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cos_tablegen.c
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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 FFmpeg.
7  *
8  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 #include "libavutil/mathematics.h"
28 
29 #define BITS 17
30 #define FLOATFMT "%.18e"
31 #define FIXEDFMT "%6d"
32 
33 static int clip_f15(int v)
34 {
35  return v < -32767 ? -32767 :
36  v > 32767 ? 32767 :
37  v;
38 }
39 
40 static void printval(double val, int fixed)
41 {
42  if (fixed) {
43  /* lrint() isn't always available, so round and cast manually. */
44  double new_val = val * (double) (1 << 15);
45 
46  new_val = new_val >= 0 ? floor(new_val + 0.5) : ceil(new_val - 0.5);
47 
48  printf(" "FIXEDFMT",", clip_f15((long int) new_val));
49  } else {
50  printf(" "FLOATFMT",", val);
51  }
52 }
53 
54 int main(int argc, char *argv[])
55 {
56  int i, j;
57  int do_sin = argc > 1 && !strcmp(argv[1], "sin");
58  int fixed = argc > 1 && strstr(argv[1], "fixed");
59  double (*func)(double) = do_sin ? sin : cos;
60 
61  printf("/* This file was automatically generated. */\n");
62  printf("#define FFT_FLOAT %d\n", !fixed);
63  printf("#include \"libavcodec/%s\"\n", do_sin ? "rdft.h" : "fft.h");
64  for (i = 4; i <= BITS; i++) {
65  int m = 1 << i;
66  double freq = 2*M_PI/m;
67  printf("%s(%i) = {\n ", do_sin ? "SINTABLE" : "COSTABLE", m);
68  for (j = 0; j < m/2 - 1; j++) {
69  int idx = j > m/4 ? m/2 - j : j;
70  if (do_sin && j >= m/4)
71  idx = m/4 - j;
72  printval(func(idx*freq), fixed);
73  if ((j & 3) == 3)
74  printf("\n ");
75  }
76  printval(func(do_sin ? -(m/4 - 1)*freq : freq), fixed);
77  printf("\n};\n");
78  }
79  return 0;
80 }
const char const char void * val
Definition: avisynth_c.h:771
#define FLOATFMT
Definition: cos_tablegen.c:30
static int clip_f15(int v)
Definition: cos_tablegen.c:33
#define fixed(width, name, value)
Definition: cbs_av1.c:589
#define FIXEDFMT
Definition: cos_tablegen.c:31
#define BITS
Definition: cos_tablegen.c:29
int(* func)(AVBPrint *dst, const char *in, const char *arg)
Definition: jacosubdec.c:67
static void printval(double val, int fixed)
Definition: cos_tablegen.c:40
int main(int argc, char *argv[])
Definition: cos_tablegen.c:54
#define M_PI
Definition: mathematics.h:52