smallft.h

00001 /********************************************************************
00002  *                                                                  *
00003  * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
00004  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
00005  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
00006  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
00007  *                                                                  *
00008  * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2001             *
00009  * by the XIPHOPHORUS Company http://www.xiph.org/                  *
00010  *                                                                  *
00011  ********************************************************************
00012 
00013  function: fft transform
00014  last mod: $Id: smallft.h,v 1.3 2003/09/16 18:35:45 jm Exp $
00015 
00016  ********************************************************************/
00017 /**
00018    @file smallft.h
00019    @brief Discrete Rotational Fourier Transform (DRFT)
00020 */
00021 
00022 #ifndef _V_SMFT_H_
00023 #define _V_SMFT_H_
00024 
00025 
00026 #ifdef __cplusplus
00027 extern "C" {
00028 #endif
00029 
00030 /** Discrete Rotational Fourier Transform lookup */
00031 struct drft_lookup{
00032   int n;
00033   float *trigcache;
00034   int *splitcache;
00035 };
00036 
00037 extern void spx_drft_forward(struct drft_lookup *l,float *data);
00038 extern void spx_drft_backward(struct drft_lookup *l,float *data);
00039 extern void spx_drft_init(struct drft_lookup *l,int n);
00040 extern void spx_drft_clear(struct drft_lookup *l);
00041 
00042 #ifdef __cplusplus
00043 }
00044 #endif
00045 
00046 #endif