp < 26)
            $final .= chr($tmp+65);
        elseif ($tmp > 25 && $tmp < 52)
            $final .= chr($tmp+71);
        elseif ($tmp == 62)
            $final .= "+";
        elseif ($tmp == 63)
            $final .= "/";
        elseif (!$tmp)
            $final .= "A";
        else
            $final .= chr($tmp-4);
        $start += 6;
    }
    if (strlen($final)%4>0)
        $final .= str_repeat("=",4-strlen($final)%4);
    return $final;
}

function convert_binary_str($string) {
    if (strlen($string)<=0) return;
    $tmp = decbin(ord($string[0]));
    $tmp = str_repeat("0",8-strlen($tmp)).$tmp;
    return $tmp.convert_binary_str(substr($string,1));
}

?>

This is the only correct answer. This question shouldn't be modded down - base64_ functions can be disabled on some hosts because of security concerns. Yes, it pretty much cripples a standard PHP install, but there are times when it's worth having the built in functions disabled. — John Hunt, Aug 17 '15 at 09:26
@JonGrant And that's why `urlencode` and `urldecode` exists sir. — David Bélanger, Aug 19 '15 at 15:59

score -1 · Answer 2 · answered Apr 16 '12 at 16:27

-1

I would use these functions to make strings URL safe.

function base64_url_encode($input) {
 return strtr(base64_encode($input), '+/=', '-_,');
}

function base64_url_decode($input) {
 return base64_decode(strtr($input, '-_,', '+/='));
}

answered Apr 16 '12 at 16:27

Xeoncross

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Custom implementation of Base32 or Base64

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