/*

 * Copyright (C) 2006, 2007 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 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. 

 */

#include "config.h"

#include "WebKitDLL.h"

#include "MemoryStream.h"

using std::min;

using namespace WebCore;

// MemoryStream ---------------------------------------------------------------

MemoryStream::MemoryStream(PassRefPtr<SharedBuffer> buffer)

: m_refCount(0)

, m_buffer(buffer)

, m_pos(0)

{

    gClassCount++;

}

MemoryStream::~MemoryStream()

{

    gClassCount--;

}

MemoryStream* MemoryStream::createInstance(PassRefPtr<SharedBuffer> buffer)

{

    MemoryStream* instance = new MemoryStream(buffer);

    instance->AddRef();

    return instance;

}

// IUnknown -------------------------------------------------------------------

HRESULT STDMETHODCALLTYPE MemoryStream::QueryInterface(REFIID riid, void** ppvObject)

{

    *ppvObject = 0;

    if (IsEqualGUID(riid, IID_IUnknown))

        *ppvObject = static_cast<IUnknown*>(this);

    else if (IsEqualGUID(riid, IID_ISequentialStream))

        *ppvObject = static_cast<ISequentialStream*>(this);

    else if (IsEqualGUID(riid, IID_IStream))

        *ppvObject = static_cast<IStream*>(this);

    else

        return E_NOINTERFACE;

    AddRef();

    return S_OK;

}

ULONG STDMETHODCALLTYPE MemoryStream::AddRef(void)

{

    return ++m_refCount;

}

ULONG STDMETHODCALLTYPE MemoryStream::Release(void)

{

    ULONG newRef = --m_refCount;

    if (!newRef)

        delete(this);

    return newRef;

}

// ISequentialStream ----------------------------------------------------------

HRESULT STDMETHODCALLTYPE MemoryStream::Read( 

    /* [length_is][size_is][out] */ void* pv,

    /* [in] */ ULONG cb,

    /* [out] */ ULONG* pcbRead)

{

    *pcbRead = 0;

    if (!m_buffer)

        return E_FAIL;

    if (m_pos >= m_buffer->size())

        return S_FALSE;

    if (m_pos + cb < m_buffer->size())

        *pcbRead = cb;

    else

        *pcbRead = (ULONG) (m_buffer->size() - m_pos);

    memcpy(pv, m_buffer->data() + m_pos, *pcbRead);

    m_pos += *pcbRead;

    return S_OK;

}

HRESULT STDMETHODCALLTYPE MemoryStream::Write( 

    /* [size_is][in] */ const void* /*pv*/,

    /* [in] */ ULONG /*cb*/,

    /* [out] */ ULONG* /*pcbWritten*/)

{

    // we use this for read-only streams

    return STG_E_ACCESSDENIED;

}

// IStream --------------------------------------------------------------------

HRESULT STDMETHODCALLTYPE MemoryStream::Seek( 

    /* [in] */ LARGE_INTEGER dlibMove,

    /* [in] */ DWORD dwOrigin,

    /* [out] */ ULARGE_INTEGER* plibNewPosition)

{

    if (!m_buffer)

        return E_FAIL;

    size_t proposedPos = m_pos;

    size_t lowPartNeg;

    switch (dwOrigin) {

        case STREAM_SEEK_SET:

            proposedPos = dlibMove.LowPart;

            if (dlibMove.HighPart)

                return E_FAIL;

            break;

        case STREAM_SEEK_CUR:

            if (!dlibMove.HighPart) {

                if (dlibMove.LowPart > (m_buffer->size() - m_pos))

                    return E_FAIL;

                proposedPos += dlibMove.LowPart;

            } else if (dlibMove.HighPart == -1) {

                lowPartNeg = (~dlibMove.LowPart)+1;

                if (lowPartNeg > m_pos)

                    return E_FAIL;

                proposedPos = m_pos - lowPartNeg;

            } else

                return E_FAIL;

            break;

        case STREAM_SEEK_END:

            if (dlibMove.HighPart != -1)

                return E_FAIL;

            lowPartNeg = (~dlibMove.LowPart)+1;

            if (lowPartNeg > m_buffer->size())

                return E_FAIL;

            proposedPos = m_buffer->size() - lowPartNeg;

            break;

        default:

            return E_FAIL;

    }

    if (proposedPos >= m_buffer->size())

        return E_FAIL;

    if (plibNewPosition) {

        plibNewPosition->HighPart = 0;

        plibNewPosition->LowPart = (DWORD) m_pos;

    }

    return S_OK;

}

HRESULT STDMETHODCALLTYPE MemoryStream::SetSize( 

    /* [in] */ ULARGE_INTEGER /*libNewSize*/)

{

    return STG_E_INVALIDFUNCTION;

}

HRESULT STDMETHODCALLTYPE MemoryStream::CopyTo( 

    /* [unique][in] */ IStream* pstm,

    /* [in] */ ULARGE_INTEGER cb,

    /* [out] */ ULARGE_INTEGER* pcbRead,

    /* [out] */ ULARGE_INTEGER* pcbWritten)

{

    if (!m_buffer)

        return E_FAIL;

    if (cb.HighPart) {

        cb.HighPart = 0;

        cb.LowPart = (DWORD)-1;

    }

    ULONG written;

    ULONG read = min(cb.LowPart, (ULONG)(m_buffer->size()-m_pos));

    HRESULT hr = pstm->Write(m_buffer->data()+m_pos, read, &written);

    if (pcbWritten) {

        pcbWritten->HighPart = 0;

        pcbWritten->LowPart = written;

    }

    if (pcbRead) {

        pcbRead->HighPart = 0;

        pcbRead->LowPart = read;

    }

    return hr;

}

HRESULT STDMETHODCALLTYPE MemoryStream::Commit( 

    /* [in] */ DWORD /*grfCommitFlags*/)

{

    return S_OK;

}

HRESULT STDMETHODCALLTYPE MemoryStream::Revert( void)

{

    return S_OK;

}

HRESULT STDMETHODCALLTYPE MemoryStream::LockRegion( 

    /* [in] */ ULARGE_INTEGER /*libOffset*/,

    /* [in] */ ULARGE_INTEGER /*cb*/,

    /* [in] */ DWORD /*dwLockType*/)

{

    return STG_E_INVALIDFUNCTION;

}

HRESULT STDMETHODCALLTYPE MemoryStream::UnlockRegion( 

    /* [in] */ ULARGE_INTEGER /*libOffset*/,

    /* [in] */ ULARGE_INTEGER /*cb*/,

    /* [in] */ DWORD /*dwLockType*/)

{

    return STG_E_INVALIDFUNCTION;

}

HRESULT STDMETHODCALLTYPE MemoryStream::Stat( 

    /* [out] */ STATSTG* pstatstg,

    /* [in] */ DWORD /*grfStatFlag*/)

{

    if (!pstatstg)

        return E_POINTER;

    if (!m_buffer)

        return E_FAIL;

    memset(pstatstg, 0, sizeof(STATSTG));

    pstatstg->type = STGTY_STREAM;

    pstatstg->cbSize.LowPart = (DWORD) m_buffer->size();

    return S_OK;

}

HRESULT STDMETHODCALLTYPE MemoryStream::Clone( 

    /* [out] */ IStream** ppstm)

{

    *ppstm = MemoryStream::createInstance(m_buffer);

    return (*ppstm) ? S_OK : E_OUTOFMEMORY;

}