nulloutstream.cxx

realvnc是一个非常流行的远程控制程序

//
// Copyright (C) 2002 RealVNC Ltd.  All Rights Reserved.
//
// This is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This software is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this software; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
// USA.

#include <rdr/NullOutStream.h>
#include <rdr/Exception.h>

using namespace rdr;

static const int bufferSize = 1024;

NullOutStream::NullOutStream()
  : offset(0)
{
  start = ptr = new U8[bufferSize];
  end = start + bufferSize;
}

NullOutStream::~NullOutStream()
{
  delete [] start;
}

int NullOutStream::length()
{
  return offset + ptr - start;
}

void NullOutStream::writeBytes(const void* data, int length)
{
  offset += length;
}

int NullOutStream::overrun(int itemSize, int nItems)
{
  if (itemSize > bufferSize)
    throw Exception("NullOutStream overrun: max itemSize exceeded");

  offset += ptr - start;
  ptr = start;

  if (itemSize * nItems > end - ptr)
    nItems = (end - ptr) / itemSize;

  return nItems;
}