1 /*

     2  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.

     3  *

     4  * Redistribution and use in source and binary forms, with or without

     5  * modification, are permitted provided that the following conditions

     6  * are met:

     7  * 1. Redistributions of source code must retain the above copyright

     8  *    notice, this list of conditions and the following disclaimer.

     9  * 2. Redistributions in binary form must reproduce the above copyright

    10  *    notice, this list of conditions and the following disclaimer in the

    11  *    documentation and/or other materials provided with the distribution.

    12  *

    13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY

    14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

    15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

    16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR

    17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

    18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

    19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

    20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

    21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

    22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

    23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

    24  */

    25 

    26 #ifndef StructureTransitionTable_h

    27 #define StructureTransitionTable_h

    28 

    29 #include "UString.h"

    30 #include <wtf/HashFunctions.h>

    31 #include <wtf/HashMap.h>

    32 #include <wtf/HashTraits.h>

    33 #include <wtf/OwnPtr.h>

    34 #include <wtf/RefPtr.h>

    35 

    36 namespace JSC {

    37 

    38     class Structure;

    39 

    40     struct StructureTransitionTableHash {

    41         typedef std::pair<RefPtr<UString::Rep>, unsigned> Key;

    42         static unsigned hash(const Key& p)

    43         {

    44             return p.first->existingHash();

    45         }

    46 

    47         static bool equal(const Key& a, const Key& b)

    48         {

    49             return a == b;

    50         }

    51 

    52         static const bool safeToCompareToEmptyOrDeleted = true;

    53     };

    54 

    55     struct StructureTransitionTableHashTraits {

    56         typedef WTF::HashTraits<RefPtr<UString::Rep> > FirstTraits;

    57         typedef WTF::GenericHashTraits<unsigned> SecondTraits;

    58         typedef std::pair<FirstTraits::TraitType, SecondTraits::TraitType > TraitType;

    59 

    60         static const bool emptyValueIsZero = FirstTraits::emptyValueIsZero && SecondTraits::emptyValueIsZero;

    61         static TraitType emptyValue() { return std::make_pair(FirstTraits::emptyValue(), SecondTraits::emptyValue()); }

    62 

    63         static const bool needsDestruction = FirstTraits::needsDestruction || SecondTraits::needsDestruction;

    64 

    65         static void constructDeletedValue(TraitType& slot) { FirstTraits::constructDeletedValue(slot.first); }

    66         static bool isDeletedValue(const TraitType& value) { return FirstTraits::isDeletedValue(value.first); }

    67     };

    68 

    69 } // namespace JSC

    70 

    71 #endif // StructureTransitionTable_h