libavcodec/cos_tablegen.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 #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         printf(" "FIXEDFMT",", clip_f15(lrint(val * (double)(1<<15))));
  42     else
  43         printf(" "FLOATFMT",", val);
  44
  45 }
  46
  47 int main(int argc, char *argv[])
  48 {
  49     int i, j;
  50     int do_sin = argc > 1 && !strcmp(argv[1], "sin");
  51     int fixed  = argc > 1 &&  strstr(argv[1], "fixed");
  52     double (*func)(double) = do_sin ? sin : cos;
  53
  54     printf("/* This file was automatically generated. */\n");
  55     printf("#define CONFIG_FFT_FLOAT %d\n", !fixed);
  56     printf("#include \"libavcodec/%s\"\n", do_sin ? "rdft.h" : "fft.h");
  57     for (i = 4; i <= BITS; i++) {
  58         int m = 1 << i;
  59         double freq = 2*M_PI/m;
  60         printf("%s(%i) = {\n   ", do_sin ? "SINTABLE" : "COSTABLE", m);
  61         for (j = 0; j < m/2 - 1; j++) {
  62             int idx = j > m/4 ? m/2 - j : j;
  63             if (do_sin && j >= m/4)
  64                 idx = m/4 - j;
  65             printval(func(idx*freq), fixed);
  66             if ((j & 3) == 3)
  67                 printf("\n   ");
  68         }
  69         printval(func(do_sin ? -(m/4 - 1)*freq : freq), fixed);
  70         printf("\n};\n");
  71     }
  72     return 0;
  73 }