Function AttributeSet_Set_Allow_Null

src/graph/entities/attribute_set.c:251–300

add, remove or update an attribute this function allows NULL value to be added to the set returns the type of change performed

// this function allows NULL value to be added to the set
// returns the type of change performed
AttributeSetChangeType AttributeSet_Set_Allow_Null
(
	AttributeSet *set,     // set to update
	Attribute_ID attr_id,  // attribute identifier
	SIValue value          // attribute value
) {
	ASSERT(set != NULL);
	ASSERT(attr_id != ATTRIBUTE_ID_NONE);

	AttributeSet _set = *set;

	// return if set is read-only
	if(unlikely(ATTRIBUTE_SET_IS_READONLY(_set))) {
		return CT_NONE;
	}

	// validate value type
	ASSERT(SI_TYPE(value) & (SI_VALID_PROPERTY_VALUE | T_NULL));

	// update the attribute if it is already presented in the set
	if(AttributeSet_Get(_set, attr_id) != ATTRIBUTE_NOTFOUND) {
		if(AttributeSet_Update(&_set, attr_id, value)) {
			// update pointer
			*set = _set;
			// if value is NULL, indicate attribute removal
			// otherwise indicate attribute update
			return SIValue_IsNull(value) ? CT_DEL : CT_UPDATE;
		}

		// value did not change, indicate no modification
		return CT_NONE;
	}

	// can't remove a none existing attribute, indicate no modification
	if(SIValue_IsNull(value)) return CT_NONE;

	// allocate room for new attribute
	_set = AttributeSet_AddPrepare(set, 1);

	// set attribute
	Attribute *attr = _set->attributes + _set->attr_count - 1;
	attr->id = attr_id;
	attr->value = SI_CloneValue(value);

	// update pointer
	*set = _set;

	// new attribute added, indicate attribute addition
	return CT_ADD;
}

// updates existing attribute, return true if attribute been updated
bool AttributeSet_UpdateNoClone