content: package cat.TRIGGER.quickhull3d;
  
  /*
   * #%L
   * A Robust 3D Convex Hull Algorithm in Java
   * %%
   * Copyright (C) 2004 - 2014 John E. Lloyd
   * %%
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   * 
   * 1. Redistributions of source code must retain the above copyright notice,
   *    this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   * #L%
   */
  
  /**
   * Maintains a single-linked list of faces for use by QuickHull3D
   */
  class FaceList {
  
      private Face head;
  
      private Face tail;
  
      /**
       * Clears this list.
       */
      public void clear() {
          head = tail = null;
      }
  
      /**
       * Adds a vertex to the end of this list.
       */
      public void add(Face vtx) {
          if (head == null) {
              head = vtx;
          } else {
              tail.next = vtx;
          }
          vtx.next = null;
          tail = vtx;
      }
  
      public Face first() {
          return head;
      }
  
      /**
       * Returns true if this list is empty.
       */
      public boolean isEmpty() {
          return head == null;
      }
  }
  