/**
* Tests whether this set is a subset of the specified set.
* It is assumed that the specified set is an instance of
* the <code>SetAsBitVector</code> class.
*
* @param object ISet $set The set to compare with this set.
* @return boolean True if the this set is a subset of the specified set;
* false otherwise.
*/
public function isSubset(ISet $set)
{
if ($this->getClass() != $set->getClass()) {
throw new TypeError();
}
if ($this->universeSize != $set->universeSize) {
throw new ArgumentError();
}
for ($i = 0; $i < $this->vector->length(); ++$i) {
if (($this->vector[$i] & ~$set->vector[$i]) != 0) {
return false;
}
}
return true;
}
/**
* Tests whether this set is a subset of the specified set.
* It is assumed that the specified set is an instance of
* the SetAsArray class.
*
* @param object ISet $set The set to compare with this set.
* @return boolean True if the this set is a subset of the specified set;
* false otherwise.
*/
public function isSubset(ISet $set)
{
if ($this->getClass() != $set->getClass()) {
throw new TypeError();
}
if ($this->universeSize != $set->universeSize) {
throw new ArgumentError();
}
for ($item = 0; $item < $this->universeSize; ++$item) {
if ($this->array[$item] && !$set->array[$item]) {
return false;
}
}
return true;
}
