kjs/SymbolTable.h

   1 /*
   2  * Copyright (C) 2007 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  *
   8  * 1.  Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  * 2.  Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  14  *     its contributors may be used to endorse or promote products derived
  15  *     from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #ifndef SymbolTable_h
  30 #define SymbolTable_h
  31
  32 #include "ustring.h"
  33 #include <wtf/AlwaysInline.h>
  34
  35 namespace KJS {
  36
  37     struct IdentifierRepHash {
  38         static unsigned hash(const RefPtr<UString::Rep>& key) { return key->computedHash(); }
  39         static bool equal(const RefPtr<UString::Rep>& a, const RefPtr<UString::Rep>& b) { return a == b; }
  40         static const bool safeToCompareToEmptyOrDeleted = true;
  41     };
  42
  43     struct IdentifierRepHashTraits : HashTraits<RefPtr<UString::Rep> > {
  44         static const RefPtr<UString::Rep>& deletedValue()
  45         {
  46             return *reinterpret_cast<RefPtr<UString::Rep>*>(&nullRepPtr);
  47         }
  48
  49     private:
  50         static UString::Rep* nullRepPtr;
  51     };
  52
  53     static ALWAYS_INLINE size_t missingSymbolMarker() { return std::numeric_limits<size_t>::max(); }
  54
  55     struct SymbolTableIndexHashTraits {
  56         typedef size_t TraitType;
  57         typedef SymbolTableIndexHashTraits StorageTraits;
  58         static size_t emptyValue() { return missingSymbolMarker(); }
  59         static const bool emptyValueIsZero = false;
  60         static const bool needsDestruction = false;
  61         static const bool needsRef = false;
  62     };
  63
  64     typedef HashMap<RefPtr<UString::Rep>, size_t, IdentifierRepHash, IdentifierRepHashTraits, SymbolTableIndexHashTraits> SymbolTable;
  65
  66 } // namespace KJS
  67
  68 #endif // SymbolTable_h