JavaScriptCore/runtime/UString.h
changeset 0 4f2f89ce4247
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/JavaScriptCore/runtime/UString.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,678 @@
+/*
+ *  Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
+ *  Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
+ *  Copyright (C) 2009 Google Inc. All rights reserved.
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Library General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Library General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Library General Public License
+ *  along with this library; see the file COPYING.LIB.  If not, write to
+ *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ *  Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef UString_h
+#define UString_h
+
+#include "Collector.h"
+#include "UStringImpl.h"
+#include <stdint.h>
+#include <string.h>
+#include <wtf/Assertions.h>
+#include <wtf/CrossThreadRefCounted.h>
+#include <wtf/OwnFastMallocPtr.h>
+#include <wtf/PassRefPtr.h>
+#include <wtf/RefPtr.h>
+#include <wtf/Vector.h>
+#include <wtf/text/CString.h>
+#include <wtf/unicode/Unicode.h>
+
+namespace JSC {
+
+    using WTF::PlacementNewAdoptType;
+    using WTF::PlacementNewAdopt;
+
+    class UString {
+        friend class JIT;
+
+    public:
+        typedef UStringImpl Rep;
+    
+    public:
+        UString() {}
+        UString(const char*); // Constructor for null-terminated string.
+        UString(const char*, unsigned length);
+        UString(const UChar*, unsigned length);
+        UString(const Vector<UChar>& buffer);
+
+        UString(const UString& s)
+            : m_rep(s.m_rep)
+        {
+        }
+
+        // Special constructor for cases where we overwrite an object in place.
+        UString(PlacementNewAdoptType)
+            : m_rep(PlacementNewAdopt)
+        {
+        }
+
+        template<size_t inlineCapacity>
+        static PassRefPtr<UStringImpl> adopt(Vector<UChar, inlineCapacity>& vector)
+        {
+            return Rep::adopt(vector);
+        }
+
+        static UString from(int);
+        static UString from(long long);
+        static UString from(unsigned);
+        static UString from(long);
+        static UString from(double);
+
+        // NOTE: This method should only be used for *debugging* purposes as it
+        // is neither Unicode safe nor free from side effects nor thread-safe.
+        char* ascii() const;
+
+        /**
+         * Convert the string to UTF-8, assuming it is UTF-16 encoded.
+         * In non-strict mode, this function is tolerant of badly formed UTF-16, it
+         * can create UTF-8 strings that are invalid because they have characters in
+         * the range U+D800-U+DDFF, U+FFFE, or U+FFFF, but the UTF-8 string is
+         * guaranteed to be otherwise valid.
+         * In strict mode, error is returned as null CString.
+         */
+        CString UTF8String(bool strict = false) const;
+
+        const UChar* data() const
+        {
+            if (!m_rep)
+                return 0;
+            return m_rep->characters();
+        }
+
+        unsigned size() const
+        {
+            if (!m_rep)
+                return 0;
+            return m_rep->length();
+        }
+
+        bool isNull() const { return !m_rep; }
+        bool isEmpty() const { return !m_rep || !m_rep->length(); }
+
+        bool is8Bit() const;
+
+        UChar operator[](unsigned pos) const;
+
+        double toDouble(bool tolerateTrailingJunk, bool tolerateEmptyString) const;
+        double toDouble(bool tolerateTrailingJunk) const;
+        double toDouble() const;
+
+        uint32_t toUInt32(bool* ok = 0) const;
+        uint32_t toUInt32(bool* ok, bool tolerateEmptyString) const;
+        uint32_t toStrictUInt32(bool* ok = 0) const;
+
+        unsigned toArrayIndex(bool* ok = 0) const;
+
+        static const unsigned NotFound = 0xFFFFFFFFu;
+        unsigned find(const UString& f, unsigned pos = 0) const;
+        unsigned find(UChar, unsigned pos = 0) const;
+        unsigned rfind(const UString& f, unsigned pos) const;
+        unsigned rfind(UChar, unsigned pos) const;
+
+        UString substr(unsigned pos = 0, unsigned len = 0xFFFFFFFF) const;
+
+        static const UString& null() { return *s_nullUString; }
+
+        Rep* rep() const { return m_rep.get(); }
+
+        UString(PassRefPtr<Rep> r)
+            : m_rep(r)
+        {
+        }
+
+        size_t cost() const
+        {
+            if (!m_rep)
+                return 0;
+            return m_rep->cost();
+        }
+
+        ALWAYS_INLINE ~UString() { }
+    private:
+        RefPtr<Rep> m_rep;
+
+        static UString* s_nullUString;
+
+        friend void initializeUString();
+        friend bool operator==(const UString&, const UString&);
+    };
+
+    ALWAYS_INLINE bool operator==(const UString& s1, const UString& s2)
+    {
+        UString::Rep* rep1 = s1.rep();
+        UString::Rep* rep2 = s2.rep();
+        unsigned size1 = 0;
+        unsigned size2 = 0;
+
+        if (rep1 == rep2) // If they're the same rep, they're equal.
+            return true;
+        
+        if (rep1)
+            size1 = rep1->length();
+            
+        if (rep2)
+            size2 = rep2->length();
+            
+        if (size1 != size2) // If the lengths are not the same, we're done.
+            return false;
+        
+        if (!size1)
+            return true;
+        
+        // At this point we know 
+        //   (a) that the strings are the same length and
+        //   (b) that they are greater than zero length.
+        const UChar* d1 = rep1->characters();
+        const UChar* d2 = rep2->characters();
+        
+        if (d1 == d2) // Check to see if the data pointers are the same.
+            return true;
+        
+        // Do quick checks for sizes 1 and 2.
+        switch (size1) {
+        case 1:
+            return d1[0] == d2[0];
+        case 2:
+            return (d1[0] == d2[0]) & (d1[1] == d2[1]);
+        default:
+            return memcmp(d1, d2, size1 * sizeof(UChar)) == 0;
+        }
+    }
+
+
+    inline bool operator!=(const UString& s1, const UString& s2)
+    {
+        return !JSC::operator==(s1, s2);
+    }
+
+    bool operator<(const UString& s1, const UString& s2);
+    bool operator>(const UString& s1, const UString& s2);
+
+    bool operator==(const UString& s1, const char* s2);
+
+    inline bool operator!=(const UString& s1, const char* s2)
+    {
+        return !JSC::operator==(s1, s2);
+    }
+
+    inline bool operator==(const char *s1, const UString& s2)
+    {
+        return operator==(s2, s1);
+    }
+
+    inline bool operator!=(const char *s1, const UString& s2)
+    {
+        return !JSC::operator==(s1, s2);
+    }
+
+    inline int codePointCompare(const UString& s1, const UString& s2)
+    {
+        return codePointCompare(s1.rep(), s2.rep());
+    }
+
+    // Rule from ECMA 15.2 about what an array index is.
+    // Must exactly match string form of an unsigned integer, and be less than 2^32 - 1.
+    inline unsigned UString::toArrayIndex(bool* ok) const
+    {
+        unsigned i = toStrictUInt32(ok);
+        if (ok && i >= 0xFFFFFFFFU)
+            *ok = false;
+        return i;
+    }
+
+    // We'd rather not do shared substring append for small strings, since
+    // this runs too much risk of a tiny initial string holding down a
+    // huge buffer.
+    static const unsigned minShareSize = Heap::minExtraCost / sizeof(UChar);
+
+    struct IdentifierRepHash : PtrHash<RefPtr<JSC::UString::Rep> > {
+        static unsigned hash(const RefPtr<JSC::UString::Rep>& key) { return key->existingHash(); }
+        static unsigned hash(JSC::UString::Rep* key) { return key->existingHash(); }
+    };
+
+    void initializeUString();
+
+    template<typename StringType>
+    class StringTypeAdapter {
+    };
+
+    template<>
+    class StringTypeAdapter<char*> {
+    public:
+        StringTypeAdapter<char*>(char* buffer)
+            : m_buffer((unsigned char*)buffer)
+            , m_length(strlen(buffer))
+        {
+        }
+
+        unsigned length() { return m_length; }
+
+        void writeTo(UChar* destination)
+        {
+            for (unsigned i = 0; i < m_length; ++i)
+                destination[i] = m_buffer[i];
+        }
+
+    private:
+        const unsigned char* m_buffer;
+        unsigned m_length;
+    };
+
+    template<>
+    class StringTypeAdapter<const char*> {
+    public:
+        StringTypeAdapter<const char*>(const char* buffer)
+            : m_buffer((unsigned char*)buffer)
+            , m_length(strlen(buffer))
+        {
+        }
+
+        unsigned length() { return m_length; }
+
+        void writeTo(UChar* destination)
+        {
+            for (unsigned i = 0; i < m_length; ++i)
+                destination[i] = m_buffer[i];
+        }
+
+    private:
+        const unsigned char* m_buffer;
+        unsigned m_length;
+    };
+
+    template<>
+    class StringTypeAdapter<UString> {
+    public:
+        StringTypeAdapter<UString>(UString& string)
+            : m_data(string.data())
+            , m_length(string.size())
+        {
+        }
+
+        unsigned length() { return m_length; }
+
+        void writeTo(UChar* destination)
+        {
+            for (unsigned i = 0; i < m_length; ++i)
+                destination[i] = m_data[i];
+        }
+
+    private:
+        const UChar* m_data;
+        unsigned m_length;
+    };
+
+    inline void sumWithOverflow(unsigned& total, unsigned addend, bool& overflow)
+    {
+        unsigned oldTotal = total;
+        total = oldTotal + addend;
+        if (total < oldTotal)
+            overflow = true;
+    }
+
+    template<typename StringType1, typename StringType2>
+    PassRefPtr<UStringImpl> tryMakeString(StringType1 string1, StringType2 string2)
+    {
+        StringTypeAdapter<StringType1> adapter1(string1);
+        StringTypeAdapter<StringType2> adapter2(string2);
+
+        UChar* buffer;
+        bool overflow = false;
+        unsigned length = adapter1.length();
+        sumWithOverflow(length, adapter2.length(), overflow);
+        if (overflow)
+            return 0;
+        PassRefPtr<UStringImpl> resultImpl = UStringImpl::tryCreateUninitialized(length, buffer);
+        if (!resultImpl)
+            return 0;
+
+        UChar* result = buffer;
+        adapter1.writeTo(result);
+        result += adapter1.length();
+        adapter2.writeTo(result);
+
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2, typename StringType3>
+    PassRefPtr<UStringImpl> tryMakeString(StringType1 string1, StringType2 string2, StringType3 string3)
+    {
+        StringTypeAdapter<StringType1> adapter1(string1);
+        StringTypeAdapter<StringType2> adapter2(string2);
+        StringTypeAdapter<StringType3> adapter3(string3);
+
+        UChar* buffer = 0;
+        bool overflow = false;
+        unsigned length = adapter1.length();
+        sumWithOverflow(length, adapter2.length(), overflow);
+        sumWithOverflow(length, adapter3.length(), overflow);
+        if (overflow)
+            return 0;
+        PassRefPtr<UStringImpl> resultImpl = UStringImpl::tryCreateUninitialized(length, buffer);
+        if (!resultImpl)
+            return 0;
+
+        UChar* result = buffer;
+        adapter1.writeTo(result);
+        result += adapter1.length();
+        adapter2.writeTo(result);
+        result += adapter2.length();
+        adapter3.writeTo(result);
+
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2, typename StringType3, typename StringType4>
+    PassRefPtr<UStringImpl> tryMakeString(StringType1 string1, StringType2 string2, StringType3 string3, StringType4 string4)
+    {
+        StringTypeAdapter<StringType1> adapter1(string1);
+        StringTypeAdapter<StringType2> adapter2(string2);
+        StringTypeAdapter<StringType3> adapter3(string3);
+        StringTypeAdapter<StringType4> adapter4(string4);
+
+        UChar* buffer;
+        bool overflow = false;
+        unsigned length = adapter1.length();
+        sumWithOverflow(length, adapter2.length(), overflow);
+        sumWithOverflow(length, adapter3.length(), overflow);
+        sumWithOverflow(length, adapter4.length(), overflow);
+        if (overflow)
+            return 0;
+        PassRefPtr<UStringImpl> resultImpl = UStringImpl::tryCreateUninitialized(length, buffer);
+        if (!resultImpl)
+            return 0;
+
+        UChar* result = buffer;
+        adapter1.writeTo(result);
+        result += adapter1.length();
+        adapter2.writeTo(result);
+        result += adapter2.length();
+        adapter3.writeTo(result);
+        result += adapter3.length();
+        adapter4.writeTo(result);
+
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2, typename StringType3, typename StringType4, typename StringType5>
+    PassRefPtr<UStringImpl> tryMakeString(StringType1 string1, StringType2 string2, StringType3 string3, StringType4 string4, StringType5 string5)
+    {
+        StringTypeAdapter<StringType1> adapter1(string1);
+        StringTypeAdapter<StringType2> adapter2(string2);
+        StringTypeAdapter<StringType3> adapter3(string3);
+        StringTypeAdapter<StringType4> adapter4(string4);
+        StringTypeAdapter<StringType5> adapter5(string5);
+
+        UChar* buffer;
+        bool overflow = false;
+        unsigned length = adapter1.length();
+        sumWithOverflow(length, adapter2.length(), overflow);
+        sumWithOverflow(length, adapter3.length(), overflow);
+        sumWithOverflow(length, adapter4.length(), overflow);
+        sumWithOverflow(length, adapter5.length(), overflow);
+        if (overflow)
+            return 0;
+        PassRefPtr<UStringImpl> resultImpl = UStringImpl::tryCreateUninitialized(length, buffer);
+        if (!resultImpl)
+            return 0;
+
+        UChar* result = buffer;
+        adapter1.writeTo(result);
+        result += adapter1.length();
+        adapter2.writeTo(result);
+        result += adapter2.length();
+        adapter3.writeTo(result);
+        result += adapter3.length();
+        adapter4.writeTo(result);
+        result += adapter4.length();
+        adapter5.writeTo(result);
+
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2, typename StringType3, typename StringType4, typename StringType5, typename StringType6>
+    PassRefPtr<UStringImpl> tryMakeString(StringType1 string1, StringType2 string2, StringType3 string3, StringType4 string4, StringType5 string5, StringType6 string6)
+    {
+        StringTypeAdapter<StringType1> adapter1(string1);
+        StringTypeAdapter<StringType2> adapter2(string2);
+        StringTypeAdapter<StringType3> adapter3(string3);
+        StringTypeAdapter<StringType4> adapter4(string4);
+        StringTypeAdapter<StringType5> adapter5(string5);
+        StringTypeAdapter<StringType6> adapter6(string6);
+
+        UChar* buffer;
+        bool overflow = false;
+        unsigned length = adapter1.length();
+        sumWithOverflow(length, adapter2.length(), overflow);
+        sumWithOverflow(length, adapter3.length(), overflow);
+        sumWithOverflow(length, adapter4.length(), overflow);
+        sumWithOverflow(length, adapter5.length(), overflow);
+        sumWithOverflow(length, adapter6.length(), overflow);
+        if (overflow)
+            return 0;
+        PassRefPtr<UStringImpl> resultImpl = UStringImpl::tryCreateUninitialized(length, buffer);
+        if (!resultImpl)
+            return 0;
+
+        UChar* result = buffer;
+        adapter1.writeTo(result);
+        result += adapter1.length();
+        adapter2.writeTo(result);
+        result += adapter2.length();
+        adapter3.writeTo(result);
+        result += adapter3.length();
+        adapter4.writeTo(result);
+        result += adapter4.length();
+        adapter5.writeTo(result);
+        result += adapter5.length();
+        adapter6.writeTo(result);
+
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2, typename StringType3, typename StringType4, typename StringType5, typename StringType6, typename StringType7>
+    PassRefPtr<UStringImpl> tryMakeString(StringType1 string1, StringType2 string2, StringType3 string3, StringType4 string4, StringType5 string5, StringType6 string6, StringType7 string7)
+    {
+        StringTypeAdapter<StringType1> adapter1(string1);
+        StringTypeAdapter<StringType2> adapter2(string2);
+        StringTypeAdapter<StringType3> adapter3(string3);
+        StringTypeAdapter<StringType4> adapter4(string4);
+        StringTypeAdapter<StringType5> adapter5(string5);
+        StringTypeAdapter<StringType6> adapter6(string6);
+        StringTypeAdapter<StringType7> adapter7(string7);
+
+        UChar* buffer;
+        bool overflow = false;
+        unsigned length = adapter1.length();
+        sumWithOverflow(length, adapter2.length(), overflow);
+        sumWithOverflow(length, adapter3.length(), overflow);
+        sumWithOverflow(length, adapter4.length(), overflow);
+        sumWithOverflow(length, adapter5.length(), overflow);
+        sumWithOverflow(length, adapter6.length(), overflow);
+        sumWithOverflow(length, adapter7.length(), overflow);
+        if (overflow)
+            return 0;
+        PassRefPtr<UStringImpl> resultImpl = UStringImpl::tryCreateUninitialized(length, buffer);
+        if (!resultImpl)
+            return 0;
+
+        UChar* result = buffer;
+        adapter1.writeTo(result);
+        result += adapter1.length();
+        adapter2.writeTo(result);
+        result += adapter2.length();
+        adapter3.writeTo(result);
+        result += adapter3.length();
+        adapter4.writeTo(result);
+        result += adapter4.length();
+        adapter5.writeTo(result);
+        result += adapter5.length();
+        adapter6.writeTo(result);
+        result += adapter6.length();
+        adapter7.writeTo(result);
+
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2, typename StringType3, typename StringType4, typename StringType5, typename StringType6, typename StringType7, typename StringType8>
+    PassRefPtr<UStringImpl> tryMakeString(StringType1 string1, StringType2 string2, StringType3 string3, StringType4 string4, StringType5 string5, StringType6 string6, StringType7 string7, StringType8 string8)
+    {
+        StringTypeAdapter<StringType1> adapter1(string1);
+        StringTypeAdapter<StringType2> adapter2(string2);
+        StringTypeAdapter<StringType3> adapter3(string3);
+        StringTypeAdapter<StringType4> adapter4(string4);
+        StringTypeAdapter<StringType5> adapter5(string5);
+        StringTypeAdapter<StringType6> adapter6(string6);
+        StringTypeAdapter<StringType7> adapter7(string7);
+        StringTypeAdapter<StringType8> adapter8(string8);
+
+        UChar* buffer;
+        bool overflow = false;
+        unsigned length = adapter1.length();
+        sumWithOverflow(length, adapter2.length(), overflow);
+        sumWithOverflow(length, adapter3.length(), overflow);
+        sumWithOverflow(length, adapter4.length(), overflow);
+        sumWithOverflow(length, adapter5.length(), overflow);
+        sumWithOverflow(length, adapter6.length(), overflow);
+        sumWithOverflow(length, adapter7.length(), overflow);
+        sumWithOverflow(length, adapter8.length(), overflow);
+        if (overflow)
+            return 0;
+        PassRefPtr<UStringImpl> resultImpl = UStringImpl::tryCreateUninitialized(length, buffer);
+        if (!resultImpl)
+            return 0;
+
+        UChar* result = buffer;
+        adapter1.writeTo(result);
+        result += adapter1.length();
+        adapter2.writeTo(result);
+        result += adapter2.length();
+        adapter3.writeTo(result);
+        result += adapter3.length();
+        adapter4.writeTo(result);
+        result += adapter4.length();
+        adapter5.writeTo(result);
+        result += adapter5.length();
+        adapter6.writeTo(result);
+        result += adapter6.length();
+        adapter7.writeTo(result);
+        result += adapter7.length();
+        adapter8.writeTo(result);
+
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2>
+    UString makeString(StringType1 string1, StringType2 string2)
+    {
+        PassRefPtr<UStringImpl> resultImpl = tryMakeString(string1, string2);
+        if (!resultImpl)
+            CRASH();
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2, typename StringType3>
+    UString makeString(StringType1 string1, StringType2 string2, StringType3 string3)
+    {
+        PassRefPtr<UStringImpl> resultImpl = tryMakeString(string1, string2, string3);
+        if (!resultImpl)
+            CRASH();
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2, typename StringType3, typename StringType4>
+    UString makeString(StringType1 string1, StringType2 string2, StringType3 string3, StringType4 string4)
+    {
+        PassRefPtr<UStringImpl> resultImpl = tryMakeString(string1, string2, string3, string4);
+        if (!resultImpl)
+            CRASH();
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2, typename StringType3, typename StringType4, typename StringType5>
+    UString makeString(StringType1 string1, StringType2 string2, StringType3 string3, StringType4 string4, StringType5 string5)
+    {
+        PassRefPtr<UStringImpl> resultImpl = tryMakeString(string1, string2, string3, string4, string5);
+        if (!resultImpl)
+            CRASH();
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2, typename StringType3, typename StringType4, typename StringType5, typename StringType6>
+    UString makeString(StringType1 string1, StringType2 string2, StringType3 string3, StringType4 string4, StringType5 string5, StringType6 string6)
+    {
+        PassRefPtr<UStringImpl> resultImpl = tryMakeString(string1, string2, string3, string4, string5, string6);
+        if (!resultImpl)
+            CRASH();
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2, typename StringType3, typename StringType4, typename StringType5, typename StringType6, typename StringType7>
+    UString makeString(StringType1 string1, StringType2 string2, StringType3 string3, StringType4 string4, StringType5 string5, StringType6 string6, StringType7 string7)
+    {
+        PassRefPtr<UStringImpl> resultImpl = tryMakeString(string1, string2, string3, string4, string5, string6, string7);
+        if (!resultImpl)
+            CRASH();
+        return resultImpl;
+    }
+
+    template<typename StringType1, typename StringType2, typename StringType3, typename StringType4, typename StringType5, typename StringType6, typename StringType7, typename StringType8>
+    UString makeString(StringType1 string1, StringType2 string2, StringType3 string3, StringType4 string4, StringType5 string5, StringType6 string6, StringType7 string7, StringType8 string8)
+    {
+        PassRefPtr<UStringImpl> resultImpl = tryMakeString(string1, string2, string3, string4, string5, string6, string7, string8);
+        if (!resultImpl)
+            CRASH();
+        return resultImpl;
+    }
+
+} // namespace JSC
+
+namespace WTF {
+
+    template<typename T> struct DefaultHash;
+    template<typename T> struct StrHash;
+
+    template<> struct StrHash<JSC::UString::Rep*> {
+        static unsigned hash(const JSC::UString::Rep* key) { return key->hash(); }
+        static bool equal(const JSC::UString::Rep* a, const JSC::UString::Rep* b) { return ::equal(a, b); }
+        static const bool safeToCompareToEmptyOrDeleted = false;
+    };
+
+    template<> struct StrHash<RefPtr<JSC::UString::Rep> > : public StrHash<JSC::UString::Rep*> {
+        using StrHash<JSC::UString::Rep*>::hash;
+        static unsigned hash(const RefPtr<JSC::UString::Rep>& key) { return key->hash(); }
+        using StrHash<JSC::UString::Rep*>::equal;
+        static bool equal(const RefPtr<JSC::UString::Rep>& a, const RefPtr<JSC::UString::Rep>& b) { return ::equal(a.get(), b.get()); }
+        static bool equal(const JSC::UString::Rep* a, const RefPtr<JSC::UString::Rep>& b) { return ::equal(a, b.get()); }
+        static bool equal(const RefPtr<JSC::UString::Rep>& a, const JSC::UString::Rep* b) { return ::equal(a.get(), b); }
+
+        static const bool safeToCompareToEmptyOrDeleted = false;
+    };
+
+    template <> struct VectorTraits<JSC::UString> : SimpleClassVectorTraits
+    {
+        static const bool canInitializeWithMemset = true;
+    };
+    
+} // namespace WTF
+
+#endif