forked from osmocom/wireshark
43 lines
1.3 KiB
C
43 lines
1.3 KiB
C
/* popcount.c
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*
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* popcount() replacement function for systems that don't provide their own.
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include "wsutil/popcount.h"
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int
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popcount(unsigned int mask)
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{
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#if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
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/* GCC 3.4 or newer */
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return __builtin_popcount(mask);
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#else
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/* HACKMEM 169 */
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unsigned long y;
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y = (mask >> 1) &033333333333;
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y = mask - y - ((y >>1) & 033333333333);
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return (((y + (y >> 3)) & 030707070707) % 077);
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#endif
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}
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