/*

 * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.

 * Copyright (C) Research In Motion Limited 2009-2010. 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 COMPUTER, 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 COMPUTER, 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 SharedBuffer_h

#define SharedBuffer_h

#include "PlatformString.h"

#include <wtf/Forward.h>

#include <wtf/OwnPtr.h>

#include <wtf/RefCounted.h>

#include <wtf/Vector.h>

#if PLATFORM(CF)

#include <wtf/RetainPtr.h>

#endif

#if PLATFORM(MAC)

#ifdef __OBJC__

@class NSData;

#else

class NSData;

#endif

#endif

namespace WebCore {

class PurgeableBuffer;

class SharedBuffer : public RefCounted<SharedBuffer> {

public:

    static PassRefPtr<SharedBuffer> create() { return adoptRef(new SharedBuffer); }

    static PassRefPtr<SharedBuffer> create(const char* c, int i) { return adoptRef(new SharedBuffer(c, i)); }

    static PassRefPtr<SharedBuffer> create(const unsigned char* c, int i) { return adoptRef(new SharedBuffer(c, i)); }

    static PassRefPtr<SharedBuffer> createWithContentsOfFile(const String& filePath);

    static PassRefPtr<SharedBuffer> adoptVector(Vector<char>& vector);

    // The buffer must be in non-purgeable state before adopted to a SharedBuffer. 

    // It will stay that way until released.

    static PassRefPtr<SharedBuffer> adoptPurgeableBuffer(PassOwnPtr<PurgeableBuffer>);

    ~SharedBuffer();

#if PLATFORM(MAC)

    NSData *createNSData();

    static PassRefPtr<SharedBuffer> wrapNSData(NSData *data);

#endif

#if PLATFORM(CF)

    CFDataRef createCFData();

    static PassRefPtr<SharedBuffer> wrapCFData(CFDataRef);

#endif

    // Calling this function will force internal segmented buffers

    // to be merged into a flat buffer. Use getSomeData() whenever possible

    // for better performance.

    const char* data() const;

    unsigned size() const;

    // Calling this function will force internal segmented buffers

    // to be merged into a flat buffer. Use getSomeData() whenever possible

    // for better performance.

    const Vector<char>& buffer() const;

    bool isEmpty() const { return !size(); }

    void append(const char*, unsigned);

    void clear();

    const char* platformData() const;

    unsigned platformDataSize() const;

    PassRefPtr<SharedBuffer> copy() const;

    bool hasPurgeableBuffer() const { return m_purgeableBuffer.get(); }

    // Ensure this buffer has no other clients before calling this.

    PassOwnPtr<PurgeableBuffer> releasePurgeableBuffer();

    // Return the number of consecutive bytes after "position". "data"

    // points to the first byte.

    // Return 0 when no more data left.

    // When extracting all data with getSomeData(), the caller should

    // repeat calling it until it returns 0.

    // Usage:

    //      const char* segment;

    //      unsigned pos = 0;

    //      while (unsigned length = sharedBuffer->getSomeData(segment, pos)) {

    //          // Use the data. for example: decoder->decode(segment, length);

    //          pos += length;

    //      }

    unsigned getSomeData(const char*& data, unsigned position = 0) const;

private:

    SharedBuffer();

    SharedBuffer(const char*, int);

    SharedBuffer(const unsigned char*, int);

    void clearPlatformData();

    void maybeTransferPlatformData();

    bool hasPlatformData() const;

    unsigned m_size;

    mutable Vector<char> m_buffer;

    mutable Vector<char*> m_segments;

    OwnPtr<PurgeableBuffer> m_purgeableBuffer;

#if PLATFORM(CF)

    SharedBuffer(CFDataRef);

    RetainPtr<CFDataRef> m_cfData;

#endif

};

}

#endif // SharedBuffer_h