content: // ////////////////////////////////////////////////////////////////////////////
  // Copyright (c) 2009, Rob Eden All Rights Reserved.
  //
  // This library is free software; you can redistribute it and/or
  // modify it under the terms of the GNU Lesser General Public
  // License as published by the Free Software Foundation; either
  // version 2.1 of the License, or (at your option) any later version.
  //
  // This library is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  // GNU General Public License for more details.
  //
  // You should have received a copy of the GNU Lesser General Public
  // License along with this program; if not, write to the Free Software
  // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  // ////////////////////////////////////////////////////////////////////////////
  
  package gnu.trove.impl.hash;
  
  import gnu.trove.iterator.TPrimitiveIterator;
  
  import java.util.ConcurrentModificationException;
  import java.util.NoSuchElementException;
  
  
  /**
   * Implements all iterator functions for the hashed object set.
   * Subclasses may override objectAtIndex to vary the object
   * returned by calls to next() (e.g. for values, and Map.Entry
   * objects).
   * <p/>
   * <p> Note that iteration is fastest if you forego the calls to
   * <tt>hasNext</tt> in favor of checking the size of the structure
   * yourself and then call next() that many times:
   * <p/>
   * <pre>
   * Iterator i = collection.iterator();
   * for (int size = collection.size(); size-- > 0;) {
   *   Object o = i.next();
   * }
   * </pre>
   * <p/>
   * <p>You may, of course, use the hasNext(), next() idiom too if
   * you aren't in a performance critical spot.</p>
   */
  public abstract class THashPrimitiveIterator implements TPrimitiveIterator {
  
      /** the data structure this iterator traverses */
      protected final TPrimitiveHash _hash;
      /**
       * the number of elements this iterator believes are in the
       * data structure it accesses.
       */
      protected int _expectedSize;
      /** the index used for iteration. */
      protected int _index;
  
  
      /**
       * Creates a <tt>TPrimitiveIterator</tt> for the specified collection.
       *
       * @param hash the <tt>TPrimitiveHash</tt> we want to iterate over.
       */
      public THashPrimitiveIterator( TPrimitiveHash hash ) {
          _hash = hash;
          _expectedSize = _hash.size();
          _index = _hash.capacity();
      }
  
  
      /**
       * Returns the index of the next value in the data structure
       * or a negative value if the iterator is exhausted.
       *
       * @return an <code>int</code> value
       * @throws java.util.ConcurrentModificationException
       *          if the underlying collection's
       *          size has been modified since the iterator was created.
       */
      protected final int nextIndex() {
          if ( _expectedSize != _hash.size() ) {
              throw new ConcurrentModificationException();
          }
  
          byte[] states = _hash._states;
          int i = _index;
          while ( i-- > 0 && ( states[i] != TPrimitiveHash.FULL ) ) {
              ;
          }
          return i;
      }
  
  
      /**
       * Returns true if the iterator can be advanced past its current
       * location.
       *
       * @return a <code>boolean</code> value
       */
      public boolean hasNext() {
          return nextIndex() >= 0;
      }
  
  
      /**
       * Removes the last entry returned by the iterator.
       * Invoking this method more than once for a single entry
       * will leave the underlying data structure in a confused
       * state.
       */
      public void remove() {
          if (_expectedSize != _hash.size()) {
              throw new ConcurrentModificationException();
          }
  
          // Disable auto compaction during the remove. This is a workaround for bug 1642768.
          try {
              _hash.tempDisableAutoCompaction();
              _hash.removeAt(_index);
          }
          finally {
              _hash.reenableAutoCompaction( false );
          }
  
          _expectedSize--;
      }
  
  
      /**
       * Sets the internal <tt>index</tt> so that the `next' object
       * can be returned.
       */
      protected final void moveToNextIndex() {
          // doing the assignment && < 0 in one line shaves
          // 3 opcodes...
          if ( ( _index = nextIndex() ) < 0 ) {
              throw new NoSuchElementException();
          }
      }
  
  
  } // TPrimitiveIterator