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/* Copyright (C) 2002-2005 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 <assert.h>
#include <rdr/ZlibInStream.h>
#include <rdr/Exception.h>
#include <zlib.h>
using namespace rdr;
enum { DEFAULT_BUF_SIZE = 16384 };
ZlibInStream::ZlibInStream(size_t bufSize_)
: underlying(0), bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0),
zs(NULL), bytesIn(0)
{
ptr = end = start = new U8[bufSize];
init();
}
ZlibInStream::~ZlibInStream()
{
deinit();
delete [] start;
}
void ZlibInStream::setUnderlying(InStream* is, size_t bytesIn_)
{
underlying = is;
bytesIn = bytesIn_;
ptr = end = start;
}
size_t ZlibInStream::pos()
{
return offset + ptr - start;
}
void ZlibInStream::flushUnderlying()
{
ptr = end = start;
while (bytesIn > 0) {
decompress(true);
end = start; // throw away any data
}
setUnderlying(NULL, 0);
}
void ZlibInStream::reset()
{
deinit();
init();
}
void ZlibInStream::init()
{
assert(zs == NULL);
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 (inflateInit(zs) != Z_OK) {
delete zs;
zs = NULL;
throw Exception("ZlibInStream: inflateInit failed");
}
}
void ZlibInStream::deinit()
{
assert(zs != NULL);
setUnderlying(NULL, 0);
inflateEnd(zs);
delete zs;
zs = NULL;
}
size_t ZlibInStream::overrun(size_t itemSize, size_t nItems, bool wait)
{
if (itemSize > bufSize)
throw Exception("ZlibInStream overrun: max itemSize exceeded");
if (end - ptr != 0)
memmove(start, ptr, end - ptr);
offset += ptr - start;
end -= ptr - start;
ptr = start;
while ((size_t)(end - ptr) < itemSize) {
if (!decompress(wait))
return 0;
}
if (itemSize * nItems > (size_t)(end - ptr))
nItems = (end - ptr) / itemSize;
return nItems;
}
// decompress() calls the decompressor once. Note that this won't necessarily
// generate any output data - it may just consume some input data. Returns
// false if wait is false and we would block on the underlying stream.
bool ZlibInStream::decompress(bool wait)
{
if (!underlying)
throw Exception("ZlibInStream overrun: no underlying stream");
zs->next_out = (U8*)end;
zs->avail_out = start + bufSize - end;
size_t n = underlying->check(1, 1, wait);
if (n == 0) return false;
zs->next_in = (U8*)underlying->getptr();
zs->avail_in = underlying->getend() - underlying->getptr();
if (zs->avail_in > bytesIn)
zs->avail_in = bytesIn;
int rc = inflate(zs, Z_SYNC_FLUSH);
if (rc != Z_OK) {
throw Exception("ZlibInStream: inflate failed");
}
bytesIn -= zs->next_in - underlying->getptr();
end = zs->next_out;
underlying->setptr(zs->next_in);
return true;
}
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