ZlibOutStream.cxx
3.88 KB
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//
// Copyright (C) 2002 RealVNC Ltd. 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 "ZlibOutStream.h"
#include "Exception.h"
#include "../zlib/zlib.h"
using namespace rdr;
enum { DEFAULT_BUF_SIZE = 16384 };
ZlibOutStream::ZlibOutStream(OutStream* os, int bufSize_)
: underlying(os), bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0)
{
zs = new z_stream;
zs->zalloc = Z_NULL;
zs->zfree = Z_NULL;
zs->opaque = Z_NULL;
if (deflateInit(zs, Z_DEFAULT_COMPRESSION) != 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;
}
int ZlibOutStream::length()
{
return offset + ptr - start;
}
void ZlibOutStream::flush()
{
zs->next_in = start;
zs->avail_in = ptr - start;
// fprintf(stderr,"zos flush: avail_in %d\n",zs->avail_in);
while (zs->avail_in != 0) {
do {
underlying->check(1);
zs->next_out = underlying->getptr();
zs->avail_out = underlying->getend() - underlying->getptr();
// fprintf(stderr,"zos flush: calling deflate, avail_in %d, avail_out %d\n",
// zs->avail_in,zs->avail_out);
int rc = deflate(zs, Z_SYNC_FLUSH);
if (rc != Z_OK) throw Exception("ZlibOutStream: deflate failed");
// fprintf(stderr,"zos flush: after deflate: %d bytes\n",
// zs->next_out-underlying->getptr());
underlying->setptr(zs->next_out);
} while (zs->avail_out == 0);
}
offset += ptr - start;
ptr = start;
}
int ZlibOutStream::overrun(int itemSize, int nItems)
{
// fprintf(stderr,"ZlibOutStream overrun\n");
if (itemSize > bufSize)
throw Exception("ZlibOutStream overrun: max itemSize exceeded");
while (end - ptr < itemSize) {
zs->next_in = start;
zs->avail_in = ptr - start;
do {
underlying->check(1);
zs->next_out = underlying->getptr();
zs->avail_out = underlying->getend() - underlying->getptr();
// fprintf(stderr,"zos overrun: calling deflate, avail_in %d, avail_out %d\n",
// zs->avail_in,zs->avail_out);
int rc = deflate(zs, 0);
if (rc != Z_OK) throw Exception("ZlibOutStream: deflate failed");
// fprintf(stderr,"zos overrun: after deflate: %d bytes\n",
// zs->next_out-underlying->getptr());
underlying->setptr(zs->next_out);
} while (zs->avail_out == 0);
// 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;
}