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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;
- }
-
- size_t nAvail;
- nAvail = (end - ptr) / itemSize;
- if (nAvail < nItems)
- return nAvail;
-
- 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 < 0) {
- 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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