Patch a string with an unified diff in PHP

Question

I am looking for a way to patch a string in PHP, using an existing unified diff. xdiff_string_patch does exactly what I want but the xdiff library is not available on my server.

Is there a way to do this in vanilla PHP or should I use something like shell_exec('patch...') ?

Regards,

Answer 1

Here is the code I ended up using:

/**
 * Applies a diff to a string
 * 
 * @param string $diff Diff
 * @param string $text String to patch
 * 
 * @return string Patched string
 * */
static function applyDiff($diff, $text)
{
    $tmpname = tempnam(sys_get_temp_dir(), "diff");
    $outname = tempnam(sys_get_temp_dir(), "diff");
    $tmp = fopen($tmpname, "w");
    $out = fopen($outname, "r");
    fwrite($tmp, $text.PHP_EOL);
    $proc = proc_open(
        'patch '.$tmpname.' -o '.$outname, array(
           0 => array("pipe", "r"),
           1 => array("pipe", "w"),
           2 => array("pipe", "w")
        ), $pipes
    );
    if (is_resource($proc)) {
        fwrite($pipes[0], $diff);
        fclose($pipes[0]);
        stream_get_contents($pipes[1]);
        $newText = stream_get_contents($out);
        fclose($pipes[1]);
        return $newText;
    }
}