KasmVNC/common/rdr/BufferedInStream.cxx
Pierre Ossman 92c7695981 Create common base classes for buffered streams
Most streams are backed by a memory buffer. Create common base classes
for this functionality to avoid code duplication.
2021-03-29 10:11:16 +03:00

73 lines
1.9 KiB
C++

/* Copyright (C) 2002-2005 RealVNC Ltd. All Rights Reserved.
* Copyright 2020 Pierre Ossman for Cendio AB
*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <rdr/BufferedInStream.h>
#include <rdr/Exception.h>
using namespace rdr;
static const size_t DEFAULT_BUF_SIZE = 8192;
BufferedInStream::BufferedInStream(size_t bufSize_)
: bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0)
{
ptr = end = start = new U8[bufSize];
}
BufferedInStream::~BufferedInStream()
{
delete [] start;
}
size_t BufferedInStream::pos()
{
return offset + ptr - start;
}
size_t BufferedInStream::overrun(size_t itemSize, size_t nItems, bool wait)
{
if (itemSize > bufSize)
throw Exception("BufferedInStream overrun: "
"requested size of %lu bytes exceeds maximum of %lu bytes",
(long unsigned)itemSize, (long unsigned)bufSize);
if (end - ptr != 0)
memmove(start, ptr, end - ptr);
offset += ptr - start;
end -= ptr - start;
ptr = start;
while (avail() < itemSize) {
if (!fillBuffer(start + bufSize - end, wait))
return 0;
}
size_t nAvail;
nAvail = avail() / itemSize;
if (nAvail < nItems)
return nAvail;
return nItems;
}