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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. #define BITS 16
  28. #define FLOATFMT "%.18e"
  29. #define FIXEDFMT "%6d"
  30.  
  31. static int clip_f15(int v)
  32. {
  33.     return v < -32767 ? -32767 :
  34.            v >  32767 ?  32767 :
  35.            v;
  36. }
  37.  
  38. static void printval(double val, int fixed)
  39. {
  40.     if (fixed) {
  41.         /* lrint() isn't always available, so round and cast manually. */
  42.         double new_val = val * (double) (1 << 15);
  43.  
  44.         new_val = new_val >= 0 ? floor(new_val + 0.5) : ceil(new_val - 0.5);
  45.  
  46.         printf(" "FIXEDFMT",", clip_f15((long int) new_val));
  47.     } else {
  48.         printf(" "FLOATFMT",", val);
  49.     }
  50. }
  51.  
  52. int main(int argc, char *argv[])
  53. {
  54.     int i, j;
  55.     int do_sin = argc > 1 && !strcmp(argv[1], "sin");
  56.     int fixed  = argc > 1 &&  strstr(argv[1], "fixed");
  57.     double (*func)(double) = do_sin ? sin : cos;
  58.  
  59.     printf("/* This file was automatically generated. */\n");
  60.     printf("#define CONFIG_FFT_FLOAT %d\n", !fixed);
  61.     printf("#include \"libavcodec/%s\"\n", do_sin ? "rdft.h" : "fft.h");
  62.     for (i = 4; i <= BITS; i++) {
  63.         int m = 1 << i;
  64.         double freq = 2*3.14159265358979323846/m;
  65.         printf("%s(%i) = {\n   ", do_sin ? "SINTABLE" : "COSTABLE", m);
  66.         for (j = 0; j < m/2 - 1; j++) {
  67.             int idx = j > m/4 ? m/2 - j : j;
  68.             if (do_sin && j >= m/4)
  69.                 idx = m/4 - j;
  70.             printval(func(idx*freq), fixed);
  71.             if ((j & 3) == 3)
  72.                 printf("\n   ");
  73.         }
  74.         printval(func(do_sin ? -(m/4 - 1)*freq : freq), fixed);
  75.         printf("\n};\n");
  76.     }
  77.     return 0;
  78. }
  79.