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<h1>csutil/bitops.h</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/*</span>
<a name="l00002"></a>00002 <span class="comment"> Copyright (C) 2007 by Marten Svanfeldt</span>
<a name="l00003"></a>00003 <span class="comment"></span>
<a name="l00004"></a>00004 <span class="comment"> This library is free software; you can redistribute it and/or</span>
<a name="l00005"></a>00005 <span class="comment"> modify it under the terms of the GNU Library General Public</span>
<a name="l00006"></a>00006 <span class="comment"> License as published by the Free Software Foundation; either</span>
<a name="l00007"></a>00007 <span class="comment"> version 2 of the License, or (at your option) any later version.</span>
<a name="l00008"></a>00008 <span class="comment"></span>
<a name="l00009"></a>00009 <span class="comment"> This library is distributed in the hope that it will be useful,</span>
<a name="l00010"></a>00010 <span class="comment"> but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<a name="l00011"></a>00011 <span class="comment"> MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</span>
<a name="l00012"></a>00012 <span class="comment"> Library General Public License for more details.</span>
<a name="l00013"></a>00013 <span class="comment"></span>
<a name="l00014"></a>00014 <span class="comment"> You should have received a copy of the GNU Library General Public</span>
<a name="l00015"></a>00015 <span class="comment"> License along with this library; if not, write to the Free</span>
<a name="l00016"></a>00016 <span class="comment"> Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.</span>
<a name="l00017"></a>00017 <span class="comment">*/</span>
<a name="l00018"></a>00018
<a name="l00019"></a>00019 <span class="preprocessor">#ifndef __CSUTIL_BITOPS_H__</span>
<a name="l00020"></a>00020 <span class="preprocessor"></span><span class="preprocessor">#define __CSUTIL_BITOPS_H__</span>
<a name="l00021"></a>00021 <span class="preprocessor"></span>
<a name="l00022"></a>00022
<a name="l00023"></a>00023 <span class="keyword">namespace </span>CS
<a name="l00024"></a>00024 {
<a name="l00025"></a>00025 <span class="keyword">namespace </span>Utility
<a name="l00026"></a>00026 {
<a name="l00030"></a><a class="code" href="namespaceCS_1_1Utility_1_1BitOps.html">00030</a> <span class="keyword">namespace </span>BitOps
<a name="l00031"></a>00031 {
<a name="l00038"></a><a class="code" href="namespaceCS_1_1Utility_1_1BitOps.html#9e6475696fc8a131a18bf0712d3394b7">00038</a> CS_FORCEINLINE <span class="keywordtype">bool</span> <a class="code" href="namespaceCS_1_1Utility_1_1BitOps.html#9e6475696fc8a131a18bf0712d3394b7" title="Compute index of first bit set, scanned from LSB to MSB.">ScanBitForward</a> (<a class="code" href="group__util.html#g1134b580f8da4de94ca6b1de4d37975e" title="unsigned 32-bit integer (0..4 294 967 295)">uint32</a> value, <span class="keywordtype">size_t</span>& index)
<a name="l00039"></a>00039 {
<a name="l00040"></a>00040 <span class="preprocessor">#ifdef CS_HAVE_BITSCAN_INTRINSICS</span>
<a name="l00041"></a>00041 <span class="preprocessor"></span> <span class="keywordflow">return</span> _BitScanForward ((<span class="keywordtype">unsigned</span> <span class="keywordtype">long</span>*)&index, value) != 0;
<a name="l00042"></a>00042 <span class="preprocessor">#else</span>
<a name="l00043"></a>00043 <span class="preprocessor"></span> <span class="comment">// Generic c++ version</span>
<a name="l00044"></a>00044 index = 0;
<a name="l00045"></a>00045
<a name="l00046"></a>00046 <span class="keywordflow">while</span> (value)
<a name="l00047"></a>00047 {
<a name="l00048"></a>00048 <span class="keywordflow">if</span> (value & 0x01)
<a name="l00049"></a>00049 {
<a name="l00050"></a>00050 <span class="keywordflow">return</span> <span class="keyword">true</span>;
<a name="l00051"></a>00051 }
<a name="l00052"></a>00052 value >>= 0x01;
<a name="l00053"></a>00053 index++;
<a name="l00054"></a>00054 }
<a name="l00055"></a>00055
<a name="l00056"></a>00056 <span class="keywordflow">return</span> <span class="keyword">false</span>;
<a name="l00057"></a>00057 <span class="preprocessor">#endif</span>
<a name="l00058"></a>00058 <span class="preprocessor"></span> }
<a name="l00059"></a>00059
<a name="l00066"></a><a class="code" href="namespaceCS_1_1Utility_1_1BitOps.html#350c0a0eab11038cd4bea342b9be3b2d">00066</a> CS_FORCEINLINE <span class="keywordtype">bool</span> <a class="code" href="namespaceCS_1_1Utility_1_1BitOps.html#350c0a0eab11038cd4bea342b9be3b2d" title="Compute index of first bit set, scanned from MSB to LSB.">ScanBitReverse</a> (<a class="code" href="group__util.html#g1134b580f8da4de94ca6b1de4d37975e" title="unsigned 32-bit integer (0..4 294 967 295)">uint32</a> value, <span class="keywordtype">size_t</span>& index)
<a name="l00067"></a>00067 {
<a name="l00068"></a>00068 <span class="preprocessor">#ifdef CS_HAVE_BITSCAN_INTRINSICS</span>
<a name="l00069"></a>00069 <span class="preprocessor"></span> <span class="keywordflow">return</span> _BitScanReverse ((<span class="keywordtype">unsigned</span> <span class="keywordtype">long</span>*)&index, value) != 0;
<a name="l00070"></a>00070 <span class="preprocessor">#else</span>
<a name="l00071"></a>00071 <span class="preprocessor"></span> index = 0;
<a name="l00072"></a>00072
<a name="l00073"></a>00073 <span class="keywordflow">while</span> (value)
<a name="l00074"></a>00074 {
<a name="l00075"></a>00075 <span class="keywordflow">if</span> (value & 0x80000000)
<a name="l00076"></a>00076 {
<a name="l00077"></a>00077 <span class="keywordflow">return</span> <span class="keyword">true</span>;
<a name="l00078"></a>00078 }
<a name="l00079"></a>00079 value <<= 0x01;
<a name="l00080"></a>00080 index++;
<a name="l00081"></a>00081 }
<a name="l00082"></a>00082
<a name="l00083"></a>00083 <span class="keywordflow">return</span> <span class="keyword">false</span>;
<a name="l00084"></a>00084 <span class="preprocessor">#endif</span>
<a name="l00085"></a>00085 <span class="preprocessor"></span> }
<a name="l00086"></a>00086
<a name="l00090"></a><a class="code" href="namespaceCS_1_1Utility_1_1BitOps.html#b402e32a94727a62254c3e0aadc55865">00090</a> CS_FORCEINLINE <a class="code" href="group__util.html#g1134b580f8da4de94ca6b1de4d37975e" title="unsigned 32-bit integer (0..4 294 967 295)">uint32</a> <a class="code" href="namespaceCS_1_1Utility_1_1BitOps.html#b402e32a94727a62254c3e0aadc55865" title="Compute number of bits set in given number.">ComputeBitsSet</a> (<a class="code" href="group__util.html#g1134b580f8da4de94ca6b1de4d37975e" title="unsigned 32-bit integer (0..4 294 967 295)">uint32</a> v)
<a name="l00091"></a>00091 {
<a name="l00092"></a>00092 v = v - ((v >> 1) & 0x55555555);
<a name="l00093"></a>00093 v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
<a name="l00094"></a>00094 <span class="keywordflow">return</span> ((v + (v >> 4) & 0x0f0f0f0f) * 0x01010101) >> 24;
<a name="l00095"></a>00095 }
<a name="l00096"></a>00096
<a name="l00097"></a>00097 }
<a name="l00098"></a>00098 }
<a name="l00099"></a>00099
<a name="l00100"></a>00100 }
<a name="l00101"></a>00101
<a name="l00102"></a>00102 <span class="preprocessor">#endif</span>
</pre></div><hr size="1"><address><small>Generated for Crystal Space 1.2.1 by
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