Completely rewritten code.

Implement read-only zip file - class \PhpZip\ZipFile, create and update zip file - \PhpZip\ZipOutputFile.
Supports ZIP64 ext, Traditional PKWARE Encryption, WinZip AES Encryption.

src/PhpZip/Util/PackUtil.php

@@ -0,0 +1,44 @@
+<?php
+namespace PhpZip\Util;
+
+use PhpZip\Exception\ZipException;
+
+/**
+ * Pack util
+ *
+ * @author Ne-Lexa alexey@nelexa.ru
+ * @license MIT
+ */
+class PackUtil
+{
+
+    /**
+     * @param int|string $longValue
+     * @return string
+     */
+    public static function packLongLE($longValue)
+    {
+        // TODO test if (version_compare(PHP_VERSION, '5.6.3') >= 0) {return pack("P", $longValue);}
+
+        $left = 0xffffffff00000000;
+        $right = 0x00000000ffffffff;
+
+        $r = ($longValue & $left) >> 32;
+        $l = $longValue & $right;
+
+        return pack('VV', $l, $r);
+    }
+
+    /**
+     * @param string|int $value
+     * @return int
+     * @throws ZipException
+     */
+    public static function unpackLongLE($value)
+    {
+        // TODO test if (version_compare(PHP_VERSION, '5.6.3') >= 0){ return current(unpack('P', $value)); }
+        $unpack = unpack('Va/Vb', $value);
+        return $unpack['a'] + ($unpack['b'] << 32);
+    }
+
+}