Function AttributeSet_Get

src/graph/entities/attribute_set.c:88–120

retrieves a value from set NOTE: if the key does not exist we return the special constant value ATTRIBUTE_NOTFOUND

// NOTE: if the key does not exist
// we return the special constant value ATTRIBUTE_NOTFOUND
SIValue *AttributeSet_Get
(
	const AttributeSet set,  // set to retieve attribute from
	Attribute_ID attr_id     // attribute identifier
) {
	// in case attribute-set is marked as read-only, clear marker
	AttributeSet _set = (AttributeSet)ATTRIBUTE_SET_CLEAR_MSB(set);

	if(_set == NULL) {
		return ATTRIBUTE_NOTFOUND;
	}

	if(attr_id == ATTRIBUTE_ID_NONE) {
		return ATTRIBUTE_NOTFOUND;
	}

	// TODO: benchmark, consider alternatives:
	// sorted set
	// array divided in two:
	// [attr_id_0, attr_id_1, attr_id_2, value_0, value_1, value_2]
	for (uint16_t i = 0; i < _set->attr_count; ++i) {
		Attribute *attr = _set->attributes + i;
		if(attr_id == attr->id) {
			// note, unsafe as attribute-set can get reallocated
			// TODO: why do we return a pointer to value instead of a copy ?
			// especially when AttributeSet_GetIdx returns SIValue
			// note AttributeSet_Update operate on this pointer
			return &attr->value;
		}
	}

	return ATTRIBUTE_NOTFOUND;
}

// retrieves a value from set by index
SIValue AttributeSet_GetIdx