Fixed-point FFT and MDCT
[libav.git] / libavcodec / costablegen.c
1 /*
2 * Generate a header file for hardcoded ff_cos_* tables
3 *
4 * Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
5 *
6 * This file is part of Libav.
7 *
8 * Libav is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * Libav is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with Libav; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include <stdio.h>
24 #include <string.h>
25 #include <math.h>
26
27 #ifndef M_PI
28 #define M_PI 3.14159265358979323846
29 #endif
30 #define BITS 16
31 #define FLOATFMT "%.18e"
32 #define FIXEDFMT "%6d"
33
34 static int clip_f15(int v)
35 {
36 return v < -32767 ? -32767 :
37 v > 32767 ? 32767 :
38 v;
39 }
40
41 static void printval(double val, int fixed)
42 {
43 if (fixed)
44 printf(" "FIXEDFMT",", clip_f15(lrint(val * (double)(1<<15))));
45 else
46 printf(" "FLOATFMT",", val);
47
48 }
49
50 int main(int argc, char *argv[])
51 {
52 int i, j;
53 int do_sin = argc > 1 && !strcmp(argv[1], "sin");
54 int fixed = argc > 2 && !strcmp(argv[2], "fixed");
55 double (*func)(double) = do_sin ? sin : cos;
56
57 printf("/* This file was generated by libavcodec/costablegen */\n");
58 printf("#define CONFIG_FFT_FLOAT %d\n", !fixed);
59 printf("#include \"libavcodec/%s\"\n", do_sin ? "rdft.h" : "fft.h");
60 for (i = 4; i <= BITS; i++) {
61 int m = 1 << i;
62 double freq = 2*M_PI/m;
63 printf("%s(%i) = {\n ", do_sin ? "SINTABLE" : "COSTABLE", m);
64 for (j = 0; j < m/2 - 1; j++) {
65 int idx = j > m/4 ? m/2 - j : j;
66 if (do_sin && j >= m/4)
67 idx = m/4 - j;
68 printval(func(idx*freq), fixed);
69 if ((j & 3) == 3)
70 printf("\n ");
71 }
72 printval(func(do_sin ? -(m/4 - 1)*freq : freq), fixed);
73 printf("\n};\n");
74 }
75 return 0;
76 }