    /* -*- 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/.
     *
     * This file incorporates work covered by the following license notice:
     *
     *   Licensed to the Apache Software Foundation (ASF) under one or more
     *   contributor license agreements. See the NOTICE file distributed
     *   with this work for additional information regarding copyright
     *   ownership. The ASF licenses this file to you under the Apache
     *   License, Version 2.0 (the "License"); you may not use this file
     *   except in compliance with the License. You may obtain a copy of
     *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
     */

    #include <algorithm>

    #include <com/sun/star/lang/IllegalArgumentException.hpp>
    #include <com/sun/star/lang/XServiceInfo.hpp>
    #include <com/sun/star/io/IOException.hpp>
    #include <com/sun/star/io/XStream.hpp>
    #include <com/sun/star/io/XSeekableInputStream.hpp>
    #include <com/sun/star/io/XTruncate.hpp>
    #include <com/sun/star/uno/XComponentContext.hpp>
    #include <cppuhelper/implbase.hxx>
    #include <cppuhelper/supportsservice.hxx>
    #include <osl/diagnose.h>

    #include <string.h>
    #include <vector>

    using ::cppu::OWeakObject;
    using ::cppu::WeakImplHelper;
    using namespace ::com::sun::star::io;
    using namespace ::com::sun::star::uno;
    using namespace ::com::sun::star::lang;
    using namespace ::osl;

    namespace comphelper
    {

    class UNOMemoryStream : public WeakImplHelper<XServiceInfo, XStream, XSeekableInputStream, XOutputStream, XTruncate>
    {
    public:
        UNOMemoryStream();

        // XServiceInfo
        virtual OUString SAL_CALL getImplementationName() override;
        virtual sal_Bool SAL_CALL supportsService(const OUString& ServiceName) override;
        virtual css::uno::Sequence<OUString> SAL_CALL getSupportedServiceNames() override;

        // XStream
        virtual Reference< XInputStream > SAL_CALL getInputStream(  ) override;
        virtual Reference< XOutputStream > SAL_CALL getOutputStream(  ) override;

        // XInputStream
        virtual sal_Int32 SAL_CALL readBytes( Sequence< sal_Int8 >& aData, sal_Int32 nBytesToRead ) override;
        virtual sal_Int32 SAL_CALL readSomeBytes( Sequence< sal_Int8 >& aData, sal_Int32 nMaxBytesToRead ) override;
        virtual void SAL_CALL skipBytes( sal_Int32 nBytesToSkip ) override;
        virtual sal_Int32 SAL_CALL available() override;
        virtual void SAL_CALL closeInput() override;

        // XSeekable
        virtual void SAL_CALL seek( sal_Int64 location ) override;
        virtual sal_Int64 SAL_CALL getPosition() override;
        virtual sal_Int64 SAL_CALL getLength() override;

        // XOutputStream
        virtual void SAL_CALL writeBytes( const Sequence< sal_Int8 >& aData ) override;
        virtual void SAL_CALL flush() override;
        virtual void SAL_CALL closeOutput() override;

        // XTruncate
        virtual void SAL_CALL truncate() override;

    private:
        std::vector< sal_Int8 > maData;
        sal_Int32 mnCursor;
    };

    UNOMemoryStream::UNOMemoryStream()
    : mnCursor(0)
    {
    }

    // XServiceInfo
    OUString SAL_CALL UNOMemoryStream::getImplementationName()
    {
        return OUString("com.sun.star.comp.MemoryStream");
    }

    sal_Bool SAL_CALL UNOMemoryStream::supportsService(const OUString& ServiceName)
    {
        return cppu::supportsService(this, ServiceName);
    }

    css::uno::Sequence<OUString> SAL_CALL UNOMemoryStream::getSupportedServiceNames()
    {
        return { "com.sun.star.comp.MemoryStream" };
    }

    // XStream
    Reference< XInputStream > SAL_CALL UNOMemoryStream::getInputStream(  )
    {
        return this;
    }

    Reference< XOutputStream > SAL_CALL UNOMemoryStream::getOutputStream(  )
    {
        return this;
    }

    // XInputStream
    sal_Int32 SAL_CALL UNOMemoryStream::readBytes( Sequence< sal_Int8 >& aData, sal_Int32 nBytesToRead )
    {
        if( nBytesToRead < 0 )
            throw IOException();

        nBytesToRead = std::min( nBytesToRead, available() );
        aData.realloc( nBytesToRead );

        if( nBytesToRead )
        {
            sal_Int8* pData = &(*maData.begin());
            sal_Int8* pCursor = &(pData[mnCursor]);
            memcpy( static_cast<void*>(aData.getArray()), static_cast<void*>(pCursor), nBytesToRead );

            mnCursor += nBytesToRead;
        }

        return nBytesToRead;
    }

    sal_Int32 SAL_CALL UNOMemoryStream::readSomeBytes( Sequence< sal_Int8 >& aData, sal_Int32 nMaxBytesToRead )
    {
        return readBytes( aData, nMaxBytesToRead );
    }

    void SAL_CALL UNOMemoryStream::skipBytes( sal_Int32 nBytesToSkip )
    {
        if( nBytesToSkip < 0 )
            throw IOException();

        mnCursor += std::min( nBytesToSkip, available() );
    }

    sal_Int32 SAL_CALL UNOMemoryStream::available()
    {
        return std::min<sal_Int64>( SAL_MAX_INT32, maData.size() - mnCursor);
    }

    void SAL_CALL UNOMemoryStream::closeInput()
    {
        mnCursor = 0;
    }

    // XSeekable
    void SAL_CALL UNOMemoryStream::seek( sal_Int64 location )
    {
        if( (location < 0) || (location > SAL_MAX_INT32) )
            throw IllegalArgumentException("this implementation does not support more than 2GB!", static_cast<OWeakObject*>(this), 0 );

        // seek operation should be able to resize the stream
        if ( location > static_cast< sal_Int64 >( maData.size() ) )
            maData.resize( static_cast< sal_Int32 >( location ) );

        if ( location > static_cast< sal_Int64 >( maData.size() ) )
            maData.resize( static_cast< sal_Int32 >( location ) );

        mnCursor = static_cast< sal_Int32 >( location );
    }

    sal_Int64 SAL_CALL UNOMemoryStream::getPosition()
    {
        return static_cast< sal_Int64 >( mnCursor );
    }

    sal_Int64 SAL_CALL UNOMemoryStream::getLength()
    {
        return static_cast< sal_Int64 >( maData.size() );
    }

    // XOutputStream
    void SAL_CALL UNOMemoryStream::writeBytes( const Sequence< sal_Int8 >& aData )
    {
        const sal_Int32 nBytesToWrite( aData.getLength() );
        if( nBytesToWrite )
        {
            sal_Int64 nNewSize = static_cast< sal_Int64 >( mnCursor + nBytesToWrite );
            if( nNewSize > SAL_MAX_INT32 )
            {
                OSL_ASSERT(false);
                throw IOException("this implementation does not support more than 2GB!", static_cast<OWeakObject*>(this) );
            }

            if( static_cast< sal_Int32 >( nNewSize ) > static_cast< sal_Int32 >( maData.size() ) )
                maData.resize( static_cast< sal_Int32 >( nNewSize ) );

            sal_Int8* pData = &(*maData.begin());
            sal_Int8* pCursor = &(pData[mnCursor]);
            memcpy( pCursor, aData.getConstArray(), nBytesToWrite );

            mnCursor += nBytesToWrite;
        }
    }

    void SAL_CALL UNOMemoryStream::flush()
    {
    }

    void SAL_CALL UNOMemoryStream::closeOutput()
    {
        mnCursor = 0;
    }

    //XTruncate
    void SAL_CALL UNOMemoryStream::truncate()
    {
        maData.resize( 0 );
        mnCursor = 0;
    }

    } // namespace comphelper

    extern "C" SAL_DLLPUBLIC_EXPORT css::uno::XInterface *
    com_sun_star_comp_MemoryStream(
        css::uno::XComponentContext *,
        css::uno::Sequence<css::uno::Any> const &)
    {
        return cppu::acquire(new ::comphelper::UNOMemoryStream());
    }

    /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

↑ V1028 Possible overflow. Consider casting arguments of the operator to the type instead of casting its result.

↑ V547 Expression 'nNewSize > ((sal_Int32) 0x7FFFFFFF)' is always false.