/**
* Serializes the 'properties' attribute (a dictionary) into the
* raw bytes making up a set of property flags and a property
* list, suitable for putting into a content frame header.
*
* @return string
* @todo Inject the AMQPWriter to make the method easier to test
*/
public function serializeProperties()
{
if ($this->properties == []) {
return "";
// optimization for empty properties
} else {
$shift = 15;
$flag_bits = 0;
$flags = array();
$raw_bytes = new AMQPBufferWriter();
foreach ($this->prop_types as $key => $prototype) {
$val = isset($this->properties[$key]) ? $this->properties[$key] : null;
// Very important: PHP type eval is weak, use the === to test the
// value content. Zero or false value should not be removed
if ($val === null) {
$shift -= 1;
continue;
}
if ($shift === 0) {
$flags[] = $flag_bits;
$flag_bits = 0;
$shift = 15;
}
$flag_bits |= 1 << $shift;
if ($prototype != 'bit') {
$raw_bytes->{'write_' . $prototype}($val);
}
$shift -= 1;
}
$flags[] = $flag_bits;
$result = new AMQPBufferWriter();
foreach ($flags as $flag_bits) {
$result->write_short($flag_bits);
}
$result->write($raw_bytes->getvalue());
return $result->getvalue();
}
}
