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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<title>NeL: NLMISC::CFastMutexMP class Reference</title>
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<h1>NLMISC::CFastMutexMP Class Reference</h1><code>#include &lt;<a class="el" href="a06088.html">mutex.h</a>&gt;</code>
<p>
<hr><a name="_details"></a><h2>Detailed Description</h2>
Fast mutex for multiprocessor implementation (not fairly). Used for multiprocessor critical section synchronisation. The mutex ARE NOT recursive (ie don't call <a class="el" href="a02517.html#NLMISC_1_1CFastMutexMPa1">enter()</a> several times on the same mutex from the same thread without having called <a class="el" href="a02517.html#NLMISC_1_1CFastMutexMPa3">leave()</a>) ; The threads use a spin system to wait a little time before be put to sleep. It waits using CPU time.<p>
Implementation notes:<ul>
<li>Implementated under WIN32</li><li>Other OS use CMutex</li></ul>
<p>
<pre class="fragment"><div> <a class="code" href="a02517.html#NLMISC_1_1CFastMutexMPa0">CFastMutexMP</a> m;
 m.enter ();
 <span class="comment">// do critical stuffs</span>
 m.leave ();
 *
</div></pre><dl compact><dt><b>Author:</b></dt><dd>Cyril 'Hulud' Corvazier <p>
Olivier Cado <p>
Nevrax France </dd></dl>
<dl compact><dt><b>Date:</b></dt><dd>2002, 2003 </dd></dl>

<p>

<p>
Definition at line <a class="el" href="a06088.html#l00309">309</a> of file <a class="el" href="a06088.html">mutex.h</a>.<table border=0 cellpadding=0 cellspacing=0>
<tr><td></td></tr>
<tr><td colspan=2><br><h2>Public Member Functions</h2></td></tr>
<tr><td class="memItemLeft" nowrap align=right valign=top>&nbsp;</td><td class="memItemRight" valign=bottom><a class="el" href="a02517.html#NLMISC_1_1CFastMutexMPa0">CFastMutexMP</a> ()</td></tr>

<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Constructor.  <a href="#NLMISC_1_1CFastMutexMPa0"></a><br><br></td></tr>
<tr><td class="memItemLeft" nowrap align=right valign=top>__forceinline void&nbsp;</td><td class="memItemRight" valign=bottom><a class="el" href="a02517.html#NLMISC_1_1CFastMutexMPa1">enter</a> () volatile</td></tr>

<tr><td class="memItemLeft" nowrap align=right valign=top>void&nbsp;</td><td class="memItemRight" valign=bottom><a class="el" href="a02517.html#NLMISC_1_1CFastMutexMPa2">init</a> () volatile</td></tr>

<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Same as constructor, useful for init in a shared memory block.  <a href="#NLMISC_1_1CFastMutexMPa2"></a><br><br></td></tr>
<tr><td class="memItemLeft" nowrap align=right valign=top>__forceinline void&nbsp;</td><td class="memItemRight" valign=bottom><a class="el" href="a02517.html#NLMISC_1_1CFastMutexMPa3">leave</a> () volatile</td></tr>

<tr><td colspan=2><br><h2>Private Attributes</h2></td></tr>
<tr><td class="memItemLeft" nowrap align=right valign=top>volatile <a class="el" href="a04558.html#a11">uint32</a>&nbsp;</td><td class="memItemRight" valign=bottom><a class="el" href="a02517.html#NLMISC_1_1CFastMutexMPr0">_Lock</a></td></tr>

</table>
<hr><h2>Constructor &amp; Destructor Documentation</h2>
<a class="anchor" name="NLMISC_1_1CFastMutexMPa0" doxytag="NLMISC::CFastMutexMP::CFastMutexMP" ></a><p>
<table class="mdTable" width="100%" cellpadding="2" cellspacing="0">
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          <td class="md" nowrap valign="top"> NLMISC::CFastMutexMP::CFastMutexMP </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="mdname1" valign="top" nowrap>          </td>
          <td class="md" valign="top">&nbsp;)&nbsp;</td>
          <td class="md" nowrap><code> [inline]</code></td>
        </tr>

      </table>
    </td>
  </tr>
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<table cellspacing=5 cellpadding=0 border=0>
  <tr>
    <td>
      &nbsp;
    </td>
    <td>

<p>
Constructor. 
<p>

<p>
Definition at line <a class="el" href="a06088.html#l00314">314</a> of file <a class="el" href="a06088.html">mutex.h</a>.
<p>
<div class="fragment"><pre>00314 : <a class="code" href="a02517.html#NLMISC_1_1CFastMutexMPr0">_Lock</a>(0) {}
</pre></div>    </td>
  </tr>
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<hr><h2>Member Function Documentation</h2>
<a class="anchor" name="NLMISC_1_1CFastMutexMPa1" doxytag="NLMISC::CFastMutexMP::enter" ></a><p>
<table class="mdTable" width="100%" cellpadding="2" cellspacing="0">
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    <td class="mdRow">
      <table cellpadding="0" cellspacing="0" border="0">
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          <td class="md" nowrap valign="top"> __forceinline void NLMISC::CFastMutexMP::enter </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="mdname1" valign="top" nowrap>          </td>
          <td class="md" valign="top">&nbsp;)&nbsp;</td>
          <td class="md" nowrap> volatile<code> [inline]</code></td>
        </tr>

      </table>
    </td>
  </tr>
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<table cellspacing=5 cellpadding=0 border=0>
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    <td>
      &nbsp;
    </td>
    <td>

<p>

<p>
Definition at line <a class="el" href="a06088.html#l00320">320</a> of file <a class="el" href="a06088.html">mutex.h</a>.
<p>
References <a class="el" href="a05981.html#l00105">uint</a>.
<p>
<div class="fragment"><pre>00321         {
00322           <span class="comment">//std::cout &lt;&lt; "Entering, Lock=" &lt;&lt; _Lock &lt;&lt; std::endl; </span>
00323                 <span class="keywordflow">while</span> (CFastMutex::atomic_swap (&amp;_Lock))
00324                 {
00325                         <span class="keyword">static</span> <a class="code" href="a04558.html#a15">uint</a> last = 0;
00326                         <span class="keyword">static</span> <a class="code" href="a04558.html#a15">uint</a> _max = 30;
00327                         <a class="code" href="a04558.html#a15">uint</a> spinMax = _max;
00328                         <a class="code" href="a04558.html#a15">uint</a> lastSpins = last;
00329                         <span class="keyword">volatile</span> <a class="code" href="a04558.html#a15">uint</a> temp = 17;
00330                         <a class="code" href="a04558.html#a15">uint</a> i;                 
00331                         <span class="keywordflow">for</span> (i = 0; i &lt; spinMax; ++i) 
00332                         {
00333                                 <span class="keywordflow">if</span> (i &lt; lastSpins/2 || <a class="code" href="a02517.html#NLMISC_1_1CFastMutexMPr0">_Lock</a>) 
00334                                 {
00335                                         temp *= temp; 
00336                                         temp *= temp;
00337                                         temp *= temp; 
00338                                         temp *= temp;
00339                                 }
00340                                 <span class="keywordflow">else</span> 
00341                                 {
00342                                         <span class="keywordflow">if</span> (!CFastMutex::atomic_swap(&amp;_Lock)) 
00343                                         {
00344                                                 last = i;
00345                                                 _max = 1000;
00346                                                 <span class="keywordflow">return</span>;
00347                                         }
00348                                 }
00349                         }
00350 
00351                         _max = 30;
00352                         
00353                         <span class="comment">// First test</span>
00354                         <span class="keywordflow">for</span> (i = 0 ;; ++i)
00355                         {
00356                                 <a class="code" href="a04558.html#a15">uint</a> wait_time = i + 6;
00357                                 
00358                                 <span class="comment">// Increment wait time with a log function</span>
00359                                 <span class="keywordflow">if</span> (wait_time &gt; 27) 
00360                                         wait_time = 27;
00361                                 
00362                                 <span class="comment">// Sleep</span>
00363                                 <span class="keywordflow">if</span> (wait_time &lt;= 20) 
00364                                         wait_time = 0;
00365                                 <span class="keywordflow">else</span>
00366                                         wait_time = 1 &lt;&lt; (wait_time - 20);
00367                                 
00368                                 <span class="keywordflow">if</span> (!CFastMutex::atomic_swap (&amp;_Lock))
00369                                         <span class="keywordflow">break</span>;
00370 
00371 <span class="preprocessor">#ifdef NL_OS_WINDOWS</span>
00372 <span class="preprocessor"></span>                                Sleep (wait_time);
00373 <span class="preprocessor">#else</span>
00374 <span class="preprocessor"></span>                                <span class="comment">//std::cout &lt;&lt;  "Sleeping i=" &lt;&lt; i &lt;&lt; std::endl;</span>
00375                                 usleep( wait_time*1000 );
00376 <span class="preprocessor">#endif                          </span>
00377 <span class="preprocessor"></span>                        }
00378                 }
00379         }
</pre></div>    </td>
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<a class="anchor" name="NLMISC_1_1CFastMutexMPa2" doxytag="NLMISC::CFastMutexMP::init" ></a><p>
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          <td class="md" nowrap valign="top"> void NLMISC::CFastMutexMP::init </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="md" nowrap valign="top">void&nbsp;</td>
          <td class="mdname1" valign="top" nowrap>          </td>
          <td class="md" valign="top">&nbsp;)&nbsp;</td>
          <td class="md" nowrap> volatile<code> [inline]</code></td>
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      &nbsp;
    </td>
    <td>

<p>
Same as constructor, useful for init in a shared memory block. 
<p>

<p>
Definition at line <a class="el" href="a06088.html#l00317">317</a> of file <a class="el" href="a06088.html">mutex.h</a>.
<p>
<div class="fragment"><pre>00317 { <a class="code" href="a02517.html#NLMISC_1_1CFastMutexMPr0">_Lock</a> = 0; }
</pre></div>    </td>
  </tr>
</table>
<a class="anchor" name="NLMISC_1_1CFastMutexMPa3" doxytag="NLMISC::CFastMutexMP::leave" ></a><p>
<table class="mdTable" width="100%" cellpadding="2" cellspacing="0">
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          <td class="md" nowrap valign="top"> __forceinline void NLMISC::CFastMutexMP::leave </td>
          <td class="md" valign="top">(&nbsp;</td>
          <td class="mdname1" valign="top" nowrap>          </td>
          <td class="md" valign="top">&nbsp;)&nbsp;</td>
          <td class="md" nowrap> volatile<code> [inline]</code></td>
        </tr>

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    </td>
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      &nbsp;
    </td>
    <td>

<p>

<p>
Definition at line <a class="el" href="a06088.html#l00382">382</a> of file <a class="el" href="a06088.html">mutex.h</a>.
<p>
<div class="fragment"><pre>00383         {
00384                 <a class="code" href="a02517.html#NLMISC_1_1CFastMutexMPr0">_Lock</a> = 0;
00385                 <span class="comment">//std::cout &lt;&lt; "Leave" &lt;&lt; std::endl;</span>
00386         }
</pre></div>    </td>
  </tr>
</table>
<hr><h2>Field Documentation</h2>
<a class="anchor" name="NLMISC_1_1CFastMutexMPr0" doxytag="NLMISC::CFastMutexMP::_Lock" ></a><p>
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          <td class="md" nowrap valign="top"> volatile <a class="el" href="a04558.html#a11">uint32</a> <a class="el" href="a02517.html#NLMISC_1_1CFastMutexMPr0">NLMISC::CFastMutexMP::_Lock</a><code> [private]</code>
      </table>
    </td>
  </tr>
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      &nbsp;
    </td>
    <td>

<p>

<p>
Definition at line <a class="el" href="a06088.html#l00389">389</a> of file <a class="el" href="a06088.html">mutex.h</a>.    </td>
  </tr>
</table>
<hr>The documentation for this class was generated from the following file:<ul>
<li><a class="el" href="a06088.html">mutex.h</a></ul>
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