io/source/stm/streamhelper.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #include <limits>
  21 #include <string.h>
  22
  23 #include <com/sun/star/uno/Sequence.hxx>
  24
  25 #include <com/sun/star/io/BufferSizeExceededException.hpp>
  26
  27 using namespace ::com::sun::star::uno;
  28
  29 #include "streamhelper.hxx"
  30
  31 namespace io_stm {
  32
  33 void MemFIFO::write( const Sequence< sal_Int8 > &seq )
  34 {
  35     writeAt(getSize(), seq);
  36 }
  37
  38 void MemFIFO::read( Sequence<sal_Int8> &seq , sal_Int32 nBufferLen )
  39 {
  40     readAt(0, seq , nBufferLen);
  41     forgetFromStart( nBufferLen );
  42 }
  43
  44 void MemFIFO::skip( sal_Int32 nBytesToSkip )
  45 {
  46     forgetFromStart( nBytesToSkip );
  47 }
  48
  49 MemRingBuffer::MemRingBuffer()
  50 {
  51     m_nBufferLen            = 0;
  52     m_p                     = nullptr;
  53     m_nStart                = 0;
  54     m_nOccupiedBuffer       = 0;
  55 }
  56
  57 MemRingBuffer::~MemRingBuffer()
  58 {
  59     std::free( m_p );
  60 }
  61
  62 void MemRingBuffer::resizeBuffer( sal_Int32 nMinSize )
  63 {
  64     sal_Int32 nNewLen = 1;
  65
  66     while( nMinSize > nNewLen ) {
  67         nNewLen = nNewLen << 1;
  68     }
  69
  70     // buffer never shrinks !
  71     if( nNewLen < m_nBufferLen ) {
  72         nNewLen = m_nBufferLen;
  73     }
  74
  75     if( nNewLen != m_nBufferLen ) {
  76         if (auto p = static_cast<sal_Int8*>(std::realloc(m_p, nNewLen)))
  77             m_p = p;
  78         else
  79         {
  80             throw css::io::BufferSizeExceededException(
  81                 "MemRingBuffer::resizeBuffer BufferSizeExceededException");
  82         }
  83
  84         if( m_nStart + m_nOccupiedBuffer > m_nBufferLen ) {
  85             memmove( &( m_p[m_nStart+(nNewLen-m_nBufferLen)]) , &(m_p[m_nStart]) , m_nBufferLen - m_nStart );
  86             m_nStart += nNewLen - m_nBufferLen;
  87         }
  88         m_nBufferLen = nNewLen;
  89     }
  90 }
  91
  92
  93 void MemRingBuffer::readAt( sal_Int32 nPos, Sequence<sal_Int8> &seq , sal_Int32 nBytesToRead ) const
  94 {
  95     if( nPos + nBytesToRead > m_nOccupiedBuffer ) {
  96         throw css::io::BufferSizeExceededException(
  97             "MemRingBuffer::readAt BufferSizeExceededException");
  98     }
  99
 100     sal_Int32 nStartReadingPos = nPos + m_nStart;
 101     if( nStartReadingPos >= m_nBufferLen ) {
 102         nStartReadingPos -= m_nBufferLen;
 103     }
 104
 105     seq.realloc( nBytesToRead );
 106
 107     if( nStartReadingPos + nBytesToRead > m_nBufferLen ) {
 108         sal_Int32 nDeltaLen = m_nBufferLen - nStartReadingPos;
 109         memcpy( seq.getArray() , &(m_p[nStartReadingPos]) , nDeltaLen );
 110         memcpy( &(seq.getArray()[nDeltaLen]), m_p , nBytesToRead - nDeltaLen );
 111     }
 112     else {
 113         memcpy( seq.getArray() , &(m_p[nStartReadingPos]) , nBytesToRead );
 114     }
 115 }
 116
 117
 118 void MemRingBuffer::writeAt( sal_Int32 nPos, const Sequence<sal_Int8> &seq )
 119 {
 120     checkInvariants();
 121     const sal_Int32 nLen = seq.getLength();
 122
 123     if( nPos < 0 || nPos > std::numeric_limits< sal_Int32 >::max() - nLen )
 124     {
 125         throw css::io::BufferSizeExceededException(
 126             "MemRingBuffer::writeAt BufferSizeExceededException");
 127     }
 128
 129     if( nPos + nLen - m_nOccupiedBuffer > 0 ) {
 130         resizeBuffer( nPos + nLen );
 131         m_nOccupiedBuffer = nPos + nLen;
 132     }
 133
 134     sal_Int32 nStartWritingIndex = m_nStart + nPos;
 135     if( nStartWritingIndex >= m_nBufferLen ) {
 136         nStartWritingIndex -= m_nBufferLen;
 137     }
 138
 139     if( const sal_Int32 nBufferRestLen = m_nBufferLen-nStartWritingIndex; nLen > nBufferRestLen ) {
 140         // two area copy
 141         memcpy( &(m_p[nStartWritingIndex]) , seq.getConstArray(), nBufferRestLen );
 142         memcpy( m_p , &( seq.getConstArray()[nBufferRestLen] ), nLen - nBufferRestLen );
 143
 144     }
 145     else {
 146         // one area copy
 147         memcpy( &( m_p[nStartWritingIndex]), seq.getConstArray() , nLen );
 148     }
 149     checkInvariants();
 150 }
 151
 152
 153 sal_Int32 MemRingBuffer::getSize()  const throw()
 154 {
 155     return m_nOccupiedBuffer;
 156 }
 157
 158 void MemRingBuffer::forgetFromStart( sal_Int32 nBytesToForget )
 159 {
 160     checkInvariants();
 161     if( nBytesToForget > m_nOccupiedBuffer ) {
 162         throw css::io::BufferSizeExceededException(
 163             "MemRingBuffer::forgetFromStart BufferSizeExceededException");
 164     }
 165     m_nStart += nBytesToForget;
 166     if( m_nStart >= m_nBufferLen ) {
 167         m_nStart = m_nStart - m_nBufferLen;
 168     }
 169     m_nOccupiedBuffer -= nBytesToForget;
 170     checkInvariants();
 171 }
 172
 173
 174 }
 175
 176 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */