/*

 * Copyright (C) 2009, 2010 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

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

 */

#ifndef RopeImpl_h

#define RopeImpl_h

#include "UStringImpl.h"

namespace JSC {

class RopeImpl : public StringImplBase {

public:

    // A RopeImpl is composed from a set of smaller strings called Fibers.

    // Each Fiber in a rope is either UStringImpl or another RopeImpl.

    typedef StringImplBase* Fiber;

    // Creates a RopeImpl comprising of 'fiberCount' Fibers.

    // The RopeImpl is constructed in an uninitialized state - initialize must be called for each Fiber in the RopeImpl.

    static PassRefPtr<RopeImpl> tryCreateUninitialized(unsigned fiberCount)

    {

        void* allocation;

        if (tryFastMalloc(sizeof(RopeImpl) + (fiberCount - 1) * sizeof(Fiber)).getValue(allocation))

            return adoptRef(new (allocation) RopeImpl(fiberCount));

        return 0;

    }

    static bool isRope(Fiber fiber)

    {

        return !fiber->isStringImpl();

    }

    static void deref(Fiber fiber)

    {

        if (isRope(fiber))

            static_cast<RopeImpl*>(fiber)->deref();

        else

            static_cast<UStringImpl*>(fiber)->deref();

    }

    void initializeFiber(unsigned &index, Fiber fiber)

    {

        m_fibers[index++] = fiber;

        fiber->ref();

        m_length += fiber->length();

    }

    unsigned fiberCount() { return m_size; }

    Fiber* fibers() { return m_fibers; }

    ALWAYS_INLINE void deref()

    {

        m_refCountAndFlags -= s_refCountIncrement;

        if (!(m_refCountAndFlags & s_refCountMask))

            destructNonRecursive();

    }

private:

    RopeImpl(unsigned fiberCount)

        : StringImplBase(ConstructNonStringImpl)

        , m_size(fiberCount)

    {

    }

    void destructNonRecursive();

    void derefFibersNonRecursive(Vector<RopeImpl*, 32>& workQueue);

    bool hasOneRef() { return (m_refCountAndFlags & s_refCountMask) == s_refCountIncrement; }

    unsigned m_size;

    Fiber m_fibers[1];

};

}

#endif