1 /*
2 * Copyright (c) 2008-2024 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 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27
28 #include <assert.h>
29 #include <stdio.h>
30
31 #include "bits.h"
32 #include "difradix2.h"
33 #include "fnt.h"
34 #include "mpdecimal.h"
35 #include "numbertheory.h"
36
37
38 /* Bignum: Fast transform for medium-sized coefficients */
39
40
41 /* forward transform, sign = -1 */
42 int
std_fnt(mpd_uint_t * a,mpd_size_t n,int modnum)43 std_fnt(mpd_uint_t *a, mpd_size_t n, int modnum)
44 {
45 struct fnt_params *tparams;
46
47 assert(ispower2(n));
48 assert(n >= 4);
49 assert(n <= 3*MPD_MAXTRANSFORM_2N);
50
51 if ((tparams = _mpd_init_fnt_params(n, -1, modnum)) == NULL) {
52 return 0;
53 }
54 fnt_dif2(a, n, tparams);
55
56 mpd_free(tparams);
57 return 1;
58 }
59
60 /* reverse transform, sign = 1 */
61 int
std_inv_fnt(mpd_uint_t * a,mpd_size_t n,int modnum)62 std_inv_fnt(mpd_uint_t *a, mpd_size_t n, int modnum)
63 {
64 struct fnt_params *tparams;
65
66 assert(ispower2(n));
67 assert(n >= 4);
68 assert(n <= 3*MPD_MAXTRANSFORM_2N);
69
70 if ((tparams = _mpd_init_fnt_params(n, 1, modnum)) == NULL) {
71 return 0;
72 }
73 fnt_dif2(a, n, tparams);
74
75 mpd_free(tparams);
76 return 1;
77 }
78