ElephantIO\Engine\AbstractSocketIO::read PHP Метод

    public function read()
    {
        if (!is_resource($this->stream)) {
            return;
        }
        /*
         * The first byte contains the FIN bit, the reserved bits, and the
         * opcode... We're not interested in them. Yet.
         * the second byte contains the mask bit and the payload's length
         */
        $data = fread($this->stream, 2);
        $bytes = unpack('C*', $data);
        $mask = ($bytes[2] & 0b10000000) >> 7;
        $length = $bytes[2] & 0b1111111;
        /*
         * Here is where it is getting tricky :
         *
         * - If the length <= 125, then we do not need to do anything ;
         * - if the length is 126, it means that it is coded over the next 2 bytes ;
         * - if the length is 127, it means that it is coded over the next 8 bytes.
         *
         * But,here's the trick : we cannot interpret a length over 127 if the
         * system does not support 64bits integers (such as Windows, or 32bits
         * processors architectures).
         */
        switch ($length) {
            case 0x7d:
                // 125
                break;
            case 0x7e:
                // 126
                $data .= $bytes = fread($this->stream, 2);
                $bytes = unpack('n', $bytes);
                if (empty($bytes[1])) {
                    throw new RuntimeException('Invalid extended packet len');
                }
                $length = $bytes[1];
                break;
            case 0x7f:
                // 127
                // are (at least) 64 bits not supported by the architecture ?
                if (8 > PHP_INT_SIZE) {
                    throw new DomainException('64 bits unsigned integer are not supported on this architecture');
                }
                /*
                 * As (un)pack does not support unpacking 64bits unsigned
                 * integer, we need to split the data
                 *
                 * {@link http://stackoverflow.com/questions/14405751/pack-and-unpack-64-bit-integer}
                 */
                $data .= $bytes = fread($this->stream, 8);
                list($left, $right) = array_values(unpack('N2', $bytes));
                $length = $left << 32 | $right;
                break;
        }
        // incorporate the mask key if the mask bit is 1
        if (true === $mask) {
            $data .= fread($this->stream, 4);
        }
        // Split the packet in case of the length > 16kb
        while ($length > 0 && ($buffer = fread($this->stream, $length))) {
            $data .= $buffer;
            $length -= strlen($buffer);
        }
        // decode the payload
        return (string) new Decoder($data);
    }