Amfphp_Core_Amf_Deserializer::readAmf3Int PHP Method

    protected function readAmf3Int()
    {
        $int = $this->readByte();
        if ($int < 128) {
            return $int;
        } else {
            $int = ($int & 0x7f) << 7;
            $tmp = $this->readByte();
            if ($tmp < 128) {
                return $int | $tmp;
            } else {
                $int = ($int | $tmp & 0x7f) << 7;
                $tmp = $this->readByte();
                if ($tmp < 128) {
                    return $int | $tmp;
                } else {
                    $int = ($int | $tmp & 0x7f) << 8;
                    $tmp = $this->readByte();
                    $int |= $tmp;
                    // Integers in Amf3 are 29 bit. The MSB (of those 29 bit) is the sign bit.
                    // In order to properly convert that integer to a PHP integer - the system
                    // might be 32 bit, 64 bit, 128 bit or whatever - all higher bits need to
                    // be set.
                    if (($int & 0x10000000) !== 0) {
                        $int |= ~0x1fffffff;
                        // extend the sign bit regardless of integer (bit) size
                    }
                    return $int;
                }
            }
        }
    }