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<h1>pppfilter.cc</h1><a href="pppfilter_8cc.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">///</span>
<a name="l00002"></a>00002 <span class="comment"></span><span class="comment">/// \file pppfilter.cc</span>
<a name="l00003"></a>00003 <span class="comment"></span><span class="comment">/// Data filter class, to morph PPP data into something that</span>
<a name="l00004"></a>00004 <span class="comment"></span><span class="comment">/// the Blackberry / Rogers / ISP can handle.</span>
<a name="l00005"></a>00005 <span class="comment"></span><span class="comment">/// This logic is based partly on XmBlackBerry's</span>
<a name="l00006"></a>00006 <span class="comment"></span><span class="comment">/// gprs_protocol_fix.c program.</span>
<a name="l00007"></a>00007 <span class="comment"></span><span class="comment">///</span>
<a name="l00008"></a>00008 <span class="comment"></span>
<a name="l00009"></a>00009 <span class="comment">/*</span>
<a name="l00010"></a>00010 <span class="comment"> Copyright (C) 2008-2010, Net Direct Inc. (http://www.netdirect.ca/)</span>
<a name="l00011"></a>00011 <span class="comment"></span>
<a name="l00012"></a>00012 <span class="comment"> This program is free software; you can redistribute it and/or modify</span>
<a name="l00013"></a>00013 <span class="comment"> it under the terms of the GNU General Public License as published by</span>
<a name="l00014"></a>00014 <span class="comment"> the Free Software Foundation; either version 2 of the License, or</span>
<a name="l00015"></a>00015 <span class="comment"> (at your option) any later version.</span>
<a name="l00016"></a>00016 <span class="comment"></span>
<a name="l00017"></a>00017 <span class="comment"> This program is distributed in the hope that it will be useful,</span>
<a name="l00018"></a>00018 <span class="comment"> but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<a name="l00019"></a>00019 <span class="comment"> MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.</span>
<a name="l00020"></a>00020 <span class="comment"></span>
<a name="l00021"></a>00021 <span class="comment"> See the GNU General Public License in the COPYING file at the</span>
<a name="l00022"></a>00022 <span class="comment"> root directory of this project for more details.</span>
<a name="l00023"></a>00023 <span class="comment">*/</span>
<a name="l00024"></a>00024
<a name="l00025"></a>00025 <span class="preprocessor">#include "<a class="code" href="pppfilter_8h.html" title="Data filter class, to morph PPP data into something that the Blackberry / Rogers...">pppfilter.h</a>"</span>
<a name="l00026"></a>00026 <span class="preprocessor">#include <string.h></span>
<a name="l00027"></a>00027
<a name="l00028"></a>00028 <span class="keyword">namespace </span>Barry {
<a name="l00029"></a>00029 <span class="comment"></span>
<a name="l00030"></a>00030 <span class="comment">//////////////////////////////////////////////////////////////////////////////</span>
<a name="l00031"></a>00031 <span class="comment"></span><span class="comment">// PppFilter class</span>
<a name="l00032"></a>00032
<a name="l00033"></a>00033 PppFilter::PppFilter()
<a name="l00034"></a>00034 : m_ppp_mode(false)
<a name="l00035"></a>00035 , m_last(0x7e)
<a name="l00036"></a>00036 {
<a name="l00037"></a>00037 }
<a name="l00038"></a>00038
<a name="l00039"></a>00039 <span class="comment">//</span>
<a name="l00040"></a>00040 <span class="comment">// Filter</span>
<a name="l00041"></a>00041 <span class="comment">//</span><span class="comment"></span>
<a name="l00042"></a>00042 <span class="comment">/// Copy PPP data from src to dest, creating needed space in dest,</span>
<a name="l00043"></a>00043 <span class="comment">/// and inserting missing 0x7e characters wherever they are detected.</span>
<a name="l00044"></a>00044 <span class="comment">/// Starts writing at the start of the dest buffer + destoffset.</span>
<a name="l00045"></a>00045 <span class="comment">///</span>
<a name="l00046"></a>00046 <span class="comment"></span><span class="keywordtype">void</span> PppFilter::Filter(Data &dest, <span class="keyword">const</span> Data &src, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> destoffset)
<a name="l00047"></a>00047 {
<a name="l00048"></a>00048 <span class="keyword">const</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *b = src.GetData(), *e = src.GetData() + src.GetSize();
<a name="l00049"></a>00049 <span class="keywordtype">size_t</span> needed = src.GetSize() / 2 * 3 + 4 + destoffset; <span class="comment">// worst case</span>
<a name="l00050"></a>00050 <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *buf = dest.GetBuffer(needed) + destoffset;
<a name="l00051"></a>00051 <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *put = buf;
<a name="l00052"></a>00052
<a name="l00053"></a>00053 <span class="keywordflow">while</span>( b != e ) {
<a name="l00054"></a>00054 <span class="comment">// if last character was 0x7e, then next one must be,</span>
<a name="l00055"></a>00055 <span class="comment">// or else we insert it ourselves</span>
<a name="l00056"></a>00056 <span class="keywordflow">if</span>( m_last == 0x7e ) {
<a name="l00057"></a>00057 m_last = 0;
<a name="l00058"></a>00058 <span class="keywordflow">if</span>( *b != 0x7e )
<a name="l00059"></a>00059 *put++ = 0x7e;
<a name="l00060"></a>00060 <span class="keywordflow">else</span>
<a name="l00061"></a>00061 *put++ = *b++;
<a name="l00062"></a>00062 }
<a name="l00063"></a>00063
<a name="l00064"></a>00064 <span class="comment">// copy all non-0x7e chars verbatim</span>
<a name="l00065"></a>00065 <span class="keywordflow">while</span>( b != e && *b != 0x7e ) {
<a name="l00066"></a>00066 *put++ = *b++;
<a name="l00067"></a>00067 }
<a name="l00068"></a>00068
<a name="l00069"></a>00069 <span class="keywordflow">if</span>( b != e ) { <span class="comment">// if b!=e then *b == 0x7e and must keep going</span>
<a name="l00070"></a>00070 *put++ = *b++;
<a name="l00071"></a>00071 m_last = 0x7e;
<a name="l00072"></a>00072 }
<a name="l00073"></a>00073 }
<a name="l00074"></a>00074
<a name="l00075"></a>00075 dest.ReleaseBuffer(put - buf + destoffset);
<a name="l00076"></a>00076 }
<a name="l00077"></a>00077
<a name="l00078"></a>00078 <span class="comment">//</span>
<a name="l00079"></a>00079 <span class="comment">// Write</span>
<a name="l00080"></a>00080 <span class="comment">//</span><span class="comment"></span>
<a name="l00081"></a>00081 <span class="comment">/// If PPP mode has not been detected, just return the data buffer.</span>
<a name="l00082"></a>00082 <span class="comment">/// If in PPP mode, then filter data into internal write buffer,</span>
<a name="l00083"></a>00083 <span class="comment">/// inserting any missing 0x7e characters and return reference</span>
<a name="l00084"></a>00084 <span class="comment">/// to internal write buffer.</span>
<a name="l00085"></a>00085 <span class="comment">///</span>
<a name="l00086"></a><a class="code" href="classBarry_1_1PppFilter.html#a84260626790a60437128f034203902af">00086</a> <span class="comment"></span><span class="keyword">const</span> <a class="code" href="classBarry_1_1Data.html">Data</a>& <a class="code" href="classBarry_1_1PppFilter.html#a84260626790a60437128f034203902af" title="If PPP mode has not been detected, just return the data buffer.">PppFilter::Write</a>(<span class="keyword">const</span> <a class="code" href="classBarry_1_1Data.html">Data</a> &data)
<a name="l00087"></a>00087 {
<a name="l00088"></a>00088 <span class="keywordflow">if</span>( data.GetSize() == 0 )
<a name="l00089"></a>00089 <span class="keywordflow">return</span> data; <span class="comment">// nothing to do</span>
<a name="l00090"></a>00090
<a name="l00091"></a>00091 <span class="keyword">const</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *b = data.GetData();
<a name="l00092"></a>00092
<a name="l00093"></a>00093 <span class="keywordflow">if</span>( !m_ppp_mode ) {
<a name="l00094"></a>00094 <span class="keywordflow">if</span>( *b == 0x7e ) {
<a name="l00095"></a>00095 m_ppp_mode = <span class="keyword">true</span>;
<a name="l00096"></a>00096 <span class="comment">// fall through</span>
<a name="l00097"></a>00097 }
<a name="l00098"></a>00098 <span class="keywordflow">else</span> {
<a name="l00099"></a>00099 <span class="comment">// not in ppp mode yet, so just pass the buffer</span>
<a name="l00100"></a>00100 <span class="comment">// straight back to the caller</span>
<a name="l00101"></a>00101 <span class="keywordflow">return</span> data;
<a name="l00102"></a>00102 }
<a name="l00103"></a>00103 }
<a name="l00104"></a>00104
<a name="l00105"></a>00105 Filter(m_writeBuf, data, 0);
<a name="l00106"></a>00106 <span class="keywordflow">return</span> m_writeBuf;
<a name="l00107"></a>00107 }
<a name="l00108"></a>00108
<a name="l00109"></a>00109 <span class="comment">//</span>
<a name="l00110"></a>00110 <span class="comment">// Write (with prepend)</span>
<a name="l00111"></a>00111 <span class="comment">//</span><span class="comment"></span>
<a name="l00112"></a>00112 <span class="comment">/// Same as Write(data), but makes sure that prepend bytes are available</span>
<a name="l00113"></a>00113 <span class="comment">/// at the beginning of the returned buffer.</span>
<a name="l00114"></a>00114 <span class="comment">/// If not in PPP mode, the extra bytes are still provided.</span>
<a name="l00115"></a>00115 <span class="comment">///</span>
<a name="l00116"></a><a class="code" href="classBarry_1_1PppFilter.html#a49bc4e92f47c36991dbc787fb0bd26fa">00116</a> <span class="comment"></span><a class="code" href="classBarry_1_1Data.html">Data</a>& <a class="code" href="classBarry_1_1PppFilter.html#a84260626790a60437128f034203902af" title="If PPP mode has not been detected, just return the data buffer.">PppFilter::Write</a>(<span class="keyword">const</span> <a class="code" href="classBarry_1_1Data.html">Data</a> &data, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> prepend)
<a name="l00117"></a>00117 {
<a name="l00118"></a>00118 <span class="keyword">const</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *b = data.GetData(), *e = data.GetData() + data.GetSize();
<a name="l00119"></a>00119
<a name="l00120"></a>00120 <span class="keywordflow">if</span>( !m_ppp_mode ) {
<a name="l00121"></a>00121 <span class="keywordflow">if</span>( b != e && *b == 0x7e ) {
<a name="l00122"></a>00122 m_ppp_mode = <span class="keyword">true</span>;
<a name="l00123"></a>00123 <span class="comment">// fall through</span>
<a name="l00124"></a>00124 }
<a name="l00125"></a>00125 <span class="keywordflow">else</span> {
<a name="l00126"></a>00126 <span class="comment">// make space, copy, return</span>
<a name="l00127"></a>00127 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> size = data.GetSize() + prepend;
<a name="l00128"></a>00128 <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *buf = m_writeBuf.GetBuffer(size);
<a name="l00129"></a>00129 memcpy(&buf[prepend], data.GetData(), data.GetSize());
<a name="l00130"></a>00130 m_writeBuf.ReleaseBuffer(size);
<a name="l00131"></a>00131 <span class="keywordflow">return</span> m_writeBuf;
<a name="l00132"></a>00132 }
<a name="l00133"></a>00133 }
<a name="l00134"></a>00134
<a name="l00135"></a>00135 Filter(m_writeBuf, data, prepend);
<a name="l00136"></a>00136 <span class="keywordflow">return</span> m_writeBuf;
<a name="l00137"></a>00137 }
<a name="l00138"></a>00138
<a name="l00139"></a>00139 } <span class="comment">// namespace Barry</span>
<a name="l00140"></a>00140
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