atomicstringhash.h

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
 * Copyright (C) 2008 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
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 *     documentation and/or other materials provided with the distribution. 
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 */

#ifndef AtomicStringHash_h
#define AtomicStringHash_h

#include "AtomicString.h"
#include <wtf/HashTraits.h>

namespace WebCore {

    struct AtomicStringHash {
        static unsigned hash(const AtomicString& key)
        {
            return key.impl()->existingHash();
        }

        static bool equal(const AtomicString& a, const AtomicString& b)
        {
            return a == b;
        }

        static const bool safeToCompareToEmptyOrDeleted = false;
    };

}

namespace WTF {

    // WebCore::AtomicStringHash is the default hash for AtomicString
    template<> struct HashTraits<WebCore::AtomicString> : GenericHashTraits<WebCore::AtomicString> {
        static const bool emptyValueIsZero = true;
        static void constructDeletedValue(WebCore::AtomicString& slot) { new (&slot) WebCore::AtomicString(HashTableDeletedValue); }
        static bool isDeletedValue(const WebCore::AtomicString& slot) { return slot.isHashTableDeletedValue(); }
    };

}

#endif