sax/source/tools/CachedOutputStream.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
  10 #ifndef INCLUDED_SAX_SOURCE_TOOLS_CACHEDOUTPUTSTREAM_HXX
  11 #define INCLUDED_SAX_SOURCE_TOOLS_CACHEDOUTPUTSTREAM_HXX
  12
  13 #include <sal/types.h>
  14
  15 #include <com/sun/star/io/XOutputStream.hpp>
  16 #include <com/sun/star/uno/Sequence.hxx>
  17
  18 #include <cstring>
  19 #include <cstdlib>
  20 #include <boost/shared_ptr.hpp>
  21
  22 namespace sax_fastparser {
  23
  24 class ForMergeBase
  25 {
  26 public:
  27     virtual ~ForMergeBase() {}
  28     virtual void append( const css::uno::Sequence<sal_Int8>& rWhat ) = 0;
  29 };
  30
  31 class CachedOutputStream
  32 {
  33     /// When buffer hits this size, it's written to mxOutputStream
  34     static const sal_Int32 mnMaximumSize = 0x10000;
  35
  36     /// Output stream, usually writing data into files.
  37     css::uno::Reference< css::io::XOutputStream > mxOutputStream;
  38     sal_Int32 mnCacheWrittenSize;
  39     const css::uno::Sequence<sal_Int8> mpCache;
  40     uno_Sequence *pSeq;
  41     bool mbWriteToOutStream;
  42     /// ForMerge structure is used for sorting elements in Writer
  43     boost::shared_ptr< ForMergeBase > mpForMerge;
  44
  45 public:
  46     CachedOutputStream() : mnCacheWrittenSize(0)
  47                          , mpCache(mnMaximumSize)
  48                          , pSeq(mpCache.get())
  49                          , mbWriteToOutStream(true)
  50                          , mpForMerge(nullptr)
  51     {}
  52     ~CachedOutputStream() {}
  53
  54     css::uno::Reference< css::io::XOutputStream > getOutputStream() const
  55     {
  56         return mxOutputStream;
  57     }
  58
  59     void setOutputStream( const css::uno::Reference< css::io::XOutputStream >& xOutputStream )
  60     {
  61         mxOutputStream = xOutputStream;
  62     }
  63
  64     void setOutput( boost::shared_ptr< ForMergeBase > pForMerge )
  65     {
  66         flush();
  67         mbWriteToOutStream = false;
  68         mpForMerge = pForMerge;
  69     }
  70
  71     void resetOutputToStream()
  72     {
  73         flush();
  74         mbWriteToOutStream = true;
  75         mpForMerge.reset();
  76     }
  77
  78     /// cache string and if limit is hit, flush
  79     void writeBytes( const sal_Int8* pStr, sal_Int32 nLen )
  80     {
  81         // Write when the buffer gets big enough
  82         if (mnCacheWrittenSize + nLen > mnMaximumSize)
  83         {
  84             flush();
  85
  86             // Writer does some elements sorting, so it can accumulate
  87             // pretty big strings in FastSaxSerializer::ForMerge.
  88             // In that case, just flush data and write immediately.
  89             if (nLen > mnMaximumSize)
  90             {
  91                 if (mbWriteToOutStream)
  92                     mxOutputStream->writeBytes( css::uno::Sequence<sal_Int8>(pStr, nLen) );
  93                 else
  94                     mpForMerge->append( css::uno::Sequence<sal_Int8>(pStr, nLen) );
  95                 return;
  96             }
  97         }
  98
  99         memcpy(pSeq->elements + mnCacheWrittenSize, pStr, nLen);
 100         mnCacheWrittenSize += nLen;
 101     }
 102
 103     /// immediately write buffer into mxOutputStream and clear
 104     void flush()
 105     {
 106         // resize the Sequence to written size
 107         pSeq->nElements = mnCacheWrittenSize;
 108         if (mbWriteToOutStream)
 109             mxOutputStream->writeBytes( mpCache );
 110         else
 111             mpForMerge->append( mpCache );
 112         // and next time write to the beginning
 113         mnCacheWrittenSize = 0;
 114     }
 115 };
 116
 117 }
 118
 119 #endif
 120
 121 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */