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/* Copyright (C) 2002-2005 RealVNC Ltd. All Rights Reserved.
* Copyright (C) 2011 D. R. Commander. 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.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <rdr/ZlibOutStream.h>
#include <rfb/LogWriter.h>
#include <zlib.h>
#undef ZLIBOUT_DEBUG
static rfb::LogWriter vlog("ZlibOutStream");
using namespace rdr;
ZlibOutStream::ZlibOutStream(OutStream* os, int compressLevel)
: underlying(os), compressionLevel(compressLevel), newLevel(compressLevel)
{
zs = new z_stream;
zs->zalloc = nullptr;
zs->zfree = nullptr;
zs->opaque = nullptr;
zs->next_in = nullptr;
zs->avail_in = 0;
if (deflateInit(zs, compressLevel) != Z_OK) {
delete zs;
throw std::runtime_error("ZlibOutStream: deflateInit failed");
}
}
ZlibOutStream::~ZlibOutStream()
{
try {
flush();
} catch (std::exception&) {
}
deflateEnd(zs);
delete zs;
}
void ZlibOutStream::setUnderlying(OutStream* os)
{
underlying = os;
if (underlying)
underlying->cork(corked);
}
void ZlibOutStream::setCompressionLevel(int level)
{
if (level < -1 || level > 9)
level = -1; // Z_DEFAULT_COMPRESSION
newLevel = level;
}
void ZlibOutStream::flush()
{
BufferedOutStream::flush();
if (underlying != nullptr)
underlying->flush();
}
void ZlibOutStream::cork(bool enable)
{
BufferedOutStream::cork(enable);
if (underlying != nullptr)
underlying->cork(enable);
}
bool ZlibOutStream::flushBuffer()
{
checkCompressionLevel();
zs->next_in = sentUpTo;
zs->avail_in = ptr - sentUpTo;
#ifdef ZLIBOUT_DEBUG
vlog.debug("Flush: avail_in %d",zs->avail_in);
#endif
// Force out everything from the zlib encoder
deflate(corked ? Z_NO_FLUSH : Z_SYNC_FLUSH);
sentUpTo = zs->next_in;
return true;
}
void ZlibOutStream::deflate(int flush)
{
int rc;
if (!underlying)
throw std::runtime_error("ZlibOutStream: Underlying OutStream has not been set");
if ((flush == Z_NO_FLUSH) && (zs->avail_in == 0))
return;
do {
size_t chunk;
zs->next_out = underlying->getptr(1);
zs->avail_out = chunk = underlying->avail();
#ifdef ZLIBOUT_DEBUG
vlog.debug("Calling deflate, avail_in %d, avail_out %d",
zs->avail_in,zs->avail_out);
#endif
rc = ::deflate(zs, flush);
if (rc < 0) {
// Silly zlib returns an error if you try to flush something twice
if ((rc == Z_BUF_ERROR) && (flush != Z_NO_FLUSH))
break;
throw std::runtime_error("ZlibOutStream: deflate failed");
}
#ifdef ZLIBOUT_DEBUG
vlog.debug("After deflate: %d bytes",
zs->next_out-underlying->getptr());
#endif
underlying->setptr(chunk - zs->avail_out);
} while (zs->avail_out == 0);
}
void ZlibOutStream::checkCompressionLevel()
{
int rc;
if (newLevel != compressionLevel) {
#ifdef ZLIBOUT_DEBUG
vlog.debug("Change: avail_in %d",zs->avail_in);
#endif
// zlib is just horribly stupid. It does an implicit flush on
// parameter changes, but the flush it does is not one that forces
// out all the data. And since you cannot flush things again, we
// cannot force out our data after the parameter change. Hence we
// need to do a more proper flush here first.
deflate(Z_SYNC_FLUSH);
rc = deflateParams (zs, newLevel, Z_DEFAULT_STRATEGY);
if (rc < 0) {
// The implicit flush can result in this error, caused by the
// explicit flush we did above. It should be safe to ignore though
// as the first flush should have left things in a stable state...
if (rc != Z_BUF_ERROR)
throw std::runtime_error("ZlibOutStream: deflateParams failed");
}
compressionLevel = newLevel;
}
}
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