/*

 *  Copyright (C) 1999-2001 Harri Porten (porten@kde.org)

 *  Copyright (C) 2001 Peter Kelly (pmk@post.com)

 *  Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009 Apple 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 JSValue_h

#define JSValue_h

#include <math.h>

#include <stddef.h> // for size_t

#include <stdint.h>

#include <wtf/AlwaysInline.h>

#include <wtf/Assertions.h>

#include <wtf/HashTraits.h>

#include <wtf/MathExtras.h>

namespace JSC {

    class ExecState;

    class Identifier;

    class JSCell;

    class JSGlobalData;

    class JSImmediate;

    class JSObject;

    class JSString;

    class PropertySlot;

    class PutPropertySlot;

    class UString;

    struct ClassInfo;

    struct Instruction;

    enum PreferredPrimitiveType { NoPreference, PreferNumber, PreferString };

#if USE(JSVALUE32_64)

    typedef int64_t EncodedJSValue;

#else

    typedef void* EncodedJSValue;

#endif

    double nonInlineNaN();

    int32_t toInt32SlowCase(double, bool& ok);

    uint32_t toUInt32SlowCase(double, bool& ok);

    class JSValue {

        friend class JSImmediate;

        friend struct EncodedJSValueHashTraits;

        friend class JIT;

        friend class JITStubs;

        friend class JITStubCall;

        friend class JSInterfaceJIT;

        friend class SpecializedThunkJIT;

    public:

        static EncodedJSValue encode(JSValue value);

        static JSValue decode(EncodedJSValue ptr);

#if !USE(JSVALUE32_64)

    private:

        static JSValue makeImmediate(intptr_t value);

        intptr_t immediateValue();

    public:

#endif

        enum JSNullTag { JSNull };

        enum JSUndefinedTag { JSUndefined };

        enum JSTrueTag { JSTrue };

        enum JSFalseTag { JSFalse };

        enum EncodeAsDoubleTag { EncodeAsDouble };

        JSValue();

        JSValue(JSNullTag);

        JSValue(JSUndefinedTag);

        JSValue(JSTrueTag);

        JSValue(JSFalseTag);

        JSValue(JSCell* ptr);

        JSValue(const JSCell* ptr);

        // Numbers

        JSValue(EncodeAsDoubleTag, ExecState*, double);

        JSValue(ExecState*, double);

        JSValue(ExecState*, char);

        JSValue(ExecState*, unsigned char);

        JSValue(ExecState*, short);

        JSValue(ExecState*, unsigned short);

        JSValue(ExecState*, int);

        JSValue(ExecState*, unsigned);

        JSValue(ExecState*, long);

        JSValue(ExecState*, unsigned long);

        JSValue(ExecState*, long long);

        JSValue(ExecState*, unsigned long long);

        JSValue(JSGlobalData*, double);

        JSValue(JSGlobalData*, int);

        JSValue(JSGlobalData*, unsigned);

        operator bool() const;

        bool operator==(const JSValue& other) const;

        bool operator!=(const JSValue& other) const;

        bool isInt32() const;

        bool isUInt32() const;

        bool isDouble() const;

        bool isTrue() const;

        bool isFalse() const;

        int32_t asInt32() const;

        uint32_t asUInt32() const;

        double asDouble() const;

        // Querying the type.

        bool isUndefined() const;

        bool isNull() const;

        bool isUndefinedOrNull() const;

        bool isBoolean() const;

        bool isNumber() const;

        bool isString() const;

        bool isGetterSetter() const;

        bool isObject() const;

        bool inherits(const ClassInfo*) const;

        // Extracting the value.

        bool getBoolean(bool&) const;

        bool getBoolean() const; // false if not a boolean

        bool getNumber(double&) const;

        double uncheckedGetNumber() const;

        bool getString(ExecState* exec, UString&) const;

        UString getString(ExecState* exec) const; // null string if not a string

        JSObject* getObject() const; // 0 if not an object

        // Extracting integer values.

        bool getUInt32(uint32_t&) const;

        // Basic conversions.

        JSValue toPrimitive(ExecState*, PreferredPrimitiveType = NoPreference) const;

        bool getPrimitiveNumber(ExecState*, double& number, JSValue&);

        bool toBoolean(ExecState*) const;

        // toNumber conversion is expected to be side effect free if an exception has

        // been set in the ExecState already.

        double toNumber(ExecState*) const;

        JSValue toJSNumber(ExecState*) const; // Fast path for when you expect that the value is an immediate number.

        UString toString(ExecState*) const;

        UString toPrimitiveString(ExecState*) const;

        JSObject* toObject(ExecState*) const;

        // Integer conversions.

        double toInteger(ExecState*) const;

        double toIntegerPreserveNaN(ExecState*) const;

        int32_t toInt32(ExecState*) const;

        int32_t toInt32(ExecState*, bool& ok) const;

        uint32_t toUInt32(ExecState*) const;

        uint32_t toUInt32(ExecState*, bool& ok) const;

#if ENABLE(JSC_ZOMBIES)

        bool isZombie() const;

#endif

        // Floating point conversions (this is a convenience method for webcore;

        // signle precision float is not a representation used in JS or JSC).

        float toFloat(ExecState* exec) const { return static_cast<float>(toNumber(exec)); }

        // Object operations, with the toObject operation included.

        JSValue get(ExecState*, const Identifier& propertyName) const;

        JSValue get(ExecState*, const Identifier& propertyName, PropertySlot&) const;

        JSValue get(ExecState*, unsigned propertyName) const;

        JSValue get(ExecState*, unsigned propertyName, PropertySlot&) const;

        void put(ExecState*, const Identifier& propertyName, JSValue, PutPropertySlot&);

        void putDirect(ExecState*, const Identifier& propertyName, JSValue, PutPropertySlot&);

        void put(ExecState*, unsigned propertyName, JSValue);

        bool needsThisConversion() const;

        JSObject* toThisObject(ExecState*) const;

        UString toThisString(ExecState*) const;

        JSString* toThisJSString(ExecState*) const;

        static bool equal(ExecState* exec, JSValue v1, JSValue v2);

        static bool equalSlowCase(ExecState* exec, JSValue v1, JSValue v2);

        static bool equalSlowCaseInline(ExecState* exec, JSValue v1, JSValue v2);

        static bool strictEqual(ExecState* exec, JSValue v1, JSValue v2);

        static bool strictEqualSlowCase(ExecState* exec, JSValue v1, JSValue v2);

        static bool strictEqualSlowCaseInline(ExecState* exec, JSValue v1, JSValue v2);

        JSValue getJSNumber(); // JSValue() if this is not a JSNumber or number object

        bool isCell() const;

        JSCell* asCell() const;

        bool isValidCallee();

#ifndef NDEBUG

        char* description();

#endif

    private:

        enum HashTableDeletedValueTag { HashTableDeletedValue };

        JSValue(HashTableDeletedValueTag);

        inline const JSValue asValue() const { return *this; }

        JSObject* toObjectSlowCase(ExecState*) const;

        JSObject* toThisObjectSlowCase(ExecState*) const;

        JSObject* synthesizePrototype(ExecState*) const;

        JSObject* synthesizeObject(ExecState*) const;

#if USE(JSVALUE32_64)

        enum { Int32Tag =        0xffffffff };

        enum { CellTag =         0xfffffffe };

        enum { TrueTag =         0xfffffffd };

        enum { FalseTag =        0xfffffffc };

        enum { NullTag =         0xfffffffb };

        enum { UndefinedTag =    0xfffffffa };

        enum { EmptyValueTag =   0xfffffff9 };

        enum { DeletedValueTag = 0xfffffff8 };

        enum { LowestTag =  DeletedValueTag };

        uint32_t tag() const;

        int32_t payload() const;

        union {

            EncodedJSValue asEncodedJSValue;

            double asDouble;

#if CPU(BIG_ENDIAN)

            struct {

                int32_t tag;

                int32_t payload;

            } asBits;

#else

            struct {

                int32_t payload;

                int32_t tag;

            } asBits;

#endif

        } u;

#else // USE(JSVALUE32_64)

        JSCell* m_ptr;

#endif // USE(JSVALUE32_64)

    };

#if USE(JSVALUE32_64)

    typedef IntHash<EncodedJSValue> EncodedJSValueHash;

    struct EncodedJSValueHashTraits : HashTraits<EncodedJSValue> {

        static const bool emptyValueIsZero = false;

        static EncodedJSValue emptyValue() { return JSValue::encode(JSValue()); }

        static void constructDeletedValue(EncodedJSValue& slot) { slot = JSValue::encode(JSValue(JSValue::HashTableDeletedValue)); }

        static bool isDeletedValue(EncodedJSValue value) { return value == JSValue::encode(JSValue(JSValue::HashTableDeletedValue)); }

    };

#else

    typedef PtrHash<EncodedJSValue> EncodedJSValueHash;

    struct EncodedJSValueHashTraits : HashTraits<EncodedJSValue> {

        static void constructDeletedValue(EncodedJSValue& slot) { slot = JSValue::encode(JSValue(JSValue::HashTableDeletedValue)); }

        static bool isDeletedValue(EncodedJSValue value) { return value == JSValue::encode(JSValue(JSValue::HashTableDeletedValue)); }

    };

#endif

    // Stand-alone helper functions.

    inline JSValue jsNull()

    {

        return JSValue(JSValue::JSNull);

    }

    inline JSValue jsUndefined()

    {

        return JSValue(JSValue::JSUndefined);

    }

    inline JSValue jsBoolean(bool b)

    {

        return b ? JSValue(JSValue::JSTrue) : JSValue(JSValue::JSFalse);

    }

    ALWAYS_INLINE JSValue jsDoubleNumber(ExecState* exec, double d)

    {

        return JSValue(JSValue::EncodeAsDouble, exec, d);

    }

    ALWAYS_INLINE JSValue jsNumber(ExecState* exec, double d)

    {

        return JSValue(exec, d);

    }

    ALWAYS_INLINE JSValue jsNumber(ExecState* exec, char i)

    {

        return JSValue(exec, i);

    }

    ALWAYS_INLINE JSValue jsNumber(ExecState* exec, unsigned char i)

    {

        return JSValue(exec, i);

    }

    ALWAYS_INLINE JSValue jsNumber(ExecState* exec, short i)

    {

        return JSValue(exec, i);

    }

    ALWAYS_INLINE JSValue jsNumber(ExecState* exec, unsigned short i)

    {

        return JSValue(exec, i);

    }

    ALWAYS_INLINE JSValue jsNumber(ExecState* exec, int i)

    {

        return JSValue(exec, i);

    }

    ALWAYS_INLINE JSValue jsNumber(ExecState* exec, unsigned i)

    {

        return JSValue(exec, i);

    }

    ALWAYS_INLINE JSValue jsNumber(ExecState* exec, long i)

    {

        return JSValue(exec, i);

    }

    ALWAYS_INLINE JSValue jsNumber(ExecState* exec, unsigned long i)

    {

        return JSValue(exec, i);

    }

    ALWAYS_INLINE JSValue jsNumber(ExecState* exec, long long i)

    {

        return JSValue(exec, i);

    }

    ALWAYS_INLINE JSValue jsNumber(ExecState* exec, unsigned long long i)

    {

        return JSValue(exec, i);

    }

    ALWAYS_INLINE JSValue jsNumber(JSGlobalData* globalData, double d)

    {

        return JSValue(globalData, d);

    }

    ALWAYS_INLINE JSValue jsNumber(JSGlobalData* globalData, int i)

    {

        return JSValue(globalData, i);

    }

    ALWAYS_INLINE JSValue jsNumber(JSGlobalData* globalData, unsigned i)

    {

        return JSValue(globalData, i);

    }

    inline bool operator==(const JSValue a, const JSCell* b) { return a == JSValue(b); }

    inline bool operator==(const JSCell* a, const JSValue b) { return JSValue(a) == b; }

    inline bool operator!=(const JSValue a, const JSCell* b) { return a != JSValue(b); }

    inline bool operator!=(const JSCell* a, const JSValue b) { return JSValue(a) != b; }

    inline int32_t toInt32(double val)

    {

        if (!(val >= -2147483648.0 && val < 2147483648.0)) {

            bool ignored;

            return toInt32SlowCase(val, ignored);

        }

        return static_cast<int32_t>(val);

    }

    inline uint32_t toUInt32(double val)

    {

        if (!(val >= 0.0 && val < 4294967296.0)) {

            bool ignored;

            return toUInt32SlowCase(val, ignored);

        }

        return static_cast<uint32_t>(val);

    }

    // FIXME: We should deprecate this and just use JSValue::asCell() instead.

    JSCell* asCell(JSValue);

    inline JSCell* asCell(JSValue value)

    {

        return value.asCell();

    }

    ALWAYS_INLINE int32_t JSValue::toInt32(ExecState* exec) const

    {

        if (isInt32())

            return asInt32();

        bool ignored;

        return toInt32SlowCase(toNumber(exec), ignored);

    }

    inline uint32_t JSValue::toUInt32(ExecState* exec) const

    {

        if (isUInt32())

            return asInt32();

        bool ignored;

        return toUInt32SlowCase(toNumber(exec), ignored);

    }

    inline int32_t JSValue::toInt32(ExecState* exec, bool& ok) const

    {

        if (isInt32()) {

            ok = true;

            return asInt32();

        }

        return toInt32SlowCase(toNumber(exec), ok);

    }

    inline uint32_t JSValue::toUInt32(ExecState* exec, bool& ok) const

    {

        if (isUInt32()) {

            ok = true;

            return asInt32();

        }

        return toUInt32SlowCase(toNumber(exec), ok);

    }

#if USE(JSVALUE32_64)

    inline JSValue jsNaN(ExecState* exec)

    {

        return JSValue(exec, nonInlineNaN());

    }

    // JSValue member functions.

    inline EncodedJSValue JSValue::encode(JSValue value)

    {

        return value.u.asEncodedJSValue;

    }

    inline JSValue JSValue::decode(EncodedJSValue encodedJSValue)

    {

        JSValue v;

        v.u.asEncodedJSValue = encodedJSValue;

#if ENABLE(JSC_ZOMBIES)

        ASSERT(!v.isZombie());

#endif

        return v;

    }

    inline JSValue::JSValue()

    {

        u.asBits.tag = EmptyValueTag;

        u.asBits.payload = 0;

    }

    inline JSValue::JSValue(JSNullTag)

    {

        u.asBits.tag = NullTag;

        u.asBits.payload = 0;

    }

    inline JSValue::JSValue(JSUndefinedTag)

    {

        u.asBits.tag = UndefinedTag;

        u.asBits.payload = 0;

    }

    inline JSValue::JSValue(JSTrueTag)

    {

        u.asBits.tag = TrueTag;

        u.asBits.payload = 0;

    }

    inline JSValue::JSValue(JSFalseTag)

    {

        u.asBits.tag = FalseTag;

        u.asBits.payload = 0;

    }

    inline JSValue::JSValue(HashTableDeletedValueTag)

    {

        u.asBits.tag = DeletedValueTag;

        u.asBits.payload = 0;

    }

    inline JSValue::JSValue(JSCell* ptr)

    {

        if (ptr)

            u.asBits.tag = CellTag;

        else

            u.asBits.tag = EmptyValueTag;

        u.asBits.payload = reinterpret_cast<int32_t>(ptr);

#if ENABLE(JSC_ZOMBIES)

        ASSERT(!isZombie());

#endif

    }

    inline JSValue::JSValue(const JSCell* ptr)

    {

        if (ptr)

            u.asBits.tag = CellTag;

        else

            u.asBits.tag = EmptyValueTag;

        u.asBits.payload = reinterpret_cast<int32_t>(const_cast<JSCell*>(ptr));

#if ENABLE(JSC_ZOMBIES)

        ASSERT(!isZombie());

#endif

    }

    inline JSValue::operator bool() const

    {

        ASSERT(tag() != DeletedValueTag);

        return tag() != EmptyValueTag;

    }

    inline bool JSValue::operator==(const JSValue& other) const

    {

        return u.asEncodedJSValue == other.u.asEncodedJSValue;

    }

    inline bool JSValue::operator!=(const JSValue& other) const

    {

        return u.asEncodedJSValue != other.u.asEncodedJSValue;

    }

    inline bool JSValue::isUndefined() const