Ejemplo n.º 1
0
  /** Skips checks for existing keys. */
  private void addResize(T key) {
    // Check for empty buckets.
    int hashCode = key.hashCode();
    int index1 = hashCode & mask;
    T key1 = keyTable[index1];
    if (key1 == null) {
      keyTable[index1] = key;
      if (size++ >= threshold) resize(capacity << 1);
      return;
    }

    int index2 = hash2(hashCode);
    T key2 = keyTable[index2];
    if (key2 == null) {
      keyTable[index2] = key;
      if (size++ >= threshold) resize(capacity << 1);
      return;
    }

    int index3 = hash3(hashCode);
    T key3 = keyTable[index3];
    if (key3 == null) {
      keyTable[index3] = key;
      if (size++ >= threshold) resize(capacity << 1);
      return;
    }

    push(key, index1, key1, index2, key2, index3, key3);
  }
Ejemplo n.º 2
0
  private void push(T insertKey, int index1, T key1, int index2, T key2, int index3, T key3) {
    T[] keyTable = this.keyTable;
    int mask = this.mask;

    // Push keys until an empty bucket is found.
    T evictedKey;
    int i = 0, pushIterations = this.pushIterations;
    do {
      // Replace the key and value for one of the hashes.
      switch (MathUtils.random(2)) {
        case 0:
          evictedKey = key1;
          keyTable[index1] = insertKey;
          break;
        case 1:
          evictedKey = key2;
          keyTable[index2] = insertKey;
          break;
        default:
          evictedKey = key3;
          keyTable[index3] = insertKey;
          break;
      }

      // If the evicted key hashes to an empty bucket, put it there and stop.
      int hashCode = evictedKey.hashCode();
      index1 = hashCode & mask;
      key1 = keyTable[index1];
      if (key1 == null) {
        keyTable[index1] = evictedKey;
        if (size++ >= threshold) resize(capacity << 1);
        return;
      }

      index2 = hash2(hashCode);
      key2 = keyTable[index2];
      if (key2 == null) {
        keyTable[index2] = evictedKey;
        if (size++ >= threshold) resize(capacity << 1);
        return;
      }

      index3 = hash3(hashCode);
      key3 = keyTable[index3];
      if (key3 == null) {
        keyTable[index3] = evictedKey;
        if (size++ >= threshold) resize(capacity << 1);
        return;
      }

      if (++i == pushIterations) break;

      insertKey = evictedKey;
    } while (true);

    addStash(evictedKey);
  }
Ejemplo n.º 3
0
 /**
  * Clears the map and reduces the size of the backing arrays to be the specified capacity if they
  * are larger.
  */
 public void clear(int maximumCapacity) {
   if (capacity <= maximumCapacity) {
     clear();
     return;
   }
   size = 0;
   resize(maximumCapacity);
 }
Ejemplo n.º 4
0
 /**
  * Reduces the size of the backing arrays to be the specified capacity or less. If the capacity is
  * already less, nothing is done. If the map contains more items than the specified capacity, the
  * next highest power of two capacity is used instead.
  */
 public void shrink(int maximumCapacity) {
   if (maximumCapacity < 0)
     throw new IllegalArgumentException("maximumCapacity must be >= 0: " + maximumCapacity);
   if (size > maximumCapacity) maximumCapacity = size;
   if (capacity <= maximumCapacity) return;
   maximumCapacity = MathUtils.nextPowerOfTwo(maximumCapacity);
   resize(maximumCapacity);
 }
Ejemplo n.º 5
0
  /** Returns true if the key was not already in the set. */
  public boolean add(T key) {
    if (key == null) throw new IllegalArgumentException("key cannot be null.");
    T[] keyTable = this.keyTable;

    // Check for existing keys.
    int hashCode = key.hashCode();
    int index1 = hashCode & mask;
    T key1 = keyTable[index1];
    if (key.equals(key1)) return false;

    int index2 = hash2(hashCode);
    T key2 = keyTable[index2];
    if (key.equals(key2)) return false;

    int index3 = hash3(hashCode);
    T key3 = keyTable[index3];
    if (key.equals(key3)) return false;

    // Find key in the stash.
    for (int i = capacity, n = i + stashSize; i < n; i++) if (key.equals(keyTable[i])) return false;

    // Check for empty buckets.
    if (key1 == null) {
      keyTable[index1] = key;
      if (size++ >= threshold) resize(capacity << 1);
      return true;
    }

    if (key2 == null) {
      keyTable[index2] = key;
      if (size++ >= threshold) resize(capacity << 1);
      return true;
    }

    if (key3 == null) {
      keyTable[index3] = key;
      if (size++ >= threshold) resize(capacity << 1);
      return true;
    }

    push(key, index1, key1, index2, key2, index3, key3);
    return true;
  }
Ejemplo n.º 6
0
 private void addStash(T key) {
   if (stashSize == stashCapacity) {
     // Too many pushes occurred and the stash is full, increase the table size.
     resize(capacity << 1);
     add(key);
     return;
   }
   // Store key in the stash.
   int index = capacity + stashSize;
   keyTable[index] = key;
   stashSize++;
   size++;
 }
Ejemplo n.º 7
0
 /**
  * Increases the size of the backing array to acommodate the specified number of additional items.
  * Useful before adding many items to avoid multiple backing array resizes.
  */
 public void ensureCapacity(int additionalCapacity) {
   int sizeNeeded = size + additionalCapacity;
   if (sizeNeeded >= threshold) resize(MathUtils.nextPowerOfTwo((int) (sizeNeeded / loadFactor)));
 }