FFmpeg: libavcodec/cbrt_tablegen.h Source File

00001 /*
00002  * Header file for hardcoded AAC cube-root table
00003  *
00004  * Copyright (c) 2010 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 #ifndef CBRT_TABLEGEN_H
00024 #define CBRT_TABLEGEN_H
00025 
00026 #include <stdint.h>
00027 #include <math.h>
00028 
00029 #if CONFIG_HARDCODED_TABLES
00030 #define cbrt_tableinit()
00031 #include "libavcodec/cbrt_tables.h"
00032 #else
00033 static uint32_t cbrt_tab[1 << 13];
00034 
00035 static void cbrt_tableinit(void)
00036 {
00037     if (!cbrt_tab[(1<<13) - 1]) {
00038         int i;
00039         for (i = 0; i < 1<<13; i++) {
00040             union {
00041                 float f;
00042                 uint32_t i;
00043             } f;
00044             f.f = cbrtf(i) * i;
00045             cbrt_tab[i] = f.i;
00046         }
00047     }
00048 }
00049 #endif /* CONFIG_HARDCODED_TABLES */
00050 
00051 #endif /* CBRT_TABLEGEN_H */