1 /* 2 * Copyright (C) 2008 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 AtomicStringHash_h 30 #define AtomicStringHash_h 31 32 #include "wtf/text/AtomicString.h" 33 #include "wtf/HashTraits.h" 34 35 namespace WTF { 36 37 struct AtomicStringHash { 38 static unsigned hash(const AtomicString& key) 39 { 40 return key.impl()->existingHash(); 41 } 42 43 static bool equal(const AtomicString& a, const AtomicString& b) 44 { 45 return a == b; 46 } 47 48 static const bool safeToCompareToEmptyOrDeleted = false; 49 }; 50 51 // AtomicStringHash is the default hash for AtomicString 52 template<> struct HashTraits<WTF::AtomicString> : GenericHashTraits<WTF::AtomicString> { 53 // Unlike other types, we can return a const reference for AtomicString's empty value (nullAtom). 54 typedef const WTF::AtomicString& PeekType; 55 56 static const WTF::AtomicString& emptyValue() { return nullAtom; } 57 static PeekType peek(const WTF::AtomicString& value) { return value; } 58 59 static const bool emptyValueIsZero = true; 60 static void constructDeletedValue(WTF::AtomicString& slot) { new (NotNull, &slot) WTF::AtomicString(HashTableDeletedValue); } 61 static bool isDeletedValue(const WTF::AtomicString& slot) { return slot.isHashTableDeletedValue(); } 62 }; 63 64 } 65 66 using WTF::AtomicStringHash; 67 68 #endif 69
