io/source/stm/streamhelper.hxx

   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 #pragma once
  21
  22 #include <com/sun/star/uno/Sequence.hxx>
  23
  24 #include <assert.h>
  25
  26 using namespace com::sun::star::uno;
  27
  28 namespace io_stm
  29 {
  30
  31 class MemRingBuffer
  32 {
  33 public:
  34     MemRingBuffer();
  35     virtual ~MemRingBuffer();
  36
  37     /***
  38     * overwrites data at given position. Size is automatically extended, when
  39     * data is written beyond end.
  40     ***/
  41     /// @throws css::io::BufferSizeExceededException
  42     void    writeAt( sal_Int32 nPos, const Sequence<sal_Int8> &);
  43     /// @throws css::io::BufferSizeExceededException
  44     void    readAt( sal_Int32 nPos, Sequence<sal_Int8> & , sal_Int32 nBytesToRead ) const;
  45     sal_Int32   getSize() const noexcept;
  46     /// @throws css::io::BufferSizeExceededException
  47     void    forgetFromStart(sal_Int32 nBytesToForget);
  48
  49 private:
  50     /// @throws css::io::BufferSizeExceededException
  51     void resizeBuffer(sal_Int32 nMinSize);
  52     void checkInvariants() const {
  53         assert( m_nBufferLen >= 0 );
  54         assert( m_nOccupiedBuffer >= 0 );
  55         assert( m_nOccupiedBuffer <= m_nBufferLen );
  56         assert( m_nStart >= 0 );
  57         assert( 0 == m_nStart || m_nStart < m_nBufferLen );
  58         (void) this; // avoid loplugin:staticmethods
  59     }
  60
  61     sal_Int8    *m_p;
  62     sal_Int32   m_nBufferLen;
  63     sal_Int32   m_nStart;
  64     sal_Int32   m_nOccupiedBuffer;
  65 };
  66
  67
  68 class MemFIFO :
  69     private MemRingBuffer
  70 {
  71 public:
  72     /// @throws css::io::BufferSizeExceededException
  73     void          write( const Sequence<sal_Int8> &);
  74     /// @throws css::io::BufferSizeExceededException
  75     void          read( Sequence<sal_Int8> & , sal_Int32 nBytesToRead );
  76     /// @throws css::io::BufferSizeExceededException
  77     void          skip( sal_Int32 nBytesToSkip );
  78     sal_Int32     getSize() const noexcept
  79                   { return MemRingBuffer::getSize(); }
  80
  81 };
  82
  83 }
  84
  85 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */