1 /*
2 * Copyright (c) 2008-2020 Stefan Krah. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28
29 #include "mpdecimal.h"
30
31 #include <assert.h>
32 #include <stdio.h>
33
34 #include "bits.h"
35 #include "difradix2.h"
36 #include "fnt.h"
37 #include "numbertheory.h"
38
39
40 /* Bignum: Fast transform for medium-sized coefficients. */
41
42
43 /* forward transform, sign = -1 */
44 int
std_fnt(mpd_uint_t * a,mpd_size_t n,int modnum)45 std_fnt(mpd_uint_t *a, mpd_size_t n, int modnum)
46 {
47 struct fnt_params *tparams;
48
49 assert(ispower2(n));
50 assert(n >= 4);
51 assert(n <= 3*MPD_MAXTRANSFORM_2N);
52
53 if ((tparams = _mpd_init_fnt_params(n, -1, modnum)) == NULL) {
54 return 0;
55 }
56 fnt_dif2(a, n, tparams);
57
58 mpd_free(tparams);
59 return 1;
60 }
61
62 /* reverse transform, sign = 1 */
63 int
std_inv_fnt(mpd_uint_t * a,mpd_size_t n,int modnum)64 std_inv_fnt(mpd_uint_t *a, mpd_size_t n, int modnum)
65 {
66 struct fnt_params *tparams;
67
68 assert(ispower2(n));
69 assert(n >= 4);
70 assert(n <= 3*MPD_MAXTRANSFORM_2N);
71
72 if ((tparams = _mpd_init_fnt_params(n, 1, modnum)) == NULL) {
73 return 0;
74 }
75 fnt_dif2(a, n, tparams);
76
77 mpd_free(tparams);
78 return 1;
79 }
80