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/* 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;
static const size_t MAX_BUF_SIZE = 32 * 1024 * 1024;
BufferedOutStream::BufferedOutStream(bool emulateCork_)
: bufSize(DEFAULT_BUF_SIZE), offset(0), emulateCork(emulateCork_)
{
ptr = start = sentUpTo = new uint8_t[bufSize];
end = start + bufSize;
gettimeofday(&lastSizeCheck, nullptr);
peakUsage = 0;
}
BufferedOutStream::~BufferedOutStream()
{
// FIXME: Complain about non-flushed buffer?
delete [] start;
}
size_t BufferedOutStream::length()
{
return offset + ptr - sentUpTo;
}
void BufferedOutStream::flush()
{
struct timeval now;
// Only give larger chunks if corked to minimize overhead
if (corked && emulateCork && ((ptr - sentUpTo) < 1024))
return;
while (sentUpTo < ptr) {
size_t len;
len = (ptr - sentUpTo);
if (!flushBuffer())
break;
offset += len - (ptr - sentUpTo);
}
// Managed to flush everything?
if (sentUpTo == ptr)
ptr = sentUpTo = start;
// Time to shrink an excessive buffer?
gettimeofday(&now, nullptr);
if ((sentUpTo == ptr) && (bufSize > DEFAULT_BUF_SIZE) &&
((now.tv_sec < lastSizeCheck.tv_sec) ||
(now.tv_sec > (lastSizeCheck.tv_sec + 5)))) {
if (peakUsage < (bufSize / 2)) {
size_t newSize;
newSize = DEFAULT_BUF_SIZE;
while (newSize < peakUsage)
newSize *= 2;
// We know the buffer is empty, so just reset everything
delete [] start;
ptr = start = sentUpTo = new uint8_t[newSize];
end = start + newSize;
bufSize = newSize;
}
gettimeofday(&lastSizeCheck, nullptr);
peakUsage = 0;
}
}
bool BufferedOutStream::hasBufferedData()
{
return sentUpTo != ptr;
}
void BufferedOutStream::overrun(size_t needed)
{
bool oldCorked;
size_t totalNeeded, newSize;
uint8_t* newBuffer;
// First try to get rid of the data we have
// (use corked to make things a bit more efficient since we're not
// trying to flush out everything, just make some room)
oldCorked = corked;
cork(true);
flush();
cork(oldCorked);
// Make note of the total needed space
totalNeeded = needed + (ptr - sentUpTo);
if (totalNeeded > peakUsage)
peakUsage = totalNeeded;
// Enough free space now?
if (avail() > needed)
return;
// Can we shuffle things around?
if (needed < bufSize - (ptr - sentUpTo)) {
memmove(start, sentUpTo, ptr - sentUpTo);
ptr = start + (ptr - sentUpTo);
sentUpTo = start;
return;
}
// We'll need to allocate more buffer space...
if (totalNeeded > MAX_BUF_SIZE)
throw Exception("BufferedOutStream overrun: requested size of "
"%lu bytes exceeds maximum of %lu bytes",
(long unsigned)totalNeeded,
(long unsigned)MAX_BUF_SIZE);
newSize = DEFAULT_BUF_SIZE;
while (newSize < totalNeeded)
newSize *= 2;
newBuffer = new uint8_t[newSize];
memcpy(newBuffer, sentUpTo, ptr - sentUpTo);
delete [] start;
bufSize = newSize;
ptr = newBuffer + (ptr - sentUpTo);
sentUpTo = start = newBuffer;
end = newBuffer + newSize;
gettimeofday(&lastSizeCheck, nullptr);
peakUsage = totalNeeded;
return;
}
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