<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"> <title>lzsscomprs.h Source File</title> <link href="doxygen.css" rel="stylesheet" type="text/css"> </head><body> <!-- Generated by Doxygen 1.2.15 --> <center> <a class="qindex" href="index.html">Main Page</a> <a class="qindex" href="namespaces.html">Namespace List</a> <a class="qindex" href="hierarchy.html">Class Hierarchy</a> <a class="qindex" href="classes.html">Alphabetical List</a> <a class="qindex" href="annotated.html">Compound List</a> <a class="qindex" href="files.html">File List</a> <a class="qindex" href="functions.html">Compound Members</a> </center> <hr><h1>lzsscomprs.h</h1><div class="fragment"><pre>00001 <font class="comment">/******************************************************************************</font> 00002 <font class="comment"> * lzsscomprs.h - definition of Class SWCompress used for data compression</font> 00003 <font class="comment"> *</font> 00004 <font class="comment"> * $Id: lzsscomprs_8h-source.html,v 1.7 2002/06/20 20:23:09 mgruner Exp $</font> 00005 <font class="comment"> *</font> 00006 <font class="comment"> * Copyright 1998 CrossWire Bible Society (http://www.crosswire.org)</font> 00007 <font class="comment"> * CrossWire Bible Society</font> 00008 <font class="comment"> * P. O. Box 2528</font> 00009 <font class="comment"> * Tempe, AZ 85280-2528</font> 00010 <font class="comment"> *</font> 00011 <font class="comment"> * This program is free software; you can redistribute it and/or modify it</font> 00012 <font class="comment"> * under the terms of the GNU General Public License as published by the</font> 00013 <font class="comment"> * Free Software Foundation version 2.</font> 00014 <font class="comment"> *</font> 00015 <font class="comment"> * This program is distributed in the hope that it will be useful, but</font> 00016 <font class="comment"> * WITHOUT ANY WARRANTY; without even the implied warranty of</font> 00017 <font class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</font> 00018 <font class="comment"> * General Public License for more details.</font> 00019 <font class="comment"> *</font> 00020 <font class="comment"> */</font> 00021 00022 <font class="preprocessor">#ifndef LZSSCOMPRS_H</font> 00023 <font class="preprocessor"></font><font class="preprocessor">#define LZSSCOMPRS_H</font> 00024 <font class="preprocessor"></font> 00025 <font class="preprocessor">#include <swcomprs.h></font> 00026 00027 <font class="preprocessor">#include <defs.h></font> 00028 00029 <font class="comment">// The following are constant sizes used by the compression algorithm.</font> 00030 <font class="comment">//</font> 00031 <font class="comment">// N - This is the size of the ring buffer. It is set</font> 00032 <font class="comment">// to 4K. It is important to note that a position</font> 00033 <font class="comment">// within the ring buffer requires 12 bits. </font> 00034 <font class="comment">//</font> 00035 <font class="comment">// F - This is the maximum length of a character sequence</font> 00036 <font class="comment">// that can be taken from the ring buffer. It is set</font> 00037 <font class="comment">// to 18. Note that a length must be 3 before it is</font> 00038 <font class="comment">// worthwhile to store a position/length pair, so the</font> 00039 <font class="comment">// length can be encoded in only 4 bits. Or, put yet</font> 00040 <font class="comment">// another way, it is not necessary to encode a length</font> 00041 <font class="comment">// of 0-18, it is necessary to encode a length of</font> 00042 <font class="comment">// 3-18, which requires 4 bits.</font> 00043 <font class="comment">// </font> 00044 <font class="comment">// THRESHOLD - It takes 2 bytes to store an offset and</font> 00045 <font class="comment">// a length. If a character sequence only</font> 00046 <font class="comment">// requires 1 or 2 characters to store </font> 00047 <font class="comment">// uncompressed, then it is better to store</font> 00048 <font class="comment">// it uncompressed than as an offset into</font> 00049 <font class="comment">// the ring buffer.</font> 00050 <font class="comment">//</font> 00051 <font class="comment">// Note that the 12 bits used to store the position and the 4 bits</font> 00052 <font class="comment">// used to store the length equal a total of 16 bits, or 2 bytes.</font> 00053 00054 <font class="preprocessor">#define N 4096</font> 00055 <font class="preprocessor"></font><font class="preprocessor">#define F 18</font> 00056 <font class="preprocessor"></font><font class="preprocessor">#define THRESHOLD 3</font> 00057 <font class="preprocessor"></font><font class="preprocessor">#define NOT_USED N</font> 00058 <font class="preprocessor"></font> 00059 00060 00061 <font class="keyword">class </font>SWDLLEXPORT LZSSCompress:<font class="keyword">public</font> SWCompress 00062 { 00063 <font class="keyword">static</font> <font class="keywordtype">unsigned</font> <font class="keywordtype">char</font> m_ring_buffer[N + F - 1]; 00064 <font class="keyword">static</font> <font class="keywordtype">short</font> <font class="keywordtype">int</font> m_match_position; 00065 <font class="keyword">static</font> <font class="keywordtype">short</font> <font class="keywordtype">int</font> m_match_length; 00066 <font class="keyword">static</font> <font class="keywordtype">short</font> <font class="keywordtype">int</font> m_lson[N + 1]; 00067 <font class="keyword">static</font> <font class="keywordtype">short</font> <font class="keywordtype">int</font> m_rson[N + 257]; 00068 <font class="keyword">static</font> <font class="keywordtype">short</font> <font class="keywordtype">int</font> m_dad[N + 1]; 00069 <font class="keywordtype">void</font> InitTree (); 00070 <font class="keywordtype">void</font> InsertNode (<font class="keywordtype">short</font> <font class="keywordtype">int</font> Pos); 00071 <font class="keywordtype">void</font> DeleteNode (<font class="keywordtype">short</font> <font class="keywordtype">int</font> Node); 00072 <font class="keyword">public</font>: 00073 LZSSCompress (); 00074 <font class="keyword">virtual</font> ~ LZSSCompress (); 00075 <font class="keyword">virtual</font> <font class="keywordtype">void</font> Encode (<font class="keywordtype">void</font>); 00076 <font class="keyword">virtual</font> <font class="keywordtype">void</font> Decode (<font class="keywordtype">void</font>); 00077 }; 00078 00079 <font class="preprocessor">#endif</font> </pre></div><hr><address align="right"><small>Generated on Thu Jun 20 22:12:59 2002 for The Sword Project by <a href="http://www.doxygen.org/index.html"> <img src="doxygen.png" alt="doxygen" align="middle" border=0 width=110 height=53></a>1.2.15 </small></address> </body> </html>