pqc/external/flint-2.4.3/nmod_vec/max_bits.c
2014-05-24 23:16:06 +02:00

49 lines
1.5 KiB
C

/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FLINT 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2010 William Hart
******************************************************************************/
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "nmod_vec.h"
mp_bitcnt_t _nmod_vec_max_bits(mp_srcptr vec, slong len)
{
mp_bitcnt_t bits = 0;
mp_limb_t mask = ~(mp_limb_t) 0;
slong i;
for (i = 0; i < len; i++)
{
if (vec[i] & mask)
{
bits = FLINT_BIT_COUNT(vec[i]);
if (bits == FLINT_BITS) break;
else mask = ~(mp_limb_t) 0 - ((UWORD(1) << bits) - UWORD(1));
}
}
return bits;
}