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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.
*/
#include <rdr/ZlibOutStream.h>
#include <rdr/Exception.h>
#include <os/print.h>
#include <zlib.h>
#undef ZLIBOUT_DEBUG
using namespace rdr;
enum { DEFAULT_BUF_SIZE = 16384 };
ZlibOutStream::ZlibOutStream(OutStream* os, int bufSize_, int compressLevel)
: underlying(os), compressionLevel(compressLevel), newLevel(compressLevel),
bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0)
{
zs = new z_stream;
zs->zalloc = Z_NULL;
zs->zfree = Z_NULL;
zs->opaque = Z_NULL;
zs->next_in = Z_NULL;
zs->avail_in = 0;
if (deflateInit(zs, compressLevel) != Z_OK) {
delete zs;
throw Exception("ZlibOutStream: deflateInit failed");
}
ptr = start = new U8[bufSize];
end = start + bufSize;
}
ZlibOutStream::~ZlibOutStream()
{
try {
flush();
} catch (Exception&) {
}
delete [] start;
deflateEnd(zs);
delete zs;
}
void ZlibOutStream::setUnderlying(OutStream* os)
{
underlying = os;
}
void ZlibOutStream::setCompressionLevel(int level)
{
if (level < -1 || level > 9)
level = -1; // Z_DEFAULT_COMPRESSION
newLevel = level;
}
int ZlibOutStream::length()
{
return offset + ptr - start;
}
void ZlibOutStream::flush()
{
checkCompressionLevel();
zs->next_in = start;
zs->avail_in = ptr - start;
#ifdef ZLIBOUT_DEBUG
fprintf(stderr,"zos flush: avail_in %d\n",zs->avail_in);
#endif
// Force out everything from the zlib encoder
deflate(Z_SYNC_FLUSH);
offset += ptr - start;
ptr = start;
}
int ZlibOutStream::overrun(int itemSize, int nItems)
{
#ifdef ZLIBOUT_DEBUG
fprintf(stderr,"zos overrun\n");
#endif
if (itemSize > bufSize)
throw Exception("ZlibOutStream overrun: max itemSize exceeded");
checkCompressionLevel();
while (end - ptr < itemSize) {
zs->next_in = start;
zs->avail_in = ptr - start;
deflate(Z_NO_FLUSH);
// output buffer not full
if (zs->avail_in == 0) {
offset += ptr - start;
ptr = start;
} else {
// but didn't consume all the data? try shifting what's left to the
// start of the buffer.
fprintf(stderr,"z out buf not full, but in data not consumed\n");
memmove(start, zs->next_in, ptr - zs->next_in);
offset += zs->next_in - start;
ptr -= zs->next_in - start;
}
}
if (itemSize * nItems > end - ptr)
nItems = (end - ptr) / itemSize;
return nItems;
}
void ZlibOutStream::deflate(int flush)
{
int rc;
if (!underlying)
throw Exception("ZlibOutStream: underlying OutStream has not been set");
if ((flush == Z_NO_FLUSH) && (zs->avail_in == 0))
return;
do {
underlying->check(1);
zs->next_out = underlying->getptr();
zs->avail_out = underlying->getend() - underlying->getptr();
#ifdef ZLIBOUT_DEBUG
fprintf(stderr,"zos: calling deflate, avail_in %d, avail_out %d\n",
zs->avail_in,zs->avail_out);
#endif
rc = ::deflate(zs, flush);
if (rc != Z_OK) {
// Silly zlib returns an error if you try to flush something twice
if ((rc == Z_BUF_ERROR) && (flush != Z_NO_FLUSH))
break;
throw Exception("ZlibOutStream: deflate failed");
}
#ifdef ZLIBOUT_DEBUG
fprintf(stderr,"zos: after deflate: %d bytes\n",
zs->next_out-underlying->getptr());
#endif
underlying->setptr(zs->next_out);
} while (zs->avail_out == 0);
}
void ZlibOutStream::checkCompressionLevel()
{
int rc;
if (newLevel != compressionLevel) {
#ifdef ZLIBOUT_DEBUG
fprintf(stderr,"zos change: avail_in %d\n",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 != Z_OK) {
// 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 Exception("ZlibOutStream: deflateParams failed");
}
compressionLevel = newLevel;
}
}
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