/usr/include/trilinos/Bits.hpp is in libtrilinos-dev 10.4.0.dfsg-1ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 | /* *****************************************************************
MESQUITE -- The Mesh Quality Improvement Toolkit
Copyright 2007 Sandia National Laboratories. Developed at the
University of Wisconsin--Madison under SNL contract number
624796. The U.S. Government and the University of Wisconsin
retain certain rights to this software.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
(lgpl.txt) along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
(2009) kraftche@cae.wisc.edu
***************************************************************** */
/** \file Bits.hpp
* \brief Functions implementing misc. bit-wise algorithms
* \author Jason Kraftcheck
*/
#ifndef MSQ_BITS_HPP
#define MSQ_BITS_HPP
#include "Mesquite.hpp"
namespace MESQUITE_NS {
/**\brief Count number of 1-bits in an unsigned integer
*
* This operation is typically referred to as 'popcount' (short for
* "population count".) For example the GCC builtin "__builtin_popcount".
* It is also sometimes referred to as "sideways addition" (e.g. Knuth
* volume 4.)
*/
inline int popcount( unsigned int x ) {
#if 0 // April '08 bug report says gcc builtin not so good unless Intel SSE4
//#ifdef __GNUC__
return __builtin_popcount( x );
#else
// Use "parallel" algorithm
// if (sizeof(x) == 4) {
x = (x & 0x55555555u) + ((x >> 1) & 0x55555555u);
x = (x & 0x33333333u) + ((x >> 2) & 0x33333333u);
x = (x & 0x0f0f0f0fu) + ((x >> 4) & 0x0f0f0f0fu);
return (x * 0x1010101u) >> 24; // x % 255
// }
// else {
// x = (x & 0x5555555555555555ULL) + ((x >> 1) & 0x5555555555555555ULL);
// x = (x & 0x3333333333333333ULL) + ((x >> 2) & 0x3333333333333333ULL);
// x = (x & 0x0F0F0F0F0F0F0F0FULL) + ((x >> 4) & 0x0F0F0F0F0F0F0F0FULL);
// return (x * 0x0101010101010101ULL) >> 56;
// }
#endif
}
} // namespace Mesquite
#endif
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