WPXSvInputStream.cxx

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
 
#include <WPXSvInputStream.hxx>
 
#include <com/sun/star/packages/zip/XZipFileAccess2.hpp>
#include <com/sun/star/uno/XComponentContext.hpp>
 
#include <comphelper/processfactory.hxx>
#include <comphelper/seekableinput.hxx>
#include <o3tl/safeint.hxx>
#include <rtl/string.hxx>
#include <sal/log.hxx>
 
#include <sot/storage.hxx>
 
#include <tools/stream.hxx>
#include <unotools/streamwrap.hxx>
#include <unotools/ucbstreamhelper.hxx>
 
#include <climits>
#include <limits>
#include <memory>
#include <string_view>
#include <unordered_map>
#include <utility>
#include <vector>
 
namespace writerperfect
{
using namespace ::com::sun::star::uno;
using namespace ::com::sun::star::io;
 
namespace container = com::sun::star::container;
namespace packages = com::sun::star::packages;
 
namespace
{
class PositionHolder
{
public:
    explicit PositionHolder(const Reference<XSeekable>& rxSeekable);
    ~PositionHolder();
    PositionHolder(const PositionHolder&) = delete;
    PositionHolder& operator=(const PositionHolder&) = delete;
 
private:
    const Reference<XSeekable> mxSeekable;
    const sal_uInt64 mnPosition;
};
 
PositionHolder::PositionHolder(const Reference<XSeekable>& rxSeekable)
    : mxSeekable(rxSeekable)
    , mnPosition(rxSeekable->getPosition())
{
}
 
PositionHolder::~PositionHolder()
{
    try
    {
        mxSeekable->seek(mnPosition);
    }
    catch (...)
    {
    }
}
 
} // anonymous namespace
 
namespace
{
OUString lcl_normalizeSubStreamPath(const OUString& rPath)
{
    // accept paths which begin by '/'
    // TODO: maybe this should do a full normalization
    if (rPath.startsWith("/") && rPath.getLength() >= 2)
        return rPath.copy(1);
    return rPath;
}
}
 
namespace
{
OUString concatPath(std::u16string_view lhs, const OUString& rhs)
{
    if (lhs.empty())
        return rhs;
    return OUString::Concat(lhs) + "/" + rhs;
}
 
struct OLEStreamData
{
    OLEStreamData(OString aName, OString rvngName);
 
    tools::SvRef<SotStorageStream> stream;
 
    OString name;
    OString RVNGname;
};
 
typedef std::unordered_map<OUString, std::size_t> NameMap_t;
typedef std::unordered_map<OUString, tools::SvRef<SotStorage>> OLEStorageMap_t;
 
struct OLEStorageImpl
{
    OLEStorageImpl();
 
    void initialize(std::unique_ptr<SvStream> pStream);
 
    tools::SvRef<SotStorageStream> getStream(const OUString& rPath);
    tools::SvRef<SotStorageStream> const& getStream(std::size_t nId);
 
private:
    void traverse(const tools::SvRef<SotStorage>& rStorage, std::u16string_view rPath);
 
    tools::SvRef<SotStorageStream> createStream(const OUString& rPath);
 
public:
    tools::SvRef<SotStorage> mxRootStorage; //< root storage of the OLE2
    OLEStorageMap_t maStorageMap; //< map of all sub storages by name
    ::std::vector<OLEStreamData> maStreams; //< list of streams and their names
    NameMap_t maNameMap; //< map of stream names to indexes (into @c maStreams)
    bool mbInitialized;
};
 
OLEStreamData::OLEStreamData(OString aName, OString rvngName)
    : name(std::move(aName))
    , RVNGname(std::move(rvngName))
{
}
 
OLEStorageImpl::OLEStorageImpl()
    : mbInitialized(false)
{
}
 
void OLEStorageImpl::initialize(std::unique_ptr<SvStream> pStream)
{
    if (!pStream)
        return;
 
    mxRootStorage = new SotStorage(pStream.release(), true);
 
    traverse(mxRootStorage, u"");
 
    mbInitialized = true;
}
 
tools::SvRef<SotStorageStream> OLEStorageImpl::getStream(const OUString& rPath)
{
    const OUString aPath(lcl_normalizeSubStreamPath(rPath));
    NameMap_t::iterator aIt = maNameMap.find(aPath);
 
    // For the while don't return stream in this situation.
    // Later, given how libcdr's zip stream implementation behaves,
    // return the first stream in the storage if there is one.
    if (maNameMap.end() == aIt)
        return tools::SvRef<SotStorageStream>();
 
    if (!maStreams[aIt->second].stream.is())
        maStreams[aIt->second].stream
            = createStream(OStringToOUString(maStreams[aIt->second].name, RTL_TEXTENCODING_UTF8));
 
    return maStreams[aIt->second].stream;
}
 
tools::SvRef<SotStorageStream> const& OLEStorageImpl::getStream(const std::size_t nId)
{
    if (!maStreams[nId].stream.is())
        maStreams[nId].stream
            = createStream(OStringToOUString(maStreams[nId].name, RTL_TEXTENCODING_UTF8));
 
    return maStreams[nId].stream;
}
 
void OLEStorageImpl::traverse(const tools::SvRef<SotStorage>& rStorage, std::u16string_view rPath)
{
    SvStorageInfoList infos;
 
    rStorage->FillInfoList(&infos);
 
    for (const auto& info : infos)
    {
        if (info.IsStream())
        {
            OUString baseName = info.GetName(), rvngName = baseName;
            // librevenge::RVNGOLEStream ignores the first character when is a control code, so ...
            if (!rvngName.isEmpty() && rvngName.toChar() < 32)
                rvngName = rvngName.copy(1);
            maStreams.emplace_back(
                OUStringToOString(concatPath(rPath, baseName), RTL_TEXTENCODING_UTF8),
                OUStringToOString(concatPath(rPath, rvngName), RTL_TEXTENCODING_UTF8));
            maNameMap[concatPath(rPath, rvngName)] = maStreams.size() - 1;
        }
        else if (info.IsStorage())
        {
            const OUString aPath = concatPath(rPath, info.GetName());
            tools::SvRef<SotStorage> aStorage
                = rStorage->OpenSotStorage(info.GetName(), StreamMode::STD_READ);
            maStorageMap[aPath] = aStorage;
 
            // deep-first traversal
            traverse(aStorage, aPath);
        }
        else
        {
            SAL_WARN("writerperfect",
                     "OLEStorageImpl::traverse: invalid storage entry, neither stream nor file");
        }
    }
}
 
tools::SvRef<SotStorageStream> OLEStorageImpl::createStream(const OUString& rPath)
{
    const sal_Int32 nDelim = rPath.lastIndexOf(u'/');
 
    if (-1 == nDelim)
        return mxRootStorage->OpenSotStream(rPath, StreamMode::STD_READ);
 
    const OUString aDir = rPath.copy(0, nDelim);
    const OUString aName = rPath.copy(nDelim + 1);
 
    const OLEStorageMap_t::const_iterator aIt = maStorageMap.find(aDir);
 
    if (maStorageMap.end() == aIt)
        return nullptr;
 
    return aIt->second->OpenSotStream(aName, StreamMode::STD_READ);
}
}
 
namespace
{
struct ZipStreamData
{
    explicit ZipStreamData(OString aName);
 
    Reference<XInputStream> xStream;
 
    OString aName;
};
 
struct ZipStorageImpl
{
    explicit ZipStorageImpl(const Reference<container::XNameAccess>& rxContainer);
 
    void initialize();
 
    Reference<XInputStream> getStream(const OUString& rPath);
    Reference<XInputStream> const& getStream(std::size_t nId);
 
private:
    void traverse(const Reference<container::XNameAccess>& rxEnum);
 
    Reference<XInputStream> createStream(const OUString& rPath);
 
public:
    Reference<container::XNameAccess> mxContainer; //< root of the Zip
    ::std::vector<ZipStreamData> maStreams; //< list of streams and their names
    NameMap_t maNameMap; //< map of stream names to indexes (into @c maStreams)
    bool mbInitialized;
};
 
ZipStreamData::ZipStreamData(OString _aName)
    : aName(std::move(_aName))
{
}
 
ZipStorageImpl::ZipStorageImpl(const Reference<container::XNameAccess>& rxContainer)
    : mxContainer(rxContainer)
    , mbInitialized(false)
{
    assert(mxContainer.is());
}
 
void ZipStorageImpl::initialize()
{
    traverse(mxContainer);
 
    mbInitialized = true;
}
 
Reference<XInputStream> ZipStorageImpl::getStream(const OUString& rPath)
{
    const OUString aPath(lcl_normalizeSubStreamPath(rPath));
    NameMap_t::iterator aIt = maNameMap.find(aPath);
 
    // For the while don't return stream in this situation.
    // Later, given how libcdr's zip stream implementation behaves,
    // return the first stream in the storage if there is one.
    if (maNameMap.end() == aIt)
        return Reference<XInputStream>();
 
    if (!maStreams[aIt->second].xStream.is())
        maStreams[aIt->second].xStream = createStream(aPath);
 
    return maStreams[aIt->second].xStream;
}
 
Reference<XInputStream> const& ZipStorageImpl::getStream(const std::size_t nId)
{
    if (!maStreams[nId].xStream.is())
        maStreams[nId].xStream
            = createStream(OStringToOUString(maStreams[nId].aName, RTL_TEXTENCODING_UTF8));
 
    return maStreams[nId].xStream;
}
 
void ZipStorageImpl::traverse(const Reference<container::XNameAccess>& rxContainer)
{
    const Sequence<OUString> lNames = rxContainer->getElementNames();
 
    maStreams.reserve(lNames.getLength());
 
    for (const auto& rName : lNames)
    {
        if (!rName.endsWith("/")) // skip dirs
        {
            maStreams.emplace_back(OUStringToOString(rName, RTL_TEXTENCODING_UTF8));
            maNameMap[rName] = maStreams.size() - 1;
        }
    }
}
 
Reference<XInputStream> ZipStorageImpl::createStream(const OUString& rPath)
{
    Reference<XInputStream> xStream;
 
    try
    {
        const Reference<XInputStream> xInputStream(mxContainer->getByName(rPath), UNO_QUERY_THROW);
        const Reference<XSeekable> xSeekable(xInputStream, UNO_QUERY);
 
        if (xSeekable.is())
            xStream = xInputStream;
        else
            xStream.set(new comphelper::OSeekableInputWrapper(
                xInputStream, comphelper::getProcessComponentContext()));
    }
    catch (const Exception&)
    {
        // nothing needed
    }
 
    return xStream;
}
}
 
class WPXSvInputStreamImpl
{
public:
    explicit WPXSvInputStreamImpl(css::uno::Reference<css::io::XInputStream> const& xStream);
 
    bool isStructured();
    unsigned subStreamCount();
    const char* subStreamName(unsigned id);
    bool existsSubStream(const char* name);
    librevenge::RVNGInputStream* getSubStreamByName(const char* name);
    librevenge::RVNGInputStream* getSubStreamById(unsigned id);
 
    const unsigned char* read(unsigned long numBytes, unsigned long& numBytesRead);
    int seek(tools::Long offset);
    tools::Long tell();
    bool isEnd();
 
    void invalidateReadBuffer();
 
private:
    bool isOLE();
    void ensureOLEIsInitialized();
 
    bool isZip();
    void ensureZipIsInitialized();
 
    static librevenge::RVNGInputStream*
    createWPXStream(const tools::SvRef<SotStorageStream>& rxStorage);
    static librevenge::RVNGInputStream* createWPXStream(const Reference<XInputStream>& rxStream);
 
private:
    css::uno::Reference<css::io::XInputStream> mxStream;
    css::uno::Reference<css::io::XSeekable> mxSeekable;
    css::uno::Sequence<sal_Int8> maData;
    std::unique_ptr<OLEStorageImpl> mpOLEStorage;
    std::unique_ptr<ZipStorageImpl> mpZipStorage;
    bool mbCheckedOLE;
    bool mbCheckedZip;
 
public:
    sal_Int64 mnLength;
    const unsigned char* mpReadBuffer;
    unsigned long mnReadBufferLength;
    unsigned long mnReadBufferPos;
};
 
WPXSvInputStreamImpl::WPXSvInputStreamImpl(Reference<XInputStream> const& xStream)
    : mxStream(xStream)
    , mxSeekable(xStream, UNO_QUERY)
    , maData(0)
    , mbCheckedOLE(false)
    , mbCheckedZip(false)
    , mnLength(0)
    , mpReadBuffer(nullptr)
    , mnReadBufferLength(0)
    , mnReadBufferPos(0)
{
    if (!xStream.is() || !mxStream.is())
        mnLength = 0;
    else
    {
        if (!mxSeekable.is())
            mnLength = 0;
        else
        {
            try
            {
                mnLength = mxSeekable->getLength();
                if (0 < mxSeekable->getPosition())
                    mxSeekable->seek(0);
            }
            catch (...)
            {
                SAL_WARN("writerperfect", "mnLength = mxSeekable->getLength() threw exception");
                mnLength = 0;
            }
        }
    }
}
 
const unsigned char* WPXSvInputStreamImpl::read(unsigned long numBytes, unsigned long& numBytesRead)
{
    numBytesRead = 0;
 
    if (numBytes == 0 || isEnd())
        return nullptr;
 
    numBytesRead = mxStream->readSomeBytes(maData, numBytes);
    if (numBytesRead == 0)
        return nullptr;
 
    return reinterpret_cast<const unsigned char*>(maData.getConstArray());
}
 
tools::Long WPXSvInputStreamImpl::tell()
{
    if ((mnLength == 0) || !mxStream.is() || !mxSeekable.is())
        return -1;
    else
    {
        const sal_Int64 tmpPosition = mxSeekable->getPosition();
        if ((tmpPosition < 0) || (tmpPosition > LONG_MAX))
            return -1;
        return static_cast<tools::Long>(tmpPosition);
    }
}
 
int WPXSvInputStreamImpl::seek(tools::Long offset)
{
    if ((mnLength == 0) || !mxStream.is() || !mxSeekable.is())
        return -1;
 
    const sal_Int64 tmpPosition = mxSeekable->getPosition();
    if ((tmpPosition < 0) || (tmpPosition > LONG_MAX))
        return -1;
 
    try
    {
        mxSeekable->seek(offset);
        return 0;
    }
    catch (...)
    {
        SAL_WARN("writerperfect", "mxSeekable->seek(offset) threw exception");
        return -1;
    }
}
 
bool WPXSvInputStreamImpl::isEnd()
{
    if ((mnLength == 0) || !mxStream.is() || !mxSeekable.is())
        return true;
    return (mxSeekable->getPosition() >= mnLength);
}
 
bool WPXSvInputStreamImpl::isStructured()
{
    if ((mnLength == 0) || !mxStream.is() || !mxSeekable.is())
        return false;
 
    PositionHolder pos(mxSeekable);
    mxSeekable->seek(0);
 
    if (isOLE())
        return true;
 
    mxSeekable->seek(0);
 
    return isZip();
}
 
unsigned WPXSvInputStreamImpl::subStreamCount()
{
    if ((mnLength == 0) || !mxStream.is() || !mxSeekable.is())
        return 0;
 
    PositionHolder pos(mxSeekable);
    mxSeekable->seek(0);
 
    if (isOLE())
    {
        ensureOLEIsInitialized();
 
        return mpOLEStorage->maStreams.size();
    }
 
    mxSeekable->seek(0);
 
    if (isZip())
    {
        ensureZipIsInitialized();
 
        return mpZipStorage->maStreams.size();
    }
 
    return 0;
}
 
const char* WPXSvInputStreamImpl::subStreamName(const unsigned id)
{
    if ((mnLength == 0) || !mxStream.is() || !mxSeekable.is())
        return nullptr;
 
    PositionHolder pos(mxSeekable);
    mxSeekable->seek(0);
 
    if (isOLE())
    {
        ensureOLEIsInitialized();
 
        if (mpOLEStorage->maStreams.size() <= id)
            return nullptr;
 
        return mpOLEStorage->maStreams[id].RVNGname.getStr();
    }
 
    mxSeekable->seek(0);
 
    if (isZip())
    {
        ensureZipIsInitialized();
 
        if (mpZipStorage->maStreams.size() <= id)
            return nullptr;
 
        return mpZipStorage->maStreams[id].aName.getStr();
    }
 
    return nullptr;
}
 
bool WPXSvInputStreamImpl::existsSubStream(const char* const name)
{
    if (!name)
        return false;
 
    if ((mnLength == 0) || !mxStream.is() || !mxSeekable.is())
        return false;
 
    PositionHolder pos(mxSeekable);
    mxSeekable->seek(0);
 
    const OUString aName(OStringToOUString(std::string_view(name), RTL_TEXTENCODING_UTF8));
 
    if (isOLE())
    {
        ensureOLEIsInitialized();
        return mpOLEStorage->maNameMap.end() != mpOLEStorage->maNameMap.find(aName);
    }
 
    mxSeekable->seek(0);
 
    if (isZip())
    {
        ensureZipIsInitialized();
        return mpZipStorage->maNameMap.end() != mpZipStorage->maNameMap.find(aName);
    }
 
    return false;
}
 
librevenge::RVNGInputStream* WPXSvInputStreamImpl::getSubStreamByName(const char* const name)
{
    if (!name)
        return nullptr;
 
    if ((mnLength == 0) || !mxStream.is() || !mxSeekable.is())
        return nullptr;
 
    PositionHolder pos(mxSeekable);
    mxSeekable->seek(0);
 
    const OUString aName(OStringToOUString(std::string_view(name), RTL_TEXTENCODING_UTF8));
 
    if (isOLE())
    {
        ensureOLEIsInitialized();
        return createWPXStream(mpOLEStorage->getStream(aName));
    }
 
    mxSeekable->seek(0);
 
    if (isZip())
    {
        ensureZipIsInitialized();
 
        try
        {
            return createWPXStream(mpZipStorage->getStream(aName));
        }
        catch (const Exception&)
        {
            // nothing needed
        }
    }
 
    return nullptr;
}
 
librevenge::RVNGInputStream* WPXSvInputStreamImpl::getSubStreamById(const unsigned id)
{
    if ((mnLength == 0) || !mxStream.is() || !mxSeekable.is())
        return nullptr;
 
    PositionHolder pos(mxSeekable);
    mxSeekable->seek(0);
 
    if (isOLE())
    {
        ensureOLEIsInitialized();
 
        if (mpOLEStorage->maStreams.size() <= id)
            return nullptr;
 
        return createWPXStream(mpOLEStorage->getStream(id));
    }
 
    mxSeekable->seek(0);
 
    if (isZip())
    {
        ensureZipIsInitialized();
 
        if (mpZipStorage->maStreams.size() <= id)
            return nullptr;
 
        try
        {
            return createWPXStream(mpZipStorage->getStream(id));
        }
        catch (const Exception&)
        {
            // nothing needed
        }
    }
    return nullptr;
}
 
void WPXSvInputStreamImpl::invalidateReadBuffer()
{
    if (mpReadBuffer)
    {
        seek(tell() + static_cast<tools::Long>(mnReadBufferPos)
             - static_cast<tools::Long>(mnReadBufferLength));
        mpReadBuffer = nullptr;
        mnReadBufferPos = 0;
        mnReadBufferLength = 0;
    }
}
 
librevenge::RVNGInputStream*
WPXSvInputStreamImpl::createWPXStream(const tools::SvRef<SotStorageStream>& rxStorage)
{
    if (rxStorage.is())
    {
        Reference<XInputStream> xContents(new utl::OSeekableInputStreamWrapper(rxStorage.get()));
        return new WPXSvInputStream(xContents);
    }
    return nullptr;
}
 
librevenge::RVNGInputStream*
WPXSvInputStreamImpl::createWPXStream(const Reference<XInputStream>& rxStream)
{
    if (rxStream.is())
        return new WPXSvInputStream(rxStream);
    else
        return nullptr;
}
 
bool WPXSvInputStreamImpl::isOLE()
{
    if (!mbCheckedOLE)
    {
        assert(0 == mxSeekable->getPosition());
 
        std::unique_ptr<SvStream> pStream(utl::UcbStreamHelper::CreateStream(mxStream));
        if (pStream && SotStorage::IsOLEStorage(pStream.get()))
            mpOLEStorage.reset(new OLEStorageImpl());
 
        mbCheckedOLE = true;
    }
 
    return bool(mpOLEStorage);
}
 
bool WPXSvInputStreamImpl::isZip()
{
    if (!mbCheckedZip)
    {
        assert(0 == mxSeekable->getPosition());
 
        try
        {
            const Reference<XComponentContext> xContext(comphelper::getProcessComponentContext(),
                                                        UNO_SET_THROW);
            const Reference<packages::zip::XZipFileAccess2> xZip(
                xContext->getServiceManager()->createInstanceWithArgumentsAndContext(
                    "com.sun.star.packages.zip.ZipFileAccess", { Any(mxStream) }, xContext),
                UNO_QUERY_THROW);
            mpZipStorage.reset(new ZipStorageImpl(xZip));
        }
        catch (const Exception&)
        {
            // ignore
        }
 
        mbCheckedZip = true;
    }
 
    return bool(mpZipStorage);
}
 
void WPXSvInputStreamImpl::ensureOLEIsInitialized()
{
    assert(mpOLEStorage);
 
    if (!mpOLEStorage->mbInitialized)
        mpOLEStorage->initialize(utl::UcbStreamHelper::CreateStream(mxStream));
}
 
void WPXSvInputStreamImpl::ensureZipIsInitialized()
{
    assert(mpZipStorage);
 
    if (!mpZipStorage->mbInitialized)
        mpZipStorage->initialize();
}
 
WPXSvInputStream::WPXSvInputStream(Reference<XInputStream> const& xStream)
    : mpImpl(new WPXSvInputStreamImpl(xStream))
{
}
 
WPXSvInputStream::~WPXSvInputStream() {}
 
#define BUFFER_MAX 65536
 
const unsigned char* WPXSvInputStream::read(unsigned long numBytes, unsigned long& numBytesRead)
{
    numBytesRead = 0;
 
    if (numBytes == 0 || numBytes > std::numeric_limits<unsigned long>::max() / 2)
        return nullptr;
 
    if (mpImpl->mpReadBuffer)
    {
        if ((mpImpl->mnReadBufferPos + numBytes > mpImpl->mnReadBufferPos)
            && (mpImpl->mnReadBufferPos + numBytes <= mpImpl->mnReadBufferLength))
        {
            const unsigned char* pTmp = mpImpl->mpReadBuffer + mpImpl->mnReadBufferPos;
            mpImpl->mnReadBufferPos += numBytes;
            numBytesRead = numBytes;
            return pTmp;
        }
 
        mpImpl->invalidateReadBuffer();
    }
 
    unsigned long curpos = static_cast<unsigned long>(mpImpl->tell());
    if (curpos == static_cast<unsigned long>(-1)) // returned ERROR
        return nullptr;
 
    if ((curpos + numBytes < curpos) /*overflow*/
        || (curpos + numBytes
            >= o3tl::make_unsigned(mpImpl->mnLength))) /*reading more than available*/
    {
        numBytes = mpImpl->mnLength - curpos;
    }
 
    if (numBytes < BUFFER_MAX)
    {
        if (BUFFER_MAX < mpImpl->mnLength - curpos)
            mpImpl->mnReadBufferLength = BUFFER_MAX;
        else /* BUFFER_MAX >= mpImpl->mnLength - curpos */
            mpImpl->mnReadBufferLength = mpImpl->mnLength - curpos;
    }
    else
        mpImpl->mnReadBufferLength = numBytes;
 
    unsigned long tmpNumBytes(0);
    mpImpl->mpReadBuffer = mpImpl->read(mpImpl->mnReadBufferLength, tmpNumBytes);
    if (tmpNumBytes != mpImpl->mnReadBufferLength)
        mpImpl->mnReadBufferLength = tmpNumBytes;
 
    mpImpl->mnReadBufferPos = 0;
    if (!mpImpl->mnReadBufferLength)
        return nullptr;
 
    if (numBytes <= mpImpl->mnReadBufferLength)
        numBytesRead = numBytes;
    else
        numBytesRead = mpImpl->mnReadBufferLength;
 
    mpImpl->mnReadBufferPos += numBytesRead;
    return mpImpl->mpReadBuffer;
}
 
long WPXSvInputStream::tell()
{
    tools::Long retVal = mpImpl->tell();
    return retVal - static_cast<tools::Long>(mpImpl->mnReadBufferLength)
           + static_cast<tools::Long>(mpImpl->mnReadBufferPos);
}
 
int WPXSvInputStream::seek(long offset, librevenge::RVNG_SEEK_TYPE seekType)
{
    sal_Int64 tmpOffset = offset;
    if (seekType == librevenge::RVNG_SEEK_CUR)
        tmpOffset += tell();
    if (seekType == librevenge::RVNG_SEEK_END)
        tmpOffset += mpImpl->mnLength;
 
    int retVal = 0;
    if (tmpOffset < 0)
    {
        tmpOffset = 0;
        retVal = -1;
    }
    if (tmpOffset > mpImpl->mnLength)
    {
        tmpOffset = mpImpl->mnLength;
        retVal = -1;
    }
 
    if (tmpOffset < mpImpl->tell()
        && o3tl::make_unsigned(tmpOffset)
               >= static_cast<unsigned long>(mpImpl->tell()) - mpImpl->mnReadBufferLength)
    {
        mpImpl->mnReadBufferPos = static_cast<unsigned long>(
            tmpOffset + static_cast<tools::Long>(mpImpl->mnReadBufferLength) - mpImpl->tell());
        return retVal;
    }
 
    mpImpl->invalidateReadBuffer();
 
    if (mpImpl->seek(tmpOffset))
        return -1;
    return retVal;
}
 
bool WPXSvInputStream::isEnd()
{
    return mpImpl->isEnd() && mpImpl->mnReadBufferPos == mpImpl->mnReadBufferLength;
}
 
bool WPXSvInputStream::isStructured()
{
    mpImpl->invalidateReadBuffer();
    return mpImpl->isStructured();
}
 
unsigned WPXSvInputStream::subStreamCount()
{
    mpImpl->invalidateReadBuffer();
    return mpImpl->subStreamCount();
}
 
const char* WPXSvInputStream::subStreamName(const unsigned id)
{
    mpImpl->invalidateReadBuffer();
    return mpImpl->subStreamName(id);
}
 
bool WPXSvInputStream::existsSubStream(const char* const name)
{
    mpImpl->invalidateReadBuffer();
    return mpImpl->existsSubStream(name);
}
 
librevenge::RVNGInputStream* WPXSvInputStream::getSubStreamByName(const char* name)
{
    mpImpl->invalidateReadBuffer();
    return mpImpl->getSubStreamByName(name);
}
 
librevenge::RVNGInputStream* WPXSvInputStream::getSubStreamById(const unsigned id)
{
    mpImpl->invalidateReadBuffer();
    return mpImpl->getSubStreamById(id);
}
}
 
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