KasmVNC/common/rdr/BufferedOutStream.cxx
2021-03-29 10:49:25 +03:00

109 lines
2.7 KiB
C++

/* Copyright (C) 2002-2005 RealVNC Ltd. All Rights Reserved.
* Copyright 2011-2020 Pierre Ossman for Cendio AB
* Copyright 2017 Peter Astrand <astrand@cendio.se> 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/BufferedOutStream.h>
#include <rdr/Exception.h>
using namespace rdr;
static const size_t DEFAULT_BUF_SIZE = 16384;
BufferedOutStream::BufferedOutStream()
: bufSize(DEFAULT_BUF_SIZE), offset(0)
{
ptr = start = sentUpTo = new U8[bufSize];
end = start + bufSize;
}
BufferedOutStream::~BufferedOutStream()
{
// FIXME: Complain about non-flushed buffer?
delete [] start;
}
size_t BufferedOutStream::length()
{
return offset + ptr - sentUpTo;
}
size_t BufferedOutStream::bufferUsage()
{
return ptr - sentUpTo;
}
void BufferedOutStream::flush()
{
while (sentUpTo < ptr) {
size_t len;
len = bufferUsage();
if (!flushBuffer(false))
break;
offset += len - bufferUsage();
}
// Managed to flush everything?
if (sentUpTo == ptr)
ptr = sentUpTo = start;
}
void BufferedOutStream::overrun(size_t needed)
{
if (needed > bufSize)
throw Exception("BufferedOutStream overrun: "
"requested size of %lu bytes exceeds maximum of %lu bytes",
(long unsigned)needed, (long unsigned)bufSize);
// First try to get rid of the data we have
flush();
// Still not enough space?
while (needed > avail()) {
// Can we shuffle things around?
// (don't do this if it gains us less than 25%)
if (((size_t)(sentUpTo - start) > bufSize / 4) &&
(needed < bufSize - (ptr - sentUpTo))) {
memmove(start, sentUpTo, ptr - sentUpTo);
ptr = start + (ptr - sentUpTo);
sentUpTo = start;
} else {
size_t len;
len = bufferUsage();
// Have to get rid of more data, so allow the flush to wait...
flushBuffer(true);
offset += len - bufferUsage();
// Managed to flush everything?
if (sentUpTo == ptr)
ptr = sentUpTo = start;
}
}
}