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/* 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 <assert.h>
#include <rdr/BufferedInStream.h>
#include <rdr/Exception.h>
using namespace rdr;
static const size_t DEFAULT_BUF_SIZE = 8192;
static const size_t MAX_BUF_SIZE = 32 * 1024 * 1024;
BufferedInStream::BufferedInStream()
: bufSize(DEFAULT_BUF_SIZE), offset(0)
{
ptr = end = start = new uint8_t[bufSize];
gettimeofday(&lastSizeCheck, nullptr);
peakUsage = 0;
}
BufferedInStream::~BufferedInStream()
{
delete [] start;
}
size_t BufferedInStream::pos()
{
return offset + ptr - start;
}
void BufferedInStream::ensureSpace(size_t needed)
{
struct timeval now;
// Given argument is how much free space is needed, but for allocation
// purposes we need to now how much space everything needs, including
// any existing data already in the buffer
needed += avail();
if (needed > bufSize) {
size_t newSize;
uint8_t* newBuffer;
if (needed > MAX_BUF_SIZE)
throw Exception("BufferedInStream overrun: requested size of "
"%lu bytes exceeds maximum of %lu bytes",
(long unsigned)needed, (long unsigned)MAX_BUF_SIZE);
newSize = DEFAULT_BUF_SIZE;
while (newSize < needed)
newSize *= 2;
newBuffer = new uint8_t[newSize];
memcpy(newBuffer, ptr, end - ptr);
delete [] start;
bufSize = newSize;
offset += ptr - start;
end = newBuffer + (end - ptr);
ptr = start = newBuffer;
gettimeofday(&lastSizeCheck, nullptr);
peakUsage = needed;
}
if (needed > peakUsage)
peakUsage = needed;
// Time to shrink an excessive buffer?
gettimeofday(&now, nullptr);
if ((avail() == 0) && (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 = end = start = new uint8_t[newSize];
bufSize = newSize;
}
gettimeofday(&lastSizeCheck, nullptr);
peakUsage = needed;
}
// Do we need to shuffle things around?
if ((bufSize - (ptr - start)) < needed) {
memmove(start, ptr, end - ptr);
offset += ptr - start;
end -= ptr - start;
ptr = start;
}
}
bool BufferedInStream::overrun(size_t needed)
{
// Make sure fillBuffer() has room for all the requested data
assert(needed > avail());
ensureSpace(needed - avail());
while (avail() < needed) {
if (!fillBuffer())
return false;
}
return true;
}
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