xref: /trunk/main/io/source/stm/streamhelper.cxx (revision 91144cd0085a7583d2099b982122deb2184ab956)

/**************************************************************
 *
 * 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
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 *************************************************************/



// MARKER(update_precomp.py): autogen include statement, do not remove
#include "precompiled_io.hxx"
#include <rtl/alloc.h>

#include <limits>
#include <string.h>

#include <com/sun/star/uno/Sequence.hxx>

#include <com/sun/star/uno/Exception.hpp>

using namespace ::com::sun::star::uno;

#include "streamhelper.hxx"

namespace io_stm {

void MemFIFO::write( const Sequence< sal_Int8 > &seq )
{
    try
    {
        writeAt(getSize(), seq );
    }
    catch( IRingBuffer_OutOfMemoryException & )
    {
        throw IFIFO_OutOfMemoryException();
    }
    catch( IRingBuffer_OutOfBoundsException & )
    {
        throw IFIFO_OutOfBoundsException();
    }
}

void MemFIFO::read( Sequence<sal_Int8> &seq , sal_Int32 nBufferLen )
{
    try
    {
        readAt(0, seq , nBufferLen);
        forgetFromStart( nBufferLen );
    }
    catch ( IRingBuffer_OutOfBoundsException & )
    {
        throw IFIFO_OutOfBoundsException();
    }
}

void MemFIFO::skip( sal_Int32 nBytesToSkip )
{
    try
    {
        forgetFromStart( nBytesToSkip );
    }
    catch( IRingBuffer_OutOfBoundsException & )
    {
        throw IFIFO_OutOfBoundsException();
    }
}



MemRingBuffer::MemRingBuffer()
{
    m_nBufferLen            = 0;
    m_p                     = 0;
    m_nStart                = 0;
    m_nOccupiedBuffer       = 0;
}

MemRingBuffer::~MemRingBuffer()
{
    if( m_p ) {
        rtl_freeMemory( m_p );
    }
}

void MemRingBuffer::resizeBuffer( sal_Int32 nMinSize )
{
    sal_Int32 nNewLen = 1;

    while( nMinSize > nNewLen ) {
        nNewLen = nNewLen << 1;
    }

    // buffer never shrinks !
    if( nNewLen < m_nBufferLen ) {
        nNewLen = m_nBufferLen;
    }

    if( nNewLen != m_nBufferLen ) {
        m_p = ( sal_Int8 * ) rtl_reallocateMemory( m_p , nNewLen );
        if( !m_p ) {
            throw IRingBuffer_OutOfMemoryException();
        }

        if( m_nStart + m_nOccupiedBuffer > m_nBufferLen ) {
            memmove( &( m_p[m_nStart+(nNewLen-m_nBufferLen)]) , &(m_p[m_nStart]) , m_nBufferLen - m_nStart );
            m_nStart += nNewLen - m_nBufferLen;
        }
        m_nBufferLen = nNewLen;
    }
}


void MemRingBuffer::readAt( sal_Int32 nPos, Sequence<sal_Int8> &seq , sal_Int32 nBytesToRead ) const
{
    if( nPos + nBytesToRead > m_nOccupiedBuffer ) {
        throw IRingBuffer_OutOfBoundsException();
    }

    sal_Int32 nStartReadingPos = nPos + m_nStart;
    if( nStartReadingPos >= m_nBufferLen ) {
        nStartReadingPos -= m_nBufferLen;
    }

    seq.realloc( nBytesToRead );

    if( nStartReadingPos + nBytesToRead > m_nBufferLen ) {
        sal_Int32 nDeltaLen = m_nBufferLen - nStartReadingPos;
        memcpy( seq.getArray() , &(m_p[nStartReadingPos]) , nDeltaLen );
        memcpy( &(seq.getArray()[nDeltaLen]), m_p , nBytesToRead - nDeltaLen );
    }
    else {
        memcpy( seq.getArray() , &(m_p[nStartReadingPos]) , nBytesToRead );
    }
}


void MemRingBuffer::writeAt( sal_Int32 nPos, const Sequence<sal_Int8> &seq )
{
    checkInvariants();
    sal_Int32 nLen = seq.getLength();

    if( nPos < 0 || nPos > std::numeric_limits< sal_Int32 >::max() - nLen )
    {
        throw IRingBuffer_OutOfBoundsException();
    }

    if( nPos + nLen - m_nOccupiedBuffer > 0 ) {
        resizeBuffer( nPos + seq.getLength() );
    }

    sal_Int32 nStartWritingIndex = m_nStart + nPos;
    if( nStartWritingIndex >= m_nBufferLen ) {
        nStartWritingIndex -= m_nBufferLen;
    }

    if( nLen + nStartWritingIndex > m_nBufferLen ) {
        // two area copy
        memcpy( &(m_p[nStartWritingIndex]) , seq.getConstArray(), m_nBufferLen-nStartWritingIndex );
        memcpy( m_p , &( seq.getConstArray()[m_nBufferLen-nStartWritingIndex] ),
                                        nLen - (m_nBufferLen-nStartWritingIndex) );

    }
    else {
        // one area copy
        memcpy( &( m_p[nStartWritingIndex]), seq.getConstArray() , nLen );
    }
    m_nOccupiedBuffer = Max( nPos + seq.getLength() , m_nOccupiedBuffer );
    checkInvariants();
}


sal_Int32 MemRingBuffer::getSize()  const throw()
{
    return m_nOccupiedBuffer;
}

void MemRingBuffer::forgetFromStart( sal_Int32 nBytesToForget )
{
    checkInvariants();
    if( nBytesToForget > m_nOccupiedBuffer ) {
        throw IRingBuffer_OutOfBoundsException();
    }
    m_nStart += nBytesToForget;
    if( m_nStart >= m_nBufferLen ) {
        m_nStart = m_nStart - m_nBufferLen;
    }
    m_nOccupiedBuffer -= nBytesToForget;
    checkInvariants();
}


void MemRingBuffer::forgetFromEnd( sal_Int32 nBytesToForget )
{
    checkInvariants();
    if( nBytesToForget > m_nOccupiedBuffer ) {
        throw IRingBuffer_OutOfBoundsException();
    }
    m_nOccupiedBuffer -= nBytesToForget;
    checkInvariants();
}


void MemRingBuffer::shrink() throw ()
{
    checkInvariants();

    // Up to now, only shrinking of while buffer works.
    // No other shrinking supported up to now.
    if( ! m_nOccupiedBuffer ) {
        if( m_p ) {
            free( m_p );
        }
        m_p = 0;
        m_nBufferLen = 0;
        m_nStart = 0;
    }

    checkInvariants();
}

}