The php_phongo_bson_typemap struct currently contains two members for each type map path:

typedef struct {
	php_phongo_bson_typemap_types document_type;
	zend_class_entry*             document;
	php_phongo_bson_typemap_types array_type;
	zend_class_entry*             array;
	php_phongo_bson_typemap_types root_type;
	zend_class_entry*             root;
// ...
}

This can be refactored to declare a new struct consisting of type and class members that are used instead of the current double entry. This future-proofs the type map struct for changes (one prototype for ODM deserialisation features adds a zval* to the type map) and allows better reusability of logic working with a type map element.