Is it possible to encode line by line in Base64?

Question

I have a code that takes binary files and converts them into Base64, but there are very large files and this ends up using much of the machine’s memory (and even process). To read large files generally (without converting them) I do this:

$handle = fopen('ARQUIVO', 'rb');

while (false === feof($handle)) {
    $data = fgets($handle);
    ...
}

fclose($handle);

So I avoid exceeding memory and other such problems. But the problem is that with base64_encode i need complete data (a string entire).

How to encode large binary files without losing performance?

Answer 1

It is possible yes, the code below was taken from a commenting about the function base64_encode.

$fh = fopen('Input-File', 'rb'); 
//$fh2 = fopen('Output-File', 'wb'); 

$cache = ''; 
$eof = false; 

while (1) { 
    if (!$eof) { 
        if (!feof($fh)) { 
            $row = fgets($fh, 4096); 
        } else { 
            $row = ''; 
            $eof = true; 
        } 
    } 

    if ($cache !== '') 
        $row = $cache.$row; 
    elseif ($eof) 
        break; 

    $b64 = base64_encode($row); 
    $put = ''; 

    if (strlen($b64) < 76) { 
        if ($eof) { 
            $put = $b64."\n"; 
            $cache = ''; 
        } else { 
            $cache = $row; 
        } 

    } elseif (strlen($b64) > 76) { 
        do { 
            $put .= substr($b64, 0, 76)."\n"; 
            $b64 = substr($b64, 76); 
        } while (strlen($b64) > 76); 

        $cache = base64_decode($b64); 

    } else { 
        if (!$eof && $b64{75} == '=') { 
            $cache = $row; 
        } else { 
            $put = $b64."\n"; 
            $cache = ''; 
        } 
    } 

    if ($put !== '') { 
        echo $put; 
        //fputs($fh2, $put); 
        //fputs($fh2, base64_decode($put));
    } 
} 

//fclose($fh2); 
fclose($fh);