text: /*
   * Copyright (C) 2011, 2013, 2015 Apple Inc. All rights reserved.
   *
   * 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 APPLE INC. ``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 APPLE INC. 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. 
   */
  
  #pragma once
  
  #if ENABLE(DFG_JIT)
  
  #include "DFGCommon.h"
  #include "DFGEdge.h"
  
  namespace JSC { namespace DFG {
  
  class AdjacencyList {
  public:
      enum Kind {
          Fixed,
          Variable
      };
      
      enum { Size = 3 };
      
      AdjacencyList() { }
      
      AdjacencyList(Kind kind)
      {
          if (kind == Variable) {
              m_words[0].m_encodedWord = UINT_MAX;
              m_words[1].m_encodedWord = UINT_MAX;
          }
      }
      
      AdjacencyList(Kind kind, Edge child1, Edge child2 = Edge(), Edge child3 = Edge())
      {
          ASSERT_UNUSED(kind, kind == Fixed);
          initialize(child1, child2, child3);
      }
      
      AdjacencyList(Kind kind, unsigned firstChild, unsigned numChildren)
      {
          ASSERT_UNUSED(kind, kind == Variable);
          setFirstChild(firstChild);
          setNumChildren(numChildren);
      }
      
      bool isEmpty() const { return !child1(); }
      
      const Edge& child(unsigned i) const
      {
          ASSERT(i < Size);
          return m_words[i];
      }    
      
      Edge& child(unsigned i)
      {
          ASSERT(i < Size);
          return m_words[i];
      }
      
      void setChild(unsigned i, Edge nodeUse)
      {
          ASSERT(i < Size);
          m_words[i] = nodeUse;
      }
      
      Edge child1() const { return child(0); }
      Edge child2() const { return child(1); }
      Edge child3() const { return child(2); }
  
      Edge& child1() { return child(0); }
      Edge& child2() { return child(1); }
      Edge& child3() { return child(2); }
      
      void setChild1(Edge nodeUse) { setChild(0, nodeUse); }
      void setChild2(Edge nodeUse) { setChild(1, nodeUse); }
      void setChild3(Edge nodeUse) { setChild(2, nodeUse); }
      
      Edge child1Unchecked() const { return m_words[0]; }
      
      Edge justOneChild() const
      {
          if (!!child1() && !child2()) {
              ASSERT(!child3());
              return child1();
          }
          return Edge();
      }
      
      void initialize(Edge child1, Edge child2, Edge child3)
      {
          child(0) = child1;
          child(1) = child2;
          child(2) = child3;
      }
      
      void initialize(Node* child1 = 0, Node* child2 = 0, Node* child3 = 0)
      {
          initialize(Edge(child1), Edge(child2), Edge(child3));
      }
      
      void reset()
      {
          initialize();
      }
      
      // Call this if you wish to remove an edge and the node treats the list of children.
      void removeEdge(unsigned edgeIndex)
      {
          for (unsigned i = edgeIndex; i < Size - 1; ++i)
              setChild(i, child(i + 1));
          setChild(Size - 1, Edge());
      }
      
      unsigned firstChild() const
      {
          return m_words[0].m_encodedWord;
      }
      void setFirstChild(unsigned firstChild)
      {
          m_words[0].m_encodedWord = firstChild;
      }
      
      unsigned numChildren() const
      {
          return m_words[1].m_encodedWord;
      }
      void setNumChildren(unsigned numChildren)
      {
          m_words[1].m_encodedWord = numChildren;
      }
      
      AdjacencyList sanitized() const
      {
          return AdjacencyList(Fixed, child1().sanitized(), child2().sanitized(), child3().sanitized());
      }
      
      AdjacencyList justChecks() const
      {
          AdjacencyList result(Fixed);
          unsigned sourceIndex = 0;
          unsigned targetIndex = 0;
          while (sourceIndex < AdjacencyList::Size) {
              Edge edge = child(sourceIndex++);
              if (!edge)
                  break;
              if (edge.willHaveCheck())
                  result.child(targetIndex++) = edge;
          }
          return result;
      }
      
      unsigned hash() const
      {
          unsigned result = 0;
          if (!child1())
              return result;
          
          result += child1().hash();
          
          if (!child2())
              return result;
          
          result *= 3;
          result += child2().hash();
          
          if (!child3())
              return result;
          
          result *= 3;
          result += child3().hash();
          
          return result;
      }
      
      bool operator==(const AdjacencyList& other) const
      {
          return child1() == other.child1()
              && child2() == other.child2()
              && child3() == other.child3();
      }
      
  private:
      Edge m_words[Size];
  };
  
  } } // namespace JSC::DFG
  
  #endif // ENABLE(DFG_JIT)
  