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

67 lines
2.0 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 <gmp.h>
#include "flint.h"
#include "nmod_poly.h"
void _nmod_poly_reverse(mp_ptr output, mp_srcptr input, slong len, slong m)
{
slong i, min;
mp_limb_t temp;
if (input != output)
{
min = FLINT_MIN(m, len);
for (i = 0; i < min; i++)
output[m - i - 1] = input[i];
for ( ; i < m; i++)
output[m - i - 1] = WORD(0);
} else
{
for (i = 0; i < m/2; i++)
{
temp = i < len ? input[i] : 0;
output[i] = m - i - 1 < len ? input[m - i - 1] : 0;
output[m - i - 1] = temp;
}
if (m & 1 && i >= len) output[i] = 0;
}
}
void nmod_poly_reverse(nmod_poly_t output, const nmod_poly_t input, slong m)
{
nmod_poly_fit_length(output, m);
_nmod_poly_reverse(output->coeffs, input->coeffs, input->length, m);
output->length = m;
_nmod_poly_normalise(output);
}