.unitypackage unpacker

<?php

$content = cmd('tar tf %s', [$argv[1]]);

$tree = [];
foreach ($content as $fn) {
    if (strpos($fn, '/')) {
        list($d, $f) = explode('/', $fn, 2);
    } else {
        $f = '';
        $d = $fn;
    }
    if ($f) {
        $tree[$d][] = $f;
    } else {
        $tree[$d] = [];
    }
}

foreach ($tree as $d => $c) {

    $e = cmd('tar xf %s -O %s', [$argv[1], "{$d}/pathname"]);
    echo $e[0], PHP_EOL;

    if (in_array('asset', $c)) {
        $pi = pathinfo($e[0]);
        @mkdir($pi['dirname'], 0755, true);
        cmd('tar xf %s -O %s > %s', [$argv[1], "{$d}/asset", $e[0]]);
    } else {
        @mkdir($e[0], 0755, true);
    }
}

function cmd($c, $args)
{
    $encoded_args = array_map(
        function ($a) {
            return escapeshellarg($a);
        },
        $args
    );

    exec(vsprintf($c, $encoded_args), $output);

    return $output;
}