/* Copyright (C) 2002-2005 RealVNC Ltd. All Rights Reserved. * Copyright (C) 2011-2019 Brian P. Hinz * * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, * USA. */ // // A ZlibInStream reads from a zlib.io.InputStream // package com.tigervnc.rdr; import com.jcraft.jzlib.*; public class ZlibInStream extends InStream { static final int defaultBufSize = 16384; public ZlibInStream(int bufSize_) { bufSize = bufSize_; b = new byte[bufSize]; bytesIn = offset = 0; ptr = end = start = 0; init(); } public ZlibInStream() { this(defaultBufSize); } public void setUnderlying(InStream is, int bytesIn_) { underlying = is; bytesIn = bytesIn_; ptr = end = start; } public int pos() { return offset + ptr - start; } public void flushUnderlying() { ptr = end = start; while (bytesIn > 0) { decompress(true); end = start; // throw away any data } setUnderlying(null, 0); } public void reset() { deinit(); init(); } public void init() { assert(zs == null); zs = new ZStream(); zs.next_in = null; zs.next_in_index = 0; zs.avail_in = 0; if (zs.inflateInit() != JZlib.Z_OK) { zs = null; throw new Exception("ZlinInStream: inflateInit failed"); } } public void deinit() { assert(zs != null); setUnderlying(null, 0); zs.inflateEnd(); zs = null; } protected int overrun(int itemSize, int nItems, boolean wait) { if (itemSize > bufSize) throw new Exception("ZlibInStream overrun: max itemSize exceeded"); if (end - ptr != 0) System.arraycopy(b, ptr, b, start, end - ptr); offset += ptr - start; end -= ptr - start; ptr = start; while (end - ptr < itemSize) { if (!decompress(wait)) return 0; } int 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. private boolean decompress(boolean wait) { if (underlying == null) throw new Exception("ZlibInStream overrun: no underlying stream"); zs.next_out = b; zs.next_out_index = end; zs.avail_out = start + bufSize - end; int n = underlying.check(1, 1, wait); if (n == 0) return false; zs.next_in = underlying.getbuf(); zs.next_in_index = underlying.getptr(); zs.avail_in = underlying.getend() - underlying.getptr(); if (zs.avail_in > bytesIn) zs.avail_in = bytesIn; int rc = zs.inflate(JZlib.Z_SYNC_FLUSH); if (rc != JZlib.Z_OK) { throw new Exception("ZlibInStream: inflate failed"); } bytesIn -= zs.next_in_index - underlying.getptr(); end = zs.next_out_index; underlying.setptr(zs.next_in_index); return true; } private InStream underlying; private int bufSize; private int offset; private com.jcraft.jzlib.ZStream zs; private int bytesIn; private int start; }