Zip.php

<?php
namsepace vakata\zip;

class Zip
{
    protected $compression = false;
    protected $data = [];
    protected $ctrl = [];
    protected $offset = 0;

    public function __construct(bool $compression = false)
    {
        $this->compression = $compression;
    }

    protected function ZipTime(int $time = null) { 
        $data = !isset($time) ? getdate() : getdate($time);
        if ($data['year'] < 1980) { 
            $data['year'] = 1980;
            $data['mon'] = 1;
            $data['mday'] = 1;
            $data['hours'] = 0;
            $data['minutes'] = 0;
            $data['seconds'] = 0;
        }
        $data['year'] -= 1980;
        return '' .
            pack('v', ($data['hours'] << 11) | ($data['minutes'] << 5) | ($data['seconds'] >> 1)) .
            pack('v', ($data['year'] << 9) | ($data['mon'] << 5) | ($data['mday']));
    }

    public function addFromString(string $name, string $content, int $time = null): static
    {
        if (!isset($time)) {
            $time = time();
        }
        $name = str_replace('\\', '/', $name);
        $time = $this->ZipTime($time);

        $ln1 = strlen($content);
        $ln2 = $ln1;
        $crc = crc32($content);
        if ($this->compression) {
            $content = gzcompress($content);
            $content = substr(substr($content, 0, strlen($content) - 4), 2);
            $ln2 = strlen($content);
        }
        $data = "\x50\x4b\x03\x04\x14\x00\x00\x00" . 
                ($this->compression ? "\x08\x00" : "\x00\x00") .
                $time .
                pack('V', $crc) . pack('V', $ln2) . pack('V', $ln1) . pack('v', strlen($name)) . pack('v', 0) .
                $name . $content;
        $this->data[] = $data; 

        $ctrl = "\x50\x4b\x01\x02\x00\x00\x14\x00\x00\x00" .
                ($this->compression ? "\x08\x00" : "\x00\x00") .
                $time .
                pack('V', $crc) . pack('V', $ln2) . pack('V', $ln1) . pack('v', strlen($name)) . pack('v', 0) .
                pack('v', 0) . pack('v', 0) . pack('v', 0) . pack('V', 32) . pack('V', $this->offset) .
                $name;
        $this->ctrl[] = $ctrl;

        $this->offset += strlen($data); 
        return $this;
    }
    public function addFile(string $name, string $path, int $time = null): static
    {
        if (!isset($time)) {
            $time = @filemtime($path);
            if (!$time) {
                $time = null;
            }
        }
        return $this->addFromString($name, file_get_contents($path), $time);
    }

    public function contents(): string
    {
        $data = implode('', $this->data);
        $ctrl = implode('', $this->ctrl);
        return '' .
            $data .
            $ctrl .
            "\x50\x4b\x05\x06\x00\x00\x00\x00" .
            pack('v', count($this->ctrl)) .
            pack('v', count($this->ctrl)) .
            pack('V', strlen($ctrl)) .
            pack('V', strlen($data)) .
            "\x00\x00";
    }
    public function __toString()
    {
        return $this->contents();
    }
}

// header('Content-Type: application/zip');
// header('Content-Disposition: attachment; filename=test.zip');
// $z = new Zip(true);
// $z->addFromString('test.txt', 'asdf', 0);
// $z->addFile('test.log', 'index.php');
// echo $z;
// die();