122 lines
2.9 KiB
C++
122 lines
2.9 KiB
C++
//
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// Copyright (C) 2002 RealVNC Ltd. All Rights Reserved.
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//
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// This is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or
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// (at your option) any later version.
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//
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// This software is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this software; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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// USA.
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#include <rdr/ZlibInStream.h>
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#include <rdr/Exception.h>
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#include <zlib.h>
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using namespace rdr;
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enum { DEFAULT_BUF_SIZE = 16384 };
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ZlibInStream::ZlibInStream(int bufSize_)
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: underlying(0), bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0),
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bytesIn(0)
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{
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zs = new z_stream;
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zs->zalloc = Z_NULL;
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zs->zfree = Z_NULL;
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zs->opaque = Z_NULL;
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zs->next_in = Z_NULL;
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zs->avail_in = 0;
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if (inflateInit(zs) != Z_OK) {
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delete zs;
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throw Exception("ZlibInStream: inflateInit failed");
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}
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ptr = end = start = new U8[bufSize];
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}
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ZlibInStream::~ZlibInStream()
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{
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delete [] start;
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inflateEnd(zs);
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delete zs;
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}
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void ZlibInStream::setUnderlying(InStream* is, int bytesIn_)
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{
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underlying = is;
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bytesIn = bytesIn_;
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ptr = end = start;
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}
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int ZlibInStream::pos()
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{
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return offset + ptr - start;
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}
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void ZlibInStream::reset()
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{
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ptr = end = start;
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if (!underlying) return;
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while (bytesIn > 0) {
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decompress();
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end = start; // throw away any data
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}
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underlying = 0;
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}
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int ZlibInStream::overrun(int itemSize, int nItems)
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{
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if (itemSize > bufSize)
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throw Exception("ZlibInStream overrun: max itemSize exceeded");
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if (!underlying)
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throw Exception("ZlibInStream overrun: no underlying stream");
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if (end - ptr != 0)
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memmove(start, ptr, end - ptr);
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offset += ptr - start;
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end -= ptr - start;
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ptr = start;
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while (end - ptr < itemSize) {
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decompress();
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}
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if (itemSize * nItems > end - ptr)
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nItems = (end - ptr) / itemSize;
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return nItems;
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}
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// decompress() calls the decompressor once. Note that this won't necessarily
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// generate any output data - it may just consume some input data.
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void ZlibInStream::decompress()
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{
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zs->next_out = (U8*)end;
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zs->avail_out = start + bufSize - end;
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underlying->check(1);
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zs->next_in = (U8*)underlying->getptr();
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zs->avail_in = underlying->getend() - underlying->getptr();
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if ((int)zs->avail_in > bytesIn)
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zs->avail_in = bytesIn;
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int rc = inflate(zs, Z_SYNC_FLUSH);
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if (rc != Z_OK) {
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throw Exception("ZlibInStream: inflate failed");
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}
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bytesIn -= zs->next_in - underlying->getptr();
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end = zs->next_out;
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underlying->setptr(zs->next_in);
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}
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