/**
* Add a new key-id pair.
*
* @param key is the key for which an id is required
* @return the new id or 0 if the key is already mapped or the operation fails
*/
public int addPair(long key) {
if (validKey(key) || (ids.firstOut() == 0)) return 0;
int id = ids.firstOut();
if (!ht.insert(key, id)) return 0;
ids.swap(id);
cnt++;
return id;
}
/**
* Remove a pair from the mapping. This operation removes a (key,id) pair from the mapping.
*
* @param key is the key whose id is to be released
*/
public void dropPair(long key) {
int id = ht.lookup(key);
if (id == 0) return;
ht.remove(key);
ids.swap(id);
cnt--;
}
/**
* Add a new key-id pair.
*
* @param key is the key for which an id is required
* @param id is the requested id that the key is to be mapped to
* @return the new id or 0 if the key is already mapped or the id is already in use or the
* operation fails
*/
public int addPair(long key, int id) {
if (validKey(key) || validId(id)) return 0;
if (!ht.insert(key, id)) return 0;
ids.swap(id);
cnt++;
return id;
}
/**
* Determine if a given identifier has been assigned to a key.
*
* @param id is the identifier to be checked
* @return true if the key has been mapped, else false
*/
public boolean validId(int id) {
return (1 <= id && id <= n && ids.isIn(id));
}
/**
* Get the next assigned identifier, in some arbitrary order.
*
* @param id is an identifer in the set
* @return number of the next identfier
*/
public int nextId(int id) {
return ids.nextIn(id);
}
/**
* Get the last assigned identifier, in some arbitrary order.
*
* @return number of the last identfier
*/
public int lastId() {
return ids.lastIn();
}
/**
* Get the first assigned identifier, in some arbitrary order.
*
* @return number of the first identfier
*/
public int firstId() {
return ids.firstIn();
}
/** Clear the IdMap. */
public void clear() {
for (int i = firstId(); i != 0; i = firstId()) ids.swap(i);
}