cpython/Modules/_decimal/libmpdec/fnt.c

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/*
* Copyright (c) 2008-2016 Stefan Krah. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "mpdecimal.h"
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "bits.h"
#include "difradix2.h"
#include "numbertheory.h"
#include "fnt.h"
/* Bignum: Fast transform for medium-sized coefficients. */
/* forward transform, sign = -1 */
int
std_fnt(mpd_uint_t *a, mpd_size_t n, int modnum)
{
struct fnt_params *tparams;
assert(ispower2(n));
assert(n >= 4);
assert(n <= 3*MPD_MAXTRANSFORM_2N);
if ((tparams = _mpd_init_fnt_params(n, -1, modnum)) == NULL) {
return 0;
}
fnt_dif2(a, n, tparams);
mpd_free(tparams);
return 1;
}
/* reverse transform, sign = 1 */
int
std_inv_fnt(mpd_uint_t *a, mpd_size_t n, int modnum)
{
struct fnt_params *tparams;
assert(ispower2(n));
assert(n >= 4);
assert(n <= 3*MPD_MAXTRANSFORM_2N);
if ((tparams = _mpd_init_fnt_params(n, 1, modnum)) == NULL) {
return 0;
}
fnt_dif2(a, n, tparams);
mpd_free(tparams);
return 1;
}