libavcodec/cos_tablegen.c
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00001 /*
00002  * Generate a header file for hardcoded ff_cos_* tables
00003  *
00004  * Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
00005  *
00006  * This file is part of FFmpeg.
00007  *
00008  * FFmpeg is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * FFmpeg is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with FFmpeg; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00023 #include <stdio.h>
00024 #include <string.h>
00025 #include <math.h>
00026 
00027 #ifndef M_PI
00028 #define M_PI 3.14159265358979323846
00029 #endif
00030 #define BITS 16
00031 #define FLOATFMT "%.18e"
00032 #define FIXEDFMT "%6d"
00033 
00034 static int clip_f15(int v)
00035 {
00036     return v < -32767 ? -32767 :
00037            v >  32767 ?  32767 :
00038            v;
00039 }
00040 
00041 static void printval(double val, int fixed)
00042 {
00043     if (fixed)
00044         printf(" "FIXEDFMT",", clip_f15(lrint(val * (double)(1<<15))));
00045     else
00046         printf(" "FLOATFMT",", val);
00047 
00048 }
00049 
00050 int main(int argc, char *argv[])
00051 {
00052     int i, j;
00053     int do_sin = argc > 1 && !strcmp(argv[1], "sin");
00054     int fixed  = argc > 1 &&  strstr(argv[1], "fixed");
00055     double (*func)(double) = do_sin ? sin : cos;
00056 
00057     printf("/* This file was automatically generated. */\n");
00058     printf("#define CONFIG_FFT_FLOAT %d\n", !fixed);
00059     printf("#include \"libavcodec/%s\"\n", do_sin ? "rdft.h" : "fft.h");
00060     for (i = 4; i <= BITS; i++) {
00061         int m = 1 << i;
00062         double freq = 2*M_PI/m;
00063         printf("%s(%i) = {\n   ", do_sin ? "SINTABLE" : "COSTABLE", m);
00064         for (j = 0; j < m/2 - 1; j++) {
00065             int idx = j > m/4 ? m/2 - j : j;
00066             if (do_sin && j >= m/4)
00067                 idx = m/4 - j;
00068             printval(func(idx*freq), fixed);
00069             if ((j & 3) == 3)
00070                 printf("\n   ");
00071         }
00072         printval(func(do_sin ? -(m/4 - 1)*freq : freq), fixed);
00073         printf("\n};\n");
00074     }
00075     return 0;
00076 }