/usr/include/crystalspace-2.0/csutil/bitops.h is in libcrystalspace-dev 2.0+dfsg-1build1.
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 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 | /*
Copyright (C) 2007 by Marten Svanfeldt
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef __CSUTIL_BITOPS_H__
#define __CSUTIL_BITOPS_H__
namespace CS
{
namespace Utility
{
/**
* Bit operations
*/
namespace BitOps
{
/**
* Compute index of first bit set, scanned from LSB to MSB
* \return true if any bit is found
* \param value Input value
* \param index Index of first bit set
*/
CS_FORCEINLINE bool ScanBitForward (uint32 value, unsigned long& index)
{
#if defined(CS_HAVE___BUILTIN_CTZ)
index = __builtin_ctz (value);
return value != 0;
#elif defined(CS_HAVE_BITSCAN_INTRINSICS)
return _BitScanForward (&index, value) != 0;
#else
// Generic c++ version
index = 0;
while (value)
{
if (value & 0x01)
{
return true;
}
value >>= 0x01;
index++;
}
return false;
#endif
}
/**
* Compute index of first bit set, scanned from MSB to LSB
* \return true if any bit is found
* \param value Input value
* \param index Index of first bit set
*/
CS_FORCEINLINE bool ScanBitReverse (uint32 value, unsigned long& index)
{
#if defined(CS_HAVE___BUILTIN_CLZ)
index = __builtin_clz (value);
return value != 0;
#elif defined(CS_HAVE_BITSCAN_INTRINSICS)
return _BitScanReverse (&index, value) != 0;
#else
index = 0;
while (value)
{
if (value & 0x80000000)
{
return true;
}
value <<= 0x01;
index++;
}
return false;
#endif
}
/**
* Compute number of bits set in given number
*/
CS_FORCEINLINE uint32 ComputeBitsSet (uint32 v)
{
#if defined(CS_HAVE___BUILTIN_POPCOUNT)
return __builtin_popcount (v);
#else
v = v - ((v >> 1) & 0x55555555);
v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
return (((v + (v >> 4)) & 0x0f0f0f0f) * 0x01010101) >> 24;
#endif
}
}
}
}
#endif
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