JavaScriptCore-903.tar.gz

[apple/javascriptcore.git] / runtime / JSString.h

diff --git a/runtime/JSString.h b/runtime/JSString.h
index e4baa73aba9809c7c753808f5fad107899304c40..668064f854a8030ad383ddc66d11d0c92d732317 100644 (file)
--- a/runtime/JSString.h
+++ b/runtime/JSString.h
@@ -23,11 +23,13 @@
 #ifndef JSString_h
 #define JSString_h
 
 #ifndef JSString_h
 #define JSString_h
 

-#include "CommonIdentifiers.h"

 #include "CallFrame.h"
 #include "CallFrame.h"

+#include "CommonIdentifiers.h"

 #include "Identifier.h"
 #include "Identifier.h"

-#include "JSNumberCell.h"
+#include "PropertyDescriptor.h"

 #include "PropertySlot.h"
 #include "PropertySlot.h"

+#include "RopeImpl.h"
+#include "Structure.h"

 
 namespace JSC {
 
 
 namespace JSC {
 


@@ -40,7 +42,6 @@ namespace JSC {
 
     JSString* jsSingleCharacterString(JSGlobalData*, UChar);
     JSString* jsSingleCharacterString(ExecState*, UChar);
 
     JSString* jsSingleCharacterString(JSGlobalData*, UChar);
     JSString* jsSingleCharacterString(ExecState*, UChar);

-    JSString* jsSingleCharacterSubstring(JSGlobalData*, const UString&, unsigned offset);

     JSString* jsSingleCharacterSubstring(ExecState*, const UString&, unsigned offset);
     JSString* jsSubstring(JSGlobalData*, const UString&, unsigned offset, unsigned length);
     JSString* jsSubstring(ExecState*, const UString&, unsigned offset, unsigned length);
     JSString* jsSingleCharacterSubstring(ExecState*, const UString&, unsigned offset);
     JSString* jsSubstring(JSGlobalData*, const UString&, unsigned offset, unsigned length);
     JSString* jsSubstring(ExecState*, const UString&, unsigned offset, unsigned length);


@@ -58,71 +59,378 @@ namespace JSC {
     JSString* jsOwnedString(JSGlobalData*, const UString&); 
     JSString* jsOwnedString(ExecState*, const UString&); 
 
     JSString* jsOwnedString(JSGlobalData*, const UString&); 
     JSString* jsOwnedString(ExecState*, const UString&); 
 

-    class JSString : public JSCell {
-        friend class JIT;
-        friend class Interpreter;
-
+    class JS_EXPORTCLASS JSString : public JSCell {

     public:
     public:

-        JSString(JSGlobalData* globalData, const UString& value)
-            : JSCell(globalData->stringStructure.get())
+        friend class JIT;
+        friend class JSGlobalData;
+        friend class SpecializedThunkJIT;
+        friend struct ThunkHelpers;
+
+        class RopeBuilder {
+        public:
+            RopeBuilder(unsigned fiberCount)
+                : m_index(0)
+                , m_rope(RopeImpl::tryCreateUninitialized(fiberCount))
+            {
+            }
+
+            bool isOutOfMemory() { return !m_rope; }
+
+            void append(RopeImpl::Fiber& fiber)
+            {
+                ASSERT(m_rope);
+                m_rope->initializeFiber(m_index, fiber);
+            }
+            void append(const UString& string)
+            {
+                ASSERT(m_rope);
+                m_rope->initializeFiber(m_index, string.impl());
+            }
+            void append(JSString* jsString)
+            {
+                if (jsString->isRope()) {
+                    for (unsigned i = 0; i < jsString->m_fiberCount; ++i)
+                        append(jsString->m_fibers[i]);
+                } else
+                    append(jsString->string());
+            }
+
+            PassRefPtr<RopeImpl> release()
+            {
+                ASSERT(m_index == m_rope->fiberCount());
+                return m_rope.release();
+            }
+
+            unsigned length() { return m_rope->length(); }
+
+        private:
+            unsigned m_index;
+            RefPtr<RopeImpl> m_rope;
+        };
+
+        class RopeIterator {
+            public:
+                RopeIterator() { }
+
+                RopeIterator(RopeImpl::Fiber* fibers, size_t fiberCount)
+                {
+                    ASSERT(fiberCount);
+                    m_workQueue.append(WorkItem(fibers, fiberCount));
+                    skipRopes();
+                }
+
+                RopeIterator& operator++()
+                {
+                    WorkItem& item = m_workQueue.last();
+                    ASSERT(!RopeImpl::isRope(item.fibers[item.i]));
+                    if (++item.i == item.fiberCount)
+                        m_workQueue.removeLast();
+                    skipRopes();
+                    return *this;
+                }
+
+                StringImpl* operator*()
+                {
+                    WorkItem& item = m_workQueue.last();
+                    RopeImpl::Fiber fiber = item.fibers[item.i];
+                    ASSERT(!RopeImpl::isRope(fiber));
+                    return static_cast<StringImpl*>(fiber);
+                }
+
+                bool operator!=(const RopeIterator& other) const
+                {
+                    return m_workQueue != other.m_workQueue;
+                }
+
+            private:
+                struct WorkItem {
+                    WorkItem(RopeImpl::Fiber* fibers, size_t fiberCount)
+                        : fibers(fibers)
+                        , fiberCount(fiberCount)
+                        , i(0)
+                    {
+                    }
+
+                    bool operator!=(const WorkItem& other) const
+                    {
+                        return fibers != other.fibers || fiberCount != other.fiberCount || i != other.i;
+                    }
+
+                    RopeImpl::Fiber* fibers;
+                    size_t fiberCount;
+                    size_t i;
+                };
+
+                void skipRopes()
+                {
+                    if (m_workQueue.isEmpty())
+                        return;
+
+                    while (1) {
+                        WorkItem& item = m_workQueue.last();
+                        RopeImpl::Fiber fiber = item.fibers[item.i];
+                        if (!RopeImpl::isRope(fiber))
+                            break;
+                        RopeImpl* rope = static_cast<RopeImpl*>(fiber);
+                        if (++item.i == item.fiberCount)
+                            m_workQueue.removeLast();
+                        m_workQueue.append(WorkItem(rope->fibers(), rope->fiberCount()));
+                    }
+                }
+
+                Vector<WorkItem, 16> m_workQueue;
+        };
+
+        ALWAYS_INLINE JSString(JSGlobalData* globalData, const UString& value)
+            : JSCell(*globalData, globalData->stringStructure.get())
+            , m_length(value.length())

             , m_value(value)
             , m_value(value)

+            , m_fiberCount(0)

         {
         {

-            Heap::heap(this)->reportExtraMemoryCost(value.cost());
+            ASSERT(!m_value.isNull());
+            Heap::heap(this)->reportExtraMemoryCost(value.impl()->cost());

         }
 
         enum HasOtherOwnerType { HasOtherOwner };
         JSString(JSGlobalData* globalData, const UString& value, HasOtherOwnerType)
         }
 
         enum HasOtherOwnerType { HasOtherOwner };
         JSString(JSGlobalData* globalData, const UString& value, HasOtherOwnerType)

-            : JSCell(globalData->stringStructure.get())
+            : JSCell(*globalData, globalData->stringStructure.get())
+            , m_length(value.length())

             , m_value(value)
             , m_value(value)

+            , m_fiberCount(0)

         {
         {

+            ASSERT(!m_value.isNull());

         }
         }

-        JSString(JSGlobalData* globalData, PassRefPtr<UString::Rep> value, HasOtherOwnerType)
-            : JSCell(globalData->stringStructure.get())
+        JSString(JSGlobalData* globalData, PassRefPtr<StringImpl> value, HasOtherOwnerType)
+            : JSCell(*globalData, globalData->stringStructure.get())
+            , m_length(value->length())

             , m_value(value)
             , m_value(value)

+            , m_fiberCount(0)

         {
         {

+            ASSERT(!m_value.isNull());
+        }
+        JSString(JSGlobalData* globalData, PassRefPtr<RopeImpl> rope)
+            : JSCell(*globalData, globalData->stringStructure.get())
+            , m_length(rope->length())
+            , m_fiberCount(1)
+        {
+            m_fibers[0] = rope.leakRef();
+        }
+        // This constructor constructs a new string by concatenating s1 & s2.
+        // This should only be called with fiberCount <= 3.
+        JSString(JSGlobalData* globalData, unsigned fiberCount, JSString* s1, JSString* s2)
+            : JSCell(*globalData, globalData->stringStructure.get())
+            , m_length(s1->length() + s2->length())
+            , m_fiberCount(fiberCount)
+        {
+            ASSERT(fiberCount <= s_maxInternalRopeLength);
+            unsigned index = 0;
+            appendStringInConstruct(index, s1);
+            appendStringInConstruct(index, s2);
+            ASSERT(fiberCount == index);
+        }
+        // This constructor constructs a new string by concatenating s1 & s2.
+        // This should only be called with fiberCount <= 3.
+        JSString(JSGlobalData* globalData, unsigned fiberCount, JSString* s1, const UString& u2)
+            : JSCell(*globalData, globalData->stringStructure.get())
+            , m_length(s1->length() + u2.length())
+            , m_fiberCount(fiberCount)
+        {
+            ASSERT(fiberCount <= s_maxInternalRopeLength);
+            unsigned index = 0;
+            appendStringInConstruct(index, s1);
+            appendStringInConstruct(index, u2);
+            ASSERT(fiberCount == index);
+        }
+        // This constructor constructs a new string by concatenating s1 & s2.
+        // This should only be called with fiberCount <= 3.
+        JSString(JSGlobalData* globalData, unsigned fiberCount, const UString& u1, JSString* s2)
+            : JSCell(*globalData, globalData->stringStructure.get())
+            , m_length(u1.length() + s2->length())
+            , m_fiberCount(fiberCount)
+        {
+            ASSERT(fiberCount <= s_maxInternalRopeLength);
+            unsigned index = 0;
+            appendStringInConstruct(index, u1);
+            appendStringInConstruct(index, s2);
+            ASSERT(fiberCount == index);
+        }
+        // This constructor constructs a new string by concatenating v1, v2 & v3.
+        // This should only be called with fiberCount <= 3 ... which since every
+        // value must require a fiberCount of at least one implies that the length
+        // for each value must be exactly 1!
+        JSString(ExecState* exec, JSValue v1, JSValue v2, JSValue v3)
+            : JSCell(exec->globalData(), exec->globalData().stringStructure.get())
+            , m_length(0)
+            , m_fiberCount(s_maxInternalRopeLength)
+        {
+            unsigned index = 0;
+            appendValueInConstructAndIncrementLength(exec, index, v1);
+            appendValueInConstructAndIncrementLength(exec, index, v2);
+            appendValueInConstructAndIncrementLength(exec, index, v3);
+            ASSERT(index == s_maxInternalRopeLength);

         }
         }

-        
-        const UString& value() const { return m_value; }
+
+        // This constructor constructs a new string by concatenating u1 & u2.
+        JSString(JSGlobalData* globalData, const UString& u1, const UString& u2)
+            : JSCell(*globalData, globalData->stringStructure.get())
+            , m_length(u1.length() + u2.length())
+            , m_fiberCount(2)
+        {
+            unsigned index = 0;
+            appendStringInConstruct(index, u1);
+            appendStringInConstruct(index, u2);
+            ASSERT(index <= s_maxInternalRopeLength);
+        }
+
+        // This constructor constructs a new string by concatenating u1, u2 & u3.
+        JSString(JSGlobalData* globalData, const UString& u1, const UString& u2, const UString& u3)
+            : JSCell(*globalData, globalData->stringStructure.get())
+            , m_length(u1.length() + u2.length() + u3.length())
+            , m_fiberCount(s_maxInternalRopeLength)
+        {
+            unsigned index = 0;
+            appendStringInConstruct(index, u1);
+            appendStringInConstruct(index, u2);
+            appendStringInConstruct(index, u3);
+            ASSERT(index <= s_maxInternalRopeLength);
+        }
+
+        ~JSString()
+        {
+            ASSERT(vptr() == JSGlobalData::jsStringVPtr);
+            for (unsigned i = 0; i < m_fiberCount; ++i)
+                RopeImpl::deref(m_fibers[i]);
+        }
+
+        const UString& value(ExecState* exec) const
+        {
+            if (isRope())
+                resolveRope(exec);
+            return m_value;
+        }
+        const UString& tryGetValue() const
+        {
+            if (isRope())
+                resolveRope(0);
+            return m_value;
+        }
+        unsigned length() { return m_length; }

 
         bool getStringPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
         bool getStringPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);
 
         bool getStringPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
         bool getStringPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);

+        bool getStringPropertyDescriptor(ExecState*, const Identifier& propertyName, PropertyDescriptor&);

 
 

-        bool canGetIndex(unsigned i) { return i < static_cast<unsigned>(m_value.size()); }
-        JSString* getIndex(JSGlobalData*, unsigned);
+        bool canGetIndex(unsigned i) { return i < m_length; }
+        JSString* getIndex(ExecState*, unsigned);
+        JSString* getIndexSlowCase(ExecState*, unsigned);

 
 

-        static PassRefPtr<Structure> createStructure(JSValuePtr proto) { return Structure::create(proto, TypeInfo(StringType, NeedsThisConversion)); }
+        JSValue replaceCharacter(ExecState*, UChar, const UString& replacement);
+
+        static Structure* createStructure(JSGlobalData& globalData, JSValue proto)
+        {
+            return Structure::create(globalData, proto, TypeInfo(StringType, OverridesGetOwnPropertySlot | NeedsThisConversion), AnonymousSlotCount, &s_info);
+        }
+        
+        static const ClassInfo s_info;

 
     private:
 
     private:

-        enum VPtrStealingHackType { VPtrStealingHack };

         JSString(VPtrStealingHackType) 
         JSString(VPtrStealingHackType) 

-            : JSCell(0)
+            : JSCell(VPtrStealingHack)
+            , m_fiberCount(0)
+        {
+        }
+
+        void resolveRope(ExecState*) const;
+        void resolveRopeSlowCase(ExecState*, UChar*) const;
+        void outOfMemory(ExecState*) const;
+        JSString* substringFromRope(ExecState*, unsigned offset, unsigned length);
+
+        void appendStringInConstruct(unsigned& index, const UString& string)
+        {
+            StringImpl* impl = string.impl();
+            impl->ref();
+            m_fibers[index++] = impl;
+        }
+
+        void appendStringInConstruct(unsigned& index, JSString* jsString)

         {
         {

+            if (jsString->isRope()) {
+                for (unsigned i = 0; i < jsString->m_fiberCount; ++i) {
+                    RopeImpl::Fiber fiber = jsString->m_fibers[i];
+                    fiber->ref();
+                    m_fibers[index++] = fiber;
+                }
+            } else
+                appendStringInConstruct(index, jsString->string());

         }
 
         }
 

-        virtual JSValuePtr toPrimitive(ExecState*, PreferredPrimitiveType) const;
-        virtual bool getPrimitiveNumber(ExecState*, double& number, JSValuePtr& value);
+        void appendValueInConstructAndIncrementLength(ExecState* exec, unsigned& index, JSValue v)
+        {
+            if (v.isString()) {
+                ASSERT(v.asCell()->isString());
+                JSString* s = static_cast<JSString*>(v.asCell());
+                ASSERT(s->fiberCount() == 1);
+                appendStringInConstruct(index, s);
+                m_length += s->length();
+            } else {
+                UString u(v.toString(exec));
+                StringImpl* impl = u.impl();
+                impl->ref();
+                m_fibers[index++] = impl;
+                m_length += u.length();
+            }
+        }
+
+        virtual JSValue toPrimitive(ExecState*, PreferredPrimitiveType) const;
+        virtual bool getPrimitiveNumber(ExecState*, double& number, JSValue& value);

         virtual bool toBoolean(ExecState*) const;
         virtual double toNumber(ExecState*) const;
         virtual bool toBoolean(ExecState*) const;
         virtual double toNumber(ExecState*) const;

-        virtual JSObject* toObject(ExecState*) const;
+        virtual JSObject* toObject(ExecState*, JSGlobalObject*) const;

         virtual UString toString(ExecState*) const;
 
         virtual JSObject* toThisObject(ExecState*) const;
         virtual UString toString(ExecState*) const;
 
         virtual JSObject* toThisObject(ExecState*) const;

-        virtual UString toThisString(ExecState*) const;
-        virtual JSString* toThisJSString(ExecState*);

 
         // Actually getPropertySlot, not getOwnPropertySlot (see JSCell).
         virtual bool getOwnPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
         virtual bool getOwnPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);
 
         // Actually getPropertySlot, not getOwnPropertySlot (see JSCell).
         virtual bool getOwnPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
         virtual bool getOwnPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);

-
-        UString m_value;
+        virtual bool getOwnPropertyDescriptor(ExecState*, const Identifier&, PropertyDescriptor&);
+
+        static const unsigned s_maxInternalRopeLength = 3;
+
+        // A string is represented either by a UString or a RopeImpl.
+        unsigned m_length;
+        mutable UString m_value;
+        mutable unsigned m_fiberCount;
+        mutable FixedArray<RopeImpl::Fiber, s_maxInternalRopeLength> m_fibers;
+
+        bool isRope() const { return m_fiberCount; }
+        UString& string() { ASSERT(!isRope()); return m_value; }
+        unsigned fiberCount() { return m_fiberCount ? m_fiberCount : 1; }
+
+        friend JSValue jsString(ExecState* exec, JSString* s1, JSString* s2);
+        friend JSValue jsString(ExecState* exec, const UString& u1, JSString* s2);
+        friend JSValue jsString(ExecState* exec, JSString* s1, const UString& u2);
+        friend JSValue jsString(ExecState* exec, Register* strings, unsigned count);
+        friend JSValue jsString(ExecState* exec, JSValue thisValue);
+        friend JSString* jsSubstring(ExecState* exec, JSString* s, unsigned offset, unsigned length);

     };
 
     };
 

-    JSString* asString(JSValuePtr);
+    JSString* asString(JSValue);

 
 

-    inline JSString* asString(JSValuePtr value)
+    // When an object is created from a different DLL, MSVC changes vptr to a "local" one right after invoking a constructor,
+    // see <http://groups.google.com/group/microsoft.public.vc.language/msg/55cdcefeaf770212>.
+    // This breaks isJSString(), and we don't need that hack anyway, so we change vptr back to primary one.
+    // The below function must be called by any inline function that invokes a JSString constructor.
+#if COMPILER(MSVC) && !defined(BUILDING_JavaScriptCore)
+    inline JSString* fixupVPtr(JSGlobalData* globalData, JSString* string) { string->setVPtr(globalData->jsStringVPtr); return string; }
+#else
+    inline JSString* fixupVPtr(JSGlobalData*, JSString* string) { return string; }
+#endif
+
+    inline JSString* asString(JSValue value)

     {
     {

-        ASSERT(asCell(value)->isString());
-        return static_cast<JSString*>(asCell(value));
+        ASSERT(value.asCell()->isString());
+        return static_cast<JSString*>(value.asCell());

     }
 
     inline JSString* jsEmptyString(JSGlobalData* globalData)
     }
 
     inline JSString* jsEmptyString(JSGlobalData* globalData)


@@ -132,18 +440,19 @@ namespace JSC {
 
     inline JSString* jsSingleCharacterString(JSGlobalData* globalData, UChar c)
     {
 
     inline JSString* jsSingleCharacterString(JSGlobalData* globalData, UChar c)
     {

-        if (c <= 0xFF)
+        if (c <= maxSingleCharacterString)

             return globalData->smallStrings.singleCharacterString(globalData, c);
             return globalData->smallStrings.singleCharacterString(globalData, c);

-        return new (globalData) JSString(globalData, UString(&c, 1));
+        return fixupVPtr(globalData, new (globalData) JSString(globalData, UString(&c, 1)));

     }
 
     }
 

-    inline JSString* jsSingleCharacterSubstring(JSGlobalData* globalData, const UString& s, unsigned offset)
+    inline JSString* jsSingleCharacterSubstring(ExecState* exec, const UString& s, unsigned offset)

     {
     {

-        ASSERT(offset < static_cast<unsigned>(s.size()));
-        UChar c = s.data()[offset];
-        if (c <= 0xFF)
+        JSGlobalData* globalData = &exec->globalData();
+        ASSERT(offset < static_cast<unsigned>(s.length()));
+        UChar c = s.characters()[offset];
+        if (c <= maxSingleCharacterString)

             return globalData->smallStrings.singleCharacterString(globalData, c);
             return globalData->smallStrings.singleCharacterString(globalData, c);

-        return new (globalData) JSString(globalData, UString::Rep::create(s.rep(), offset, 1));
+        return fixupVPtr(globalData, new (globalData) JSString(globalData, UString(StringImpl::create(s.impl(), offset, 1))));

     }
 
     inline JSString* jsNontrivialString(JSGlobalData* globalData, const char* s)
     }
 
     inline JSString* jsNontrivialString(JSGlobalData* globalData, const char* s)


@@ -151,25 +460,81 @@ namespace JSC {
         ASSERT(s);
         ASSERT(s[0]);
         ASSERT(s[1]);
         ASSERT(s);
         ASSERT(s[0]);
         ASSERT(s[1]);

-        return new (globalData) JSString(globalData, s);
+        return fixupVPtr(globalData, new (globalData) JSString(globalData, s));

     }
 
     inline JSString* jsNontrivialString(JSGlobalData* globalData, const UString& s)
     {
     }
 
     inline JSString* jsNontrivialString(JSGlobalData* globalData, const UString& s)
     {

-        ASSERT(s.size() > 1);
-        return new (globalData) JSString(globalData, s);
+        ASSERT(s.length() > 1);
+        return fixupVPtr(globalData, new (globalData) JSString(globalData, s));

     }
 
     }
 

-    inline JSString* JSString::getIndex(JSGlobalData* globalData, unsigned i)
+    inline JSString* JSString::getIndex(ExecState* exec, unsigned i)

     {
         ASSERT(canGetIndex(i));
     {
         ASSERT(canGetIndex(i));

-        return jsSingleCharacterSubstring(globalData, m_value, i);
+        if (isRope())
+            return getIndexSlowCase(exec, i);
+        ASSERT(i < m_value.length());
+        return jsSingleCharacterSubstring(exec, m_value, i);
+    }
+
+    inline JSString* jsString(JSGlobalData* globalData, const UString& s)
+    {
+        int size = s.length();
+        if (!size)
+            return globalData->smallStrings.emptyString(globalData);
+        if (size == 1) {
+            UChar c = s.characters()[0];
+            if (c <= maxSingleCharacterString)
+                return globalData->smallStrings.singleCharacterString(globalData, c);
+        }
+        return fixupVPtr(globalData, new (globalData) JSString(globalData, s));
+    }
+
+    inline JSString* jsSubstring(ExecState* exec, JSString* s, unsigned offset, unsigned length)
+    {
+        ASSERT(offset <= static_cast<unsigned>(s->length()));
+        ASSERT(length <= static_cast<unsigned>(s->length()));
+        ASSERT(offset + length <= static_cast<unsigned>(s->length()));
+        JSGlobalData* globalData = &exec->globalData();
+        if (!length)
+            return globalData->smallStrings.emptyString(globalData);
+        if (s->isRope())
+            return s->substringFromRope(exec, offset, length);
+        return jsSubstring(globalData, s->m_value, offset, length);
+    }
+
+    inline JSString* jsSubstring(JSGlobalData* globalData, const UString& s, unsigned offset, unsigned length)
+    {
+        ASSERT(offset <= static_cast<unsigned>(s.length()));
+        ASSERT(length <= static_cast<unsigned>(s.length()));
+        ASSERT(offset + length <= static_cast<unsigned>(s.length()));
+        if (!length)
+            return globalData->smallStrings.emptyString(globalData);
+        if (length == 1) {
+            UChar c = s.characters()[offset];
+            if (c <= maxSingleCharacterString)
+                return globalData->smallStrings.singleCharacterString(globalData, c);
+        }
+        return fixupVPtr(globalData, new (globalData) JSString(globalData, UString(StringImpl::create(s.impl(), offset, length)), JSString::HasOtherOwner));
+    }
+
+    inline JSString* jsOwnedString(JSGlobalData* globalData, const UString& s)
+    {
+        int size = s.length();
+        if (!size)
+            return globalData->smallStrings.emptyString(globalData);
+        if (size == 1) {
+            UChar c = s.characters()[0];
+            if (c <= maxSingleCharacterString)
+                return globalData->smallStrings.singleCharacterString(globalData, c);
+        }
+        return fixupVPtr(globalData, new (globalData) JSString(globalData, s, JSString::HasOtherOwner));

     }
 
     inline JSString* jsEmptyString(ExecState* exec) { return jsEmptyString(&exec->globalData()); }
     inline JSString* jsString(ExecState* exec, const UString& s) { return jsString(&exec->globalData(), s); }
     inline JSString* jsSingleCharacterString(ExecState* exec, UChar c) { return jsSingleCharacterString(&exec->globalData(), c); }
     }
 
     inline JSString* jsEmptyString(ExecState* exec) { return jsEmptyString(&exec->globalData()); }
     inline JSString* jsString(ExecState* exec, const UString& s) { return jsString(&exec->globalData(), s); }
     inline JSString* jsSingleCharacterString(ExecState* exec, UChar c) { return jsSingleCharacterString(&exec->globalData(), c); }

-    inline JSString* jsSingleCharacterSubstring(ExecState* exec, const UString& s, unsigned offset) { return jsSingleCharacterSubstring(&exec->globalData(), s, offset); }

     inline JSString* jsSubstring(ExecState* exec, const UString& s, unsigned offset, unsigned length) { return jsSubstring(&exec->globalData(), s, offset, length); }
     inline JSString* jsNontrivialString(ExecState* exec, const UString& s) { return jsNontrivialString(&exec->globalData(), s); }
     inline JSString* jsNontrivialString(ExecState* exec, const char* s) { return jsNontrivialString(&exec->globalData(), s); }
     inline JSString* jsSubstring(ExecState* exec, const UString& s, unsigned offset, unsigned length) { return jsSubstring(&exec->globalData(), s, offset, length); }
     inline JSString* jsNontrivialString(ExecState* exec, const UString& s) { return jsNontrivialString(&exec->globalData(), s); }
     inline JSString* jsNontrivialString(ExecState* exec, const char* s) { return jsNontrivialString(&exec->globalData(), s); }


@@ -178,14 +543,14 @@ namespace JSC {
     ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
     {
         if (propertyName == exec->propertyNames().length) {
     ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
     {
         if (propertyName == exec->propertyNames().length) {

-            slot.setValue(jsNumber(exec, m_value.size()));
+            slot.setValue(jsNumber(m_length));

             return true;
         }
 
         bool isStrictUInt32;
             return true;
         }
 
         bool isStrictUInt32;

-        unsigned i = propertyName.toStrictUInt32(&isStrictUInt32);
-        if (isStrictUInt32 && i < static_cast<unsigned>(m_value.size())) {
-            slot.setValue(jsSingleCharacterSubstring(exec, m_value, i));
+        unsigned i = propertyName.toUInt32(isStrictUInt32);
+        if (isStrictUInt32 && i < m_length) {
+            slot.setValue(getIndex(exec, i));

             return true;
         }
 
             return true;
         }
 


@@ -194,19 +559,55 @@ namespace JSC {
         
     ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot)
     {
         
     ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot)
     {

-        if (propertyName < static_cast<unsigned>(m_value.size())) {
-            slot.setValue(jsSingleCharacterSubstring(exec, m_value, propertyName));
+        if (propertyName < m_length) {
+            slot.setValue(getIndex(exec, propertyName));

             return true;
         }
 
         return false;
     }
 
             return true;
         }
 
         return false;
     }
 

+    inline bool isJSString(JSGlobalData* globalData, JSValue v) { return v.isCell() && v.asCell()->vptr() == globalData->jsStringVPtr; }
+

     // --- JSValue inlines ----------------------------
 
     // --- JSValue inlines ----------------------------
 

-    inline JSString* JSValuePtr::toThisJSString(ExecState* exec)
+    inline UString JSValue::toString(ExecState* exec) const
+    {
+        if (isString())
+            return static_cast<JSString*>(asCell())->value(exec);
+        if (isInt32())
+            return exec->globalData().numericStrings.add(asInt32());
+        if (isDouble())
+            return exec->globalData().numericStrings.add(asDouble());
+        if (isTrue())
+            return "true";
+        if (isFalse())
+            return "false";
+        if (isNull())
+            return "null";
+        if (isUndefined())
+            return "undefined";
+        ASSERT(isCell());
+        return asCell()->toString(exec);
+    }
+
+    inline UString JSValue::toPrimitiveString(ExecState* exec) const

     {
     {

-        return JSImmediate::isImmediate(asValue()) ? jsString(exec, JSImmediate::toString(asValue())) : asCell()->toThisJSString(exec);
+        ASSERT(!isString());
+        if (isInt32())
+            return exec->globalData().numericStrings.add(asInt32());
+        if (isDouble())
+            return exec->globalData().numericStrings.add(asDouble());
+        if (isTrue())
+            return "true";
+        if (isFalse())
+            return "false";
+        if (isNull())
+            return "null";
+        if (isUndefined())
+            return "undefined";
+        ASSERT(isCell());
+        return asCell()->toPrimitive(exec, NoPreference).toString(exec);

     }
 
 } // namespace JSC
     }
 
 } // namespace JSC