1 /******************************************************************** 2 * * 3 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. * 4 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * 5 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * 6 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * 7 * * 8 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2001 * 9 * by the XIPHOPHORUS Company http://www.xiph.org/ * 10 * * 11 ******************************************************************** 12 13 function: fft transform 14 last mod: $Id: smallft.h,v 1.3 2003/09/16 18:35:45 jm Exp $ 15 16 ********************************************************************/ 17 /** 18 @file smallft.h 19 @brief Discrete Rotational Fourier Transform (DRFT) 20 */ 21 22 #ifndef _V_SMFT_H_ 23 #define _V_SMFT_H_ 24 25 26 #ifdef __cplusplus 27 extern "C" { 28 #endif 29 30 /** Discrete Rotational Fourier Transform lookup */ 31 struct drft_lookup{ 32 int n; 33 float *trigcache; 34 int *splitcache; 35 }; 36 37 extern void spx_drft_forward(struct drft_lookup *l,float *data); 38 extern void spx_drft_backward(struct drft_lookup *l,float *data); 39 extern void spx_drft_init(struct drft_lookup *l,int n); 40 extern void spx_drft_clear(struct drft_lookup *l); 41 42 #ifdef __cplusplus 43 } 44 #endif 45 46 #endif 47