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() : m_p(nullptr), m_nBufferLen(0), m_nStart(0), m_nOccupiedBuffer(0)
  50 {
  51 }
  52
  53 MemRingBuffer::~MemRingBuffer()
  54 {
  55     std::free( m_p );
  56 }
  57
  58 void MemRingBuffer::resizeBuffer( sal_Int32 nMinSize )
  59 {
  60     sal_Int32 nNewLen = 1;
  61
  62     while( nMinSize > nNewLen ) {
  63         nNewLen = nNewLen << 1;
  64     }
  65
  66     // buffer never shrinks !
  67     if( nNewLen < m_nBufferLen ) {
  68         nNewLen = m_nBufferLen;
  69     }
  70
  71     if( nNewLen == m_nBufferLen )
  72         return;
  73
  74     auto p = static_cast<sal_Int8*>(std::realloc(m_p, nNewLen));
  75     if (!p)
  76         throw css::io::BufferSizeExceededException(
  77             u"MemRingBuffer::resizeBuffer BufferSizeExceededException"_ustr);
  78
  79     m_p = p;
  80
  81
  82     if( m_nStart + m_nOccupiedBuffer > m_nBufferLen ) {
  83         memmove( &( m_p[m_nStart+(nNewLen-m_nBufferLen)]) , &(m_p[m_nStart]) , m_nBufferLen - m_nStart );
  84         m_nStart += nNewLen - m_nBufferLen;
  85     }
  86     m_nBufferLen = nNewLen;
  87 }
  88
  89
  90 void MemRingBuffer::readAt( sal_Int32 nPos, Sequence<sal_Int8> &seq , sal_Int32 nBytesToRead ) const
  91 {
  92     if( nPos + nBytesToRead > m_nOccupiedBuffer ) {
  93         throw css::io::BufferSizeExceededException(
  94             u"MemRingBuffer::readAt BufferSizeExceededException"_ustr);
  95     }
  96
  97     sal_Int32 nStartReadingPos = nPos + m_nStart;
  98     if( nStartReadingPos >= m_nBufferLen ) {
  99         nStartReadingPos -= m_nBufferLen;
 100     }
 101
 102     seq.realloc( nBytesToRead );
 103
 104     if( nStartReadingPos + nBytesToRead > m_nBufferLen ) {
 105         sal_Int32 nDeltaLen = m_nBufferLen - nStartReadingPos;
 106         memcpy( seq.getArray() , &(m_p[nStartReadingPos]) , nDeltaLen );
 107         memcpy( &(seq.getArray()[nDeltaLen]), m_p , nBytesToRead - nDeltaLen );
 108     }
 109     else {
 110         memcpy( seq.getArray() , &(m_p[nStartReadingPos]) , nBytesToRead );
 111     }
 112 }
 113
 114
 115 void MemRingBuffer::writeAt( sal_Int32 nPos, const Sequence<sal_Int8> &seq )
 116 {
 117     checkInvariants();
 118     const sal_Int32 nLen = seq.getLength();
 119
 120     if( nPos < 0 || nPos > std::numeric_limits< sal_Int32 >::max() - nLen )
 121     {
 122         throw css::io::BufferSizeExceededException(
 123             u"MemRingBuffer::writeAt BufferSizeExceededException"_ustr);
 124     }
 125
 126     if( nPos + nLen - m_nOccupiedBuffer > 0 ) {
 127         resizeBuffer( nPos + nLen );
 128         m_nOccupiedBuffer = nPos + nLen;
 129     }
 130
 131     sal_Int32 nStartWritingIndex = m_nStart + nPos;
 132     if( nStartWritingIndex >= m_nBufferLen ) {
 133         nStartWritingIndex -= m_nBufferLen;
 134     }
 135
 136     if( const sal_Int32 nBufferRestLen = m_nBufferLen-nStartWritingIndex; nLen > nBufferRestLen ) {
 137         // two area copy
 138         memcpy( &(m_p[nStartWritingIndex]) , seq.getConstArray(), nBufferRestLen );
 139         memcpy( m_p , &( seq.getConstArray()[nBufferRestLen] ), nLen - nBufferRestLen );
 140
 141     }
 142     else {
 143         // one area copy
 144         memcpy( &( m_p[nStartWritingIndex]), seq.getConstArray() , nLen );
 145     }
 146     checkInvariants();
 147 }
 148
 149
 150 sal_Int32 MemRingBuffer::getSize()  const noexcept
 151 {
 152     return m_nOccupiedBuffer;
 153 }
 154
 155 void MemRingBuffer::forgetFromStart( sal_Int32 nBytesToForget )
 156 {
 157     checkInvariants();
 158     if( nBytesToForget > m_nOccupiedBuffer ) {
 159         throw css::io::BufferSizeExceededException(
 160             u"MemRingBuffer::forgetFromStart BufferSizeExceededException"_ustr);
 161     }
 162     m_nStart += nBytesToForget;
 163     if( m_nStart >= m_nBufferLen ) {
 164         m_nStart = m_nStart - m_nBufferLen;
 165     }
 166     m_nOccupiedBuffer -= nBytesToForget;
 167     checkInvariants();
 168 }
 169
 170
 171 }
 172
 173 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */