text: /*
   * Copyright (C) 2008, 2009 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 COMPUTER, 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 COMPUTER, 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. 
   */
  
  #ifndef StructureTransitionTable_h
  #define StructureTransitionTable_h
  
  #include "UString.h"
  #include <wtf/HashFunctions.h>
  #include <wtf/HashMap.h>
  #include <wtf/HashTraits.h>
  #include <wtf/OwnPtr.h>
  #include <wtf/RefPtr.h>
  
  namespace JSC {
  
      class Structure;
  
      struct StructureTransitionTableHash {
          typedef std::pair<RefPtr<UString::Rep>, unsigned> Key;
          static unsigned hash(const Key& p)
          {
              return p.first->existingHash();
          }
  
          static bool equal(const Key& a, const Key& b)
          {
              return a == b;
          }
  
          static const bool safeToCompareToEmptyOrDeleted = true;
      };
  
      struct StructureTransitionTableHashTraits {
          typedef WTF::HashTraits<RefPtr<UString::Rep> > FirstTraits;
          typedef WTF::GenericHashTraits<unsigned> SecondTraits;
          typedef std::pair<FirstTraits::TraitType, SecondTraits::TraitType > TraitType;
  
          static const bool emptyValueIsZero = FirstTraits::emptyValueIsZero && SecondTraits::emptyValueIsZero;
          static TraitType emptyValue() { return std::make_pair(FirstTraits::emptyValue(), SecondTraits::emptyValue()); }
  
          static const bool needsDestruction = FirstTraits::needsDestruction || SecondTraits::needsDestruction;
  
          static void constructDeletedValue(TraitType& slot) { FirstTraits::constructDeletedValue(slot.first); }
          static bool isDeletedValue(const TraitType& value) { return FirstTraits::isDeletedValue(value.first); }
      };
  
  } // namespace JSC
  
  #endif // StructureTransitionTable_h
  